Stuart Bloor
Laboratory of Molecular Biology
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Publication
Featured researches published by Stuart Bloor.
Nature Immunology | 2009
Teresa L. M. Thurston; Grigory Ryzhakov; Stuart Bloor; Natalia von Muhlinen; Felix Randow
Cell-autonomous innate immune responses against bacteria attempting to colonize the cytosol of mammalian cells are incompletely understood. Polyubiquitylated proteins can accumulate on the surface of such bacteria, and bacterial growth is restricted by Tank-binding kinase (TBK1). Here we show that NDP52, not previously known to contribute to innate immunity, recognizes ubiquitin-coated Salmonella enterica in human cells and, by binding the adaptor proteins Nap1 and Sintbad, recruits TBK1. Knockdown of NDP52 and TBK1 facilitated bacterial proliferation and increased the number of cells containing ubiquitin-coated salmonella. NDP52 also recruited LC3, an autophagosomal marker, and knockdown of NDP52 impaired autophagy of salmonella. We conclude that human cells utilize the ubiquitin system and NDP52 to activate autophagy against bacteria attempting to colonize their cytosol.
Cell | 2009
Simin Rahighi; Fumiyo Ikeda; Masato Kawasaki; Masato Akutsu; Nobuhiro Suzuki; Ryuichi Kato; Tobias Kensche; Tamami Uejima; Stuart Bloor; David Komander; Felix Randow; Soichi Wakatsuki; Ivan Dikic
Activation of nuclear factor-kappaB (NF-kappaB), a key mediator of inducible transcription in immunity, requires binding of NF-kappaB essential modulator (NEMO) to ubiquitinated substrates. Here, we report that the UBAN (ubiquitin binding in ABIN and NEMO) motif of NEMO selectively binds linear (head-to-tail) ubiquitin chains. Crystal structures of the UBAN motif revealed a parallel coiled-coil dimer that formed a heterotetrameric complex with two linear diubiquitin molecules. The UBAN dimer contacted all four ubiquitin moieties, and the integrity of each binding site was required for efficient NF-kappaB activation. Binding occurred via a surface on the proximal ubiquitin moiety and the canonical Ile44 surface on the distal one, thereby providing specificity for linear chain recognition. Residues of NEMO involved in binding linear ubiquitin chains are required for NF-kappaB activation by TNF-alpha and other agonists, providing an explanation for the detrimental effect of NEMO mutations in patients suffering from X-linked ectodermal dysplasia and immunodeficiency.
Molecular Cell | 2012
Natalia von Muhlinen; Masato Akutsu; Benjamin J. Ravenhill; Ágnes Foeglein; Stuart Bloor; Trevor J. Rutherford; Stefan M. V. Freund; David Komander; Felix Randow
Summary Autophagy protects cellular homeostasis by capturing cytosolic components and invading pathogens for lysosomal degradation. Autophagy receptors target cargo to autophagy by binding ATG8 on autophagosomal membranes. The expansion of the ATG8 family in higher eukaryotes suggests that specific interactions with autophagy receptors facilitate differential cargo handling. However, selective interactors of ATG8 orthologs are unknown. Here we show that the selectivity of the autophagy receptor NDP52 for LC3C is crucial for innate immunity since cells lacking either protein cannot protect their cytoplasm against Salmonella. LC3C is required for antibacterial autophagy because in its absence the remaining ATG8 orthologs do not support efficient antibacterial autophagy. Structural analysis revealed that the selectivity of NDP52 for LC3C is conferred by a noncanonical LIR, in which lack of an aromatic residue is balanced by LC3C-specific interactions. Our report illustrates that specificity in the interaction between autophagy receptors and autophagy machinery is of functional importance to execute selective autophagy.
