Ste20-like protein kinases are required for normal localization of cell growth and for cytokinesis in budding yeast.
The yeast Ste20 protein kinase is involved in pheromone response. Mammalian homologs of Ste20 exist, but their function remains unknown. We identified a novel yeast STE20 homolog, CLA4, in a screen for mutations lethal in the absence of the G1 cyclins Cln1 and Cln2. Cla4 is involved in budding and cytokinesis and interacts with Cdc42, a GTPase required for polarized cell growth. Despite a cytokinesis defect, cla4 mutants are viable. However, double cla4 ste20 mutants cannot maintain septin rings at the bud neck and cannot undergo cytokinesis. Mutations in CDC12, which encodes one of the septins, were found in the same screen. Cla4 and Ste20 kinases apparently share a function in localizing cell growth with respect to the septin ring.
Cvrcková
F
F
Institute of Molecular Pathology (IMP), Wien, Austria.
De Virgilio
C
C
Manser
E
E
Pringle
J R
JR
Nasmyth
K
K
D000595:Amino Acid Sequence; D002451:Cell Compartmentation / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics; D002455:Cell Division / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D005800:Genes, Fungal / Q000235:genetics*; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D008969:Molecular Sequence Data; D010675:Pheromones / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D015003:Yeasts / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*
C082719:CLN1 protein, S cerevisiae; C082721:CLN2 protein, S cerevisiae; D018797:Cell Cycle Proteins; D016213:Cyclins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010675:Pheromones; D029701:Saccharomyces cerevisiae Proteins; C095212:CLA4 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D020930:MAP Kinase Kinase Kinases; C078754:STE20 protein, S cerevisiae; D020558:GTP Phosphohydrolases