Taxonomic distribution of proteins containing STE domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing STE domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Suppression of hyphal formation in Candida albicans by mutation of a STE12 homolog.

Liu H, Kohler J, Fink GR
Science. 1994; 266: 1723-6

A Candida albicans gene (CPH1) was cloned that encodes a protein homologous to Saccharomyces cerevisiae Ste12p, a transcription factor that is the target of the pheromone response mitogen-activated protein kinase cascade. CPH1 complements both the mating defect of ste12 haploids and the filamentous growth defect of ste12/ste12 diploids. Candida albicans strains without a functional CPH1 gene (cph1/cph1) show suppressed hyphal formation on solid medium. However, cph1/cph1 strains can still form hyphae in liquid culture and in response to serum. Thus, filamentous growth may be activated in C. albicans by the same signaling kinase cascade that activates Ste12p in S. cerevisiae; however, alternative pathways may exist in C. albicans.

Coupling of cell identity to signal response in yeast: interaction between the alpha 1 and STE12 proteins.

Yuan YO, Stroke IL, Fields S
Genes Dev. 1993; 7: 1584-97

In Saccharomyces cerevisiae, the STE12 protein mediates transcriptional induction of cell type-specific genes in response to pheromones. STE12 binds in vitro to the pheromone response elements (PREs) present in the control region of a-specific genes. STE12 is also required for transcription of alpha-specific genes, but there is no evidence that it binds directly to these genes. Instead, the MAT alpha-encoded protein alpha 1 and the MCM1 product bind to the DNA element that is responsible for alpha-specific and a-factor-inducible expression. To explore the role of STE12 in the pheromone induction of alpha-specific genes, we cloned STE12 and MAT alpha 1 homologs from the related yeast Kluyveromyces lactis. The K. lactis STE12 protein did not cooperate with the S. cerevisiae alpha 1 protein to promote the overall mating process or the induction of transcription of an alpha-specific gene. However, introduction of both K. lactis STE12 along with K. lactis alpha 1 did restore mating, suggesting that an interaction between STE12 and alpha 1 is important for alpha-specific gene activation. We also show that bacterially expressed STE12 and alpha 1 are able to form a complex in vitro. Thus, we demonstrate a coupling in alpha cells between a protein functioning in cell identity, alpha 1, with a protein responsive to the pheromone-induced signal STE12.