Human somatostatin receptor, SSTR2, is coupled to adenylyl cyclase in the presence of Gi alpha 1 protein.
Somatostatin has been shown to exert diverse biological effects in various tissues. Recently, the human genes encoding five subtypes of somatostatin receptor (SSTR1-SSTR5) were cloned. Among these subtypes SSTR2 is present in many endocrine tumors as well as normal tissues and may mediate the effects of somatostatin analog, SMS201-995. In this study, we have investigated the intracellular effect of SSTR2 stably expressed in Chinese hamster ovary cells. Somatostatin-14 does not affect the forskolin stimulated cAMP formation when human SSTR2 is expressed in CHO cells, which lack internal Gi alpha 1 protein. However, somatostatin-14 inhibits the adenylyl cyclase in a dose dependent and pertussis toxin-sensitive manner when human SSTR2 is co-expressed with Gi alpha 1 in CHO cells. These results indicate that human SSTR2 is functionally coupled to Gi alpha 1 protein but not to Gi alpha 2 or Gi alpha 3 when expressed in CHO cells.
Kagimoto
S
S
Department of Metabolism and Clinical Nutrition, Kyoto University Faculty of Medicine, Japan.
Yamada
Y
Y
Kubota
A
A
Someya
Y
Y
Ihara
Y
Y
Yasuda
K
K
Kozasa
T
T
Imura
H
H
Seino
S
S
Seino
Y
Y
D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D015152:Blotting, Northern; D016466:CHO Cells; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000096:biosynthesis; D019204:GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D006801:Humans; D037342:Pertussis Toxin; D017481:Receptors, Somatostatin / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013004:Somatostatin / Q000494:pharmacology; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D017481:Receptors, Somatostatin; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D013004:Somatostatin; D000242:Cyclic AMP; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases