Thrombin stimulates pertussis toxin-sensitive and -insensitive GTPase activities and ADP-ribosylation of G(i) in human neuroblastoma SH-EP.
Kinetic interaction between thrombin receptor and G proteins was investigated in human epithelial neuroblastoma cell line, SH-EP. In these cells, both alpha-thrombin and SFLLRNP (one-letter amino-acid code) stimulated GTPase activity and enhanced cholera toxin-catalyzed ADP-ribosylation of G(i2) in a concentration-dependent manner. Basal GTPase activity was attenuated by pertussis toxin treatment by 35%, however, agonist stimulation was preserved significantly. These results together indicated that thrombin receptor simultaneously activates G(i2) and PTX-insensitive G protein(s).
Ogino
Y
Y
Third Department of Internal Medicine, Teikyo University School of Medicine, Ichihara, Chiba, Japan. kamekichi6@aol.com
Sakamoto
Y
Y
Kinouchi
T
T
Shimizu
N
N
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000494:pharmacology; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism; D018179:Receptors, Thrombin / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D010446:Peptide Fragments; D010716:Phosphatidylinositols; D018179:Receptors, Thrombin; D010566:Virulence Factors, Bordetella; C086309:thrombin receptor peptide SFLLRNP; D000246:Adenosine Diphosphate Ribose; D037342:Pertussis Toxin; D013917:Thrombin; D020558:GTP Phosphohydrolases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D002118:Calcium