TY - JOUR
T1 - Involvement of G(s) and G(i) proteins in dual coupling of the luteinizing hormone receptor to adenylyl cyclase and phospholipase C
AU - Herrlich, Andreas
AU - Kühn, Bernhard
AU - Grosse, Robert
AU - Schmid, Andrea
AU - Schultz, Günter
AU - Gudermann, Thomas
PY - 1996
Y1 - 1996
N2 - Binding of lutropin/choriogonadotropin to its cognate receptor results in the activation of adenylyl cyclase and phospholipase C. The mechanism underlying the generation of this bifurcating signal is presently not known. To analyze the coupling mechanism of the LH receptor, activated G proteins were labeled with [α-32P]GTP azidoanilide and identified by selective immunoprecipitation. In membranes of bovine corpora lutea and of L cells stably expressing the murine LH receptor (LHR cells), human chorionic gonadotropin (hCG) led to incorporation of the label into α(s) and α(i2). Stimulation of LHR cells or of L cells expressing the M5 muscarinic receptor (LM5 cells) with the respective agonist resulted in activation of phospholipase C in both cell lines. However, α(q) and α11 were only labeled upon stimulation of the M5 muscarinic receptor. Agonist-induced Ca2+ mobilization and inositol phosphate accumulation were partially sensitive to pertussis toxin, and the expression of the βγ-stimulable phospholipase C isoforms β2 and β3 could be demonstrated in LHR cells. Overexpression of phospholipase C-β2 led to increased hCG-stimulated inositol phosphate accumulation, and expression of a β-ARK1 C-terminal polypeptide effectively suppressed hCG-mediated phosphatidylinositol hydrolysis. Thus, the LH receptor couples to both G(s) and G(i), and βγ- subunits released from either G protein contribute to the stimulation of phospholipase C-β isoforms.
AB - Binding of lutropin/choriogonadotropin to its cognate receptor results in the activation of adenylyl cyclase and phospholipase C. The mechanism underlying the generation of this bifurcating signal is presently not known. To analyze the coupling mechanism of the LH receptor, activated G proteins were labeled with [α-32P]GTP azidoanilide and identified by selective immunoprecipitation. In membranes of bovine corpora lutea and of L cells stably expressing the murine LH receptor (LHR cells), human chorionic gonadotropin (hCG) led to incorporation of the label into α(s) and α(i2). Stimulation of LHR cells or of L cells expressing the M5 muscarinic receptor (LM5 cells) with the respective agonist resulted in activation of phospholipase C in both cell lines. However, α(q) and α11 were only labeled upon stimulation of the M5 muscarinic receptor. Agonist-induced Ca2+ mobilization and inositol phosphate accumulation were partially sensitive to pertussis toxin, and the expression of the βγ-stimulable phospholipase C isoforms β2 and β3 could be demonstrated in LHR cells. Overexpression of phospholipase C-β2 led to increased hCG-stimulated inositol phosphate accumulation, and expression of a β-ARK1 C-terminal polypeptide effectively suppressed hCG-mediated phosphatidylinositol hydrolysis. Thus, the LH receptor couples to both G(s) and G(i), and βγ- subunits released from either G protein contribute to the stimulation of phospholipase C-β isoforms.
UR - http://www.scopus.com/inward/record.url?scp=0029666283&partnerID=8YFLogxK
U2 - 10.1074/jbc.271.28.16764
DO - 10.1074/jbc.271.28.16764
M3 - Article
C2 - 8663226
AN - SCOPUS:0029666283
SN - 0021-9258
VL - 271
SP - 16764
EP - 16772
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 28
ER -