title: Atypical protein kinase C regulates primary dendrite specification of cerebellar Purkinje cells by localizing Golgi apparatus.
abstract: Neurons have highly polarized structures that determine what parts of the soma elaborate the axon and dendrites. However, little is known about the mechanisms that establish neuronal polarity in vivo. Cerebellar Purkinje cells extend a single primary dendrite from the soma that ramifies into a highly branched dendritic arbor. We used the zebrafish cerebellum to investigate the mechanisms by which Purkinje cells acquire these characteristics. To examine dendritic morphogenesis in individual Purkinje cells, we marked the cell membrane using a Purkinje cell-specific promoter to drive membrane-targeted fluorescent proteins. We found that zebrafish Purkinje cells initially extend multiple neurites from the soma and subsequently retract all but one, which becomes the primary dendrite. In addition, the Golgi apparatus specifically locates to the root of the primary dendrite, and its localization is already established in immature Purkinje cells that have multiple neurites. Inhibiting secretory trafficking through the Golgi apparatus reduces dendritic growth, suggesting that the Golgi apparatus is involved in the dendritic morphogenesis. We also demonstrated that in a mutant of an atypical protein kinase C (aPKC), Prkci, Purkinje cells retain multiple primary dendrites and show disrupted localization of the Golgi apparatus. Furthermore, a mosaic inhibition of Prkci in Purkinje cells recapitulates the aPKC mutant phenotype. These results suggest that the aPKC cell autonomously controls the Golgi localization and thereby regulates the specification of the primary dendrite of Purkinje cells.
authors.affiliation: Laboratory for Vertebrate Axis Formation, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Tanabe
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kani
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Bae
authors.forename: Takaya
authors.initials: T
authors.lastname: Abe
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hibi
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002531:Cerebellum / Q000254:growth & development* / Q000378:metabolism; D003712:Dendrites / Q000502:physiology*; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000502:physiology*; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D011493:Protein Kinase C / Q000235:genetics / Q000502:physiology*; D011689:Purkinje Cells / Q000166:cytology*; D015027:Zebrafish; D000099293:Protein Kinase C-lambda
chemical_list: D007527:Isoenzymes; D011493:Protein Kinase C; D000099293:Protein Kinase C-lambda