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. G protein z alpha, encoded by the GNAZ gene, is enriched in neural tissue and differs in sequence from other G alpha subunits. Alpha Subunits are encoded in 15 genes and several transcripts are alternatively spliced. Receptors may discriminate between splice variants; whether splice variants are functionally different in regulating effectors is not known. All alpha subunits appear to be palmitoylated near the N-terminus.