title: Structural basis of Ist1 function and Ist1-Did2 interaction in the multivesicular body pathway and cytokinesis.
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.
authors.affiliation: Life Sciences Institute and Department of Biological Chemistry, Department of Molecular and Integrative Physiology, Medical School, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Junyu
authors.initials: J
authors.lastname: Xiao
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Chen
authors.forename: Brian A
authors.initials: BA
authors.lastname: Davies
authors.forename: Alan R
authors.initials: AR
authors.lastname: Saltiel
authors.forename: David J
authors.initials: DJ
authors.lastname: Katzmann
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D018360:Crystallography, X-Ray; D048749:Cytokinesis; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D057146:Multivesicular Bodies / Q000378:metabolism*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C511158:DID2 protein, S cerevisiae; D056827:Endosomal Sorting Complexes Required for Transport; C532818:Ist1 protein, S cerevisiae; C492709:MIM1 protein, S cerevisiae; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins