Folding and cell surface expression of the vasopressin V2 receptor: requirement of the intracellular C-terminus.
We characterized truncations of the human vasopressin V2 receptor to determine the role of the intracellular C-terminus (comprising about 44 amino acids) in receptor function and cell surface expression. In contrast to the wild-type receptor, the naturally occurring mutant R337X failed to confer specific [3H]AVP binding to transfected cells. In addition, no vasopressin-sensitive adenylyl cyclase was detectable in membrane preparations of these cells. Laser scanning microscopy revealed that c-myc epitope- or green fluorescent protein-tagged R337X mutant receptors were retained within the endoplasmic reticulum. Increasing the number of C-terminal residues (truncations after codons 348, 354 and 356) restored G protein coupling, but revealed a length-dependent reduction of cell surface expression. Replacement of positively charged residues within the C-terminus by glutamine residues also decreased cell surface expression. A chimeric V2 receptor with the C-terminus replaced by that of the beta2-adrenergic receptor did not bind [3H]AVP and was retained within the cell. These data suggest that residues in the N-terminal part of the C-terminus are necessary for correct folding and that C-terminal residues are important for efficient cell surface expression.
Oksche
A
A
Forschungsinstitut für Molekulare Phamakologie, Berlin, Germany. oksche@fmp-berlin.de
Dehe
M
M
Schülein
R
R
Wiesner
B
B
Rosenthal
W
W
D000262:Adenylyl Cyclases / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D016466:CHO Cells; D019556:COS Cells; D018929:Cell Culture Techniques; D006224:Cricetinae; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009154:Mutation; D011487:Protein Conformation; D017510:Protein Folding; D017483:Receptors, Vasopressin / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D011993:Recombinant Fusion Proteins
D017483:Receptors, Vasopressin; D011993:Recombinant Fusion Proteins; D001127:Arginine Vasopressin; D000262:Adenylyl Cyclases