title: Polo kinase mediates the phosphorylation and cellular localization of Nuf/FIP3, a Rab11 effector.
abstract: Animal cytokinesis involves both actin-myosin-based contraction and vesicle-mediated membrane addition. In many cell types, including earlyDrosophilaembryos, Nuf/FIP3, a Rab11 effector, mediates recycling endosome (RE)-based vesicle delivery to the cytokinesis furrow. Nuf exhibits a cell cycle-regulated concentration at the centrosome that is accompanied by dramatic changes in its phosphorylation state. Here we demonstrate that maximal phosphorylation of Nuf occurs at prophase, when centrosome-associated Nuf disperses throughout the cytoplasm. Accordingly, ectopic Cdk1 activation results in immediate Nuf dispersal from the centrosome. Screening of candidate kinases reveals a specific, dosage-sensitive interaction between Nuf and Polo with respect to Nuf-mediated furrow formation. Inhibiting Polo activity results in Nuf underphosphorylation and prolonged centrosome association. In vitro, Polo directly binds and is required for Nuf phosphorylation at Ser-225 and Thr-227, matching previous in vivo-mapped phosphorylation sites.These results demonstrate a role for Polo kinase in directly mediating Nuf cell cycle-dependent localization.
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064.
authors.forename: Lotti
authors.initials: L
authors.lastname: Brose
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064.|Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.
authors.forename: Justin
authors.initials: J
authors.lastname: Crest
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064 wtsulliv@ucsc.edu ltao2@hawaii.edu.|Department of Biology, University of Hawaii, Hilo, HI 96720.
authors.forename: Li
authors.initials: L
authors.lastname: Tao
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064 wtsulliv@ucsc.edu ltao2@hawaii.edu.
authors.forename: William
authors.initials: W
authors.lastname: Sullivan
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle; D002455:Cell Division; D018385:Centrosome / Q000378:metabolism; D048749:Cytokinesis / Q000235:genetics; D004330:Drosophila / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: D000199:Actins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; C111662:nuf protein, Drosophila; C072004:polo protein, Drosophila; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; C000601753:Cdk1 protein, Drosophila; D020691:rab GTP-Binding Proteins