ORCID Profile
0000-0003-0862-0012
Current Organisations
City, University of London
,
University of Sydney
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Gene Expression (incl. Microarray and other genome-wide approaches) | Structural Biology (incl. Macromolecular Modelling) | Genetics
Expanding Knowledge in the Biological Sciences | Expanding Knowledge in the Medical and Health Sciences |
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CS00548K
Abstract: This tutorial review provides an introduction to a wide range of methods used to quantify protein interactions, outlining their strengths, weaknesses and requirements.
Publisher: Wiley
Date: 08-12-2020
DOI: 10.1002/PRO.4006
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.CELREP.2018.10.085
Abstract: Some epigenetic modifications are inherited from one generation to the next, providing a potential mechanism for the inheritance of environmentally acquired traits. Transgenerational inheritance of RNAi phenotypes in Caenorhabditis elegans provides an excellent model to study this phenomenon, and although studies have implicated both chromatin modifications and small RNA pathways in heritable silencing, their relative contributions remain unclear. Here, we demonstrate that the putative histone methyltransferases SET-25 and SET-32 are required for establishment of a transgenerational silencing signal but not for long-term maintenance of this signal between subsequent generations, suggesting that transgenerational epigenetic inheritance is a multi-step process with distinct genetic requirements for establishment and maintenance of heritable silencing. Furthermore, small RNA sequencing reveals that the abundance of secondary siRNAs (thought to be the effector molecules of heritable silencing) does not correlate with silencing phenotypes. Together, our results suggest that the current mechanistic models of epigenetic inheritance are incomplete.
Publisher: Maad Rayan Publishing Company
Date: 28-01-2018
DOI: 10.15171/BI.2018.19
Publisher: Elsevier BV
Date: 12-2021
Publisher: Research Square Platform LLC
Date: 06-01-2022
DOI: 10.21203/RS.3.RS-1172665/V1
Abstract: Although ACE2 is the primary receptor for SARS-CoV-2 infection, a systematic assessment of factors controlling SARS-CoV-2 host interactions has not been described. Here we used whole genome CRISPR activation to identify host factors controlling SARS-CoV-2 Spike binding. The top hit was a Toll-like receptor-related cell surface receptor called leucine-rich repeat-containing protein 15 (LRRC15). LRRC15 expression was sufficient to promote SARS-CoV-2 Spike binding where it forms a cell surface complex with LRRC15 but does not support infection. Instead, LRRC15 functioned as a negative receptor suppressing both pseudotyped and live SARS-CoV-2 infection. LRRC15 is expressed in collagen-producing lung myofibroblasts where it can sequester virus and reduce infection in trans. Mechanistically LRRC15 is regulated by TGF-β, where moderate LRRC15 expression drives collagen production but high levels suppress it, revealing a novel lung fibrosis feedback circuit. Overall, LRRC15 is a master regulator of SARS-CoV-2, suppressing infection and controlling collagen production associated with “long-haul” COVID-19.
Publisher: Wiley
Date: 18-05-2016
DOI: 10.1002/PRO.2943
Publisher: Wiley
Date: 02-2016
Abstract: Arginine methylation on nonhistone proteins is associated with a number of cellular processes including RNA splicing, protein localization, and the formation of protein complexes. In this manuscript, Saccharomyces cerevisiae proteome arrays carrying 4228 proteins were used with an antimethylarginine antibody to first identify 88 putatively arginine-methylated proteins. By treating the arrays with recombinant arginine methyltransferase Hmt1, 42 proteins were found to be possible substrates of this enzyme. Analysis of the putative arginine-methylated proteins revealed that they were predominantly nuclear or nucleolar in localization, consistent with the localization of Hmt1. Many are involved in known methylarginine-associated functions, such as RNA processing and ribonucleoprotein complex biogenesis, yet others are of newer classes, namely RNA/DNA helicases and tRNA-associated proteins. Using ex vivo methylation and MS/MS, a set of 12 proteins (Brr1, Dia4, Hts1, Mpp10, Mrd1, Nug1, Prp43, Rpa43, Rrp43, Spp381, Utp4, and Npl3), including the RNA helicase Prp43 and tRNA ligases Dia4 and Hts1, were all validated as Hmt1 substrates. Interestingly, the majority of these also had human orthologs, or family members, that have been documented elsewhere to carry arginine methylation. These results confirm arginine methylation as a widespread modification and Hmt1 as the major arginine methyltransferase in the S. cerevisiae cell.
