ORCID Profile
0000-0002-7290-1217
Current Organisations
BellwaldTEC
,
POC APP
,
Children's Medical Research Institute
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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 | Proteomics and Intermolecular Interactions (excl. Medical Proteomics) | Analytical Biochemistry | Protein Targeting And Signal Transduction | Cell Neurochemistry | Analytical Biochemistry | Bioinformatics
ANZSRC Socio-Economic Objective (SEO)
Immune system and allergy | Infectious diseases | Nervous system and disorders | Biological sciences | Cancer and related disorders | Chemical sciences |
Related Links
Publications
Differentiation of cortical brain organoids and optic nerve-like structures from retinal confluent cultures of pluripotent stem cells
Publisher: Cold Spring Harbor Laboratory
Date: 17-05-2021
DOI: 10.1101/2021.05.16.444356
Abstract: Advances in the study of neurological conditions have been possible due to induced pluripotent stem cell technologies and the generation of neural cell types and organoids. Numerous studies have described the generation of neural ectoderm-derived retinal and brain structures from pluripotent stem cells. However, the field is still troubled by technical challenges, including high culture costs and organoid-to-organoid variability. Here, we describe a simple and economical protocol that reproducibly gives rise to the neural retina and cortical brain regions from confluent cultures of stem cells. The spontaneously generated cortical organoids were isolated and cultured in suspension conditions for maturation and are transcriptionally comparable to organoids generated by other methods and to human foetal cortex. Furthermore, these organoids show spontaneous functional network activity with proteomic analysis and electron microscopy demonstrating the presence of synaptic components and maturity. The generation of retinal and brain organoids in close proximity also enabled their mutual isolation. Further culture of this complex organoid system demonstrated the formation of optic nerve-like structures connecting retinal and brain organoids, which might facilitate the investigation of the mechanisms of neurological diseases of the eye and brain.
TWIST1 and chromatin regulatory proteins interact to guide neural crest cell differentiation
Publisher: eLife Sciences Publications, Ltd
Date: 08-02-2021
DOI: 10.7554/ELIFE.62873
Abstract: Protein interaction is critical molecular regulatory activity underlining cellular functions and precise cell fate choices. Using TWIST1 BioID-proximity-labeling and network propagation analyses, we discovered and characterized a TWIST-chromatin regulatory module (TWIST1-CRM) in the neural crest cells (NCC). Combinatorial perturbation of core members of TWIST1-CRM: TWIST1, CHD7, CHD8, and WHSC1 in cell models and mouse embryos revealed that loss of the function of the regulatory module resulted in abnormal differentiation of NCCs and compromised craniofacial tissue patterning. Following NCC delamination, low level of TWIST1-CRM activity is instrumental to stabilize the early NCC signatures and migratory potential by repressing the neural stem cell programs. High level of TWIST1 module activity at later phases commits the cells to the ectomesenchyme. Our study further revealed the functional interdependency of TWIST1 and potential neurocristopathy factors in NCC development.
Phosphorylation of dynamin II at serine-764 is associated with cytokinesis
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.BBAMCR.2010.12.018
Abstract: Calcineurin is a phosphatase that is activated at the last known stage of mitosis, abscission. Among its many substrates, it dephosphorylates dynamin II during cytokinesis at the midbody of iding cells. However, dynamin II has several cellular roles including clathrin-mediated endocytosis, centrosome cohesion and cytokinesis. It is not known whether dynamin II phosphorylation plays a role in any of these functions nor have the phosphosites involved in cytokinesis been directly identified. We now report that dynamin II from rat lung is phosphorylated to a low stoichiometry on a single major site, Ser-764, in the proline-rich domain. Phosphorylation on Ser-764 also occurred in asynchronously growing HeLa cells and was greatly increased upon mitotic entry. Tryptic phospho-peptides isolated by TiO(2) chromatography revealed only a single phosphosite in mitotic cells. Mitotic phosphorylation was abolished by roscovitine, suggesting the mitotic kinase is cyclin-dependent kinase 1. Cyclin-dependent kinase 1 phosphorylated full length dynamin II and Glutathione-S-Transferase-tagged-dynamin II-proline-rich domain in vitro, and mutation of Ser-764 to alanine reduced proline-rich domain phosphorylation by 80%, supporting that there is only a single major phosphosite. Ser-764 phosphorylation did not affect clathrin-mediated endocytosis or bulk endocytosis using penetratin-based phospho-deficient or phospho-mimetic peptides or following siRNA depletion/rescue experiments. Phospho-dynamin II was enriched at the mitotic centrosome, but this targeting was unaffected by the phospho-deficient or phospho-mimetic peptides. In contrast, the phospho-mimetic peptide displaced endogenous dynamin II, but not calcineurin, from the midbody and induced cytokinesis failure. Therefore, phosphorylation of dynamin II primarily occurs on a single site that regulates cytokinesis downstream of calcineurin, rather than regulating endocytosis or centrosome function.
