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. Expressed primarily in hematopoietic cells. Coexpressed with EDG6 at the same relative levels in all tissues examined, with the highest levels in adult spleen and lung. Belongs to the G-alpha family. G(q) subfamily.