The kic1 kinase of schizosaccharomyces pombe is a CLK/STY orthologue that regulates cell-cell separation.
The CLK/STY kinases are a family of dual-specificity protein kinases implicated in the regulation of cellular growth and differentiation. Some of the kinases in the family are shown to phosphorylate serine-arginine-rich splicing factors and to regulate pre-mRNA splicing. However, the actual cellular mechanism that regulates cell growth, differentiation, and development by CLK/STY remains unclear. Here we show that a functionally conserved CLK/STY kinase exists in Schizosaccharomyces pombe, and this orthologue, called Kic1, regulates the cell surface and septum formation as well as a late step in cytokinesis. The Kic1 protein is modified in vivo, likely by phosphorylation, suggesting that it can be involved in a control cascade. In addition, kic1(+) together with dsk1(+), which encodes a related SR-specific protein kinase, constitutes a critical in vivo function for cell growth. The results provide the first in vivo evidence for the functional conservation of the CLK/STY family through evolution from fission yeast to mammals. Furthermore, since cell division and cell-cell interaction are fundamental for the differentiation and development of an organism, the novel cellular role of kic1(+) revealed from this study offers a clue to the understanding of its counterparts in higher eukaryotes.
Tang
Zhaohua
Z
Division of Molecular Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
Mandel
Linda L
LL
Yean
Shyue-Lee
SL
Lin
Cindy X
CX
Chen
Tina
T
Yanagida
Mitsuhiro
M
Lin
Ren-Jang
RJ
D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D016764:Cell Polarity / Q000235:genetics; D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone; D019143:Evolution, Molecular; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D035362:Transcription Factor TFIID / Q000235:genetics / Q000378:metabolism
D002135:Calcium-Binding Proteins; D002868:Chromosomal Proteins, Non-Histone; D035362:Transcription Factor TFIID; C056608:caltractin; C066780:Clk dual-specificity kinases; C403617:Dsk1 protein kinase; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases