Cell cycle-dependent coupling of the vasopressin V1a receptor to different G proteins.
Arginine vasopressin (AVP) regulates biological processes by binding to G protein-coupled receptors. In Swiss 3T3 fibroblasts, expressing the V(1a) subtype of vasopressin receptors, AVP mobilizes calcium from intracellular stores. In proliferating cells, the AVP-induced increase in intracellular calcium concentration ([Ca(2+)](i)) was mediated by G proteins of the G(q) family, which are insensitive to pertussis toxin (PTX) pretreatment of the cells. In quiescent cells, the AVP-induced increase in [Ca(2+)](i) was partially PTX-sensitive, suggesting an involvement of G(i) proteins. We confirmed this by photoaffinity labeling of G proteins in Swiss 3T3 cell membranes activated by AVP. In Swiss 3T3 cells arrested in the G(0)/G(1) phase of the cell cycle, the AVP-induced increase in [Ca(2+)](i) was also partially PTX-sensitive but was PTX-insensitive in cells arrested in other phases of the cell cycles. The blocking effect of PTX pretreatment in G(0)/G(1) cells was mimicked by microinjection of antisense oligonucleotides suppressing the expression of the Galpha(i3) subunits. These results were confirmed by microinjection of antibodies directed against the C terminus of G protein alpha-subunits. The data presented indicate that in Swiss 3T3 fibroblasts synchronized in the G(0)/G(1) phase of the cell cycle the V(1a) receptor couples to G(q/11) and G(i3) to activate the phospholipase C-beta, leading to release of intracellular calcium.
Abel
A
A
Institut für Pharmakologie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Thielallee 69-73, D-14195 Berlin, Germany.
Wittau
N
N
Wieland
T
T
Schultz
G
G
Kalkbrenner
F
F
D016475:3T3 Cells; D000345:Affinity Labels; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D016193:G1 Phase; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D037342:Pertussis Toxin; D021122:Protein Subunits; D011869:Radioligand Assay; D017483:Receptors, Vasopressin / Q000187:drug effects / Q000502:physiology*; D016192:Resting Phase, Cell Cycle; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000345:Affinity Labels; D000906:Antibodies; D020319:Oligodeoxyribonucleotides, Antisense; D021122:Protein Subunits; D017483:Receptors, Vasopressin; D010566:Virulence Factors, Bordetella; D001127:Arginine Vasopressin; D037342:Pertussis Toxin; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins; D002118:Calcium