Regulation of stress response signaling by the N-terminal dishevelled/EGL-10/pleckstrin domain of Sst2, a regulator of G protein signaling in Saccharomyces cerevisiae.
All members of the regulator of G protein signaling (RGS) family contain a conserved core domain that can accelerate G protein GTPase activity. The RGS in yeast, Sst2, can inhibit a G protein signal leading to mating. In addition, some RGS proteins contain an N-terminal domain of unknown function. Here we use complementary whole genome analysis methods to investigate the function of the N-terminal Sst2 domain. To identify a signaling pathway regulated by N-Sst2, we performed genome-wide transcription profiling of cells expressing this fragment alone and found differences in 53 transcripts. Of these, 40 are induced by N-Sst2, and nearly all contain a stress response element (STRE) in the promoter region. To identify components of a signaling pathway leading from N-Sst2 to STREs, we performed a genome-wide two-hybrid analysis using N-Sst2 as bait and found 17 interacting proteins. To identify the functionally relevant interacting proteins, we analyzed all of the available gene deletion mutants and found three (vps36 Delta, pep12 Delta, and tlg2 Delta) that induce STRE and also repress pheromone-dependent transcription. We selected VPS36 for further characterization. A vps36 Delta mutation diminishes signaling by pheromone as well as by downstream components including the G protein, effector kinase (Ste11), and transcription factor (Ste12). Conversely, overexpression of Vps36 enhances the pheromone response in sst2 Delta cells but not in wild type. These findings indicate that Vps36 and Sst2 have opposite and opposing effects on the pheromone and stress response pathways, with Vps36 acting downstream of the G protein and independently of Sst2 RGS activity.
Burchett
Scott A
SA
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
Flanary
Paul
P
Aston
Christopher
C
Jiang
Lixin
L
Young
Kathleen H
KH
Uetz
Peter
P
Fields
Stanley
S
Dohlman
Henrik G
HG
D048868:Adaptor Proteins, Signal Transducing; D001798:Blood Proteins / Q000737:chemistry*; D029742:Caenorhabditis elegans Proteins; D002455:Cell Division; D000072261:Dishevelled Proteins; D004305:Dose-Response Relationship, Drug; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D010641:Phenotype; D010750:Phosphoproteins / Q000737:chemistry*; D010766:Phosphorylation; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D020710:RGS Proteins / Q000737:chemistry*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; D001798:Blood Proteins; D029742:Caenorhabditis elegans Proteins; D000072261:Dishevelled Proteins; C105577:EGL-10 protein, C elegans; D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D010750:Phosphoproteins; D020710:RGS Proteins; D012333:RNA, Messenger; C094301:SST2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C039077:platelet protein P47; D012313:RNA