3ggz
From Proteopedia
Crystal Structure of S.cerevisiae Ist1 N-terminal domain in complex with Did2 MIM motif
Structural highlights
Function[IST1_YEAST] Involved in a late step in sorting of cargo proteins of the multivesicular body (MVB) for incorporation into intralumenal vesicles. The lumenal sequestrated membrane proteins are targeted into the vacuole after fusion of the endosome with the vacuole. Regulates the recruitment of VPS4 to the ESCRT-III complex, probably in conjunction with DID2, and VPS4 catalyzes the disassembly of the ESCRT-III complex.[1] [2] [DID2_YEAST] Class E VPS protein implicated in concentration and sorting of cargo proteins of the multivesicular body (MVB) for incorporation into intralumenal vesicles. The lumenal sequestrated membrane proteins will be targeted into the vacuole after fusion of the endosome with the vacuole. Probably acts as a peripherally associated component of the ESCRT-III complex, which appears to be critical for late steps in MVB sorting, such as membrane invagination and final cargo sorting and recruits late-acting components of the sorting machinery. The MVB pathway requires the sequential function of ESCRT-O, -I,-II and -III complex assemblies. Regulates the membrane association of VPS4. Can stimulate VPS4 ATPase activity directly or via VTA1.[3] [4] [5] [6] [7] [8] [9] 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 machinery functions in several important eukaryotic cellular processes. The AAA-ATPase Vps4 catalyzes disassembly of the ESCRT-III complex and may regulate membrane deformation and vesicle scission as well. Ist1 was proposed to be a regulator of Vps4, but its mechanism of action was unclear. The crystal structure of the N-terminal domain of Ist1 (Ist1NTD) reveals an ESCRT-III subunit-like fold, implicating Ist1 as a divergent ESCRT-III family member. Ist1NTD specifically binds to the ESCRT-III subunit Did2, and cocrystallization of Ist1NTD with a Did2 fragment shows that Ist1 interacts with the Did2 C-terminal MIM1 (MIT-interacting motif 1) via a novel MIM-binding structural motif. This arrangement indicates a mechanism for intermolecular ESCRT-III subunit association and may also suggest one form of ESCRT-III subunit autoinhibition via intramolecular interaction. Structural basis of Ist1 function and Ist1-Did2 interaction in the multivesicular body pathway and cytokinesis.,Xiao J, Chen XW, Davies BA, Saltiel AR, Katzmann DJ, Xu Z Mol Biol Cell. 2009 Aug;20(15):3514-24. Epub 2009 May 28. PMID:19477918[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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