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About Ste11

  • Phosphorylation of S302, and/or S306 and T307 by Ste20 is sufficient and necessary to activate Ste11. van Drogen et al. 2000 PMID 10837245
    • Mutation of all three sites to alanine results in a non-functioning pathway (as judged by halo assay, FUS1-lacZ transcriptional reporter, and mating assay)
    • Each single mutant (S302, S306 or T307 to alanine) was able to function in the pathway (as judged by halo assay, FUS1-lacZ transcriptional reporter, and mating assay)
    • Mutation of all three sites to aspartic acid (mimicking phosphorylation) results in a constitutive phenotype whose activation of transcription is independent of Ste20, but dependent on Ste7 (this mutant is also able to constitutively activate the high osmolarity pathway)
  • Ste11's amino-terminal domain inhibits the activity of Ste11's carboxy-terminal catalytic domain when S302, S306 and T307 are not phosphorylated. When these residues are phosphorylated, this inhibition is relieved. van Drogen et al. 2000 PMID 10837245
    • Ste11 amino-terminal domain (residues 1-424) mutant Ste11(S302A S306A T307A) interacts with the Ste11 carboxy-terminal catalytic domain (residues 424-738) by yeast two-hybrid, whereas the Ste11 amino-terminal domain (residues 1-424) mutant Ste11(S302D S306D T307D) does not.
  • Ste11's interaction with Ste5 may also help relive the N-terminal inhibition. Cairns et al. 1992 PMID 1628833; Stevenson et al. 1992 PMID 1628832
  • Ste11 interacts with Ste5 via residues 133-335 (by coimmunoprecipitation). Wu et al. 1999 PMID 10397774
  • Ste11 N-terminal fragment containing residues 1-386 fused to MalBP (MalBP-Ste11NT) interacts with Ste11 C-terminal residues 385-738 fused to GST and myc (GST-Ste11CT-myc). This interaction was inhibited by the presence of GST-Ste50, which bound to MalBP-Ste11NT. Wu et al. 1999 PMID 10397774
  • The Ste11 SAM domain (residues 27-108) forms a dimer with an approximate Kd of 0.5 mM. Grimshaw et al. 2004 PMID 14573615
  • The Ste11 SAM domain (residues 37-104) exists in solution as a dimer in the concentration range of 0.1 mM to 1 mM (by NMR spectroscopy). Bhattacharjya et al. 2004 PMID 15544813
  • Ste11 interacts with itself via yeast two-hybrid. Barr et al. 1996 PMID 8816472
    • This was done in a yeast strain that contains the other members of the pheromone response pathway, so it is likely that this interaction is through a bridging protein or complex.
  • Overexpressed Myc-Ste11 copurifies with overexpressed GST-Ste11. Ramezani-Rad et al. 1998 PMID 9738877
  • At millimolar concentrations, the Ste11 SAM domain (residues 15-92) forms aggregates in a pH and ionic strength dependent manner, whereas at micromolar concentrations, Ste11SAM is a monomer (determined by gel-filtration). Kwan et al. 2004 PMID 15327964
  • Ste11 failed to interact with itself via yeast two-hybrid in a diploid (using Gal4's activating domain and Gal4's DNA-binding domain). Kwan et al. 2004 PMID 15327964
  • Fluorescently-tagged Ste11, expressed at wild-type levels, is largely cytoplasmic in the absence and presence of pheromone. Maeder et al. 2007 PMID 17952059


Ste5/MAPK cascade interactions
MAPK phosphorylation cascade
Ste11/Ste50 interactions
Ste11 synthesis/degradation
Non-specific dephosphorylation
Protein dilution/synthesis due to cell growth

Species Representation

Molecule Type

Ste11(Ste5_site, MAPK_site, S302_S306_T307~none~pS~pSpS~pSpSpT, Feedback_PO4~none~PO4)

Model Seed

Ste11(Ste5_site, MAPK_site, S302_S306_T307~none, Feedback_PO4~none) Ste11_tot_conc

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