8d4f
beta-Arf1 mediated dimeric assembly of AP-1, Arf1, Nef complex within lattice on MHC-I lipopeptide incorporated wide(r) membrane tubesbeta-Arf1 mediated dimeric assembly of AP-1, Arf1, Nef complex within lattice on MHC-I lipopeptide incorporated wide(r) membrane tubes
Structural highlights
FunctionAP1G1_MOUSE Subunit of clathrin-associated adaptor protein complex 1 that plays a role in protein sorting in the late-Golgi/trans-Golgi network (TGN) and/or endosomes. The AP complexes mediate both the recruitment of clathrin to membranes and the recognition of sorting signals within the cytosolic tails of transmembrane cargo molecules. Publication Abstract from PubMedThe adaptor protein (AP) complexes not only form the inner layer of clathrin coats but also have clathrin-independent roles in membrane traffic whose mechanisms are unknown. HIV-1 Nef hijacks AP-1 to sequester major histocompatibility complex class I (MHC-I), evading immune detection. We found that AP-1:Arf1:Nef:MHC-I forms a coat on tubulated membranes without clathrin and determined its structure. The coat assembles via Arf1 dimer interfaces. AP-1-positive tubules are enriched in cells upon clathrin knockdown. Nef localizes preferentially to AP-1 tubules in cells, explaining how Nef sequesters MHC-I. Coat contact residues are conserved across Arf isoforms and the Arf-dependent AP complexes AP-1, AP-3, and AP-4. Thus, AP complexes can self-assemble with Arf1 into tubular coats without clathrin or other scaffolding factors. The AP-1:Arf1 coat defines the structural basis of a broader class of tubulovesicular membrane coats as an intermediate in clathrin vesicle formation from internal membranes and as an MHC-I sequestration mechanism in HIV-1 infection. Self-assembly and structure of a clathrin-independent AP-1:Arf1 tubular membrane coat.,Hooy RM, Iwamoto Y, Tudorica DA, Ren X, Hurley JH Sci Adv. 2022 Oct 21;8(42):eadd3914. doi: 10.1126/sciadv.add3914. Epub 2022 Oct, 21. PMID:36269825[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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