Identification of a novel dual angiotensin II/vasopressin receptor on the basis of molecular recognition theory

Abstract

The molecular recognition theory suggests that binding sites of interacting proteins, for example, peptide hormone and its receptor binding site, were originally encoded by and evolved from complementary strands of genomic DNA. To test this theory, we screened a rat kidney complementary DNA library twice: first with the angiotensin II (AII) followed by the vasopressin (AVP) antisense oligonucleotide probe, expecting to isolate cDNA clones of the respective receptors. Surprisingly, the identical cDNA clone was isolated twice independently. Structural analysis revealed a single receptor polypeptide with seven predicted transmembrane regions, distinct AII and AVP putative binding domains, a Gs protein-activation motif, and an internalization recognition sequence. Functional analysis revealed specific binding to both AII and AVP as well as AII- and AVP-induced coupling to the adenylate cyclase second messenger system. Site-directed mutagenesis of the predicted AII binding domain obliterates AII binding but preserves AVP binding. This corroborates the dual nature of the receptor and provides direct molecular genetic evidence for the molecular recognition theory.

Angiotensin II AT1receptor blockade decreases vasopressin-induced water reabsorption and AQP2 levels in NaCl-restricted rats

“…This indicates that the occupation of the ANG II AT 1 receptor plays a role in the regulation of vasopressin-regulated AQP2 expression in collecting ducts and urine concentration in vivo. Moreover, the dual ANG II/AVP receptor, which is a novel receptor coupled to adenylate cyclase that responds with equal sensitivity to ANG II and AVP, has been isolated (49). The renal immunocytochemical distribution of the ANG II/AVP receptor to IMCDs also strongly suggests the role of ANG II in the regulation of vasopressin-regulated AQP2 expression in the collecting ducts and urine concentration in vivo (17).…”

Renal actions of angiotensin-(1-7)

“…The stimulatory effect of Ang-(1-7) on water permeability in this nephron segment is dose-dependent, can be blocked by A-779 and, interestingly, also by an AVP-V 2 receptor antagonist (Magaldi AJ, personal communication). Regarding this last observation, it would be interesting to explore the involvement of the recently described AVP-angiotensin receptor (50) in the renal effects of Ang-(1-7). In contrast to the dose-related increase of water reabsorption induced by Ang-(1-7) in IMCD (22), in the frog skin the heptapeptide alters osmotic permeability biphasically, increasing it at low concentrations (1 nM) and decreasing it at higher concentrations (10 nM) (21).…”

Inhibition of HIV‐1 Infection by an Intramolecular Antisense Peptide to T20 in gp160

“…The molecular basis for such interactions has not been elucidated to date, although several models have been proposed (19,24). MRT has successfully been used to identify the dual angiotensin-vasopressin receptor (25) and the prion receptor (30). We have demonstrated that there are several peptide motifs, each of which has multiple ASP sites within a protein molecule, and we designated such motifs antisense homology boxes (AHBs) (2).…”

“…This theory is based on the observation that there is a tendency in the genetic code for codons of hydrophilic amino acids to be complemented on the complementary DNA strand by codons for hydrophobic amino acids and vice versa. In spite of ambiguities concerning the universality of the interactions involved in the binding of complementary peptides, the number of reports on complementary peptide pairs has been increasing (2,12,14,15,25,28,30,38). Furthermore, we have suggested that sense and antisense peptide interactions may be involved in the generation and maintenance of the tertiary structure of proteins (2).…”