G protein alpha subunit involved in the pheromone response; GTP-binding subunit of the heterotrimeric G protein; negatively regulates mating pathway by sequestering G(beta)gamma and triggering an adaptive response; interacts with the Ste5p scaffold protein to enhance the efficiency of polarity site alignment;  activates Vps34p at endosome; protein abundance increases in response to DNA replication stress; mutations in human homolog GNAS associated with McCune-Albright syndrome