ORCID Profile
0000-0003-4360-9927
Current Organisation
Flinders University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biochemistry and Cell Biology | Medical Biochemistry: Proteins And Peptides | Catalysis and Mechanisms of Reactions | Biochemistry And Cell Biology Not Elsewhere Classified | Organic Chemistry | Analytical Spectrometry | Analytical Biochemistry | Organic Green Chemistry | Colloid and Surface Chemistry | Physical Chemistry (Incl. Structural) | Physical Organic Chemistry | Basic Pharmacology | Medical Molecular Engineering of Nucleic Acids and Proteins | Biophysics
ANZSRC Socio-Economic Objective (SEO)
Human Pharmaceutical Treatments (e.g. Antibiotics) | Diabetes | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Treatments (e.g. chemicals, antibiotics) | Cancer and related disorders | Biological sciences | Inherited diseases (incl. gene therapy) | Physical sciences |
Related Links
Publications
Alanine scanning of a putative receptor binding surface of insulin-like growth factor-I
Publisher: Elsevier BV
Date: 07-2008
The interaction of insulin-like growth factors (IGFs) with insulin-like growth factor binding proteins (IGFBPs): A review
Publisher: Springer Science and Business Media LLC
Date: 2002
Production and Characterisation of Monoclonal Antibodies Against Insulin-like Growth Factor Type 1 Receptor (IGF-1R).
Publisher: Mary Ann Liebert Inc
Date: 08-2006
Abstract: The type 1 insulin-like growth factor receptor (IGF-1R) has been extensively reported to play an important role in cancer. Activation of the IGF-1R by IGF-I and IGF-II binding to the extracellular domains of the receptor induces mitogenic and anti-apoptotic effects, which are important events in tumor growth and survival. Several cancer cell types overexpress IGF-1R, suggesting a possible use of monoclonal antibodies (MAbs) against IGF-1R as diagnostic reagents. Here, we report the production and characterization of two independent MAbs, namely 7C2 and 9E11, generated by immunizing mice with the soluble extracellular part of this receptor (amino acids 1-906). Both MAbs bind to membrane bound IGF-1R and do not cross-react with insulin receptor isoforms, IR-A and IR-B expressed on IGF-1R() cells. MAbs 7C2 and 9E11 stained the IGF- 1R on frozen or paraffin-embedded tissue sections or frozen cells. The MAbs 7C2 and 9E11 immunoprecipitated the IGF-1R from P6 cell lysates (cells overexpressing human IGF-1R) and could detect non-reduced intact IGF-1R on immunoblots. However, the MAbs were not able to detect reduced and denatured receptor alpha and beta chains. Sequencing of the heavy- and light-chain variable regions revealed that the 7C2 and 9E11 CDR amino acid sequences are different but result in antibodies with similar properties. MAbs 7C2 and 9E11 are therefore potentially useful diagnostic tools and could be of therapeutic use for humans in the future.
A novel binding site for the human insulin-like growth factor-II (IGF-II)/mannose 6-phosphate receptor on IGF-II
Publisher: Elsevier BV
Date: 06-2007
Differential Activation of Insulin Receptor Substrates 1 and 2 by Insulin-Like Growth Factor-Activated Insulin Receptors
Publisher: Informa UK Limited
Date: 09-2007
DOI: 10.1128/MCB.01150-07
The Insulin Receptor Isoform Exon 11- (IR-A) in Cancer and Other Diseases: A Review
Publisher: Georg Thieme Verlag KG
Date: 11-2003
Abstract: The insulin receptor plays a vital role in mediating the actions of insulin. These include metabolic and mitogenic effects. This review will focus on the role of the insulin receptor isoforms in normal development and the pathogenesis of certain cancers and type 2 diabetes. There are two insulin receptor isoforms arising from the alternative splicing of exon 11 resulting in either the exon 11+ (IR-B) isoform (including 12 amino acids encoded by exon 11) or the exon 11- (IR-A) isoform. The isoforms have different affinities for insulin, IGF-II and IGF-I with the exon 11- isoform binding both insulin and IGF-II with high affinities. Interestingly, differential expression of the insulin receptor isoforms has been demonstrated in disease. Several cancer cell types that also overexpress IGF-II preferentially express the exon 11- isoform. Activation of the exon 11- insulin receptor by IGF-II and insulin results in mitogenic effects and a potentiation of the cancer phenotype. Also hyperinsulinemia has been associated with increased risk of cancer. Differential expression of the insulin receptor isoforms has also been demonstrated in type 2 diabetes although there is some discrepancy in the literature as to which isoform is expressed.
Total Chemical Synthesis of Palmitoyl-Conjugated Insulin
Publisher: American Chemical Society (ACS)
Date: 06-04-2023
Total Chemical Synthesis of an Intra‐A‐Chain Cystathionine Human Insulin Analogue with Enhanced Thermal Stability
Publisher: Wiley
Date: 20-10-2016
Interaction of insulin-like growth factor (IGF)-I and -II with IGF binding protein-2: mapping the binding surfaces by nuclear magnetic resonance
Publisher: Bioscientifica
Date: 06-2005
DOI: 10.1677/JME.1.01756
Abstract: The interaction of IGF binding protein-2 (IGFBP-2) with IGF-I and -II has been investigated in solution using nuclear magnetic resonance (NMR) spectroscopy. Chemical shift perturbations in 15 N- and 2 H/ 15 N-labelled IGF-I or -II upon binding to unlabelled thioredoxin-tagged bovine IGFBP-2 (Trx 1–279 IGFBP-2) have been monitored to identify residues involved directly in the binding interaction as well as any affected by conformational changes associated with the interaction. A key step in obtaining high-quality spectra of the complexes was the use of transverse relaxation optimised spectroscopy (TROSY) methods with partially deuterated ligands. Indeed, because the effects of conformational averaging and aggregation are eliminated in IGF-I and -II bound to IGFBP-2, the spectra of the complexes are actually superior to those of the free ligands. Comparison of our results with the crystal structure of the complex between IGF-I and an N-terminal fragment of IGFBP-5 allowed identification of those residues perturbed by the C-domain of IGFBP-2. Other perturbations, such as those of Gly 19 and Asp 20 of IGF-I (and the corresponding residues in IGF-II) – which are located in a reverse turn linking N-domain and C-domain interactive surfaces – are due to local conformational changes in the IGF-I and -II. Our results confirm that the C-domain of IGFBP-2 plays a key role in binding regions of IGF-I and -II that are also involved in binding to the type-1 IGF receptor and thereby blocking ligand binding to this receptor.
Chemical Synthesis and Characterization of a Nonfibrillating Glycoglucagon.
Publisher: American Chemical Society (ACS)
Date: 08-09-2021
DOI: 10.1021/ACS.BIOCONJCHEM.1C00419
Abstract: The current commercially available glucagon formulations for the treatment of severe hypoglycemia must be reconstituted immediately prior to use, owing to the susceptibility of glucagon to fibrillation and aggregation in an aqueous solution. This results in the inconvenience of handling, misuse, and wastage of this drug. To address these issues, we synthesized a glycosylated glucagon analogue in which the 25th residue (Trp) was replaced with a cysteine (Cys) and a Br-disialyloligosaccharide was conjugated at the Cys thiol moiety. The resulting analogue, glycoglucagon, is a highly potent full agonist at the glucagon receptor. Importantly, glycoglucagon exhibits markedly reduced propensity for fibrillation and enhanced thermal and metabolic stability. This novel analogue is thus a valuable lead for producing stable liquid glucagon formulations that will improve patient compliance and minimize wastage.
