The signaling mucins Msb2 and Hkr1 differentially regulate the filamentation mitogen-activated protein kinase pathway and contribute to a multimodal response.
A central question in the area of signal transduction is why pathways utilize common components. In the budding yeast Saccharomyces cerevisiae, the HOG and filamentous growth (FG) MAPK pathways require overlapping components but are thought to be induced by different stimuli and specify distinct outputs. To better understand the regulation of the FG pathway, we examined FG in one of yeast's native environments, the grape-producing plant Vitis vinifera. In this setting, different aspects of FG were induced in a temporal manner coupled to the nutrient cycle, which uncovered a multimodal feature of FG pathway signaling. FG pathway activity was modulated by the HOG pathway, which led to the finding that the signaling mucins Msb2p and Hkr1p, which operate at the head of the HOG pathway, differentially regulate the FG pathway. The two mucins exhibited different expression and secretion patterns, and their overproduction induced nonoverlapping sets of target genes. Moreover, Msb2p had a function in cell polarization through the adaptor protein Sho1p that Hkr1p did not. Differential MAPK activation by signaling mucins brings to light a new point of discrimination between MAPK pathways.
Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260-1300, USA.
Andrew
A
Pitoniak
Barbara
B
Birkaya
Heather M
HM
Dionne
Nadia
N
Vadaie
Paul J
PJ
Cullen
D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D025282:Mycelium / Q000235:genetics / Q000254:growth & development; D020411:Oligonucleotide Array Sequence Analysis; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013012:Sorbitol / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D027843:Vitis / Q000737:chemistry / Q000382:microbiology
D003470:Culture Media; C110690:FLO11 protein, S cerevisiae; D020690:GTPase-Activating Proteins; C512735:HKR1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; C076360:MSB2 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C459787:SHO1 protein, S cerevisiae; C489241:STE12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D013012:Sorbitol; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D005947:Glucose