The subcellular and cellular distribution of G protein-coupled receptor kinase 2 in rat brain.
G protein-coupled receptor kinase 2 has been found to phosphorylate and thus regulate the activity of several G protein-coupled receptors implicated in neuronal signalling pathways. Although this kinase was initially described as a soluble protein, our laboratory has recently found that a significant amount of G protein-coupled receptor kinase 2 is associated with microsomal membranes in liver and different types of cultured cells. In the present report we show that high G protein-coupled receptor kinase 2 specific activity and protein levels are present in microsomal fractions of rat brain homogenates. On the other hand, immunochemical detection using a new antibody raised against the N-terminus of the kinase revealed a specific and widely distributed staining in different areas of the central nervous system, and the association of G protein-coupled receptor kinase 2 with intracellular structures in nervous cells. Our results further suggest that this receptor kinase may be involved in the modulation of G protein-coupled receptor-mediated neurotransmission and that association with microsomal membranes may play a role in G protein-coupled receptor kinase 2 functions in the brain.
Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Spain.
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D000818:Animals; D001921:Brain / Q000166:cytology / Q000201:enzymology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis*; D054769:G-Protein-Coupled Receptor Kinase 2; D019204:GTP-Binding Proteins / Q000032:analysis*; D011689:Purkinje Cells / Q000201:enzymology; D017966:Pyramidal Cells / Q000201:enzymology; D051381:Rats; D017208:Rats, Wistar; D013347:Subcellular Fractions / Q000737:chemistry; D013574:Synaptosomes / Q000201:enzymology; D051552:beta-Adrenergic Receptor Kinases
D017868:Cyclic AMP-Dependent Protein Kinases; C496569:Grk2 protein, rat; D051552:beta-Adrenergic Receptor Kinases; D054769:G-Protein-Coupled Receptor Kinase 2; D019204:GTP-Binding Proteins