title: Atypical protein kinase C controls sea urchin ciliogenesis.
abstract: The atypical protein kinase C (aPKC) is part of the conserved aPKC/PAR6/PAR3 protein complex, which regulates many cell polarity events, including the formation of a primary cilium at the apical surface of epithelial cells. Cilia are highly organized, conserved, microtubule-based structures involved in motility, sensory processes, signaling, and cell polarity. We examined the distribution and function of aPKC in the sea urchin embryo, which forms a swimming blastula covered with motile cilia. We found that in the early embryo aPKC is uniformly cortical and becomes excluded from the vegetal pole during unequal cleavages at the 8- to 64-cell stages. During the blastula and gastrula stages the kinase localizes at the base of cilia, forming a ring at the transition zone between the basal body and the elongating axoneme. A dose-dependent and reversible inhibition of aPKC results in mislocalization of the kinase, defective ciliogenesis, and lack of swimming. Thus, as in the primary cilium of differentiated mammalian cells, aPKC controls the growth of motile cilia in invertebrate embryos. We suggest that aPKC might function to phosphorylate kinesin and so activate the transport of intraflagellar vesicles.
authors.affiliation: Observatoire Océanologique, Biologie du Développement, Université Pierre et Marie Curie and CNRS, Villefranche-sur-Mer, France. pruliere@obs-vlfr.fr
authors.forename: Gérard
authors.initials: G
authors.lastname: Prulière
authors.forename: Jacky
authors.initials: J
authors.lastname: Cosson
authors.forename: Sandra
authors.initials: S
authors.lastname: Chevalier
authors.forename: Christian
authors.initials: C
authors.lastname: Sardet
authors.forename: Janet
authors.initials: J
authors.lastname: Chenevert
mesh_terms: D000818:Animals; D016764:Cell Polarity; D002923:Cilia / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D016547:Kinesins / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology; D008870:Microtubules / Q000378:metabolism; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012617:Sea Urchins / Q000196:embryology* / Q000378:metabolism*
chemical_list: D007211:Indoles; D008301:Maleimides; D020033:Protein Isoforms; D011493:Protein Kinase C; D016547:Kinesins; C088060:bisindolylmaleimide