Publisher: Elsevier BV
Date: 2016
Publisher: Wiley
Date: 31-07-2021
DOI: 10.1111/FEBS.16112
Abstract: The combination of four proteins and their paralogues including MBD2/3, GATAD2A/B, CDK2AP1 and CHD3/4/5, which we refer to as the MGCC module, form the chromatin remodelling module of the nucleosome remodelling and deacetylase (NuRD) complex. To date, mechanisms by which the MGCC module acquires paralogue‐specific function and specificity have not been addressed. Understanding the protein–protein interaction (PPI) network of the MGCC subunits is essential for defining underlying mechanisms of gene regulation. Therefore, using pulldown followed by mass spectrometry analysis (PD‐MS), we report a proteome‐wide interaction network of the MGCC module in a paralogue‐specific manner. Our data also demonstrate that the disordered C‐terminal region of CHD3/4/5 is a gateway to incorporate remodelling activity into both ChAHP (CHD4, ADNP, HP1γ) and NuRD complexes in a mutually exclusive manner. We define a short aggregation‐prone region (APR) within the C‐terminal segment of GATAD2B that is essential for the interaction of CHD4 and CDK2AP1 with the NuRD complex. Finally, we also report an association of CDK2AP1 with the nuclear receptor co‐repressor (NCOR) complex. Overall, this study provides insight into the possible mechanisms through which the MGCC module can achieve specificity and erse biological functions.
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.BMC.2015.01.023
Abstract: We have developed an approach for directly isolating an intact multi-protein chromatin remodeling complex from mammalian cell extracts using synthetic peptide affinity reagent 4. FOG1(1-15), a short peptide sequence known to target subunits of the nucleosome remodeling and deacetylase (NuRD) complex, was joined via a 35-atom hydrophilic linker to the StreptagII peptide. Loading this peptide onto Streptactin beads enabled capture of the intact NuRD complex from MEL cell nuclear extract. Gentle biotin elution yielded the desired intact complex free of significant contaminants and in a form that was catalytically competent in a nucleosome remodeling assay. The efficiency of 4 in isolating the NuRD complex was comparable to other reported methods utilising recombinantly produced GST-FOG1(1-45).
Publisher: Wiley
Date: 25-02-2013
Abstract: The original bacterial two-hybrid system is widely used but does not permit the study of interactions regulated by PTMs. Here, we have built a conditional two-hybrid (C2H) system, in which bait and prey proteins can be co-expressed in the presence of a modifying enzyme such as a methyltransferase, acetyltransferase, or kinase. Any increase or decrease in interaction due to the modification of the proteins can be measured by an increased or decreased level of reporter gene expression. The C2H system is comprised of eight new vectors based on the Novagen Duet co-expression plasmids. These vectors include two multiple cloning sites per vector as well as a hexahistidine tag or S-tag to aid in purification, if desired. We demonstrate the use of the C2H system to study the dimerization of the yeast protein Npl3, which is increased when methylated by the methyltransferase Hmt1.
Publisher: Cold Spring Harbor Laboratory
Date: 17-02-2020
DOI: 10.1101/2020.02.17.951822
Abstract: The Nucleosome Remodeling and Deacetylase (NuRD) complex is essential for development in complex animals but has been refractory to biochemical analysis. We present the first integrated analysis of the architecture of the native mammalian NuRD complex, combining quantitative mass spectrometry, covalent cross-linking, protein biochemistry and electron microscopy. NuRD is built around a 2:2:4 pseudo-symmetric deacetylase module comprising MTA, HDAC and RBBP subunits. This module interacts asymmetrically with a remodeling module comprising one copy each of MBD, GATAD2 and CHD subunits. The previously enigmatic GATAD2 controls the asymmetry of the complex and directly recruits the ATP-dependent CHD remodeler. Unexpectedly, the MTA-MBD interaction acts as a point of functional switching. The transcriptional regulator PWWP2A modulates NuRD assembly by competing directly with MBD for binding to the MTA-HDAC-RBBP subcomplex, forming a ‘moonlighting’ PWWP2A-MTA-HDAC-RBBP complex that likely directs deacetylase activity to PWWP2A target sites. Taken together, our data describe the overall architecture of the intact NuRD complex and reveal aspects of its structural dynamics and functional plasticity.