Phosphorylation of septin 3 on Ser-91 by cGMP-dependent protein kinase-I in nerve terminals
Publisher: Portland Press Ltd.
Date: 27-07-2004
DOI: 10.1042/BJ20040455
Abstract: The septins are a family of GTPase enzymes required for cytokinesis and play a role in exocytosis. Among the ten vertebrate septins, Sept5 (CDCrel-1) and Sept3 (G-septin) are primarily concentrated in the brain, wherein Sept3 is a substrate for PKG-I (cGMP-dependent protein kinase-I) in nerve terminals. There are two motifs for potential PKG-I phosphorylation in Sept3, Thr-55 and Ser-91, but phosphoamino acid analysis revealed that the primary site is a serine. Derivatization of phosphoserine to S-propylcysteine followed by N-terminal sequence analysis revealed Ser-91 as a major phosphorylation site. Tandem MS revealed a single phosphorylation site at Ser-91. Substitution of Ser-91 with Ala in a synthetic peptide abolished phosphorylation. Mutation of Ser-91 to Ala in recombinant Sept3 also abolished PKG phosphorylation, confirming that Ser-91 is the major site in vitro. Antibodies raised against a peptide containing phospho-Ser-91 detected phospho-Sept3 only in the cytosol of nerve terminals, whereas Sept3 was located in a peripheral membrane extract. Therefore Sept3 is phosphorylated on Ser-91 in nerve terminals and its phosphorylation may contribute to the regulation of its subcellular localization in neurons.
Cdk5 is essential for synaptic vesicle endocytosis
Publisher: Springer Science and Business Media LLC
Date: 13-07-2003
DOI: 10.1038/NCB1020
Characterization of the phosphorylation of rat tyrosine hydroxylase using electrospray mass spectrometry
Publisher: Wiley
Date: 15-06-1998
DOI: 10.1002/(SICI)1097-0231(19980615)12:11<746::AID-RCM225>3.0.CO;2-N
Abstract: Connective tissue disorders can be associated with significant cardiovascular morbidity needing cardiac surgery during childhood. In this retrospective study, we used the Pediatric Cardiac Care Consortium, a multicenter United States-based registry of pediatric cardiac interventions, to describe the long-term outcomes of patients who underwent their first surgery for connective tissue-related cardiovascular conditions aged <21 years. Between 1982 and 2003, a total of 103 patients were enrolled who underwent cardiac surgery for a connective tissue-related cardiovascular disorder, including 3 severe infantile cases operated on within the first year of life. Most patients underwent aortic site surgery (n = 85) as a composite graft (n = 50), valve-sparing (n = 33), or other aortic surgery (n = 2). The remaining patients underwent atrioventricular valve surgery (mitral 17, tricuspid 1). Of the 99 patients surviving to discharge, 80 (including the 3 infantile) had adequate identifiers for tracking long-term outcomes through 2019 through linkage with the National Death Index and the Organ Procurement. Over a median period of 19.5 years (interquartile range 16.0 to 23.1), 29 deaths and 1 transplant occurred in the noninfantile group, whereas all 3 infantile patients died before the age of 4 years. The postdischarge survival for the noninfantile group was 92.2%, 68.2%, and 56.7% at 10, 20, and 25 years, respectively. Cardiovascular-related pathology contributed to all deaths in the infantile and 89% (n = 27) of deaths for the noninfantile cases after hospital discharge. The significant late attrition from cardiovascular causes emphasizes the need for close monitoring and ongoing management in this population.
