Alpha subunit of the heterotrimeric guanine nucleotide-binding protein (G protein) involved in glucose-induced cAMP signaling. Binds to its cognate transmembrane receptor GPR1, which senses extracellular carbon sources, and activates cAMP-PKA signaling and governs diploid pseudohyphal differentiation and haploid invasive growth. The G protein beta-mimic proteins GPB1 and GPB2 inhibit GPA2-GPR1 coupling, probably to reduce signaling in the absence of glucose. Alternates between an inactive form bound to GDP and an active form bound to GTP. Activated by the G protein coupled receptor (GPCR) GPR1, which serves as a guanine nucleotide-exchange factor (GEF), and inactivated by RGS2, acting as a GTPase-activating protein (GAP) for GPA2. G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site. GPA2 interacts with the kelch repeat beta-mimic proteins GPB1 and GPB2 and with the gamma subunit GPG1. Interacts with the G protein coupled receptor GPR1. Interacts also with regulators of G protein signaling (RGS) protein RGS2. Myristoylation at Gly-2 and palmitoylation at Cys-4 are required for membrane localization and function of the protein. Present with 4570 molecules/cell in log phase SD medium. Belongs to the G-alpha family. G(q) subfamily.