The C-IV cytoplasmic domain of the human Beta-1 adrenergic receptor (B1-AR) is a novel 10 amino acid alpha-helical structure. It encompasses the residues between 381proline to 390leucine. The organization of C-IV provides a novel architecture for the guanine-nucleotide binding-protein-coupled receptor (GPCR) superfamily that was identified in the crystal structure of the GPCR rhodopsin. Because of their locations within this alpha-helix 384arginine (R384) and 385lysine (L385) are putative candidates for coupling the B1-AR to the guanine-nucleotide binding protein (G-protein) and adenylyl cyclase signal transduction system. The purpose of this study is to characterize the role of the C-IV domain of the B1-AR in signal transduction. Specifically residues R384 and K385 were mutated by site-directed mutagenesis into residues that were not disruptive to the domain's tertiary structure. The involvement of these specific residues will be characterized by receptor agonist-mediated desensitization, sequestration, and down-regulation; radioligand binding; cyclic AMP accumulation/adenylyl cyclase activation; confocal/fluorescence microscopy; and bioluminescence resonance energy transfer assays. This study focuses on an important area of sympathetic innervation which is relevant to hypertension, fluid homeostasis, and renal disease progression. ? ?
| Gardner, Lidia A; Tavalin, Steven J; Goehring, April S et al. (2006) AKAP79-mediated targeting of the cyclic AMP-dependent protein kinase to the beta1-adrenergic receptor promotes recycling and functional resensitization of the receptor. J Biol Chem 281:33537-53 |
| Delos Santos, Noel M; Gardner, Lidia A; White, Stephen W et al. (2006) Characterization of the residues in helix 8 of the human beta1-adrenergic receptor that are involved in coupling the receptor to G proteins. J Biol Chem 281:12896-907 |
| Gardner, Lidia A; Delos Santos, Noel M; Matta, Shannon G et al. (2004) Role of the cyclic AMP-dependent protein kinase in homologous resensitization of the beta1-adrenergic receptor. J Biol Chem 279:21135-43 |
