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

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.
Mesh Terms:
Amino Acid Sequence, Binding Sites, Crystallography, X-Ray, Cytokinesis, Endosomal Sorting Complexes Required for Transport, Membrane Proteins, Microscopy, Confocal, Microscopy, Fluorescence, Models, Molecular, Molecular Sequence Data, Multivesicular Bodies, Protein Binding, Protein Structure, Secondary, Protein Structure, Tertiary, Protein Transport, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Surface Plasmon Resonance, Vesicular Transport Proteins
Mol. Biol. Cell
Date: Aug. 01, 2009
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