The SLT2(MPK1) MAP kinase is activated during periods of polarized cell growth in yeast.
The SLT2(MPK1) mitogen-activated protein kinase signal transduction pa thway has been implicated in several biological processes in Saccharomyces cerevisiae, including the regulation of cytoskeletal and cell wall structure, polarized cell growth, and response to nutrient availability, hypo-osmotic shock and heat shock. We examined the conditions under which the SLT2 pathway is activated. We found that the SLT2 kinase is tyrosine phosphorylated and activated during periods in which yeast cells are undergoing polarized cell growth, namely during bud formation of vegetative cell division and during projection formation upon treatment with mating pheromone. BCK1(SLK1), a MEK kinase, is required for SLT2 activation in both of these situations. Upstream of BCK1(SLK1), we found that the STE20 kinase was required for SLT2 activation by mating pheromone, but was unnecessary for its activation during the vegetative cell cycle. Finally, SLT2 activation during vegetative growth was partially dependent on CDC28 in that the stimulation of SLT2 tyrosine phosphorylation was significantly reduced directly after a temperature shift in cdc28 ts mutants. Our data are consistent with a role for SLT2 in promoting polarized cell growth.
Zarzov
P
P
Département de Biologie Cellulaire et Moléculaire, Centre d'Etudes deSaclay, France.
Mazzoni
C
C
Mann
C
C
D000595:Amino Acid Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002453:Cell Cycle; D017931:DNA Primers / Q000737:chemistry; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D000072235:Mating Factor; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship
D017931:DNA Primers; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D019000:Phosphotyrosine; D000072235:Mating Factor; D011494:Protein Kinases; C072075:BCK1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D020930:MAP Kinase Kinase Kinases; C078754:STE20 protein, S cerevisiae; D020929:Mitogen-Activated Protein Kinase Kinases