Publisher: MDPI AG
Date: 18-11-2020
DOI: 10.3390/MOLECULES25225392
Abstract: Proteases catalyse irreversible posttranslational modifications that often alter a biological function of the substrate. The protease dipeptidyl peptidase 4 (DPP4) is a pharmacological target in type 2 diabetes therapy primarily because it inactivates glucagon-like protein-1. DPP4 also has roles in steatosis, insulin resistance, cancers and inflammatory and fibrotic diseases. In addition, DPP4 binds to the spike protein of the MERS virus, causing it to be the human cell surface receptor for that virus. DPP4 has been identified as a potential binding target of SARS-CoV-2 spike protein, so this question requires experimental investigation. Understanding protein structure and function requires reliable protocols for production and purification. We developed such strategies for baculovirus generated soluble recombinant human DPP4 (residues 29–766) produced in insect cells. Purification used differential ammonium sulphate precipitation, hydrophobic interaction chromatography, dye affinity chromatography in series with immobilised metal affinity chromatography, and ion-exchange chromatography. The binding affinities of DPP4 to the SARS-CoV-2 full-length spike protein and its receptor-binding domain (RBD) were measured using surface plasmon resonance and ELISA. This optimised DPP4 purification procedure yielded 1 to 1.8 mg of pure fully active soluble DPP4 protein per litre of insect cell culture with specific activity U/mg, indicative of high purity. No specific binding between DPP4 and CoV-2 spike protein was detected by surface plasmon resonance or ELISA. In summary, a procedure for high purity high yield soluble human DPP4 was achieved and used to show that, unlike MERS, SARS-CoV-2 does not bind human DPP4.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2020
DOI: 10.1038/S41467-020-15183-2
Abstract: Chromatin remodellers hydrolyse ATP to move nucleosomal DNA against histone octamers. The mechanism, however, is only partially resolved, and it is unclear if it is conserved among the four remodeller families. Here we use single-molecule assays to examine the mechanism of action of CHD4, which is part of the least well understood family. We demonstrate that the binding energy for CHD4-nucleosome complex formation—even in the absence of nucleotide—triggers significant conformational changes in DNA at the entry side, effectively priming the system for remodelling. During remodelling, flanking DNA enters the nucleosome in a continuous, gradual manner but exits in concerted 4–6 base-pair steps. This decoupling of entry- and exit-side translocation suggests that ATP-driven movement of entry-side DNA builds up strain inside the nucleosome that is subsequently released at the exit side by DNA expulsion. Based on our work and previous studies, we propose a mechanism for nucleosome sliding.
Publisher: Proceedings of the National Academy of Sciences
Date: 18-04-2023
Abstract: Significant recent advances in structural biology, particularly in the field of cryoelectron microscopy, have dramatically expanded our ability to create structural models of proteins and protein complexes. However, many proteins remain refractory to these approaches because of their low abundance, low stability, or—in the case of complexes—simply not having yet been analyzed. Here, we demonstrate the power of using cross-linking mass spectrometry (XL-MS) for the high-throughput experimental assessment of the structures of proteins and protein complexes. This included those produced by high-resolution but in vitro experimental data, as well as in silico predictions based on amino acid sequence alone. We present the largest XL-MS dataset to date, describing 28,910 unique residue pairs captured across 4,084 unique human proteins and 2,110 unique protein–protein interactions. We show that models of proteins and their complexes predicted by AlphaFold2, and inspired and corroborated by the XL-MS data, offer opportunities to deeply mine the structural proteome and interactome and reveal mechanisms underlying protein structure and function.
Publisher: American Chemical Society (ACS)
Date: 21-02-2014
DOI: 10.1021/PR401251K
Abstract: Post-translational lysine methylation is well established as a regulator of histone activity however, it is emerging that these modifications are also likely to play extensive roles outside of the histone code. Here we obtain new insights into non-histone lysine methylation and protein lysine methyltransferase (PKMT) activity by elucidating absolute stoichiometries of lysine methylation, using mass spectrometry and absolute quantification (AQUA), in wild-type and 5 PKMT gene deletion strains of Saccharomyces cerevisiae. By analyzing 8 sites of methylation in 3 non-histone proteins, elongation factor 1-α (EF1α), elongation factor 2 (EF2), and 60S ribosomal protein L42-A/B (Rpl42ab), we find that production of preferred methylation states on in idual lysine residues is commonplace and likely occurs through processive PKMT activity, Class I PKMTs can be associated with processive methylation, lysine residues are selectively methylated by specific PKMTs, and lysine methylation exists over a broad range of stoichiometries. Together these findings suggest that specific sites and forms of lysine methylation may play specialized roles in the regulation of non-histone protein activity. We also uncover new relationships between two proteins previously characterized as PKMTs, SEE1 and EFM1, in EF1α methylation and show that past characterizations of EFM1 as having direct PKMT activity may require reinterpretation.
Publisher: Wiley
Date: 22-11-2012
DOI: 10.1111/FEBS.12039
Abstract: Recent research has implicated arginine methylation as a major regulator of cellular processes, including transcription, translation, nucleocytoplasmic transport, signalling, DNA repair, RNA processing and splicing. Arginine methylation is evolutionarily conserved, and it is now thought that it may rival other post-translational modifications such as phosphorylation in terms of its occurrence in the proteome. In addition, multiple recent ex les demonstrate an exciting new theme: the interplay between methylation and other post-translational modifications such as phosphorylation. In this review, we summarize our current understanding of arginine methylation and the recent advances made, with a focus on the lower eukaryote Saccharomyces cerevisiae. We cover the types of methylated proteins, their responsible methyltransferases, where and how the effects of arginine methylation are seen in the cell, and, finally, discuss the conservation of the biological function of methylarginines between S. cerevisiae and mammals.
