Ste12

Ste12 regulates a diverse set of genes required for different developmental phenotypes in yeast. The environment-dependent association of Ste12 with other proteins can lead to its binding to different sets of genes (Zeitlinger et al., 2003).

Pheromone signaling leads to phosphorylation of Ste12, and Ste12-dependent induction of a set of mating genes (Hung et al., 1997; Roberts et al., 2000). Under these conditions, Ste12 binds some sets of genes independently (Dolan et al., 1989; Hagen et al., 1993; Sengupta and Cochran, 1990), while binding to other sets require interaction with the transcriptional regulator Mcm1 (Errede and Ammerer, 1989; Kirkman-Correia et al., 1993; Oehlen et al., 1996; Primig et al., 1991).

Certain nutrient limitation environments result in a filamentous phenotype in yeast. Ste12 is required for the expression of the many of the genes associated with filamentation (Madhani et al., 1999). Binding to these genes by Ste12 occurs only in the presence of the regulator Tec1 (Baur et al., 1997; Madhani and Fink, 1997).

Two different MAPK signal transduction pathways control the activity of Ste12. The MAPKs Fus3 and Kss1 can affect developmental fates of cells (Liu et al., 1993; Roberts and Fink, 1994) likely through the regulation of the Ste12 inhibitors Dig1 and Dig2 (Bardwell et al., 1998; Olson et al., 2000; Tedford et al., 1997).

Ste12 also appears to bind its own promoter, and shows increased transcript levels in the presence of pheromone (Ren et al., 2000).