4u7e
From Proteopedia
The crystal structure of the complex of LIP5 NTD and IST1 MIM
Structural highlights
Function[VTA1_HUMAN] Involved in the endosomal multivesicular bodies (MVB) pathway. 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. Thought to be a cofactor of VPS4A/B, which catalyzes disassembles membrane-associated ESCRT-III assemblies. Involved in the sorting and down-regulation of EGFR (By similarity). Involved in HIV-1 budding.[1] [IST1_HUMAN] Proposed to be involved in specific functions of the ESCRT machinery. Is required for efficient abscission during cytokinesis, but not for HIV-1 budding. The involvement in the MVB pathway is not established. Involved in recruiting VPS4A and/or VPS4B to the midbody of dividing cells.[2] [3] Publication Abstract from PubMedThe endosomal sorting complex required for transport (ESCRT) machinery is responsible for membrane remodeling in a number of biological processes including multi-vesicular body biogenesis, cytokinesis, and enveloped virus budding. In mammalian cells, efficient abscission during cytokinesis requires proper function of the ESCRT-III protein IST1, which binds to the Microtubule Interacting and Trafficking (MIT) domains of VPS4, LIP5, and Spartin via its C-terminal MIT-Interacting Motif (MIM). Here, we studied the molecular interactions between IST1 and the three MIT domain-containing proteins to understand the structural basis that governs pairwise MIT-MIM interaction. Crystal structures of the three molecular complexes revealed that IST1 binds to the MIT domains of VPS4, LIP5 and Spartin using two different mechanisms (MIM1 mode versus MIM3 mode). Structural comparison revealed that structural features in both MIT and MIM contribute to determine the specific binding mechanism. Within the IST1 MIM sequence, two phenylalanine residues were shown to be important in discriminating MIM1 versus MIM3 binding. These observations enabled us to deduce a preliminary binding code, which we applied to provide CHMP2A, a protein that normally only binds the MIT domain in the MIM1 mode, the additional ability to bind the MIT domain of Spartin in the MIM3 mode. Distinct Mechanisms of Recognizing Endosomal Sorting Complex Required for Transport (ESCRT)-III Protein IST1 by Different Microtubule Interacting and Trafficking (MIT) Domains.,Guo EZ, Xu Z J Biol Chem. 2015 Feb 5. pii: jbc.M114.607903. PMID:25657007[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Guo, E Z | Xu, Z | Complex | Mim1 | Protein transport