Publisher: American Chemical Society (ACS)
Date: 27-05-2021
Publisher: American Chemical Society (ACS)
Date: 07-06-2012
DOI: 10.1007/S13361-012-0417-8
Abstract: When localizing protein post-translational modifications (PTMs) using liquid-chromatography (LC)-tandem mass spectrometry (MS/MS), existing implementations are limited by inefficient selection of PTM-carrying peptides for MS/MS, particularly when PTM site occupancy is sub-stoichiometric. The present contribution describes a method by which peptides carrying specific PTMs of interest-in this study, methylarginines-may be selectively targeted for MS/MS: peptide features are extracted from high mass accuracy single-stage MS data, searched against theoretical PTM-carrying peptide masses, and matching features are subjected to targeted data acquisition LC-MS/MS. Using trypsin digested Saccharomyces cerevisiae Npl3, in which evidence is presented for 18 methylarginine sites-17 of which fall within a glycine-arginine-rich (GAR) domain spanning <120 amino acids-it is shown that this approach outperforms conventional data dependent acquisition (DDA): when applied to a complex protein mixture featuring in vivo methylated Npl3, 95% more (P=0.030) methylarginine-carrying peptides are selected for MS/MS than DDA, leading to an 86% increase (P=0.044) in the number of methylated peptides producing Mascot ion scores ≥20 following electron-transfer dissociation (ETD). Notably, significantly more low abundance arginine methylated peptides (maximum ion intensities <6×10(4) cps) are selected for MS/MS using this approach relative to DDA (50% more in a digest of purified in vitro methylated Npl3). It is also demonstrated that relative to collision-induced dissociation (CID), ETD facilitates a 586% increase (P=0.016) in average Mascot ion scores of methylarginine-carrying peptides. The present PTM-specific targeted data acquisition approach, though described using methylarginine, is applicable to any ionizable PTM of known mass.
Publisher: IEEE
Date: 11-2016
Publisher: Springer Science and Business Media LLC
Date: 06-12-2022
DOI: 10.1038/S41467-022-35002-0
Abstract: CHD4 is an essential, widely conserved ATP-dependent translocase that is also a broad tumour dependency. In common with other SF2-family chromatin remodelling enzymes, it alters chromatin accessibility by repositioning histone octamers. Besides the helicase and adjacent tandem chromodomains and PHD domains, CHD4 features 1000 residues of N- and C-terminal sequence with unknown structure and function. We demonstrate that these regions regulate CHD4 activity through different mechanisms. An N-terminal intrinsically disordered region (IDR) promotes remodelling integrity in a manner that depends on the composition but not sequence of the IDR. The C-terminal region harbours an auto-inhibitory region that contacts the helicase domain. Auto-inhibition is relieved by a previously unrecognized C-terminal SANT-SLIDE domain split by ~150 residues of disordered sequence, most likely by binding of this domain to substrate DNA. Our data shed light on CHD4 regulation and reveal strong mechanistic commonality between CHD family members, as well as with ISWI-family remodellers.
Publisher: Cold Spring Harbor Laboratory
Date: 27-09-2018
DOI: 10.1101/426163
Abstract: East London Genes & Health (ELGH) is a large scale, community genomics and health study (to date ,000 volunteers target 100,000 volunteers). ELGH was set up in 2015 to gain deeper understanding of health and disease, and underlying genetic influences, in British-Bangladeshi and British-Pakistani people living in east London. ELGH prioritises studies in areas important to, and identified by, the community it represents. Current priorities include cardiometabolic diseases and mental illness, these being of notably high prevalence and severity. However studies in any scientific area are possible, subject to community advisory group and ethical approval. ELGH combines health data science (using linked UK National Health Service (NHS) electronic health record data) with exome sequencing and SNP array genotyping to elucidate the genetic influence on health and disease, including the contribution from high rates of parental relatedness on rare genetic variation and homozygosity (autozygosity), in two understudied ethnic groups. Linkage to longitudinal health record data enables both retrospective and prospective analyses. Through Stage 2 studies, ELGH offers researchers the opportunity to undertake recall-by-genotype and/or recall-by-phenotype studies on volunteers. Sub-cohort, trial-within-cohort, and other study designs are possible. ELGH is a fully collaborative, open access resource, open to academic and life sciences industry scientific research partners.
