title: Molecular cloning of two rat GRK6 splice variants.
abstract: Desensitization of G protein-coupled receptors is frequently triggered by G protein-coupled receptor kinases (GRKs) that preferentially phosphorylate agonist-occupied receptors. In this study, two GRK6 splice variants were cloned from the rat kidney. One isoform (GRK6a) encodes a 576-amino acid protein that is virtually identical (98% identity) to human GRK6. The second isoform is similar except for a 2-base pair insert that constitutes part of an intron interrupting the 3'-end coding region. This new isoform (GRK6b, 589 amino acids) has therefore a specific COOH-terminal region. A reverse transcription-polymerase chain reaction assay designed to discriminate GRK6 splice variants demonstrated that GRK6b mRNA is widely distributed and expressed at much higher levels than GRK6a mRNA in most peripheral tissues. In contrast, GRK6a predominates in brain. Functional studies, performed with cytosol extracts from transfected Chinese hamster ovary cells, indicated that GRK6a and GRK6b both phosphorylate light-activated rhodopsin as well as a synthetic peptide. The identification of GRK6b extends the family of GRKs. Further studies will be required to establish the tissue and subcellular distribution of this protein and to delineate its physiological role.
authors.affiliation: Département de Biologie Cellulaire et Moléculaire, Commissariat à l'Energie Atomique Saclay, Gif-Sur-Yvette, France.
authors.forename: D
authors.initials: D
authors.lastname: Firsov
authors.forename: J M
authors.initials: JM
authors.lastname: Elalouf
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D054771:G-Protein-Coupled Receptor Kinase 4; D054774:G-Protein-Coupled Receptor Kinase 5; D054768:G-Protein-Coupled Receptor Kinases; D019204:GTP-Binding Proteins / Q000378:metabolism; D014644:Genetic Variation; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection
chemical_list: D011994:Recombinant Proteins; D020794:Receptor Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D054771:G-Protein-Coupled Receptor Kinase 4; D054774:G-Protein-Coupled Receptor Kinase 5; D054768:G-Protein-Coupled Receptor Kinases; C089176:G-protein-coupled receptor kinase 6; C517855:GRK4 protein, human; C517898:GRK5 protein, human; C517854:Grk4 protein, rat; C517897:Grk5 protein, rat; D019204:GTP-Binding Proteins