Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. Plays a role in glial cell differentiation during embryogenesis; loco, Galphai and the G-protein coupled receptor, moody, are required in the surface glia to achieve effective insulation of the nerve cord. G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site. Expressed primarily in neuronal cell bodies in the brain, optic lobe, and thoracic and abdominal ganglia. Also expressed in antenna, oocytes and ovarian nurse cells. Expressed in the surface glial cells of the nerve cords at the larval stage (at protein level). Expressed throughout development. Belongs to the G-alpha family. G(i/o/t/z) subfamily. Truncated C-terminus.