Changes in the ghrelin hormone pathway maybe part of an unusual gastric system in monotremes.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.YGCEN.2013.06.003
Abstract: Ghrelin is a growth hormone (GH)-releasing and appetite-regulating peptide predominately released from the stomach. Ghrelin is evolutionarily highly conserved and known to have a wide range of functions including the regulation of metabolism by maintaining an insulin-glucose balance. The peptide is produced as a single proprotein, which is later proteolytically cleaved. Ghrelin exerts its biological function after O-n-octanoylation at residue serine 3, which is catalyzed by ghrelin O-acyl transferase (GOAT) and allows binding to the growth hormone secretagogue receptor (GHS-R 1a). Genes involved in the ghrelin pathway have been identified in a broad range of vertebrate species, however, little is known about this pathway in the basal mammalian lineage of monotremes (platypus and echidna). Monotremes are particularly interesting in this context, as they have undergone massive changes in stomach anatomy and physiology, accompanied by a striking loss of genes involved in gastric function. In this study, we investigated genes in the ghrelin pathway in monotremes. Using degenerate PCR, database searches and synteny analysis we found that genes encoding ghrelin and GOAT are missing in the platypus genome, whilst, as has been reported in other species, the GHSR is present and expressed in brain, pancreas, kidney, intestine, heart and stomach. This is the first report suggesting the loss of ghrelin in a mammal. The loss of this gene may be related to changes to the platypus digestive system and raises questions about the control of blood glucose levels and insulin response in monotreme mammals. In addition, the conservation of the ghrelin receptor gene in platypus indicates that another ligand(s) maybe acting via this receptor in monotremes.
Covalent modification of an exposed surface turn alters the global conformation of the biotin carrier domain of Escherichia coli acetyl-CoA carboxylase
Publisher: Elsevier BV
Date: 10-1997
The ability to utilise ammonia as nitrogen source is cell type specific and intricately linked to GDH, AMPK and mTORC1
Publisher: Springer Science and Business Media LLC
Date: 06-02-2019
DOI: 10.1038/S41598-018-37509-3
Abstract: Ammonia can be utilised as an alternative nitrogen source to glutamine to support cell proliferation. However, the underlying molecular mechanisms and whether all cells have this ability is not fully understood. We find that eleven cancer and non-cancerous cell lines have opposite abilities to tolerate and utilise ammonia to support proliferation in a glutamine-depleted environment. HEK293, Huh7, T47D and MCF7 cells can use ammonia, when starved of glutamine, to support proliferation to varying degrees. Glutamine depletion reduced mTORC1 activity, while additional ammonia supplementation diminished this mTORC1 inhibition. Depletion of glutamine promoted a rapid and transient activation of AMPK, whereas, additional ammonia supplementation blocked this starvation-induced AMPK activation. As expected, drug-induced AMPK activation reduced cell proliferation in glutamine-depleted cells supplemented with ammonia. Surprisingly, mTORC1 activity was largely unchanged despite the enhanced AMPK activity, suggesting that AMPK does not inhibit mTORC1 signalling under these conditions. Finally, glutamate dehydrogenase (GDH) inhibition, a key enzyme regulating ammonia assimilation, leads to AMPK activation, mTORC1 inhibition and reduced proliferation. Ammonia provides an alternative nitrogen source that aids certain cancer cells ability to thrive in nutrient-deprived environment. The ability of cells to utilise ammonia as a nitrogen source is intricately linked to AMPK, mTORC1 and GDH.
Structural Basis for the Lower Affinity of the Insulin-like Growth Factors for the Insulin Receptor
Publisher: Elsevier BV
Date: 02-2008
Structural and Functional Characteristics of the Val44Met Insulin-Like Growth Factor I Missense Mutation: Correlation with Effects on Growth and Development
Publisher: The Endocrine Society
Date: 03-2005
DOI: 10.1210/ME.2004-0409
Abstract: We have previously described the phenotype resulting from a missense mutation in the IGF-I gene, which leads to expression of IGF-I with a methionine instead of a valine at position 44 (Val44Met IGF-I). This mutation caused severe growth and mental retardation as well as deafness evident at birth and growth retardation in childhood, but is relatively well tolerated in adulthood. We have conducted a biochemical and structural analysis of Val44Met IGF-I to provide a molecular basis for the phenotype observed. Val44Met IGF-I exhibits a 90-fold decrease in type 1 IGF receptor (IGF-1R) binding compared with wild-type human IGF-I and only poorly stimulates autophosphorylation of the IGF-1R. The ability of Val44Met IGF-I to signal via the extracellular signal-regulated kinase 1/2 and Akt rotein kinase B pathways and to stimulate DNA synthesis is correspondingly poorer. Binding or activation of both insulin receptor isoforms is not detectable even at micromolar concentrations. However, Val44Met IGF-I binds IGF-binding protein-2 (IGFBP-2), IGFBP-3, and IGFBP-6 with equal affinity to IGF-I, suggesting the maintenance of overall structure, particularly in the IGFBP binding domain. Structural analysis by nuclear magnetic resonance confirms retention of near-native structure with only local side-chain disruptions despite the significant loss of function. To our knowledge, our results provide the first structural study of a naturally occurring mutant human IGF-I associated with growth and developmental abnormalities and identifies Val44 as an essential residue involved in the IGF-IGF-1R interaction.
Symmetric and asymmetric receptor conformation continuum induced by a new insulin
Publisher: Springer Science and Business Media LLC
Date: 14-03-2022
Keeping IGF-II under control: Lessons from the IGF-II–IGF2R crystal structure
Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1016/J.TIBS.2009.07.003
Abstract: Insulin-like growth factor-II (IGF-II) is a key regulator of cell growth, survival, migration and differentiation. Its pivotal role in these processes requires tight regulation of both expression and activity. The type 1 IGF receptor tyrosine kinase (IGF-1R) mediates IGF-II actions, and a family of six high affinity IGF binding proteins (IGFBPs) regulates IGF-II circulating half-life and its availability to bind IGF-1R. In addition, the type 2 IGF receptor (IGF2R also called the cation-independent mannose-6-phosphate receptor) modulates the circulating and tissue levels of IGF-II by targeting it to lysosomes for degradation. The recently elucidated crystal structure of IGF-II-IGF2R complex provides new insight into IGF-II regulation, and reveals a common binding surface on IGF-II for the regulatory proteins, IGF2R and the IGFBPs.