Subcellular analysis of blood-brain barrier function by micro-impalement of vessels in acute brain slices
Publisher: Springer Science and Business Media LLC
Date: 30-01-2023
DOI: 10.1038/S41467-023-36070-6
Abstract: The blood-brain barrier (BBB) is a tightly and actively regulated vascular barrier. Answering fundamental biological and translational questions about the BBB with currently available approaches is h ered by a trade-off between accessibility and biological validity. We report an approach combining micropipette-based local perfusion of capillaries in acute brain slices with multiphoton microscopy. Micro-perfusion offers control over the luminal solution and allows application of molecules and drug delivery systems, whereas the bath solution defines the extracellular milieu in the brain parenchyma. Here we show, that this combination allows monitoring of BBB transport at the cellular level, visualization of BBB permeation of cells and molecules in real-time and resolves subcellular details of the neurovascular unit. In combination with electrophysiology, it permits comparison of drug effects on neuronal activity following luminal versus parenchymal application. We further apply micro-perfusion to the human and mouse BBB of epileptic hippoc i highlighting its utility for translational research and analysis of therapeutic strategies.
Reactive oxygen species (ROS)-activated ATM-dependent phosphorylation of cytoplasmic substrates identified by large-scale phosphoproteomics screen
Publisher: Elsevier BV
Date: 03-2016
The similar to 16 kDa C-Terminal Sequence of Clathrin Assembly Protein AP180 Is Essential for Efficient Clathrin Binding
Publisher: Public Library of Science (PLoS)
Date: 20-10-2014
A Novel Sequence in AP180 and CALM Promotes Efficient Clathrin Binding and Assembly
Publisher: Public Library of Science (PLoS)
Date: 30-08-2016
Telomerase Recognizes G-Quadruplex and Linear DNA as Distinct Substrates
Publisher: American Chemical Society (ACS)
Date: 18-09-2007
DOI: 10.1021/BI700993Q
Abstract: Telomeric DNA can assemble into a nonlinear, higher-order conformation known as a G-quadruplex. Here, we demonstrate by electrospray ionization mass spectrometry that the two repeat telomeric sequence d(TGGGGTTGGGGT) from Tetrahymena thermophila gives rise to a novel parallel four-stranded G-quadruplex in the presence of sodium. The G-quadruplex directly interacts with the catalytic subunit of Tetrahymena telomerase (TERT) with micromolar affinity, and the presence of telomerase RNA is not obligatory for this interaction. Both N- and C-terminal halves of TERT bind the G-quadruplex independently. This G-quadruplex is a robust substrate for both recombinant and cell extract-derived telomerase in vitro. Furthermore, the G-quadruplex weakens the affinity of wild-type telomerase for the incoming nucleotide (dTTP) and likely perturbs the nucleotide binding pocket of the enzyme. In agreement with this, a lysine to alanine substitution at amino acid 538 (K538A) within motif 1 of TERT dramatically reduces the ability of telomerase to extend G-quadruplex but not linear DNA. The K538A mutant retains binding affinity for the quadruplex. This suggests that telomerase undergoes changes in conformation in its active site to specifically accommodate binding and subsequent extension of G-quadruplex DNA. We propose that telomerase recognizes G-quadruplex DNA as a substrate that is distinct from linear DNA.
The in Vivo Phosphorylation and Glycosylation of Human Insulin-like Growth Factor-binding Protein-5
Publisher: Elsevier BV
Date: 08-2007
The Biochemical Properties and Functions of CALM and AP180 in Clathrin Mediated Endocytosis.
Publisher: MDPI AG
Date: 31-07-2014
Differential Phosphorylation of Dynamin I Isoforms in Subcellular Compartments Demonstrates the Hidden Complexity of Phosphoproteomes
Publisher: American Chemical Society (ACS)
Date: 07-07-2010
DOI: 10.1021/PR100223N
Abstract: Large-scale comparative phosphoproteomics studies have frequently been done on whole cells or organs by conventional bottom-up mass spectrometry approaches, that is, at the phosphopeptide level. Using this approach, there is no way to know which protein isoforms the phosphopeptide signal originated from. Also, as a consequence of the scale of these studies, important information on the localization of phosphorylation sites in subcellular compartments is not surveyed. As a case study, we investigated whether the isoforms of dynamin I (dynI), at the whole brain and subcellular level, had differential phosphorylation. We first established that the dynI isoforms xa, xb, and xd were expressed in nerve terminals. Our investigation revealed that dynI xa was constitutively phosphorylated to a higher extent than the other isoforms despite identical sequences in the phosphorylated subdomains. DynI xa had a 10-fold higher stoichiometry of diphosphorylation at Ser-774 and Ser-778 than dynI xb and xd combined. Diphosphorylation was 2-fold enriched in nerve terminals relative to whole brain and was preferentially targeted for stimulus-dependent dephosphorylation. Phospho-Ser-851 and Ser-857 were depleted from nerve terminals. Our data reveals major differential phosphorylation of dynI phosphosites in different variants and in different neuronal compartments that would be completely imperceptible to a large-scale phosphoproteomics approach.