Publisher: Elsevier BV
Date: 08-2009
DOI: 10.1016/J.BBAPAP.2009.03.016
Abstract: RNase E is an essential enzyme that catalyses RNA processing. Microdomains which mediate interactions between RNase E and other members of the degradosome have been defined. To further elucidate the role of these microdomains in molecular interactions, we studied RNase E from Vibrio angustum S14. Protein sequence analysis revealed that its C-terminal half is less conserved and structured than its N-terminal half. Within this structural disorder, however, exist five small regions of predicted structural propensity. Four are similar to interaction-mediating microdomains identified in other RNase E proteins the fifth did not correspond to any known functional motif. The function of the V. angustum S14 enolase-binding microdomain was confirmed using bacterial two-hybrid analysis, demonstrating the conserved function of this microdomain for the first time in a species other than Escherichia coli. Further, PNPase in V. angustum S14 was shown to interact with the last 80 amino acids of the C-terminal region of RNase E. This raises the possibility that PNPase interacts with the small ordered region at residues 1026-1041. The role of RNase E as a hub protein and the implications of microdomain-mediated interactions in relation to specificity and function are discussed.
Publisher: Cold Spring Harbor Laboratory
Date: 31-05-2018
DOI: 10.1101/335232
Abstract: Apolipoprotein-D is a 25 kDa glycosylated member of the lipocalin family that folds into an eight-stranded β-barrel with a single adjacent α-helix. Apolipoprotein-D specifically binds a range of small hydrophobic ligands such as progesterone and arachidonic acid and has an antioxidant function that is in part due to the reduction of peroxidised lipids by methionine-93. Therefore, apolipoprotein-D plays multiple roles throughout the body and is protective in Alzheimer’s disease, where apolipoprotein-D overexpression reduces the amyloid-β burden in Alzheimer’s disease mouse models. Oligomerisation is a common feature of lipocalins that can influence ligand binding. The native structure of apolipoprotein-D, however, has not been conclusively defined. Apolipoprotein-D is generally described as a monomeric protein, although it dimerises when reducing peroxidised lipids. Here, we investigated the native structure of apolipoprotein-D derived from plasma, breast cyst fluid (BCF) and cerebrospinal fluid. In plasma and cerebrospinal fluid, apolipoprotein-D was present in high-molecular weight complexes, potentially in association with lipoproteins. In contrast, apolipoprotein-D in BCF formed distinct oligomeric species. We assessed apolipoprotein-D oligomerisation using native apolipoprotein-D purified from BCF and a suite of complementary methods, including multi-angle laser light scattering, analytical ultracentrifugation and small-angle X-ray scattering. Our analyses showed that apolipoprotein-D predominantly forms a ∽95 to ∽100 kDa tetramer. Small-angle X-ray scattering analysis confirmed these findings and provided a structural model for apolipoprotein-D tetramer. These data indicate apolipoprotein-D rarely exists as a free monomer under physiological conditions and provide insights into novel native structures of apolipoprotein-D and into oligomerisation behaviour in the lipocalin family.
Publisher: American Society for Clinical Investigation
Date: 03-04-2023
DOI: 10.1172/JCI162685
Publisher: Elsevier BV
Date: 12-2020
Publisher: Wiley
Date: 12-2007
DOI: 10.1111/DEWB_210.X
Publisher: Cold Spring Harbor Laboratory
Date: 25-11-2021
DOI: 10.1101/2021.11.25.469965
Abstract: The Nucleosome Remodeling and Deacetylase (NuRD) complex is a chromatin-modifying assembly that regulates gene expression and DNA damage repair. Despite its importance, limited structural information describing the complete NuRD complex is available and a detailed understanding of its mechanism is therefore lacking. Drawing on information from SEC-MALLS, DIA-MS, XLMS, negative-stain EM, X-ray crystallography, NMR spectroscopy, secondary structure predictions and homology models, we applied Bayesian integrative structure determination to investigate the molecular architecture of three NuRD sub-complexes: MTA1-HDAC1-RBBP4 (MHR), MTA1 N -HDAC1-MBD3 GATAD2CC (MHM), and MTA1-HDAC1-RBBP4-MBD3-GATAD2A (NuDe). The integrative structures were corroborated by examining independent crosslinks, cryo-EM maps, biochemical assays, known cancer-associated mutations, and structure predictions from AlphaFold. The robustness of the models was assessed by jack-knifing. Localization of the full-length MBD3, which connects the deacetylase and chromatin remodeling modules in NuRD, has not previously been possible our models indicate two different locations for MBD3, suggesting a mechanism by which MBD3 in the presence of GATAD2A asymmetrically bridges the two modules in NuRD. Further, our models uncovered three previously unrecognized subunit interfaces in NuDe: HDAC1 C -MTA1 BAH , MTA1 BAH -MBD3 MBD , and HDAC1 60-100 -MBD3 MBD . Our approach also allowed us to localize regions of unknown structure, such as HDAC1 C and MBD3 IDR , thereby resulting in the most complete and robustly cross-validated structural characterization of these NuRD sub-complexes so far.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.JSB.2018.05.012
