Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems (PubMed:9687499). Required for platelet activation (PubMed:9296496). Regulates B-cell selection and survival and is required to prevent B-cell-dependent autoimmunity (PubMed:20624888). Regulates chemotaxis of BM-derived neutrophils and dendritic cells (in vitro) (PubMed:17938235). Transduces FFAR4 signaling in response to long-chain fatty acids (LCFAs) (By similarity). Together with GNA11, required for heart development (PubMed:9687499). G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site. Binds SLC9A3R1. Forms a complex with PECAM1 and BDKRB2. Interacts with PECAM1 (By similarity). Interacts with GAS2L2 (PubMed:23994616). Colocalizes with the adrenergic receptors, ADREN1A and ADREN1B, at the nuclear membrane of cardiac myocytes. Palmitoylated by ZDHHC3 and ZDHHC7 (PubMed:19001095). Palmitoylation occurs in the Golgi and participates in the localization of GNAQ to the plasma membrane (PubMed:19001095). Histaminylated at Gln-209 residues by TGM2. Mice are viable but suffer from cerebellar ataxia and display deficiencies in primary hemostasis due to a defect in platelet activation (PubMed:9296496, PubMed:9391157). Mice lacking Gnaq and Gna11 are embryonic lethal due to cardiomyocyte hypoplasia (PubMed:9687499). Mice lacking Gnaq and with one single intact copy of Gna11, as well as mice lacking Gna11 and with one single intact copy of Gnaq die shortly after birth; lethality is caused by heart malformations (PubMed:9687499). Newborns display craniofacial defects (PubMed:9687499). Belongs to the G-alpha family. G(q) subfamily.