Gamma subunit of a guanine nucleotide-binding protein (G protein). G proteins are involved as modulators or transducers in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction. Involved in the determination of the cAMP level according to nutritional conditions, most probably as a regulator of cAMP phosphodiesterase. Required for the control of pseudohyphal and haploid invasive growth. G proteins are composed of 3 units, alpha, beta and gamma. GPG1 interacts with the beta subunits GBP1 and GPB2. By heat.