Truncation of N-terminal extracellular or C-terminal intracellular domains of human ETA receptor abrogated the binding activity to ET-1

Molecular cloning and functional characterization of V2 [8‐lysine] vasopressin and oxytocin receptors from a pig kidney cell line

“…Studies primarily performed on adrenergic and muscarinic receptors suggest that the N-terminal part of G-protein-coupled receptors for catecholamines and acetylcholine is responsible for the transport of receptors to the cell membrane, but contains no determinants for ligand binding (Ostrowski et al, 1992). However, for receptors that recognize peptide hormones, the importance of the N-terminal region for ligand binding has been shown : for the lutropin-choriogonadotropin receptor (Xie et al, 1990;Nagayama et al, 1991) and recently for tachikinin and endothelin-receptor subfamilies (Yokota et al, 1992;Hashido et al, 1992). Thus, we suggest that the Nterminus of V, VP receptors may be involved in determining the relative affinity for Comparison of the three V, VP receptors also shows that only the porcine V, receptor contains three potential phosphorylation sites for protein kinase C (Woodget et al, 1986) and CAMP-dependent protein kinase (Kennelly and Krebs, 1991) in its C-terminal region.…”

Identification of a ligand‐binding site of the human endothelin‐A receptor and specific regions required for ligand selectivity

“…Next, we examined the ET-1 -induced transient increase in [Ca"], in CHO cells transfected with the expression plasmids for parental and mutated ETA receptors. CHO cells were selected as host, because ET-1 induced a 5-10-fold higher increase in [Ca*+], in CHO cells than that in COS-7 cells when transfected with pCDM8-ETA [31]. When the ET-1 dependent induction of [Ca2+], was analyzed, no [Ca2+], was induced for CHO cells transfected with pCDM8-ETA-PZAW B2 and the mutant pCDM8-[K1401]ETA plasmids by the addition of 1 nM ET-1 (Fig.…”

“…ET-2 has a close resemblance to with Leu6 and Met7 substituted for Trp6 and Leu7, respectively, whereas ET-3 is different from both ET-1 and ET-2 at six positions located in the inner loop common to all three ET peptides [2]. These peptides show a wide range of biological activities such as receptor binding, contraction, phosphatidylinositol turnover, neurotransmitter, increase in intracellular calcium concentration, stimulation of DNA synthesis, secretion of aldosterone, atrial natriuretic peptide and gonadotropin, and increase in blood pressure [2-91.We have previously reported cloning of the two human proximity to the first transmembrane region is required for the ligand-binding activity of the ETA receptor [14]. The overall structure of the ET receptor shows significant sequence and topographical similarities with the photoreceptor rhodopsin and other guanine-nucleotide-binding-regulatory protein(G-protein)-coupled receptors.…”

“…We have previously reported cloning of the two human proximity to the first transmembrane region is required for the ligand-binding activity of the ETA receptor [14]. The overall structure of the ET receptor shows significant sequence and topographical similarities with the photoreceptor rhodopsin and other guanine-nucleotide-binding-regulatory protein(G-protein)-coupled receptors.…”

Inhibition of Inward Rectifier K+ Currents by Angiotensin II in Rat Atrial Myocytes: Lack of Effects in Cells from Spontaneously Hypertensive Rats

“…Although the precise reason for this discrepancy remains uncertain, this phenomenon is not specific to AT1 (32). Similar discrepancies between ligand-binding capacities and protein levels detected with anti-receptor antibodies have been described for various GPCRs, such as endothelin receptor type A (33), platelet-activation factor receptors (34) and opioid receptors (35). Recently, it has been reported that alternative splicing of AT1 results in differential protein levels (36).…”