Structural requirements for V2 vasopressin receptor proteolytic cleavage

The ligand‐induced proteolytic cleavage of the V2 vasopressin receptor transiently expressed in COS cells was investigated. After incubation of the cell membranes with a photoreactive ligand possessing full agonistic properties for V2 receptors, approximately 90% of the porcine and bovine V2 vasopre...

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Bibliographic Details
Published inEuropean journal of biochemistry Vol. 266; no. 2; pp. 538 - 548
Main Authors Kojro, Elzbieta, Postina, Rolf, Gilbert, Sandra, Bender, Frank, Krause, Gerd, Fahrenholz, Falk
Format Journal Article
LanguageEnglish
Published Oxford, UK Blackwell Science Ltd 01.12.1999
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Summary:The ligand‐induced proteolytic cleavage of the V2 vasopressin receptor transiently expressed in COS cells was investigated. After incubation of the cell membranes with a photoreactive ligand possessing full agonistic properties for V2 receptors, approximately 90% of the porcine and bovine V2 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 V2/oxytocin receptors obtained by transfer of extracellular domains of the oxytocin receptor into the V2 receptor showed an increase in binding affinity for oxytocin versus vasopressin and a diminished cleavage. The proteolysis‐resistant chimeric V2/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 V2 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 V2 receptor cleavage might play a role in signal termination at elevated hormone concentrations.
ISSN:0014-2956
1432-1033
DOI:10.1046/j.1432-1327.1999.00892.x