Protein Composition of Catalytically Active Human Telomerase from Immortal Cells
Publisher: American Association for the Advancement of Science (AAAS)
Date: 30-03-2007
Abstract: Telomerase is a ribonucleoprotein enzyme complex that adds 5′-TTAGGG-3′ repeats onto the ends of human chromosomes, providing a telomere maintenance mechanism for ∼90% of human cancers. We have purified human telomerase ∼10 8 -fold, with the final elution dependent on the enzyme's ability to catalyze nucleotide addition onto a DNA oligonucleotide of telomeric sequence, thereby providing specificity for catalytically active telomerase. Mass spectrometric sequencing of the protein components and molecular size determination indicated an enzyme composition of two molecules each of telomerase reverse transcriptase, telomerase RNA, and dyskerin.
The in Vivo Phosphorylation Sites in Multiple Isoforms of Amphiphysin I from Rat Brain Nerve Terminals
Publisher: Elsevier BV
Date: 06-2008
Phosphorylation of syndapin I F-BAR domain at two helix-capping motifs regulates membrane tubulation.
Publisher: Proceedings of the National Academy of Sciences
Date: 21-02-2012
Abstract: Syndapin I (PACSIN 1) is a synaptically enriched membrane tubulating protein that plays important roles in activity-dependent bulk endocytosis and neuronal morphogenesis. While syndapin I is an in vitro phosphoprotein, it is not known to be phosphorylated in neurons. Here, we report the identification of two phosphorylation sites, S76 and T181, of syndapin I from nerve terminals. Both residues are located at the N-terminal helix-capping motifs (N-Cap) of different α-helices in the F-BAR domain, important for F-BAR homodimer curvature and dimer-dimer filament assembly, respectively. Phospho-mimetic mutations of these residues regulate lipid-binding and tubulation both in vitro and in cells. Neither phosphosite regulated syndapin I function in activity-dependent bulk endocytosis. Rather, T181 phosphorylation was developmentally regulated and inhibited syndapin I function in neuronal morphogenesis. This suggests a novel mechanism for phosphorylation control of an F-BAR function through the regulation of α-helix interactions and stability within the folded F-BAR domain.
The actin-binding and bundling protein, EPLIN, is required for cytokinesis
Publisher: Informa UK Limited
Date: 03-2009
DOI: 10.4161/CC.8.5.7878
Abstract: Cytokinesis involves two phases: (1) membrane ingression followed by (2) membrane abscission. The ingression phase generates a cleavage furrow and this requires co-operative function of the actin-myosin II contractile ring and septin filaments. We demonstrate that the actin-binding protein, EPLIN, locates to the cleavage furrow during cytokinesis and this is possibly via association with the contractile ring components, myosin II and the septin, Sept2. Depletion of EPLIN results in formation of multinucleated cells and this is associated with inefficient accumulation of active myosin II (MRLC(S19)) and Sept2 and their regulatory small GTPases, RhoA and Cdc42, respectively, to the cleavage furrow during the final stages of cytokinesis. We suggest that EPLIN may function during cytokinesis to maintain local accumulation of key cytokinesis proteins at the furrow.
Autophosphorylation and ATM Activation
Publisher: Elsevier BV
Date: 03-2011
Improved Detection of Hydrophilic Phosphopeptides Using Graphite Powder Microcolumns and Mass Spectrometry
Publisher: Elsevier BV
Date: 05-2004
Synthesis and protein binding studies of a peptide fragment of clathrin assembly protein AP180 bearing an O-linked β-N-acetylglucosaminyl-6-phosphate modification
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2OB07139H
Abstract: A novel post-translational modification of threonine, β-N-acetylglucosaminyl-phosphate, was recently discovered on assembly protein AP180, a protein which plays a crucial role in clathrin coated vesicle formation in synaptic vesicle endocytosis (SVE). Herein, we report studies aimed at probing the effect of this modification on binding to proteins in rat brain lysate using pull down experiments with peptide fragments of AP180.
