GRK4: Proteins and Enzymes

A guanine nucleotide-binding protein (G Protein)-coupled receptor kinase subfamily, of the Ser/Thr protein kinase family, is encoded by the gene GRK4. There are a total of four isoforms of this gene: GRK4-alpha is 578 amino acids long at 66 kDA; GRK4-beta is 546 amino acids long at 63 kDA; GRK4-delta is 500 amino acids long at 57 kDA; and isoform 4, GRK4-gamma is 532 amino acids long at 61 kDA. GRK4-alpha is inhibited by caulmodulin and can phosphorylate rhodopsin, however the three other forms of GRK4 do not interact with calmodulin. GRK4 has been investigated in hypertension, breast cancer, aortic coarctation, and atherosclerosis. It participates in endocytosis and the chemokine signaling pathway through interactions with the CALM1, CALM2, CALM3, FSHR, and IKBKG genes.