Open AccessStructural requirements for V 2 vasopressin receptor proteolytic cleavage
Author(s) -
Kojro Elzbieta,
Postina Rolf,
Gilbert Sandra,
Bender Frank,
Krause Gerd,
Fahrenholz Falk
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00892.x
Subject(s) - receptor , agonist , vasopressin , proteolysis , oxytocin receptor , vasopressin receptor , arginine vasopressin receptor 2 , extracellular , biology , oxytocin , biochemistry , enzyme linked receptor , chemistry , endocrinology , antagonist , enzyme
The ligand‐induced proteolytic cleavage of the V 2 vasopressin receptor transiently expressed in COS cells was investigated. After incubation of the cell membranes with a photoreactive ligand possessing full agonistic properties for V 2 receptors, approximately 90% of the porcine and bovine V 2 vasopressin receptors were cleaved in the upper part of transmembrane helix 2 at a heptapeptide sequence conserved in both vasopressin and oxytocin receptors. The oxytocin receptor was completely resistant to proteolysis after binding the same photoreactive ligand, which is only a partial agonist for this receptor. Chimeric V 2 /oxytocin receptors obtained by transfer of extracellular domains of the oxytocin receptor into the V 2 receptor showed an increase in binding affinity for oxytocin versus vasopressin and a diminished cleavage. The proteolysis‐resistant chimeric V 2 /oxytocin receptor, which contains the first three extracellular domains of the oxytocin receptor, stimulated cAMP accumulation to a larger extent in response to vasopressin than the wild‐type receptor and showed impaired desensitization of the adenylate cyclase system. Our data indicate that the proteolytic cleavage of the V 2 receptor requires a defined conformation, especially of the first two extracellular domains that is induced by agonist binding. Furthermore, the results suggest that the proteolytic V 2 receptor cleavage might play a role in signal termination at elevated hormone concentrations.