h-89 and mastoparan

h-89 has been researched along with mastoparan* in 1 studies

Other Studies

1 other study(ies) available for h-89 and mastoparan

Article	Year
Evidence of heterotrimeric G-protein involvement in regulated exocytosis from permeabilized pancreatic acini. Pancreas, 1995, Volume: 10, Issue:4 Constitutive membrane trafficking events are regulated by heterotrimeric G-proteins (G-proteins) in addition to their regulation by small GTP-binding proteins (smgs). Here, we used streptolysin O-permeabilized mouse pancreatic acini and compounds that interact with G-proteins, but not smgs, to examine whether G-proteins are also involved in regulated pancreatic exocytosis. The wasp venom mastoparan (10 microM) inhibited by 25-50% amylase release from permeabilized acini stimulated by various combinations of Ca2+, cyclic AMP (cAMP), 12-O-tetradecanoylphorbol 13-acetate, and guanosine (5'-[gamma-thio]triphosphate (GTP gamma S), while the inactive analogue Mas17 was without effect. Pretreatment of intact acini with pertussis toxin resulted in an approximately 30% reduction of amylase secretion from cells subsequently permeabilized and stimulated with calcium and GTP gamma S. Pretreatment of intact acini with cholera toxin increased stimulated amylase release by 30% from subsequently permeabilized cells, and this effect was mimicked by 8-Br-cAMP. The cAMP-dependent protein kinase inhibitor H-89 (3 microM) largely reversed the effect of cholera toxin, indicating that cholera toxin's effect is due to increased cellular cAMP levels. The inhibitory effects of mastoparan and pertussis toxin suggest that a Gi/Go-type G-protein(s) is (are) involved in the regulation of exocytosis. Since mastoparan inhibited exocytosis stimulated by all intracellular mediators tested, it indicates that the G-protein acts at a distal step in the exocytic process. Topics: 8-Bromo Cyclic Adenosine Monophosphate; Animals; Bacterial Proteins; Calcium; Cell Membrane Permeability; Cholera Toxin; Cyclic AMP; Exocytosis; GTP-Binding Proteins; Guanosine 5'-O-(3-Thiotriphosphate); Intercellular Signaling Peptides and Proteins; Isoquinolines; Macromolecular Substances; Mice; Pancreas; Peptides; Pertussis Toxin; Protein Kinase Inhibitors; Streptolysins; Sulfonamides; Tetradecanoylphorbol Acetate; Virulence Factors, Bordetella; Wasp Venoms	1995

Article

Year

Evidence of heterotrimeric G-protein involvement in regulated exocytosis from permeabilized pancreatic acini.

Pancreas, 1995, Volume: 10, Issue:4

Constitutive membrane trafficking events are regulated by heterotrimeric G-proteins (G-proteins) in addition to their regulation by small GTP-binding proteins (smgs). Here, we used streptolysin O-permeabilized mouse pancreatic acini and compounds that interact with G-proteins, but not smgs, to examine whether G-proteins are also involved in regulated pancreatic exocytosis. The wasp venom mastoparan (10 microM) inhibited by 25-50% amylase release from permeabilized acini stimulated by various combinations of Ca2+, cyclic AMP (cAMP), 12-O-tetradecanoylphorbol 13-acetate, and guanosine (5'-[gamma-thio]triphosphate (GTP gamma S), while the inactive analogue Mas17 was without effect. Pretreatment of intact acini with pertussis toxin resulted in an approximately 30% reduction of amylase secretion from cells subsequently permeabilized and stimulated with calcium and GTP gamma S. Pretreatment of intact acini with cholera toxin increased stimulated amylase release by 30% from subsequently permeabilized cells, and this effect was mimicked by 8-Br-cAMP. The cAMP-dependent protein kinase inhibitor H-89 (3 microM) largely reversed the effect of cholera toxin, indicating that cholera toxin's effect is due to increased cellular cAMP levels. The inhibitory effects of mastoparan and pertussis toxin suggest that a Gi/Go-type G-protein(s) is (are) involved in the regulation of exocytosis. Since mastoparan inhibited exocytosis stimulated by all intracellular mediators tested, it indicates that the G-protein acts at a distal step in the exocytic process.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Animals; Bacterial Proteins; Calcium; Cell Membrane Permeability; Cholera Toxin; Cyclic AMP; Exocytosis; GTP-Binding Proteins; Guanosine 5'-O-(3-Thiotriphosphate); Intercellular Signaling Peptides and Proteins; Isoquinolines; Macromolecular Substances; Mice; Pancreas; Peptides; Pertussis Toxin; Protein Kinase Inhibitors; Streptolysins; Sulfonamides; Tetradecanoylphorbol Acetate; Virulence Factors, Bordetella; Wasp Venoms

1995