Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. G alpha-8 is a potential analog for the G(s)-like G-proteins which stimulate adenylate cyclase in mammals. G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site. Expressed primarily at the mound stage. Belongs to the G-alpha family.