Activation of yeast PBS2 MAPKK by MAPKKKs or by binding of an SH3-containing osmosensor.
The role of mitogen-activated protein (MAP) kinase cascades in integrating distinct upstream signals was studied in yeast. Mutants that were not able to activate PBS2 MAP kinase kinase (MAPKK; Pbs2p) at high osmolarity were characterized. Pbs2p was activated by two independent signals that emanated from distinct cell-surface osmosensors. Pbs2p was activated by MAP kinase kinase kinases (MAPKKKs) Ssk2p and Ssk22p that are under the control of the SLN1-SSK1 two-component osmosensor. Alternatively, Pbs2p was activated by a mechanism that involves the binding of its amino terminal proline-rich motif to the Src homology 3 (SH3) domain of a putative transmembrane osmosensor Sho1p.
Maeda
T
T
Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Takekawa
M
M
Saito
H
H
D000595:Amino Acid Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D003001:Cloning, Molecular; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000378:metabolism; D005800:Genes, Fungal; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D009154:Mutation; D009994:Osmolar Concentration; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction
D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C087199:SSK1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; C083749:SLN1 protein, S cerevisiae