Roles of Pdk1p, a fission yeast protein related to phosphoinositide-dependent protein kinase, in the regulation of mitosis and cytokinesis.
Proteins related to the phosphoinositide-dependent protein kinase family have been identified in the majority of eukaryotes. Although much is known about upstream mechanisms that regulate the PDK1-family of kinases in metazoans, how these kinases regulate cell growth and division remains unclear. Here, we characterize a fission yeast protein related to members of this family, which we have termed Pdk1p. Pdk1p localizes to the spindle pole body and the actomyosin ring in early mitotic cells. Cells deleted for pdk1 display multiple defects in mitosis and cytokinesis, all of which are exacerbated when the function of fission yeast polo kinase, Plo1p, is partially compromised. We conclude that Pdk1p functions in concert with Plo1p to regulate multiple processes such as the establishment of a bipolar mitotic spindle, transition to anaphase, placement of the actomyosin ring and proper execution of cytokinesis. We also present evidence that the effects of Pdk1p on cytokinesis are likely mediated via the fission yeast anillin-related protein, Mid1p, and the septation initiation network.
Bimbó
Andrea
A
Cell Division Laboratory, Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore.
Liu
Jianhua
J
Balasubramanian
Mohan K
MK
D064413:3-Phosphoinositide-Dependent Protein Kinases; D000205:Actomyosin / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D003285:Contractile Proteins / Q000737:chemistry; D048749:Cytokinesis; D019084:Fluorescent Antibody Technique, Indirect; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D008677:Metaphase; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010802:Phylogeny; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus; D013997:Time Factors
D064413:3-Phosphoinositide-Dependent Protein Kinases; D000205:Actomyosin; D003285:Contractile Proteins; D049452:Green Fluorescent Proteins; D008562:Membrane Glycoproteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C090463:MID1 protein, S cerevisiae; C489694:Mid1 protein, S pombe; C095886:anillin; C578562:PDPK1 protein, human; C501407:Plo1 protein, S pombe