Solid Phase Synthesis of an Analogue of Insulin, A0:R glargine, That Exhibits Decreased Mitogenic Activity
Publisher: Springer Science and Business Media LLC
Date: 09-07-2010
Structure and functional analysis of the IGF-II/IGF2R interaction
Publisher: Wiley
Date: 29-11-2007
Dissociation of reward and effort sensitivity in methcathinone‐induced Parkinsonism
Publisher: Wiley
Date: 05-04-2018
DOI: 10.1111/JNP.12122
Role of N- and C-terminal Residues of Insulin-like Growth Factor (IGF)-binding Protein-3 in Regulating IGF Complex Formation and Receptor Activation
Publisher: Elsevier BV
Date: 12-2004
A minimized human insulin-receptor-binding motif revealed in a Conus geographus venom insulin
Publisher: Springer Science and Business Media LLC
Date: 12-09-2016
DOI: 10.1038/NSMB.3292
Abstract: Insulins in the venom of certain fish-hunting cone snails facilitate prey capture by rapidly inducing hypoglycemic shock. One such insulin, Conus geographus G1 (Con-Ins G1), is the smallest known insulin found in nature and lacks the C-terminal segment of the B chain that, in human insulin, mediates engagement of the insulin receptor and assembly of the hormone's hexameric storage form. Removal of this segment (residues B23-B30) in human insulin results in substantial loss of receptor affinity. Here, we found that Con-Ins G1 is monomeric, strongly binds the human insulin receptor and activates receptor signaling. Con-Ins G1 thus is a naturally occurring B-chain-minimized mimetic of human insulin. Our crystal structure of Con-Ins G1 reveals a tertiary structure highly similar to that of human insulin and indicates how Con-Ins G1's lack of an equivalent to the key receptor-engaging residue Phe
Differential Activation of Insulin Receptor Substrates 1 and 2 by Insulin-Like Growth Factor-Activated Insulin Receptors
Publisher: Informa UK Limited
Date: 05-2007
DOI: 10.1128/MCB.01447-06
Insulin in motion: The A6-A11 disulfide bond allosterically modulates structural transitions required for insulin activity
Publisher: Springer Science and Business Media LLC
Date: 08-12-2017
DOI: 10.1038/S41598-017-16876-3
Abstract: The structural transitions required for insulin to activate its receptor and initiate regulation of glucose homeostasis are only partly understood. Here, using ring-closing metathesis, we substitute the A6-A11 disulfide bond of insulin with a rigid, non-reducible dicarba linkage, yielding two distinct stereo-isomers ( cis and trans ). Remarkably, only the cis isomer displays full insulin potency, rapidly lowering blood glucose in mice (even under insulin-resistant conditions). It also posseses reduced mitogenic activity in vitro . Further biophysical, crystallographic and molecular-dynamics analyses reveal that the A6-A11 bond configuration directly affects the conformational flexibility of insulin A-chain N -terminal helix, dictating insulin’s ability to engage its receptor. We reveal that in native insulin, contraction of the C α -C α distance of the flexible A6-A11 cystine allows the A-chain N -terminal helix to unwind to a conformation that allows receptor engagement. This motion is also permitted in the cis isomer, with its shorter C α -C α distance, but prevented in the extended trans analogue. These findings thus illuminate for the first time the allosteric role of the A6-A11 bond in mediating the transition of the hormone to an active conformation, significantly advancing our understanding of insulin action and opening up new avenues for the design of improved therapeutic analogues.
Visualization of Insulin Receptor Activation by a Novel Insulin Analog with Elongated A Chain and Truncated B Chain
Publisher: Research Square Platform LLC
Date: 18-05-2021
DOI: 10.21203/RS.3.RS-501661/V1
Abstract: Cone snail venoms contain a wide variety of bioactive peptides, including insulin-like molecules with distinct structural features, binding modes, and biochemical properties. Here, we report a fully active humanized cone snail venom insulin with an elongated A chain and a truncated B chain, and use cryo-electron microscopy and protein engineering to elucidate its interactions with the human insulin receptor ectodomain. We reveal how an extended A chain can compensate for deletion of B-chain residues, which are essential for activity of native insulin but also compromise therapeutic utility by delaying the onset action, suggesting approaches to develop improved therapeutic insulins. Curiously, a receptor conformation present in low abundance adopts a highly asymmetric structure that displays novel coordination of a single humanized venom insulin using elements from both of the previously characterized site 1 and site 2 interactions.
Alanine screening mutagenesis establishes tyrosine 60 of bovine insulin- like growth factor binding protein-2 as a determinant of insulin-like growth factor binding
Publisher: Elsevier BV
Date: 07-1998
Secretion in Escherichia coli and phage-display of recombinant insulin-like growth factor binding protein-2
Publisher: Elsevier BV
Date: 04-1998
DOI: 10.1016/S0168-1656(98)00012-1
Abstract: Insulin-like growth factors (IGFs) promote cell growth and differentiation. Their actions are regulated by six different, but related, binding proteins (IGFBPs). To investigate the molecular interactions between IGFs and IGFBPs, an Escherichia coli based production method and a phage display system has been developed. The cDNA for bovine IGFBP-2 was inserted between regions coding for the pelB signal sequence and geneIII product, g3p, of bacteriophage fd in a phagemid vector to generate pGF14. The coding sequences of IGFBP-2 and g3p were separated by an amber stop codon and a flexible linker containing the cleavage recognition site for H64A subtilisin. Using this system in BL21, a non-supE strain lacking ompT, most product, approximately 4 mg 1(-1) of IGFBP-2, was obtained in the growth medium. The bacterially derived IGFBP-2 had a correct N-terminal sequence, molecular mass on SDS-PAGE and the same affinity for IGF-1 and IGF-II as IGFBP-2 from mammalian cells. In a supE strain of E. coli, IGFBP-2 was produced as an IGF-binding fusion to g3p. Procedures for display and approximately 10000 fold enrichment of IGFBP-2 bearing phage using adsorption to IGF-II coated microtitre plates were developed. Thus IGFBP-2 can be secreted in E. coli and displayed on filamentous phage. These can be selectively enriched by binding to immobilised IGF-II.
Insulin-like growth factor binding protein-2: NMR analysis and structural characterization of the N-terminal domain
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.BIOCHI.2011.09.012
Abstract: The insulin-like growth factor binding proteins are a family of six proteins (IGFBP-1 to -6) that bind insulin-like growth factors-I and -II (IGF-I/II) with high affinity. In addition to regulating IGF actions, IGFBPs have IGF-independent functions. IGFBP-2, the largest member of this family, is over-expressed in many cancers and has been proposed as a possible target for the development of novel anti-cancer therapeutics. The IGFBPs have a common architecture consisting of conserved N- and C-terminal domains joined by a variable linker domain. The solution structure and dynamics of the C-terminal domain of human IGFBP-2 have been reported (Kuang Z. et al. J. Mol. Biol. 364, 690-704, 2006) but neither the N-domain (N-BP-2) nor the linker domain have been characterised. Here we present NMR resonance assignments for human N-BP-2, achieved by recording spectra at low protein concentration using non-uniform s ling and maximum entropy reconstruction. Analysis of secondary chemical shifts shows that N-BP-2 possesses a secondary structure similar to that of other IGFBPs. Although aggregation h ered determination of the solution structure for N-BP-2, a homology model was generated based on the high degree of sequence and structure homology exhibited by the IGFBPs. This model was consistent with experimental NMR and SAXS data and displayed some unique features such as a Pro/Ala-rich non-polar insert, which formed a flexible solvent-exposed loop on the surface of the protein opposite to the IGF-binding interface. NMR data indicated that this loop could adopt either of two alternate conformations in solution - an entirely flexible conformation and one containing nascent helical structure. This loop and an adjacent poly-proline sequence may comprise a potential SH3 domain interaction site for binding to other proteins.
