|Regulation of MAPK Function by Direct Interaction with the Mating-Specific Galpha in Yeast.|
Metodiev MV, Matheos D, Rose MD, Stone DE
Category: yeast mating ¤ Added: May 24, 2002 ¤ Rating: ◊◊
The mating response of the budding yeast Saccharomyces cerevisiae is mediated by a prototypical heterotrimeric GTP-binding protein (G protein) and mitogenactivated protein kinase (MAPK) cascade. Although signal transmission by such pathways has been modeled in detail, postreceptor down-regulation is less well understood. The pheromone-responsive G protein a subunit (Ga) of yeast down-regulates the mating signal, but its targets are unknown. We have found that Ga binds directly to the mating-specific MAPK in yeast cells responding to pheromone. This interaction contributes both to modulation of the mating signal and to the chemotropic response, and it demonstrates direct communication between the top and bottom of a Ga-MAPK pathway.