Schizosaccharomyces pombe NIMA-related kinase, Fin1, regulates spindle formation and an affinity of Polo for the SPB.
The Aspergillus nidulans protein kinase NIMA regulates mitotic commitment, while the human and Xenopus equivalents influence centrosome function. Two recessive, temperature-sensitive mutations in the Schizosaccharomyces pombe NIMA homologue, Fin1, blocked spindle formation at 37 degrees C. One of the two spindle pole bodies (SPBs) failed to nucleate microtubules. This phenotype was reduced by accelerating mitotic commitment through genetic inhibition of Wee1 or activation of either Cdc25 or Cdc2. Polo kinase (Plo1) normally associates with the SPB of mitotic, but not interphase cells. cut12.s11 is a dominant mutation in an SPB component that both suppresses cdc25 mutants and promotes Plo1 association with the interphase SPB. Both cut12.s11 phenotypes were abolished by removing Fin1 function. Elevating Fin1 levels promoted Plo1 recruitment to the interphase SPB of wild-type cells and reduced the severity of the cdc25.22 phenotype. These data are consistent with Fin1 regulating Plo1 function during mitotic commitment. The fin1 mitotic commitment and spindle phenotypes resemble distinct nimA phenotypes in different systems and suggest that the function of this family of kinases may be conserved across species.
Grallert
Agnes
A
Paterson Institute for Cancer Research, Wilmslow Road, Manchester M20 4BX, UK.
Hagan
Iain M
IM
D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D000072380:NIMA-Related Kinase 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology* / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*
D018797:Cell Cycle Proteins; C111708:Cut12 protein, S pombe; D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C000606914:NEK1 protein, human; D000072380:NIMA-Related Kinase 1; D017346:Protein Serine-Threonine Kinases; C000606921:fin1 protein, S pombe