Localization of an insulin-like growth factor (IGF) binding site of bovine IGF binding protein-2 using disulfide mapping and deletion mutation analysis of the C-terminal domain
Publisher: Elsevier BV
Date: 02-1998
Structural determinants for high-affinity binding of insulin-like growth factor II to insulin receptor (IR)-A, the exon 11 minus isoform of the IR
Publisher: The Endocrine Society
Date: 10-2004
DOI: 10.1210/ME.2004-0183
Abstract: The insulin receptor (IR) lacking the alternatively spliced exon 11 (IR-A) is preferentially expressed in fetal and cancer cells. The IR-A has been identified as a high-affinity receptor for insulin and IGF-II but not IGF-I, which it binds with substantially lower affinity. Several cancer cell types that express the IR-A also overexpress IGF-II, suggesting a possible autocrine proliferative loop. To determine the regions of IGF-I and IGF-II responsible for this differential affinity, chimeras were made where the C and D domains were exchanged between IGF-I and IGF-II either singly or together. The abilities of these chimeras to bind to, and activate, the IR-A were investigated. We also investigated the ability of these chimeras to bind and activate the IR exon 11+ isoform (IR-B) and as a positive control, the IGF-I receptor (IGF-1R). We show that the C domain and, to a lesser extent, the D domains represent the principal determinants of the binding differences between IGF-I and IGF-II to IR-A. The C and D domains of IGF-II promote higher affinity binding to the IR-A than the equivalent domains of IGF-I, resulting in an affinity close to that of insulin for the IR-A. The C and D domains also regulate the IR-B binding specificity of the IGFs in a similar manner, although the level of binding for all IGF ligands to IR-B is lower than to IR-A. In contrast, the C and D domains of IGF-I allow higher affinity binding to the IGF-1R than the analogous domains of IGF-II. Activation of IGF-1R by the chimeras reflected their binding affinities whereas the phosphorylation of the two IR isoforms was more complex.
Chemical Synthesis of a Fluorescent IGF-II Analogue
Publisher: Springer Science and Business Media LLC
Date: 07-12-2012
Monotreme glucagon-like peptide-1 in venom and gut: one gene – two very different functions
Publisher: Springer Science and Business Media LLC
Date: 29-11-2016
DOI: 10.1038/SREP37744
Abstract: The importance of Glucagon like peptide 1 (GLP-1) for metabolic control and insulin release sparked the evolution of genes mimicking GLP-1 action in venomous species (e.g. Exendin-4 in Heloderma suspectum (gila monster)). We discovered that platypus and echidna express a single GLP-1 peptide in both intestine and venom. Specific changes in GLP-1 of monotreme mammals result in resistance to DPP-4 cleavage which is also observed in the GLP-1 like Exendin-4 expressed in Heloderma venom. Remarkably we discovered that monotremes evolved an alternative mechanism to degrade GLP-1. We also show that monotreme GLP-1 stimulates insulin release in cultured rodent islets, but surprisingly shows low receptor affinity and bias toward Erk signaling. We propose that these changes in monotreme GLP-1 are the result of conflicting function of this peptide in metabolic control and venom. This evolutionary path is fundamentally different from the generally accepted idea that conflicting functions in a single gene favour duplication and ersification, as is the case for Exendin-4 in gila monster. This provides novel insight into the remarkably different metabolic control mechanism and venom function in monotremes and an unique ex le of how different selective pressures act upon a single gene in the absence of gene duplication.
The insulin-like growth factor mutation database (IGFmdb)
Publisher: Elsevier BV
Date: 10-2012
DOI: 10.1016/J.GHIR.2012.05.001
Abstract: Insulin-like growth factors (IGF-I and IGF-II), and insulin are evolutionarily conserved hormonal regulators of eukaryotic growth and development. Through interactions with their cognate receptors, all three molecules can influence cellular growth, proliferation, differentiation, migration, and survival, as well as metabolic processes. As such, perturbations in signaling by IGFs and insulin are a well-documented cause of altered growth, development and survival during both embryonic and post-natal life. A key approach in understanding how IGFs and insulin elicit their biological effects has been through identifying structural features of the ligands that influence their receptor interactions. Over the years, the study of many hundreds of specifically engineered IGF and insulin analogues has provided a wealth of knowledge about how specific residues of these ligands contribute to ligand:receptor interactions. Some analogues have even provided the basis for designing therapeutic agents for the treatment of IGF and insulin-related diseases. As the list of IGF and insulin analogues continues to grow we find that, while many have been produced and studied, it would be of considerable value to have a central repository from which information about specific analogues and their receptor binding data were readily available in an easily searchable and comparable format. To address this, we have created the "Insulin-like growth factor mutation database" (IGFmdb). The IGFmdb is a web-based curated database of annotated ligand analogues and their receptor binding affinities that can be accessed via www.adelaide.edu.au/igfmutation. Currently the IGFmdb contains receptor-binding data for 67 IGF-II analogues that were publicly accessible prior to 2012, as well as 67 IGF-I analogues, including all of those produced and characterised in our laboratory. A small number of these are IGF species homologues. There are also 32 insulin analogues within IGFmdb that were reported within the included IGF analogue studies, representing only a small fraction of existing insulin mutants. Future developments of the IGFmdb will incorporate receptor-binding data for all publicly accessible IGF-I analogues and the data will be expanded to include IGF-binding protein (IGFBP) binding affinities.
Engineering of a Biologically Active Insulin Dimer.
Publisher: American Chemical Society (ACS)
Date: 19-11-2021
DOI: 10.1021/ACS.JMEDCHEM.1C01594
Abstract: The growing epidemic of diabetes means that there is a need for therapies that are more efficacious, safe, and convenient. Here, we report the efficient synthesis of a novel disulfide dimer of human insulin tethered at the N-terminus of its B-chain through placement of a cysteine residue. The resulting peptide was shown to bind to both the insulin receptor isoform B and insulin-like growth factor-1 receptor with comparable affinity to native insulin. In
Total Chemical Synthesis of an Intra‐A‐Chain Cystathionine Human Insulin Analogue with Enhanced Thermal Stability
Publisher: Wiley
Date: 20-10-2016
Abstract: Despite recent advances in the treatment of diabetes mellitus, storage of insulin formulations at 4 °C is still necessary to minimize chemical degradation. This is problematic in tropical regions where reliable refrigeration is not ubiquitous. Some degradation byproducts are caused by disulfide shuffling of cystine that leads to covalently bonded oligomers. Consequently we examined the utility of the non‐reducible cystine isostere, cystathionine, within the A‐chain. Reported herein is an efficient method for forming this mimic using simple monomeric building blocks. The intra‐A‐chain cystathionine insulin analogue was obtained in good overall yield, chemically characterized and demonstrated to possess native binding affinity for the insulin receptor isoform B. It was also shown to possess significantly enhanced thermal stability indicating potential application to next‐generation insulin analogues.
Immunohistochemical analysis of pancreatic islets of platypus (Ornithorhynchus anatinus) and echidna (Tachyglossus aculeatus ssp.).
Publisher: Wiley
Date: 09-02-2015
DOI: 10.1111/JOA.12279
A Review of the Biosynthesis and Structural Implications of Insulin Gene Mutations Linked to Human Disease
Publisher: MDPI AG
Date: 25-03-2023
Abstract: The discovery of the insulin hormone over 100 years ago, and its subsequent therapeutic application, marked a key landmark in the history of medicine and medical research. The many roles insulin plays in cell metabolism and growth have been revealed by extensive investigations into the structure and function of insulin, the insulin tyrosine kinase receptor (IR), as well as the signalling cascades, which occur upon insulin binding to the IR. In this review, the insulin gene mutations identified as causing disease and the structural implications of these mutations will be discussed. Over 100 studies were evaluated by one reviewing author, and over 70 insulin gene mutations were identified. Mutations may impair insulin gene transcription and translation, preproinsulin trafficking and proinsulin sorting, or insulin-IR interactions. A better understanding of insulin gene mutations and the resultant pathophysiology can give essential insight into the molecular mechanisms underlying impaired insulin biosynthesis and insulin-IR interaction.
