Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site. During embryogenesis, expressed primarily in the developing gut and transiently in the amnioserosa. Expressed primarily during embryonic, larval and early pupal development and at low levels in late pupae and adults. Belongs to the G-alpha family.