2k3w
NMR structure of VPS4A-MIT-CHMP6
Structural highlights
FunctionVPS4A_HUMAN Involved in late steps of the endosomal multivesicular bodies (MVB) pathway. Recognizes membrane-associated ESCRT-III assemblies and catalyzes their disassembly, possibly in combination with membrane fission. Redistributes the ESCRT-III components to the cytoplasm for further rounds of MVB sorting. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. In conjunction with the ESCRT machinery also appears to function in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis and enveloped virus budding (HIV-1 and other lentiviruses). Involved in cytokinesis.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe ESCRT pathway mediates membrane remodeling during enveloped virus budding, cytokinesis, and intralumenal endosomal vesicle formation. Late in the pathway, a subset of membrane-associated ESCRT-III proteins display terminal amphipathic "MIM1" helices that bind and recruit VPS4 ATPases via their MIT domains. We now report that VPS4 MIT domains also bind a second, "MIM2" motif found in a different subset of ESCRT-III subunits. The solution structure of the VPS4 MIT-CHMP6 MIM2 complex revealed that MIM2 elements bind in extended conformations along the groove between the first and third helices of the MIT domain. Mutations that block VPS4 MIT-MIM2 interactions inhibit VPS4 recruitment, lysosomal protein targeting, and HIV-1 budding. MIT-MIM2 interactions appear to be common throughout the ESCRT pathway and possibly elsewhere, and we suggest how these interactions could contribute to a mechanism in which VPS4 and ESCRT-III proteins function together to constrict the necks of budding vesicles. Two distinct modes of ESCRT-III recognition are required for VPS4 functions in lysosomal protein targeting and HIV-1 budding.,Kieffer C, Skalicky JJ, Morita E, De Domenico I, Ward DM, Kaplan J, Sundquist WI Dev Cell. 2008 Jul;15(1):62-73. PMID:18606141[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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