May play a role in a signal transduction pathway used during gastrulation. Required specifically for the ventral furrow and posterior midgut invaginations, where it is necessary for coordinating cell shape changes. 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. In ovary, expressed in nurse cells and oocyte. In early embryos, distributed uniformly. At the extended germband stage, accumulates in the mesoderm. Expressed throughout oogenesis. In early embryos, expression drops during cellularization, remains low throughout gastrulation and increases once germband extension has begun. Belongs to the G-alpha family. G(12) subfamily.