Abstract: Apolipoprotein-D is a 25 kDa glycosylated member of the lipocalin family that folds into an eight-stranded β-barrel with a single adjacent α-helix. Apolipoprotein-D specifically binds a range of small hydrophobic ligands such as progesterone and arachidonic acid and has an antioxidant function that is in part due to the reduction of peroxidised lipids by methionine-93. Therefore, apolipoprotein-D plays multiple roles throughout the body and is protective in Alzheimer's disease, where apolipoprotein-D overexpression reduces the amyloid-β burden in Alzheimer's disease mouse models. Oligomerisation is a common feature of lipocalins that can influence ligand binding. The native structure of apolipoprotein-D, however, has not been conclusively defined. Apolipoprotein-D is generally described as a monomeric protein, although it dimerises when reducing peroxidised lipids. Here, we investigated the native structure of apolipoprotein-D derived from plasma, breast cyst fluid (BCF) and cerebrospinal fluid. In plasma and cerebrospinal fluid, apolipoprotein-D was present in high-molecular weight complexes, potentially in association with lipoproteins. In contrast, apolipoprotein-D in BCF formed distinct oligomeric species. We assessed apolipoprotein-D oligomerisation using native apolipoprotein-D purified from BCF and a suite of complementary methods, including multi-angle laser light scattering, analytical ultracentrifugation and small-angle X-ray scattering. Our analyses showed that apolipoprotein-D predominantly forms a ∼95 to ∼100 kDa tetramer. Small-angle X-ray scattering analysis confirmed these findings and provided a structural model for apolipoprotein-D tetramer. These data indicate apolipoprotein-D rarely exists as a free monomer under physiological conditions and provide insights into novel native structures of apolipoprotein-D and into oligomerisation behaviour in the lipocalin family.
Publisher: Oxford University Press (OUP)
Date: 07-2016
DOI: 10.1093/NAR/GKW590
Publisher: Proceedings of the National Academy of Sciences
Date: 12-10-2020
Abstract: Large DNA-encoded libraries of cyclic peptides are emerging as powerful sources of molecules to tackle challenging drug targets. The structural and functional ersity contained within these libraries is, however, little explored. Here we demonstrate that one such library contains members that use unexpectedly erse mechanisms to recognize the same surface on the same target proteins with high affinity and specificity. This range of binding modes is much larger than observed in natural ligands of the same proteins, demonstrating the power and versatility of the technology. Our data also reveal opportunities for the development of more sophisticated approaches to achieving specificity when trying to selectively target one member of a family of closely related proteins.
Publisher: Wiley
Date: 15-06-2006
Publisher: Cold Spring Harbor Laboratory
Date: 10-11-2021
DOI: 10.1101/2021.11.09.467981
Abstract: Although ACE2 is the primary receptor for SARS-CoV-2 infection, a systematic assessment of host factors that regulate binding to SARS-CoV-2 spike protein has not been described. Here we use whole genome CRISPR activation to identify host factors controlling cellular interactions with SARS-CoV-2. Our top hit was a TLR -related cell surface receptor called leucine-rich repeat-containing protein 15 ( LRRC15 ). LRRC15 expression was sufficient to promote SARS-CoV-2 Spike binding where they form a cell surface complex. LRRC15 mRNA is expressed in human collagen-producing lung myofibroblasts and LRRC15 protein is induced in severe COVID-19 infection where it can be found lining the airways. Mechanistically, LRRC15 does not itself support SARS-CoV-2 infection, but fibroblasts expressing LRRC15 can suppress both pseudotyped and authentic SARS-CoV-2 infection in trans . Moreover, LRRC15 expression in fibroblasts suppresses collagen production and promotes expression of IFIT, OAS, and MX-family antiviral factors. Overall, LRRC15 is a novel SARS-CoV-2 spike-binding receptor that can help control viral load and regulate antiviral and antifibrotic transcriptional programs in the context of COVID-19 infection.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Elsevier BV
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 04-2000
DOI: 10.1007/BF03351234
Publisher: Proceedings of the National Academy of Sciences
Date: 03-02-2022
Abstract: Bloom syndrome complex (BS complex) is necessary for maintenance of genome stability and suppression of cancer-causing mutations. Composed of a helicase, a topoisomerase, and two scaffolds, the BS complex is implicated in several steps that ensure the high fidelity of DNA repair by recombination. One step, called “double Holliday junction dissolution,” ensures untangling of DNA at the conclusion of repair. Here, we used cross-link mass spectrometry to show how the BS complex assembles. Using biochemical reactions and cell complementation with mutant proteins, our results reveal an important role of helicase dimerization (and tight coupling of proteins within the complex) for double Holliday junction dissolution and genome stability.
