title: Structural Fine-Tuning of MIT-Interacting Motif 2 (MIM2) and Allosteric Regulation of ESCRT-III by Vps4 in Yeast.
abstract: The endosomal sorting complex required for transport (ESCRT) facilitates roles in membrane remodeling, such as multivesicular body biogenesis, enveloped virus budding and cell division. In yeast, Vps4 plays a crucial role in intraluminal vesicle formation by disassembling ESCRT proteins. Vps4 is recruited by ESCRT-III proteins to the endosomal membrane through the interaction between the microtubule interacting and trafficking (MIT) domain of Vps4 and the C-terminal MIT-interacting motif (MIM) of ESCRT-III proteins. Here, we have determined the crystal structure of Vps4-MIT in a complex with Vps20, a member of ESCRT-III, and revealed that Vps20 adopts a unique MIM2 conformation. Based on structural comparisons with other known MIM2s, we have refined the consensus sequence of MIM2. We have shown that another ESCRT-III protein, Ist1, binds to Vps4-MIT via its C-terminal MIM1 with higher affinity than Vps2, but lacks MIM2 by surface plasmon resonance. Surprisingly, the Ist1 MIM1 competed with the MIM2 of Vfa1, a regulator of Vps4, for binding to Vps4-MIT, even though these MIMs bind in non-overlapping sites on the MIT. These findings provide insight into the allosteric recognition of MIMs of ESCRT-III by Vps4 and also the regulation of ESCRT machinery at the last step of membrane remodeling.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Rieko
authors.initials: R
authors.lastname: Kojima
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan. Electronic address: obita@pha.u-toyama.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Obita
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Onoue
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Mineyuki
authors.initials: M
authors.lastname: Mizuguchi
mesh_terms: D000494:Allosteric Regulation / Q000502:physiology*; D000595:Amino Acid Sequence; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding / Q000502:physiology; D000072417:Protein Domains / Q000502:physiology; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D015003:Yeasts / Q000378:metabolism*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D005656:Fungal Proteins
keywords: AAA+ ATPase; Ist1; MIT domain; Vfa1; Vps20