Sst2

From Yeast Pheromone Model

Back to main model page

---

Contents 1 About Sst2 2 Reactions 3 Species Representation 3.1 Molecule Type 3.2 Model Seed

About Sst2

• N terminal 300 residues show homology to segments in two mammalian GTPase-activating proteins (GAPs). The segments have been shown to be necessary and sufficient for GAP activity. Dohlman et al. 1996 PMID 8756677

• Sst2-Myc is found throughout the cytosol, but it not found in the vacuole or nucleus (determined by confocal microscopy). Dohlman et al. 1996 PMID 8756677

• C terminal RGS(Regulator of G protein Signaling)-like domain is also necesary for Sst2 activity in vivo. Dohlman et al. 1996 PMID 8756677

• Sst2 is largely membrane associated. Dohlman et al. 1996 PMID 8756677

• Sst2 stands for SuperSensiTivity to pheromone. Apanovitch et al. 1998 PMID 9537998

• Sst2 acts as a GAP for Gpa1 by stabilizing the transition state of the GTP hydrolysis reaction. Apanovitch et al. PMID 9537998

• Sst2 association with membrane appears to be mainly electrostatic. Dohlman et al. 1996 PMID 8756677

• Sst2 is phosphorylated at S539 in response to pheromone. Garrison et al. 1999 PMID 10593933

• Quantitative Western blots were used to show that there are ~2000 Sst2 molecules per cell prior to pheromone stimulation, and a peak of ~5000 Sst2 molecules per cell about 1 hour after pheromone stimulation. Hao et al. 2003 PMID 12968019

• Sst2 deletion results in 100-fold increase in pheromone sensitivity, but no increase in maximum gene expression. Hao et al. 2003 PMID 12968019

Reactions

RGS(Sst2)/Galpha(Gpa1)/Receptor(Ste2) interactions
G protein nucleotide hydrolysis/exchange
Sst2 synthesis/degradation
Ste12 mediated protein synthesis
Non-specific dephosphorylation
Protein dilution/synthesis due to cell growth

Species Representation

Molecule Type

Sst2(Ste2_site, MAPK_site, S539~none~PO4)

Model Seed

Sst2(Ste2_site, MAPK_site, S539~none) Sst2_tot_conc