Implicated in the a- and alpha-factor response pathway. The beta and gamma chains of the putative yeast mating response pathway G protein play a positive role in initiation of the mating response. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction. G proteins are composed of 3 units, alpha, beta and gamma. The beta-gamma subunit complex (STE4-STE18 complex) interacts with PLP1 and PLP2. Interacts with SYG1. Present with 2050 molecules/cell in log phase SD medium. Belongs to the WD repeat G protein beta family.