Publisher: Springer Science and Business Media LLC
Date: 30-11-2021
DOI: 10.1038/S41541-021-00406-4
Abstract: Global control of COVID-19 requires broadly accessible vaccines that are effective against SARS-CoV-2 variants. In this report, we exploit the immunostimulatory properties of bacille Calmette-Guérin (BCG), the existing tuberculosis vaccine, to deliver a vaccination regimen with potent SARS-CoV-2-specific protective immunity. Combination of BCG with a stabilised, trimeric form of SARS-CoV-2 spike antigen promoted rapid development of virus-specific IgG antibodies in the blood of vaccinated mice, that was further augmented by the addition of alum. This vaccine formulation, BCG:CoVac, induced high-titre SARS-CoV-2 neutralising antibodies (NAbs) and Th1-biased cytokine release by vaccine-specific T cells, which correlated with the early emergence of T follicular helper cells in local lymph nodes and heightened levels of antigen-specific plasma B cells after vaccination. Vaccination of K18-hACE2 mice with a single dose of BCG:CoVac almost completely abrogated disease after SARS-CoV-2 challenge, with minimal inflammation and no detectable virus in the lungs of infected animals. Boosting BCG:CoVac-primed mice with a heterologous vaccine further increased SARS-CoV-2-specific antibody responses, which effectively neutralised B.1.1.7 and B.1.351 SARS-CoV-2 variants of concern. These findings demonstrate the potential for BCG-based vaccination to protect against major SARS-CoV-2 variants circulating globally.
Publisher: American Chemical Society (ACS)
Date: 13-08-2013
DOI: 10.1021/PR400556C
Abstract: Arginine methylation is a post-translational modification that has been implicated in a plethora of cellular processes. In the present manuscript, using two antimethylarginine antibodies and combinatorial deletion mutants of arginine methyltransferases, we found evidence of widespread arginine methylation in the Saccharomyces cerevisiae proteome. Immunoprecipitation was used for enrichment of methylarginine-containing proteins, which were identified via tandem mass spectrometry. From this, we identified a total of 90 proteins, of which 5 were previously known to be methylated. The proteins identified were involved in known methylarginine-associated biological functions such as RNA processing, nuclear transport, carbohydrate metabolic process, GMP biosynthetic process and protein folding. Through in vivo methylation by the incorporation of [3H]-methyl groups, we validated the methylation of 7 proteins (Ded1, Imd4, Lhp1, Nop1, Cdc11, Gus1, Pob3). By LC-MS/MS, we then confirmed a total of 15 novel methylarginine sites on 5 proteins (Ded1, Lhp1, Nop1, Pab1, and Ugp1). By examination of methylation on proteins from the triple knockout of methyltransferases Hmt1, Hsl7, Rmt2, we present evidence for the existence of additional unidentified arginine methyltransferases in the Saccharomyces cerevisiae proteome.
Publisher: Wiley
Date: 12-2010
DOI: 10.1111/J.1742-4658.2010.07934.X
Abstract: The RNA degradosome is built on the C-terminal half of ribonuclease E (RNase E) which shows high sequence variation, even amongst closely related species. This is intriguing given its central role in RNA processing and mRNA decay. Previously, we have identified RhlB (ATP-dependent DEAD-box RNA helicase)-binding, PNPase (polynucleotide phosphorylase)-binding and enolase-binding microdomains in the C-terminal half of Vibrio angustum S14 RNase E, and have shown through two-hybrid analysis that the PNPase and enolase-binding microdomains have protein-binding function. We suggest that the RhlB-binding, enolase-binding and PNPase-binding microdomains may be interchangeable between Escherichia coli and V. angustum S14 RNase E. In this study, we used two-hybrid techniques to show that the putative RhlB-binding microdomain can bind RhlB. We then used Blue Native-PAGE, a technique commonly employed in the separation of membrane protein complexes, in a study of the first of its kind to purify and analyse the RNA degradosome. We showed that the V. angustum S14 RNA degradosome comprises at least RNase E, RhlB, enolase and PNPase. Based on the results obtained from sequence analyses, two-hybrid assays, immunoprecipitation experiments and Blue Native-PAGE separation, we present a model for the V. angustum S14 RNA degradosome. We discuss the benefits of using Blue Native-PAGE as a tool to analyse the RNA degradosome, and the implications of microdomain-mediated RNase E interaction specificity.
Publisher: Wiley
Date: 13-11-2017
DOI: 10.1111/FEBS.14301
Publisher: American Chemical Society (ACS)
Date: 23-02-2021
Publisher: Wiley
Date: 19-03-2019
DOI: 10.1111/FEBS.14800
Abstract: The nucleosome remodelling and deacetylase complex (NuRD) is a widely conserved regulator of gene expression. The determination of the subunit composition of the complex and identification of its binding partners are important steps towards understanding its architecture and function. The question of how these properties of the complex vary across different cell types has not been addressed in detail to date. Here, we set up a two-step purification protocol coupled to liquid chromatography-tandem mass spectrometry to assess NuRD composition and interaction partners in three different cancer cell lines, using label-free intensity-based absolute quantification (iBAQ). Our data indicate that the stoichiometry of the NuRD complex is preserved across our three different cancer cell lines. In addition, our interactome data suggest ZNF219 and SLC25A5 as possible interaction partners of the complex. To corroborate this latter finding, in vitro and cell-based pull-down experiments were carried out. These experiments indicated that ZNF219 can interact with RBBP4, GATAD2A/B and chromodomain helicase DNA binding 4, whereas SLC25A5 might interact with MTA2 and GATAD2A.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.BBRC.2013.12.009
Abstract: Poly(A)-binding protein in mouse and man was recently found to be highly post-translationally modified. Here we analysed an ortholog of this protein, Pab1 from Saccharomyces cerevisiae, to assess the conservation and thus likely importance of these modifications. Pab1 showed the presence of six sites of methylated glutamate, five sites of lysine acetylation, and one phosphorylation of serine. Many modifications on Pab1 showed either complete conservation with those on human or mouse PABPC1, were present on nearby residues and/or were present in the same domain(s). The conservation of methylated glutamate, an unusual modification, was of particular note and suggests a conserved function. Comparison of methylated glutamate sites in human, mouse and yeast poly(A)-binding protein, along with methylation sites catalysed by CheR L-glutamyl protein methyltransferase from Salmonella typhimurium, revealed that the methylation of glutamate preferentially occurs in EE and DE motifs or other small regions of acidic amino acids. The conservation of methylated glutamate in the same protein between mouse, man and yeast suggests the presence of a eukaryotic l-glutamyl protein methyltransferase and that the modification is of functional significance.
Publisher: Elsevier BV
Date: 05-2018
Publisher: Cold Spring Harbor Laboratory
Date: 16-11-2022
DOI: 10.1101/2022.11.16.516813
Abstract: Significant recent advances in structural biology, particularly in the field of cryo-electron microscopy, have dramatically expanded our ability to create structural models of proteins and protein complexes. However, many proteins remain refractory to these approaches because of their low abundance, low stability or – in the case of complexes – simply not having yet been analysed. Here, we demonstrate the power of combining cross-linking mass spectrometry (XL-MS) with artificial intelligence-based structure prediction to discover and experimentally substantiate models for protein and protein complex structures at proteome scale. We present the deepest XL-MS dataset to date, describing 28,910 unique residue pairs captured across 4,084 unique human proteins and 2,110 unique protein-protein interactions. We show that integrative models of complexes driven by AlphaFold Multimer and inspired and corroborated by the XL-MS data offer new opportunities to deeply mine the structural proteome and interactome and reveal new mechanisms underlying protein structure and function.
Publisher: Wiley
Date: 26-08-2022
DOI: 10.1002/PRO.4387
Abstract: The nucleosome remodeling and deacetylase (NuRD) complex is a chromatin‐modifying assembly that regulates gene expression and DNA damage repair. Despite its importance, limited structural information describing the complete NuRD complex is available and a detailed understanding of its mechanism is therefore lacking. Drawing on information from SEC‐MALLS, DIA‐MS, XLMS, negative‐stain EM, X‐ray crystallography, NMR spectroscopy, secondary structure predictions, and homology models, we applied Bayesian integrative structure determination to investigate the molecular architecture of three NuRD sub‐complexes: MTA1‐HDAC1‐RBBP4, MTA1 N ‐HDAC1‐MBD3 GATAD2CC , and MTA1‐HDAC1‐RBBP4‐MBD3‐GATAD2A [nucleosome deacetylase (NuDe)]. The integrative structures were corroborated by examining independent crosslinks, cryo‐EM maps, biochemical assays, known cancer‐associated mutations, and structure predictions from AlphaFold. The robustness of the models was assessed by jack‐knifing. Localization of the full‐length MBD3, which connects the deacetylase and chromatin remodeling modules in NuRD, has not previously been possible our models indicate two different locations for MBD3, suggesting a mechanism by which MBD3 in the presence of GATAD2A asymmetrically bridges the two modules in NuRD. Further, our models uncovered three previously unrecognized subunit interfaces in NuDe: HDAC1 C ‐MTA1 BAH , MTA1 BAH ‐MBD3 MBD , and HDAC1 60–100 ‐MBD3 MBD . Our approach also allowed us to localize regions of unknown structure, such as HDAC1 C and MBD3 IDR , thereby resulting in the most complete and robustly cross‐validated structural characterization of these NuRD sub‐complexes so far.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2018
End Date: 12-2020
Amount: $598,198.00
Funder: Australian Research Council
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