title: AIP1/WDR1 supports mitotic cell rounding.
abstract: The actin cytoskeleton plays a fundamental role in configuring cell shapes and movements. Actin interacting protein 1 (AIP1)/tryptophan-aspartate-repeat protein 1 (WDR1) induces actin severing and disassembly cooperating with ADF/cofilin. We found that mitotic cell flattening but not rounding was manifested by suppression of AIP1/WDR1 in cells. This mitotic cell flattening was not due to any changes in phosphorylation and distribution of cofilin in cells. We carried out a direct observation of actin filament severing/disassembly assay and found that phosphorylated cofilin still somewhat severs/disassembles actin filaments and that AIP1/WDR1 effaces this in vitro. We suggest that the phosphorylation of ADF/cofilin will be insufficient to completely inhibit actin turnover during mitosis, and that AIP1/WDR1 could abort the severing/disassembly activity somewhat still carried out due to phosphorylated ADF/cofilin. This mechanism could be required to induce cell morphologic changes, especially mitotic cell rounding.
authors.affiliation: Division of Molecular Pathology, Department of Pathology, National University Corporation, Ehime University School of Medicine, Toh-on, Ehime 791-0295, Japan.
authors.forename: Taketsugu
authors.initials: T
authors.lastname: Fujibuchi
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Abe
authors.forename: Takashi
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Imai
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kamei
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Murase
authors.forename: Norifumi
authors.initials: N
authors.lastname: Ueda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shigemoto
authors.forename: Haruyasu
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kito
mesh_terms: D051339:Actin Depolymerizing Factors; D000199:Actins / Q000378:metabolism; D002453:Cell Cycle; D045744:Cell Line, Tumor; D048430:Cell Shape; D020090:Chromosome Segregation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D008840:Microfilament Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D004791:Enzyme Inhibitors; D008840:Microfilament Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C118067:WDR1 protein, human; D020742:rhoA GTP-Binding Protein