Diversity of the G-protein family: sequences from five additional alpha subunits in the mouse.

Biochemical analysis has revealed a number of guanine nucleotide-binding regulatory proteins (G proteins) that mediate signal transduction in mammalian systems. Characterization of their cDNAs uncovered a family of proteins with regions of highly conserved amino acid sequence. To examine the extent of diversity of the G protein family, we used the polymerase chain reaction to detect additional gene products in mouse brain and spermatid RNA that share these conserved regions. Sequences corresponding to six of the eight known G protein alpha subunits were obtained. In addition, we found sequences corresponding to five newly discovered alpha subunits. Our results suggest that the complexity of the G protein family is much greater than previously suspected.