Proceedings of the National Academy of Sciences of the United States of America | 2008
Stuart Bloor; Grigory Ryzhakov; Sebastian A. Wagner; P. J. G. Butler; D. L. Smith; Rebekka Krumbach; Ivan Dikic; Felix Randow
NF-κB activation occurs upon degradation of its inhibitor I-κB and requires prior phosphorylation of the inhibitor by I-κB kinase (IKK). Activity of IKK is governed by its noncatalytic subunit IKKγ. Signaling defects due to missense mutations in IKKγ have been correlated to its inability to either become ubiquitylated or bind ubiquitin noncovalently. Because the relative contribution of these events to signaling had remained unknown, we have studied mutations in the coil-zipper (CoZi) domain of IKKγ that either impair signaling or cause constitutive NF-κB activity. Certain signaling-deficient alleles neither bound ubiquitin nor were they ubiquitylated by TRAF6. Introducing an activating mutation into those signaling-impaired alleles restored their ubiquitylation and created mutants constitutively activating NF-κB without repairing the ubiquitin-binding defect. Constitutive activity therefore arises downstream of ubiquitin binding but upstream of ubiquitylation. Such constitutive activity reveals a signal-processing function for IKKγ beyond that of a mere ubiquitin-binding adaptor. We propose that this signal processing may involve homophilic CoZi interactions as suggested by the enhanced affinity of CoZi domains from constitutively active IKKγ.
Nature | 2017
Marian L. Burr; Christina E Sparbier; Yih-Chih Chan; James Colin Williamson; Katherine Woods; Paul A. Beavis; Enid Y. N. Lam; Melissa A. Henderson; Charles C. Bell; Sabine Stolzenburg; Omer Gilan; Stuart Bloor; Tahereh Noori; David W. Morgens; Michael C. Bassik; Paul Neeson; Andreas Behren; Phillip K. Darcy; Sarah-Jane Dawson; Ilia Voskoboinik; Joseph A. Trapani; Jonathan Cebon; Paul J. Lehner; Mark A. Dawson
Cancer cells exploit the expression of the programmed death-1 (PD-1) ligand 1 (PD-L1) to subvert T-cell-mediated immunosurveillance. The success of therapies that disrupt PD-L1-mediated tumour tolerance has highlighted the need to understand the molecular regulation of PD-L1 expression. Here we identify the uncharacterized protein CMTM6 as a critical regulator of PD-L1 in a broad range of cancer cells, by using a genome-wide CRISPR–Cas9 screen. CMTM6 is a ubiquitously expressed protein that binds PD-L1 and maintains its cell surface expression. CMTM6 is not required for PD-L1 maturation but co-localizes with PD-L1 at the plasma membrane and in recycling endosomes, where it prevents PD-L1 from being targeted for lysosome-mediated degradation. Using a quantitative approach to profile the entire plasma membrane proteome, we find that CMTM6 displays specificity for PD-L1. Notably, CMTM6 depletion decreases PD-L1 without compromising cell surface expression of MHC class I. CMTM6 depletion, via the reduction of PD-L1, significantly alleviates the suppression of tumour-specific T cell activity in vitro and in vivo. These findings provide insights into the biology of PD-L1 regulation, identify a previously unrecognized master regulator of this critical immune checkpoint and highlight a potential therapeutic target to overcome immune evasion by tumour cells.
Proceedings of the National Academy of Sciences of the United States of America | 2010
Stuart Bloor; Jonathan Maelfait; Rebekka Krumbach; Rudi Beyaert; Felix Randow
The envelope glycoprotein of vesicular stomatitis virus (VSV-G) enables viral entry into hosts as distant as insects and vertebrates. Because of its ability to support infection of most, if not all, human cell types VSV-G is used in viral vectors for gene therapy. However, neither the receptor nor any specific host factor for VSV-G has been identified. Here we demonstrate that infection with VSV and innate immunity via Toll-like receptors (TLRs) require a shared component, the endoplasmic reticulum chaperone gp96. Cells without gp96 or with catalytically inactive gp96 do not bind VSV-G. The ubiquitous expression of gp96 is therefore essential for the remarkably broad tropism of VSV-G. Cells deficient in gp96 also lack functional TLRs, which suggests that pathogen-driven pressure for TLR-mediated immunity maintains the broad host range of VSV-G by positively selecting for the ubiquitous expression of gp96.
Journal of Cell Biology | 2014
Jessica M. Boname; Stuart Bloor; Michal P. Wandel; James A. Nathan; Robin Antrobus; Kevin S. Dingwell; Teresa L. M. Thurston; Duncan L. Smith; James C. Smith; Felix Randow; Paul J. Lehner
Intramembrane proteolytic cleavage by signal peptide peptidase is required for the turnover of some ER-resident, tail-anchored membrane proteins.
