title: Drosophila p115 is required for Cdk1 activation and G2/M cell cycle transition.
abstract: Golgi complex inheritance and its relationship with the cell cycle are central in cell biology. Golgi matrix proteins, known as golgins, are one of the components that underlie the shape and functionality of this organelle. In mammalian cells, golgins are phosphorylated during mitosis to allow fragmentation of the Golgi ribbon and they also participate in spindle dynamics; both processes are required for cell cycle progression. Little is known about the function of golgins during mitosis in metazoans in vivo. This is particularly significant in Drosophila, in which the Golgi architecture is distributed in numerous units scattered throughout the cytoplasm, in contrast with mammalian cells. We examined the function of the ER/cis-Golgi golgin p115 during the proliferative phase of the Drosophila wing imaginal disc. Knockdown of p115 decreased tissue size. This phenotype was not caused by programmed cell death or cell size reductions, but by a reduction in the final cell number due to an accumulation of cells at the G2/M transition. This phenomenon frequently allows mitotic bypass and re-replication of DNA. These outcomes are similar to those observed following the partial loss of function of positive regulators of Cdk1 in Drosophila. In agreement with this, Cdk1 activation was reduced upon p115 knockdown. Interestingly, these phenotypes were fully rescued by Cdk1 overexpression and partially rescued by Myt1 depletion, but not by String (also known as Cdc25) overexpression. Additionally, we confirmed the physical interaction between p115 and Cdk1, suggesting that the formation of a complex where both proteins are present is essential for the full activation of Cdk1 and thus the correct progression of mitosis in proliferating tissues.
authors.affiliation: FONDAP Center for Genome Regulation, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Santiago, Chile. Electronic address: conibar@waksman.rutgers.edu.
authors.forename: Consuelo
authors.initials: C
authors.lastname: Ibar
authors.affiliation: FONDAP Center for Genome Regulation, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Santiago, Chile. Electronic address: alglavic@uchile.cl.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Glavic
mesh_terms: D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D049109:Cell Proliferation; D029721:Drosophila Proteins / Q000378:metabolism* / Q000502:physiology*; D004331:Drosophila melanogaster / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development; D004789:Enzyme Activation; D005089:Exocytosis; D005260:Female; D059565:G2 Phase Cell Cycle Checkpoints; D015870:Gene Expression; D000077614:Golgi Matrix Proteins; D059566:M Phase Cell Cycle Checkpoints; D008565:Membrane Proteins / Q000502:physiology*; D014921:Wings, Animal / Q000254:growth & development
chemical_list: D029721:Drosophila Proteins; D000077614:Golgi Matrix Proteins; D008565:Membrane Proteins; C477241:p115 protein, Drosophila; D016203:CDC2 Protein Kinase; C000601753:Cdk1 protein, Drosophila
keywords: Cdk1; Cell cycle; Drosophila; Golgi; p115