Molecular interactions of the IGF system
Publisher: Elsevier BV
Date: 08-2005
DOI: 10.1016/J.CYTOGFR.2005.04.004
Abstract: The insulin-like growth factor (IGF) system is a complex network of two soluble ligands several cell surface transmembrane receptors and six soluble high-affinity binding-proteins. The IGF system is essential for normal embryonic and postnatal growth, and plays an important role in the function of a healthy immune system, lymphopoiesis, myogenesis and bone growth among other physiological functions. Deregulation of the IGF system leads to stimulation of cancer cell growth and survival. In order to manipulate the IGF system in the treatment of certain disorders, we must understand the protein-protein interactions at a molecular level. The complex molecular interactions of the ligands and receptors of the IGF system underlie all the biological actions mentioned above and will be the focus of this review.
Classification of the insulin-like growth factor binding proteins into three distinct categories according to their binding specificities
Publisher: Elsevier BV
Date: 11-1988
DOI: 10.1016/S0006-291X(88)80032-9
Abstract: Competitive binding experiments with insulin-like growth factor (IGF)-1, IGF-2 and des-(1-3)-IGF-1 have confirmed the interpretation based on limited amino-terminal sequence analysis that at least three types of IGF binding protein occur. In addition to the acid stable subunit of the large serum binding protein which exhibits des-(1-3)-IGF-1 binding only slightly less than IGF-1, the small IGF binding proteins can be separated into two classes based on differences in des-(1-3)-IGF-1 and IGF-2 binding potencies.
[P143]: Modelling forebrain formation using ES cells: The role of Hesx1
Publisher: Wiley
Date: 16-11-2006
2‐Nitroveratryl as a Photocleavable Thiol‐Protecting Group for Directed Disulfide Bond Formation in the Chemical Synthesis of Insulin
Publisher: Wiley
Date: 24-06-2014
Abstract: Chemical synthesis of peptides can allow the option of sequential formation of multiple cysteines through exploitation of judiciously chosen regioselective thiol-protecting groups. We report the use of 2-nitroveratryl (oNv) as a new orthogonal group that can be cleaved by photolysis under ambient conditions. In combination with complementary S-pyridinesulfenyl activation, disulfide bonds are formed rapidly in situ. The preparation of Fmoc-Cys(oNv)-OH is described together with its use for the solid-phase synthesis of complex cystine-rich peptides, such as insulin.
The N-Terminal Subdomain of Insulin-like Growth Factor (IGF) Binding Protein 6. Structure and Interaction with IGFs
Publisher: American Chemical Society (ACS)
Date: 17-02-2007
DOI: 10.1021/BI0619876
Abstract: Insulin-like growth factor binding proteins (IGFBPs) modulate the activity and distribution of insulin-like growth factors (IGFs). IGFBP-6 differs from other IGFBPs in being a relatively specific inhibitor of IGF-II actions. Another distinctive feature of IGFBP-6 is its unique N-terminal disulfide linkages the N-domains of IGFBPs 1-5 contain six disulfides and share a conserved GCGCC motif, but IGFBP-6 lacks the two adjacent cysteines in this motif, so its first three N-terminal disulfide linkages differ from those of the other IGFBPs. The contributions of the N- and C-domains of IGFBP-6 to its IGF binding properties and their structure-function relationships have been characterized in part, but the structure and function of the distinctive N-terminal subdomain of IGFBP-6 are unknown. Here we report the solution structure of a polypeptide corresponding to residues 1-45 of the N-terminal subdomain of IGFBP-6 (NN-BP-6). The extended structure of the N-terminal subdomain of IGFBP-6 is very different from that of the short two-stranded beta-sheet of the N-terminal subdomain of IGFBP-4 and, by implication, the other IGFBPs. NN-BP-6 contains a potential cation-binding motif lanthanide ion binding was observed, but no significant interaction was found with physiologically relevant metal ions like calcium or magnesium. However, this subdomain of IGFBP-6 has a higher affinity for IGF-II than IGF-I, suggesting that it may contribute to the marked IGF-II binding preference of IGFBP-6. The extended structure and flexibility of this subdomain of IGFBP-6 could play a role in enhancing the rate of ligand association and thereby be significant in IGF recognition.
Structure, Dynamics and Heparin Binding of the C-terminal Domain of Insulin-like Growth Factor-binding Protein-2 (IGFBP-2)
Publisher: Elsevier BV
Date: 12-2006
DOI: 10.1016/J.JMB.2006.09.006
Abstract: Insulin-like growth factor-binding protein-2 (IGFBP-2) is the largest member of a family of six proteins (IGFBP-1 to 6) that bind insulin-like growth factors I and II (IGF-I/II) with high affinity. In addition to regulating IGF actions, IGFBPs have IGF-independent functions. The C-terminal domains of IGFBPs contribute to high-affinity IGF binding, and confer binding specificity and have overlapping but variable interactions with many other molecules. Using nuclear magnetic resonance (NMR) spectroscopy, we have determined the solution structure of the C-terminal domain of IGFBP-2 (C-BP-2) and analysed its backbone dynamics based on 15N relaxation parameters. C-BP-2 has a thyroglobulin type 1 fold consisting of an alpha-helix, a three-stranded anti-parallel beta-sheet and three flexible loops. Compared to C-BP-6 and C-BP-1, structural differences that may affect IGF binding and underlie other functional differences were found. C-BP-2 has a longer disordered loop I, and an extended C-terminal tail, which is unstructured and very mobile. The length of the helix is identical with that of C-BP-6 but shorter than that of C-BP-1. Reduced spectral density mapping analysis showed that C-BP-2 possesses significant rapid motion in the loops and termini, and may undergo slower conformational or chemical exchange in the structured core and loop II. An RGD motif is located in a solvent-exposed turn. A pH-dependent heparin-binding site on C-BP-2 has been identified. Protonation of two histidine residues, His271 and His228, seems to be important for this binding, which occurs at slightly acidic pH (6.0) and is more significant at pH 5.5, but is largely suppressed at pH 7.4. Possible preferential binding of IGFBP-2 and its C- domain fragments to glycosaminoglycans in the acidic extracellular matrix (ECM) of tumours may be related to their roles in cancer.
