Structural basis of Ist1 function and Ist1-Did2 interaction in the multivesicular body pathway and cytokinesis.

Mol Biol Cell

Life Sciences Institute and Department of Biological Chemistry, Department of Molecular and Integrative Physiology, Medical School, University of Michigan, Ann Arbor, MI 48109, USA.

Published: August 2009


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Article Abstract

The 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.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2719569PMC
http://dx.doi.org/10.1091/mbc.e09-05-0403DOI Listing

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