title: Structural basis for Arf6-MKLP1 complex formation on the Flemming body responsible for cytokinesis.
abstract: A small GTPase, Arf6, is involved in cytokinesis by localizing to the Flemming body (the midbody). However, it remains unknown how Arf6 contributes to cytokinesis. Here, we demonstrate that Arf6 directly interacts with mitotic kinesin-like protein 1 (MKLP1), a Flemming body-localizing protein essential for cytokinesis. The crystal structure of the Arf6-MKLP1 complex reveals that MKLP1 forms a homodimer flanked by two Arf6 molecules, forming a 2:2 heterotetramer containing an extended β-sheet composed of 22 β-strands that spans the entire heterotetramer, suitable for interaction with a concave membrane surface at the cleavage furrow. We show that, during cytokinesis, Arf6 is first accumulated around the cleavage furrow and, prior to abscission, recruited onto the Flemming body via interaction with MKLP1. We also show by structure-based mutagenesis and siRNA-mediated knockdowns that the complex formation is required for completion of cytokinesis. A model based on these results suggests that the Arf6-MKLP1 complex plays a crucial role in cytokinesis by connecting the microtubule bundle and membranes at the cleavage plane.
authors.affiliation: Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Ibaraki, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Makyio
authors.forename: Minako
authors.initials: M
authors.lastname: Ohgi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Takei
authors.forename: Senye
authors.initials: S
authors.lastname: Takahashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takatsu
authors.forename: Yohei
authors.initials: Y
authors.lastname: Katoh
authors.forename: Ayako
authors.initials: A
authors.lastname: Hanai
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ueda
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Kanaho
authors.forename: Yong
authors.initials: Y
authors.lastname: Xie
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Shin
authors.forename: Hironari
authors.initials: H
authors.lastname: Kamikubo
authors.forename: Mikio
authors.initials: M
authors.lastname: Kataoka
authors.forename: Masato
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kato
authors.forename: Soichi
authors.initials: S
authors.lastname: Wakatsuki
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D018360:Crystallography, X-Ray; D048749:Cytokinesis; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding
chemical_list: D000089982:ADP-Ribosylation Factor 6; C092935:KIF23 protein, human; D008869:Microtubule-Associated Proteins; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human; C000715727:Arf6 protein, mouse