Ligand-binding affinity at the insulin receptor isoform-A and subsequent IR-A tyrosine phosphorylation kinetics are important determinants of mitogenic biological outcomes
Publisher: Frontiers Media SA
Date: 07-07-2015
Understanding the mechanism of insulin and insulin-like growth factor (IGF) receptor activation by IGF-II
Publisher: Public Library of Science (PLoS)
Date: 28-11-2011
P-17 STRUCTURAL BASIS FOR THE LOWER AFFINITY OF THE INSULIN-LIKE GROWTH FACTORS FOR THE INSULIN RECEPTOR
Publisher: Elsevier BV
Date: 11-2006
Cooperativity of the N- and C-Terminal Domains of Insulin-like Growth Factor (IGF) Binding Protein 2 in IGF Binding
Publisher: American Chemical Society (ACS)
Date: 07-11-2007
DOI: 10.1021/BI701251D
Abstract: A family of six insulin-like growth factor (IGF) binding proteins (IGFBP-1-6) binds IGF-I and IGF-II with high affinity and thus regulates their bioavailability and biological functions. IGFBPs consist of N- and C-terminal domains, which are highly conserved and cysteine-rich, joined by a variable linker domain. The role of the C-domain in IGF binding is not completely understood in that C-domain fragments have very low or even undetectable IGF binding affinity, but loss of the C-domain dramatically disrupts IGF binding by IGFBPs. We recently reported the solution structure and backbone dynamics of the C-domain of IGFBP-2 (C-BP-2) and identified a pH-dependent heparin binding site [Kuang, Z., Yao, S., Keizer, D. W., Wang, C. C., Bach, L. A., Forbes, B. E., Wallace, J. C., and Norton, R. S. (2006) Structure, dynamics and heparin binding of the C-terminal domain of insulin-like growth factor-binding protein-2 (IGFBP-2), J. Mol. Biol. 364, 690-704]. Here, we have analyzed the molecular interactions among the N-domain of IGFBP-2 (N-BP-2), C-BP-2, and IGFs using cross-linking and nuclear magnetic resonance (NMR) spectroscopy. The binding of C-BP-2 to the IGF-I.N-BP-2 binary complex was significantly stronger than the binding of C-BP-2 to IGF-I alone, switching from intermediate exchange to slow exchange on the NMR time scale. A conformational change or stabilization of the IGF-I Phe49-Leu54 region and the Phe49 aromatic ring upon binding to the N-domains, as well as an interdomain interaction between N-BP-2 and C-BP-2 (which is also detectable in the absence of ligand), may contribute to this cooperativity in IGF binding. Glycosaminoglycan binding by IGFBPs can affect their IGF binding although the effects appear to differ among different IGFBPs here, we found that heparin bound to the IGF-I.N-BP-2.C-BP-2 ternary complex, but did not cause it to dissociate.
Differential Activation of Insulin Receptor Isoforms by Insulin-Like Growth Factors Is Determined by the C Domain
Publisher: The Endocrine Society
Date: 02-2006
DOI: 10.1210/EN.2005-0736
Abstract: The actions of IGF-I and IGF-II are thought to be largely due to their activation of the IGF-I receptor. However, IGF-II can also bind with high affinity to, and effectively activate, an isoform of the insulin receptor (IR-A) that lacks a sequence at the carboxyl-terminal end of the extracellular alpha subunit due to the alternative splicing of exon 11. This isoform is poorly activated by IGF-I. Here, we show that IGF-II, but not IGF-I, induces potent autophosphorylation of residues Y1158, Y1162, and Y1163 in the activation loop of the kinase domain and tyrosine 960 in the juxtamembrane region of both IR-A and IR-B (exon 11+) isoforms. We have also found, by using IGF chimeras, that the C domain of IGF-II completely accounts for the ability of IGF-II to stimulate IR autophosphorylation compared with IGF-I. We further show that the C domains are responsible for the differential abilities of IGF-II and IGF-I to activate phosphorylation of insulin receptor substrate-1 and Akt, as well as their ability to induce migration and cell survival via the IR-A. Finally, we show for the first time that IGF signaling through the IR-A can protect cells from butyrate-induced apoptosis. In summary, our studies define the structural determinants that allow potent IGF-II signaling and regulation of cellular functions through the IR-A and provide novel insights into IGF signaling via the IR.
Decision letter: Molecular basis for the role of disulfide-linked αCTs in the activation of insulin-like growth factor 1 receptor and insulin receptor
Publisher: eLife Sciences Publications, Ltd
Date: 31-08-2022
Insulin-like growth factor-I (IGF-I): Solution properties and NMR chemical shift assignments near physiological pH
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.GHIR.2008.10.003
Abstract: Insulin-like growth factor-I (IGF-I) plays important roles in normal growth and development, as well as in disease states, and its structure and function have been studied extensively using nuclear magnetic resonance (NMR) spectroscopy. However, IGF-I typically gives poor quality NMR spectra containing many broad peaks, because of aggregation at the protein concentrations generally required for NMR experiments as well as the internal dynamics of the molecule. The present study was undertaken to determine a reliable set of assignments under more physiological conditions. Several reports of chemical shift assignments have been published previously for IGF-I either bound to a ligand or at relatively low pH (approximately 3-4), but there are many contradictions among them, reflecting the poor behaviour of IGF-I. Low pH conditions are also suboptimal for the analysis of interactions between IGF-I and IGF binding proteins (IGFBP) or IGFBP fragments. Spectra were recorded at low concentrations in order to identify conditions of temperature and pH where all peaks could be observed. We show that good quality 2D (1)H-(15)N HSQC spectra of (15)N-labelled IGF-I can be obtained at pH 6 and 37 degrees C, much closer to physiological conditions, by using lower IGF-I concentrations (0.05 mM). Surprisingly, at this concentration and temperature, spectra were of better quality at pH 6 than at pH 4, in contrast to previous observations made at millimolar concentrations of IGF-I. We were then also able to assign the chemical shifts of IGF-I at pH 6 and 37 degrees C using 3D heteronuclear spectra recorded on a 0.7 mM (15)N/(13)C-labelled IGF-I s le. These results provide a valuable resource for future studies of the structure, dynamics, folding, and binding interactions of IGF-I, as well as analogues thereof, by means of NMR spectroscopy.
Computational model for the IGF‐II/IGF2r complex that is predictive of mutational and surface plasmon resonance data
Publisher: Wiley
Date: 06-2006
DOI: 10.1002/PROT.21035
Abstract: Insulin-like growth factors (IGFs) are key regulators of cell proliferation, differentiation, and transformation, and are thus pivotal in cancer, especially breast, prostate, and colon neoplasm. Their potent mitogenic and anti-apoptotic actions depend primarily on their availability to bind to the signaling IGF cell surface receptors. One mechanism by which IGF-II availability is thought to be modulated is by binding to the nonsignaling IGF-II receptor (IGF2R). This binding is essentially mediated by domain 11 in the multidomain IGF2R extracellular region. The crystal structure of domain 11 of the human IGF-II receptor (IGF2R-d11) has identified a putative IGF-II binding site, and a nuclear magnetic resonance (NMR) solution structure for the IGF-II ligand has also been characterized. These structures have now been used to model in silico the protein-protein interaction between IGF-II and IGF2R-d11 using the program 3D-Dock. Because the IGF-II data comprise an ensemble of 20 structures, all of which satisfy the NMR constraints, the docking procedure was applied to each member of the ensemble. Only those models in which residue Ile1572 of IGF2R-d11, known to be essential for the binding of IGF-II, was at the interface were considered further. These plausible complexes were then critically assessed using an array of analysis techniques including consideration of additional mutagenesis data. One model was strongly supported by these analyses and is discussed here in detail. Furthermore, we demonstrate in vitro experimental support for this model by studying the binding of chimeras of IGF-I and IGF-II to IGF2R fragments.