Journal of Proteome Research | 2012
Michael P. Weekes; Robin Antrobus; Suzanne Talbot; Simon Hör; Nikol Simecek; Duncan L. Smith; Stuart Bloor; Felix Randow; Paul J. Lehner
The endoplasmic reticulum chaperone gp96 is required for the cell surface expression of a narrow range of proteins, including toll-like receptors (TLRs) and integrins. To identify a more comprehensive repertoire of proteins whose cell surface expression is dependent on gp96, we developed plasma membrane profiling (PMP), a technique that combines SILAC labeling with selective cell surface aminooxy-biotinylation. This approach allowed us to compare the relative abundance of plasma membrane (PM) proteins on gp96-deficient versus gp96-reconstituted murine pre-B cells. Analysis of unfractionated tryptic peptides initially identified 113 PM proteins, which extended to 706 PM proteins using peptide prefractionation. We confirmed a requirement for gp96 in the cell surface expression of certain TLRs and integrins and found a marked decrease in cell surface expression of four members of the extended LDL receptor family (LDLR, LRP6, Sorl1 and LRP8) in the absence of gp96. Other novel gp96 client proteins included CD180/Ly86, important in the B-cell response to lipopolysaccharide. We highlight common structural motifs in these client proteins that may be recognized by gp96, including the beta-propeller and leucine-rich repeat. This study therefore identifies the extended LDL receptor family as an important new family of proteins whose cell surface expression is regulated by gp96.
The EMBO Journal | 2016
Teresa L. M. Thurston; Keith B. Boyle; Mark D. Allen; Benjamin J. Ravenhill; Maryia Karpiyevich; Stuart Bloor; Annie Kaul; Jessica Noad; Ágnes Foeglein; Sophie A. Matthews; David Komander; Mark Bycroft; Felix Randow
Mammalian cells deploy autophagy to defend their cytosol against bacterial invaders. Anti‐bacterial autophagy relies on the core autophagy machinery, cargo receptors, and “eat‐me” signals such as galectin‐8 and ubiquitin that label bacteria as autophagy cargo. Anti‐bacterial autophagy also requires the kinase TBK1, whose role in autophagy has remained enigmatic. Here we show that recruitment of WIPI2, itself essential for anti‐bacterial autophagy, is dependent on the localization of catalytically active TBK1 to the vicinity of cytosolic bacteria. Experimental manipulation of TBK1 recruitment revealed that engagement of TBK1 with any of a variety of Salmonella‐associated “eat‐me” signals, including host‐derived glycans and K48‐ and K63‐linked ubiquitin chains, suffices to restrict bacterial proliferation. Promiscuity in recruiting TBK1 via independent signals may buffer TBK1 functionality from potential bacterial antagonism and thus be of evolutionary advantage to the host.
Autophagy | 2013
Natalia von Muhlinen; Masato Akutsu; Benjamin J. Ravenhill; Ágnes Foeglein; Stuart Bloor; Trevor J. Rutherford; Stefan M. V. Freund; David Komander; Felix Randow
Autophagy defends the mammalian cytosol against bacterial invasion. Efficient bacterial engulfment by autophagy requires cargo receptors that bind (a) homolog(s) of the ubiquitin-like protein Atg8 on the phagophore membrane. The existence of multiple ATG8 orthologs in higher eukaryotes suggests that they may perform distinct functions. However, no specific role has been assigned to any mammalian ATG8 ortholog. We recently discovered that the autophagy receptor CALCOCO2/NDP52, which detects cytosol-invading Salmonella enterica serovar Typhimurium (S. Typhimurium), preferentially binds LC3C. The CALCOCO2/NDP52-LC3C interaction is essential for cell-autonomous immunity against cytosol-exposed S. Typhimurium, because cells lacking either protein fail to target bacteria into the autophagy pathway. The selectivity of CALCOCO2/NDP52 for LC3C is determined by a novel LC3C interacting region (CLIR), in which the lack of the key aromatic residue of canonical LIRs is compensated by LC3C-specific interactions. Our findings provide a new layer of regulation to selective autophagy, suggesting that specific interactions between autophagy receptors and the ATG8 orthologs are of biological importance.