Determination of Phosphorylation Levels of Tyrosine Hydroxylase by Electrospray Mass Spectrometry
Publisher: Elsevier BV
Date: 05-2000
Abstract: A novel approach has been developed to quantify the extent of phosphorylation of tyrosine hydroxylase (TH). The strategy consists of a chemical cleavage and characterization of the products using electrospray mass spectrometry (ESMS). The chemical cleavage involves selective hydrolysis of the aspartyl-peptide bond. Of the peptides formed, an 8-kDa NH2-terminus fragment is found to accurately duplicate the phosphorylation of TH using standard mixtures of TH-P/TH. The calibration yields a straight line with an R2 of 0.996, which is valid within the 10-90% range. The ESMS protocol has been used to determine the extent of phosphorylation of TH in the presence of CaM-PKII. The experimental conditions were designed to produce low levels of phosphorylation. Nevertheless, the ESMS analysis yielded single, double, and nonphosphorylation forms of TH. With respect to in vivo measurements, this ESMS protocol may be a generic procedure for determining the extent of phosphorylation of proteins.
A presynaptic phosphosignaling hub for lasting homeostatic plasticity
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.CELREP.2022.110696
Abstract: Stable function of networks requires that synapses adapt their strength to levels of neuronal activity, and failure to do so results in cognitive disorders. How such homeostatic regulation may be implemented in mammalian synapses remains poorly understood. Here we show that the phosphorylation status of several positions of the active-zone (AZ) protein RIM1 are relevant for synaptic glutamate release. Position RIMS1045 is necessary and sufficient for expression of silencing-induced homeostatic plasticity and is kept phosphorylated by serine arginine protein kinase 2 (SRPK2). SRPK2-induced upscaling of synaptic release leads to additional RIM1 nanoclusters and docked vesicles at the AZ and is not observed in the absence of RIM1 and occluded by RIM
Author response: TWIST1 and chromatin regulatory proteins interact to guide neural crest cell differentiation
Publisher: eLife Sciences Publications, Ltd
Date: 25-01-2021
Characterisation of tryptic peptides of phosphorylated tyrosine hydroxylase by high-pressure liquid chromatography electrospray ionisation mass spectrometry
Publisher: Elsevier BV
Date: 03-2005
A Novel Post-translational Modification in Nerve Terminals: O-Linked N-Acetylglucosamine Phosphorylation
Publisher: American Chemical Society (ACS)
Date: 02-05-2011
DOI: 10.1021/PR1011153
Abstract: Protein phosphorylation and glycosylation are the most common post-translational modifications observed in biology, frequently on the same protein. Assembly protein AP180 is a synapse-specific phosphoprotein and O-linked beta-N-acetylglucosamine (O-GlcNAc) modified glycoprotein. AP180 is involved in the assembly of clathrin coated vesicles in synaptic vesicle endocytosis. Unlike other types of O-glycosylation, O-GlcNAc is nucleocytoplasmic and reversible. It was thought to be a terminal modification, that is, the O-GlcNAc was not found to be additionally modified in any way. We now show that AP180 purified from rat brain contains a phosphorylated O-GlcNAc (O-GlcNAc-P) within a highly conserved sequence. O-GlcNAc or O-GlcNAc-P, but not phosphorylation alone, was found at Thr-310. Analysis of synthetic GlcNAc-6-P produced identical fragmentation products to GlcNAc-P from AP180. Direct O-linkage of GlcNAc-P to a Thr residue was confirmed by electron transfer dissociation MS. A second AP180 tryptic peptide was also glycosyl phosphorylated, but the site of modification was not assigned. Sequence similarities suggest there may be a common motif within AP180 involving glycosyl phosphorylation and dual flanking phosphorylation sites within 4 amino acid residues. This novel type of protein glycosyl phosphorylation adds a new signaling mechanism to the regulation of neurotransmission and more complexity to the study of O-GlcNAc modification.