Insulin-Like Growth Factor Binding Proteins: A Structural Perspective
Publisher: Frontiers Media SA
Date: 2012
OR09-1 NEW INSIGHTS INTO MOLECULAR INTERACTIONS INFLUENCING IGF-II ACTION
Publisher: Elsevier BV
Date: 11-2006
Medical Complications of Type 2 Diabetes -- Insulin Secretion and Actions
Publisher: InTech
Date: 12-09-2011
DOI: 10.5772/21631
OR13-3 AN INVESTIGATION INTO THE RECEPTOR BINDING SURFACE(S) OF INSULIN-LIKE GROWTH FACTOR II
Publisher: Elsevier BV
Date: 11-2006
A structurally minimized yet fully active insulin based on cone-snail venom insulin principles
Publisher: Springer Science and Business Media LLC
Date: 06-2020
OR12,71 IGF2 promotes murine forebrain neural stem/progenitor cell self-renewal via the insulin receptor
Publisher: Elsevier BV
Date: 2010
Total Chemical Synthesis of a Nonfibrillating Human Glycoinsulin.
Publisher: American Chemical Society (ACS)
Date: 18-12-2020
DOI: 10.1021/JACS.9B11424
Abstract: Glycosylation is an accepted strategy to improve the therapeutic value of peptide and protein drugs. Insulin and its analogues are life-saving drugs for all type I and 30% of type II diabetic patients. However, they can readily form fibrils which is a significant problem especially for their use in insulin pumps. Because of the solubilizing and hydration effects of sugars, it was thought that glycosylation of insulin could inhibit fibril formation and lead to a more stable formulation. Since enzymatic glycosylation results in heterogeneous products, we developed a novel chemical strategy to produce a homogeneous glycoinsulin (disialo-glycoinsulin) in excellent yield (∼60%). It showed a near-native binding affinity for insulin receptors A and B
Two years in IGF research
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.GHIR.2016.09.006
Abstract: The last two years of insulin-like growth factor (IGF) research has yielded a vast literature highlighting the central role IGFs factors play in processes such as development, growth, aging and neurological function. It also provides our latest understanding of how IGF system perturbation is linked to diseases including growth deficiency, cancer, and neurological and cardiovascular diseases. A snapshot of the highlights is presented in this review, focussing on the topics of IGFs and growth, comparative and structural biology to understand insulin-like peptide function, IGFs and cancer, and IGFs and neurological function. New revelations in the IGF field include the unexpected discovery that the gut microbiome has a remarkable influence on the GH/IGF axis to influence growth, that the insulin of cone snails provides novel insight into the mechanism of receptor binding, and that macrophages in the tumour microenvironment can provide IGF-I to promote drug resistance. These advances and many others provide the exciting basis for future development of disease treatments and for biomarkers of disease.
Fluorescent IGF-II analogues for FRET-based investigations into the binding of IGF-II to the IGF-1R
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5OB02110C
Abstract: Convergent-based synthesis of native IGF-II and two IGF-II analogues, with coumarin fluorescent probes incorporated at residues 19 and 28, and their use in FRET-based identification of interactions with the type 1 insulin-like growth factor receptor (IGF-IR).
P46 Studies on the bivalent interaction of IGF-II with the insulin and type 1 IGF receptors
Publisher: Elsevier BV
Date: 2010
Silencing of the Insulin Receptor Isoform A Favors Formation of Type 1 Insulin-Like Growth Factor Receptor (IGF-IR) Homodimers and Enhances Ligand-Induced IGF-IR Activation and Viability of Human Colo
Publisher: The Endocrine Society
Date: 23-02-2010
DOI: 10.1210/EN.2009-1006
Abstract: Insulin receptor (IR) overexpression is common in cancers, with expression of the A isoform (IR-A, exon 11−) predominating over the B isoform. The IR-A signals a proliferative, antiapoptotic response to IGF-II, which itself can be secreted by tumors to establish an autocrine proliferative loop. Therefore, IGF-II signaling via the IR-A could mediate resistance to type 1 IGF receptor (IGF-IR) inhibitory drugs that are currently in development. This study addressed the role of the IR-A, using a small interfering RNA-based approach in SW480 human colon adenocarcinoma cells that coexpress the IGF-IR. Clonogenic survival was inhibited by depletion of the IGF-IR but not the IR-A, and dual receptor depletion had no greater effect than IGF-IR knockdown alone, suggesting that the IR-A could not compensate for IGF-IR loss. IGF-IR knockdown also resulted in a decrease in viability, whereas IR-A depletion resulted in increased viability. Consistent with this, upon IR-A depletion, we found a concomitant enhancement of IGF-IR activation by IGF-I and IGF-II, reduced formation of IGF-IR:IR-A hybrid receptors and increased IGF-IR homodimer formation. Together, these results suggest that IGF bioactivity is mediated more effectively by the IGF-IR than by the IR-A or receptor hybrids and that signaling via the IGF-IR is dominant to the IR-A in colon cancer cells that express both receptors.
BIAcore Analysis of Bovine Insulin-like Growth Factor (IGF)-binding Protein-2 Identifies Major IGF Binding Site Determinants in Both the Amino- and Carboxyl-terminal Domains
Publisher: Elsevier BV
Date: 07-2001
Solution structure of human insulin-like growth factor II. Relationship to receptor and binding protein interactions.
Publisher: Elsevier BV
Date: 1995
DOI: 10.1016/S0022-2836(95)80058-1
Abstract: The three-dimensional structure of human insulin-like growth factor (IGF) II in aqueous solution at pH 3.1 and 300 K has been determined from nuclear magnetic resonance data and restrained molecular dynamics calculations. Structural constraints consisting of 502 NOE-derived distance constraints, 11 dihedral angle restraints, and three disulfide bridges were used as input for distance geometry calculations in DIANA and X-PLOR, followed by simulated annealing refinement and energy minimization in X-PLOR. The resulting family of 20 structures was well defined in the regions of residues 5 to 28 and 41 to 62, with an average pairwise root-mean-square deviation of 1.24 A for the backbone heavy-atoms (N, C2, C) and 1.90 A for all heavy atoms. The poorly defined regions consist of the N and C termini, part of the B-domain, and the C-domain loop. Resonances from these regions of the protein gave stronger cross peaks in two dimensional NMR spectra, consistent with significant motional averaging. The main secondary structure elements in IGF-II are alpha-helices encompassing residues 11 to 21, 42 to 49 and 53 to 59. A small anti-parallel beta-sheet is formed by residues 59 to 61 and 25 to 27, while residues 26 to 28 appear to participate in intermolecular beta-sheet formation. The structure of IGF-II in the well-defined regions is very similar to those of the corresponding regions of insulin and IGF-I. Significant differences between IGF-II and IGF-I occur near the start of the third helix, in a region known to modulate affinity for the type 2 IGF receptor, and at the C terminus. The IGF II structure is discussed in relation to its binding sites for the insulin and IGF receptors and the IGF binding proteins.
