title: The Schizosaccharomyces pombe aurora-related kinase Ark1 interacts with the inner centromere protein Pic1 and mediates chromosome segregation and cytokinesis.
abstract: The chromosomal passenger proteins aurora-B, survivin, and inner centromere protein (INCENP) have been implicated in coordinating chromosome segregation with cell division. This work describes the interplay between aurora, survivin, and INCENP orthologs in the fission yeast Schizosaccharomyces pombe and defines their roles in regulating chromosome segregation and cytokinesis. We describe the cloning and characterization of the aurora-related kinase gene ark1(+), demonstrating that it is an essential gene required for sister chromatid segregation. Cells lacking Ark1p exhibit the cut phenotype, DNA fragmentation, and other defects in chromosome segregation. Overexpression of a kinase-defective version of Ark1, Ark1-K147R, inhibits cytokinesis, with cells exhibiting an elongated, multiseptate phenotype. Ark1p interacts physically and/or genetically with the survivin and INCENP orthologs Bir1p and Pic1p. We identified Pic1p in a two-hybrid screen for Ark1-K147R interacting partners and went on to map domains in both proteins that mediate their binding. Pic1p residues 925-972 are necessary and sufficient for Ark1p binding, which occurs through the kinase domain. As with Ark1-K147R, overexpression of Ark1p-binding fragments of Pic1p leads to multiseptate phenotypes. We also provide evidence that the dominant-negative effect of Ark1-K147R requires Pic1p binding, indicating that the formation of Ark1p-Pic1p complexes is required for the execution of cytokinesis.
authors.affiliation: Molecular and Cell Biology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037.
authors.forename: Joel D
authors.initials: JD
authors.lastname: Leverson
authors.forename: Han-kuei
authors.initials: HK
authors.lastname: Huang
authors.forename: Susan L
authors.initials: SL
authors.lastname: Forsburg
authors.forename: Tony
authors.initials: T
authors.lastname: Hunter
mesh_terms: D064127:Aurora Kinases; D002455:Cell Division; D002503:Centromere / Q000378:metabolism; D020090:Chromosome Segregation; D002875:Chromosomes / Q000378:metabolism; D003001:Cloning, Molecular; D005799:Genes, Dominant; D005982:Glutathione Transferase / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010766:Phosphorylation; D015221:Potassium Channels / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins; D013997:Time Factors; D020798:Two-Hybrid System Techniques
chemical_list: D015221:Potassium Channels; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D029702:Schizosaccharomyces pombe Proteins; D005982:Glutathione Transferase; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; C576962:ark1 protein, S pombe