Azido and Diazarinyl Analogues of Bis‐Tyrphostin as Asymmetrical Inhibitors of Dynamin GTPase
Publisher: Wiley
Date: 29-06-2009
Abstract: Probing the dynamin binding site: Bis-tyrphostin (1, Bis-T), is a potent inhibitor of the phospholipid-stimulated GTPase activity of dynamin I. Analogues of Bis-T have significant potential as a biological probes for the dissection of endocytic pathways. Bis-T-derived compounds were synthesised and evaluated for their ability to inhibit the GTPase activity of dynamin I. Two analogues (23 and 24) represent the first asymmetrically substituted Bis-T analogues to retain dynamin inhibition.Two azidobenzyl amide (4 and 23) and one 3-trifluoromethyl-3H-diazirin-3-ylphenyl (24) analogues of bis-tyrphostin (1, Bis-T) were synthesised as potential photoaffinity labels for the elucidation of the binding site of compound 1 in dynamin I. Of the two azidobenzyl amide analogues (4 and 23), the terminally substituted 23 retained dynamin I GTPase inhibition (IC(50)=6.4+/-2.8 microM) whilst 4, which was substituted on the central carbon of the amide linker, displayed no activity. Analogue 24 also retained inhibitory activity (IC(50)=36+/-9 microM). Photoaffinity labelling experiments did not unequivocally elucidate the binding pocket of compound 1. However, compounds 23 and 24 represent the first asymmetrically substituted Bis-T analogues to retain dynamin inhibitory activity, providing a new direction for analogue synthesis.
The phosphorylation of p25/TPPP by LIM kinase 1 inhibits its ability to assemble microtubules
Publisher: Elsevier BV
Date: 12-2007
DOI: 10.1016/J.YEXCR.2007.08.012
Abstract: LIM kinase 1 (LIMK1) is a key regulator of actin dynamics as it phosphorylates and inactivates cofilin, an actin-depolymerizing factor. LIMK1 activity is also required for microtubule disassembly in endothelial cells. A search for LIMK1-interacting proteins identified p25alpha, a phosphoprotein that promotes tubulin polymerization. We found that p25 is phosphorylated by LIMK1 on serine residues in vitro and in cells. Immunoblotting analysis revealed that p25 is not a brain specific protein as previously reported, but is expressed in all mouse tissues. Immunofluorescence analysis demonstrated that endogenous p25 is co-localized with microtubules and is also found in the nucleus. Down-regulation of p25 by siRNA decreased microtubule levels while its overexpression in stable NIH-3T3 cell lines increased cell size and levels of stable tubulin. Bacterially expressed unphosphorylated p25 promotes microtubule assembly in vitro however, when phosphorylated in cells, p25 lost its ability to assemble microtubule. Our results represent a surprising connection between the tubulin and the actin cytoskeleton mediated by LIMK1. We propose that the LIMK1 phosphorylation of p25 blocks p25 activity, thus promoting microtubule disassembly.
Tyrosine hydroxylase phosphorylation: regulation and consequences
Publisher: Wiley
Date: 18-11-2004
DOI: 10.1111/J.1471-4159.2004.02797.X
Abstract: The rate-limiting enzyme in catecholamine synthesis is tyrosine hydroxylase. It is phosphorylated at serine (Ser) residues Ser8, Ser19, Ser31 and Ser40 in vitro, in situ and in vivo. A range of protein kinases and protein phosphatases are able to phosphorylate or dephosphorylate these sites in vitro. Some of these enzymes are able to regulate tyrosine hydroxylase phosphorylation in situ and in vivo but the identity of the kinases and phosphatases is incomplete, especially for physiologically relevant stimuli. The stoichiometry of tyrosine hydroxylase phosphorylation in situ and in vivo is low. The phosphorylation of tyrosine hydroxylase at Ser40 increases the enzyme's activity in vitro, in situ and in vivo. Phosphorylation at Ser31 also increases the activity but to a much lesser extent than for Ser40 phosphorylation. The phosphorylation of tyrosine hydroxylase at Ser19 or Ser8 has no direct effect on tyrosine hydroxylase activity. Hierarchical phosphorylation of tyrosine hydroxylase occurs both in vitro and in situ, whereby the phosphorylation at Ser19 increases the rate of Ser40 phosphorylation leading to an increase in enzyme activity. Hierarchical phosphorylation depends on the state of the substrate providing a novel form of control of tyrosine hydroxylase activation.