Homozygous and Heterozygous Expression of a Novel Insulin-Like Growth Factor-I Mutation
Publisher: The Endocrine Society
Date: 05-2005
DOI: 10.1210/JC.2004-1254
Abstract: IGF-I is a key factor in intrauterine development and postnatal growth and metabolism. The secretion of IGF-I in utero is not dependent on GH, whereas in childhood and adult life, IGF-I secretion seems to be mainly controlled by GH, as revealed from studies on patients with GHRH receptor and GH receptor mutations. In a 55-yr-old male, the first child of consanguineous parents, presenting with severe intrauterine and postnatal growth retardation, microcephaly, and sensorineural deafness, we found a homozygous G to A nucleotide substitution in the IGF-I gene changing valine 44 into methione. The inactivating nature of the mutation was proven by functional analysis demonstrating a 90-fold reduced affinity of recombinantly produced for the IGF-I receptor. Additional investigations revealed osteoporosis, a partial gonadal dysfunction, and a relatively well-preserved cardiac function. Nine of the 24 relatives studied carried the mutation. They had a significantly lower birth weight, final height, and head circumference than noncarriers. In conclusion, the phenotype of our patient consists of severe intrauterine growth retardation, deafness, and mental retardation, reflecting the GH-independent secretion of IGF-I in utero. The postnatal growth pattern, similar to growth of untreated GH-deficient or GH-insensitive children, is in agreement with the hypothesis that IGF-I secretion in childhood is mainly GH dependent. Remarkably, IGF-I deficiency is relatively well tolerated during the subsequent four decades of adulthood. IGF-I haploinsufficiency results in subtle inhibition of intrauterine and postnatal growth.
Chapter 25 Interactions of IGF‐II with the IGF2R/Cation‐Independent Mannose‐6‐Phosphate Receptor
Publisher: Elsevier
Date: 2009
Structural Insights into the Interaction of Insulin-like Growth Factor 2 with IGF2R Domain 11
Publisher: Elsevier BV
Date: 09-2007
DOI: 10.1016/J.STR.2007.07.007
Abstract: The insulin-like growth factor II/mannose-6-phosphate receptor (IGF2R) mediates trafficking of mannose-6-phosphate (M6P)-containing proteins and the mitogenic hormone IGF2. IGF2R also plays an important role as a tumor suppressor, as mutation is frequently associated with human carcinogenesis. IGF2 binds to domain 11, one of 15 extracellular domains on IGF2R. The crystal structure of domain 11 and the solution structure of IGF2 have been reported, but, to date, there has been limited success when using crystallography to study the interaction of IGFs with their binding partners. As an approach to investigate the interaction between IGF2 and IGF2R, we have used heteronuclear NMR in combination with existing mutagenesis data to derive models of the domain 11-IGF2 complex by using the program HADDOCK. The models reveal that the molecular interaction is driven by critical hydrophobic residues on IGF2 and IGF2R, while a ring of flexible, charged residues on IGF2R may modulate binding.
The insulin-like growth factor (IGF) binding site of bovine insulin-like growth factor binding protein-2 (bIGFBP-2) probed by iodination.
Publisher: Elsevier BV
Date: 11-1996
A novel approach to identify two distinct receptor binding surfaces of insulin-like growth factor II
Publisher: Elsevier BV
Date: 03-2009
Author Correction: A structurally minimized yet fully active insulin based on cone-snail venom insulin principles
Publisher: Springer Science and Business Media LLC
Date: 12-06-2020
OR04-3 C-TERMINAL DOMAIN OF INSULIN-LIKE GROWTH FACTOR BINDING PROTEIN-2 (IGFBP-2): STRUCTURE, DYNAMICS AND INTERACTION WITH IGFS
Publisher: Elsevier BV
Date: 11-2006
Assessing the potential usefulness of IGF-related peptides and adiponectin for predicting disease risk
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.GHIR.2007.08.005
Abstract: Insulin-like growth factors (IGF), their binding proteins and adiponectin have been investigated as potential blood-based biomarkers for a variety of diseases. Before these circulating proteins can be considered as biomarkers, their variation within and between in iduals and between published studies must be critically assessed. The purpose of this study was to use the D-value to predict the potential usefulness of IGF-related peptides and adiponectin as biomarkers for the diagnosis of colorectal cancer (CRC). Intra- and inter-in idual variation of total IGF-I and -II, IGF binding protein 1 (IGFBP-1), -2 and -3 and adiponectin, was examined in 10 healthy subjects over a 5 week period. This data was analysed in conjunction with previous publications to provide a D-value, which is a theoretical value that identifies the usefulness of the analyte in idually and as a panel, as a biomarker for CRC. A single measurement of total IGF-I and -II, and adiponectin provided a reproducible representation of their circulating concentrations. The D-value for total IGF-II and IGFBP-3 were 0.5 and 0.47, respectively, which corresponded to area under the curve (AUC) values of 64 and 63%. Combining these analytes into a panel only slightly improved the D-value to 0.63 (AUC was 67%). Although serum levels of total IGF-I, total IGF-II and IGFBP-3 are stable and reproducible, the D-value calculations indicate that they have limited importance when used as biomarkers of CRC.
Precise mapping of an IGF-I-binding site on the IGF-1R
Publisher: Portland Press Ltd.
Date: 11-12-2007
DOI: 10.1042/BJ20060890
Abstract: The IGF-1R [type 1 IGF (insulin-like growth factor) receptor] is activated upon binding to IGF-I and IGF-II leading to cell growth, survival and migration of both normal and cancerous cells. We have characterized the binding interaction between the IGF-1R and its ligands using two high-affinity mouse anti-IGF-1R mAbs (monoclonal antibodies), 7C2 and 9E11. These mAbs both block IGF-I binding to the IGF-1R but have no effect on IGF-II binding. Epitope mapping using chimaeras of the IGF-1R and insulin receptor revealed that the mAbs bind to the CR (cysteine-rich) domain of IGF-1R. The epitope was finely mapped using single point mutations in the IGF-1R. Mutation of Phe241, Phe251 or Phe266 completely abolished 7C2 and 9E11 binding. The three-dimensional structure showed that these residues cluster on the surface of the CR-domain. BIAcore analyses revealed that IGF-I and a chimaeric IGF-II with the IGF-I C-domain competed for the binding of both mAbs with the IGF-1R, whereas neither IGF-II nor a chimaeric IGF-I with the IGF-II C-domain affected antibody binding. We therefore conclude the IGF-I C-domain interacts with the CR (cysteine-rich) domain of the receptor at the cluster of residues Phe241, Phe251 and Phe266. These results allow precise orientation of IGF-I within the IGF-I–IGF-1R complex involving the IGF-I C-domain binding to the IGF-1R CR domain. In addition, mAbs 7C2 and 9E11 inhibited both IGF-I- and IGF-II-induced cancer cell proliferation, migration and IGF-1R down-regulation, demonstrating that targeting the IGF-1R is an effective strategy for inhibition of cancer cell growth.
How ligand binds to the type 1 insulin-like growth factor receptor
Publisher: Springer Science and Business Media LLC
Date: 26-02-2018
DOI: 10.1038/S41467-018-03219-7
Abstract: Human type 1 insulin-like growth factor receptor is a homodimeric receptor tyrosine kinase that signals into pathways directing normal cellular growth, differentiation and proliferation, with aberrant signalling implicated in cancer. Insulin-like growth factor binding is understood to relax conformational restraints within the homodimer, initiating transphosphorylation of the tyrosine kinase domains. However, no three-dimensional structures exist for the receptor ectodomain to inform atomic-level understanding of these events. Here, we present crystal structures of the ectodomain in apo form and in complex with insulin-like growth factor I, the latter obtained by crystal soaking. These structures not only provide a wealth of detail of the growth factor interaction with the receptor’s primary ligand-binding site but also indicate that ligand binding separates receptor domains by a mechanism of induced fit. Our findings are of importance to the design of agents targeting IGF-1R and its partner protein, the human insulin receptor.
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