G Protein Activation of a Hormone-Stimulated Phosphatase in Human Tumor Cells

• Published in: Science (American Association for the Advancement of Science) Vol. 256; no. 5060; pp. 1215 - 1217
• Main Authors: Pan, Ming Gui, Florio, Tuillio, Philip J. S. Stork
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 22-05-1992; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Adenosine Triphosphate - metabolism; Biological and medical sciences; Cancer cells; Carcinoma, Squamous Cell; Cell growth; Cell Line; Cell lines; Cell Membrane - metabolism; Cell membranes; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Cells; Cellular biology; Cytology; Dose-Response Relationship, Drug; Enzyme Activation; ErbB Receptors - metabolism; Fundamental and applied biological sciences. Psychology; G proteins; GTP-Binding Proteins - metabolism; Guanosine 5'-O-(3-Thiotriphosphate) - pharmacology; Guanosine Diphosphate - analogs & derivatives; Guanosine Diphosphate - pharmacology; Hormones; Humans; Inhibition; Kinetics; Medical research; Molecular and cellular biology; P branes; Pancreatic cells; Pancreatic Neoplasms; Peptides - metabolism; Pertussis Toxin; Phosphatases; Phosphorylation; Physiological aspects; Protein Kinases - metabolism; Protein Tyrosine Phosphatases - metabolism; Proteins; Somatostatin; Somatostatin - pharmacology; String theory; Thionucleotides - pharmacology; Tumors; Vanadates; Virulence Factors, Bordetella - pharmacology; Whooping cough; Human; Cell proliferation; Enzyme; Peptide hormone; Phosphatase; Neuropeptide; Carcinogenesis; Binding protein; Cell line; Hormonal regulation; Inhibition; Somatostatin; Mechanism of action; Pancreas; Tumor cell; G protein
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.256.5060.1215

The growth-inhibiting peptide hormone somatostatin stimulates phosphotyrosine phosphatase activity in the human pancreatic cell line MIA PaCa-2. This hormonal activation was mediated by a pertussis toxin-sensitive guanosine 5′-triphosphate-binding protein (G protein) in the membranes of these cells. Activation of this G protein by somatostatin stimulated the dephosphorylation of exogenous epidermal growth factor receptor prepared from A-431 cells in vitro. This pathway may mediate the antineoplastic action of somatostatin in these cells and in human tumors and could represent a general mechanism of G protein coupling that is utilized by normal cells in the hormonal control of cell growth.