Krüppel-associated box (KRAB)-associated co-repressor (KAP-1) Ser-473 phosphorylation regulates heterochromatin protein 1β (HP1-β) mobilization and DNA repair in heterochromatin
Publisher: Elsevier BV
Date: 08-2012
In-Hospital 3D Printed Scaphoid Prosthesis Using Medical-Grade Polyetheretherketone (PEEK) Biomaterial
Publisher: Hindawi Limited
Date: 11-01-2021
DOI: 10.1155/2021/1301028
Abstract: Recently, three-dimensional (3D) printing has become increasingly popular in the medical sector for the production of anatomical biomodels, surgical guides, and prosthetics. With the availability of low-cost desktop 3D printers and affordable materials, the in-house or point-of-care manufacturing of biomodels and Class II medical devices has gained considerable attention in personalized medicine. Another projected development in medical 3D printing for personalized treatment is the in-house production of patient-specific implants (PSIs) for partial and total bone replacements made of medical-grade material such as polyetheretherketone (PEEK). We present the first in-hospital 3D printed scaphoid prosthesis using medical-grade PEEK with fused filament fabrication (FFF) 3D printing technology.
Cdk1/Erk2- and Plk1-dependent phosphorylation of a centrosome protein, Cep55, is required for its recruitment to midbody and cytokinesis
Publisher: Elsevier BV
Date: 10-2005
DOI: 10.1016/J.DEVCEL.2005.09.003
Abstract: Centrosomes in mammalian cells have recently been implicated in cytokinesis however, their role in this process is poorly defined. Here, we describe a human coiled-coil protein, Cep55 (centrosome protein 55 kDa), that localizes to the mother centriole during interphase. Despite its association with gamma-TuRC anchoring proteins CG-NAP and Kendrin, Cep55 is not required for microtubule nucleation. Upon mitotic entry, centrosome dissociation of Cep55 is triggered by Erk2/Cdk1-dependent phosphorylation at S425 and S428. Furthermore, Cep55 locates to the midbody and plays a role in cytokinesis, as its depletion by siRNA results in failure of this process. S425/428 phosphorylation is required for interaction with Plk1, enabling phosphorylation of Cep55 at S436. Cells expressing phosphorylation-deficient mutant forms of Cep55 undergo cytokinesis failure. These results highlight the centrosome as a site to organize phosphorylation of Cep55, enabling it to relocate to the midbody to function in mitotic exit and cytokinesis.
Label-Free Quantitation of Phosphopeptide Changes During Rat Sperm Capacitation
Publisher: American Chemical Society (ACS)
Date: 08-01-2010
DOI: 10.1021/PR900513D
Abstract: Before fertilization can occur, ejaculated mammalian spermatozoa must undergo a maturation process known as capacitation, which is dominated by post-translational modifications, particularly phosphorylation. Despite its biological importance, characterization of those proteins targeted for phosphorylation during capacitation remains ill-defined. Here, we report the isolation and purification of 288 phosphorylated peptides from rat spermatozoa using titanium dioxide columns in combination with nanoflow mass spectrometry. This equated to 120 identified phosphorylated proteins present in pure populations of spermatozoa. The MS survey scans of replicate titanium dioxide eluates, derived from both noncapacitated and capacitated sperm lysates, were then compared in silico using a virtual 2D PAGE format and DeCyderMS software. This analysis found 15 differentially phosphorylated proteins during capacitation. Included in this list were sperm qualifiers such as Izumo, a known sperm-oocyte fusion protein. To demonstrate that this label-free quantitative approach to phosphoprotein analysis was viable, we measured the enzymatic activity of 5'-nucleotidase, the phosphorylation status of which changed during capacitation. The results revealed, for the first time, that 5'-nucleotidase activity is up-regulated as sperm capacitate. This change, together with the other protein identifications reported in this study, constitute important new leads in elucidating the biochemical mechanisms by which spermatozoa attain a capacitated state.
Involvement of novel autophosphorylation sites in ATM activation
Publisher: Wiley
Date: 13-07-2006
The in Vivo Phosphorylation Sites of Rat Brain Dynamin I
Publisher: Elsevier BV
Date: 05-2007
Small Molecule Inhibitors of Dynamin I GTPase Activity: Development of Dimeric Tyrphostins
Publisher: American Chemical Society (ACS)
Date: 29-10-2005
DOI: 10.1021/JM040208L
Abstract: Dynamin I is a GTPase enzyme required for endocytosis and is an excellent target for the design of potential endocytosis inhibitors. Screening of a library of tyrphostins, in our laboratory, against the GTPase activity of dynamin I gave rise to a microM potent lead, 2-cyano-3-(3,4-dihydroxyphenyl)thioacrylamide (1, IC50 70 microM). Our initial investigations suggested that only the dimeric form of 1 displayed dynamin I GTPase inhibitory activity. Subsequent synthetic iterations were based on dimeric analogues and afforded a number of small molecules, low microM potent, inhibitors of dynamin I GTPase, in particular, symmetrical analogues with a minimum of two free phenolic -OHs: catechol-acrylamide (9) (IC50= 5.1 +/- 0.6 microM), its 3,4,5-trihydroxy congener (10) (IC50= 1.7 +/- 0.2 microM), and the corresponding 3-methyl ether (11) (IC50= 9 +/- 3 microM). Increasing the length of the central alkyl spacer from ethyl to propyl (22-24) afforded essentially identical activity with IC50's of 1.7 +/- 0.2, 1.7 +/- 0.2, and 5 +/- 1 microM, respectively. No decrease in activity was noted until the introduction of a hexyl spacer. Our studies highlight the requirement for two free amido NHs with neither the mono-N-methyl (86) nor the bis-N-methyl (87) analogues inhibiting dynamin I GTPase. A similar effect was noted for the removal of the nitrile moieties. However, modest potency was observed with the corresponding ester analogues of 9-11: ethyl ester (90), propyl ester (91), and butyl ester (92), with IC50's of 42 +/- 3, 38 +/- 2, and 61 +/- 2 microM, respectively. Our studies reveal the most potent and promising dynamin I GTPase inhibitor in this series as (22), which is also known as BisT.
The temporal profile of activity-dependent presynaptic phospho-signalling reveals long-lasting patterns of poststimulus regulation
Publisher: Public Library of Science (PLoS)
Date: 03-2019
Site-Specific Glycan-Peptide Analysis for Determination of N-Glycoproteome Heterogeneity
Publisher: American Chemical Society (ACS)
Date: 11-2013
DOI: 10.1021/PR400783J
Abstract: A combined glycomics and glycoproteomics strategy was developed for the site-specific analysis of N-linked glycosylation heterogeneity from a complex mammalian protein mixture. Initially, global characterization of the N-glycome was performed using porous graphitized carbon liquid chromatography-tandem mass spectrometry (PGC-LC-MS/MS) and the data used to create an N-glycan modification database. In the next step, tryptic glycopeptides were enriched using zwitterionic hydrophilic interaction liquid chromatography (Zic-HILIC) and fractionated by reversed-phase liquid chromatography (RPLC pH 7.9). The resulting fractions were each separated into two equal aliquots. The first set of aliquots were treated with peptide-N-glycosidase F (PNGase F) to remove N-glycans and the former N-glycopeptides analyzed by nano-RPLC-MS/MS (pH 2.7) and identified by Mascot database search. This enabled the creation of a glycopeptide-centric concatenated database for each fraction. The second set of aliquots was analyzed directly by nanoRPLC-MS/MS (pH 2.7), employing fragmentation by CID and HCD. The assignment of glycan compositions to peptide sequences was achieved by searching the N-glycopeptide HCD MS/MS spectra against the glycopeptide-centric concatenated databases employing the N-glycan modification database. CID spectra were used to assign glycan structures identified in the glycomic analysis to peptide sequences. This multidimensional approach allowed confident identification of 863 unique intact N-linked glycopeptides from 161 rat brain glycoproteins.
A Novel Method for the Simultaneous Enrichment, Identification, and Quantification of Phosphopeptides and Sialylated Glycopeptides Applied to a Temporal Profile of Mouse Brain Development
Publisher: Elsevier BV
Date: 11-2012
Syndapin I is the phosphorylation-regulated dynamin I partner in synaptic vesicle endocytosis.
Publisher: Springer Science and Business Media LLC
Date: 30-04-2006
DOI: 10.1038/NN1695
Phosphorylation of Ser19 Alters the Conformation of Tyrosine Hydroxylase to Increase the Rate of Phosphorylation of Ser40
Publisher: Elsevier BV
Date: 11-2001
Related Organisations
University Of Applied Sciences And Arts Northwestern Switzerland
Location: Switzerland
Related Funding Activities
Discovery Projects - Grant ID: DP0987706
Start Date: 03-2009
End Date: 03-2013
Amount: $300,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE100100150
Start Date: 2010
End Date: 12-2012
Amount: $500,000.00
Funder: Australian Research Council
View Funded Activity