Functional localization of an exocytosis-triggering G-protein in human cytotoxic T lymphocytes

TY - JOUR

T1 - Functional localization of an exocytosis-triggering G-protein in human cytotoxic T lymphocytes

AU - Mittrücker, H W

AU - Fleischer, B

PY - 1992/8/1

Y1 - 1992/8/1

N2 - Human cloned CD8+ cytotoxic T lymphocytes permeabilized with alpha-toxin of Staphylococcus aureus can be triggered by the guanosine triphosphate (GTP) analogue GTP gamma S to release the contents of their granula by exocytosis. To localize the guanosine nucleotide-binding protein (G-protein) activated by GTP gamma S in the sequence of events after T-lymphocyte triggering we have used several inhibitors of T-cell activation that inhibit early stages in T-cell triggering. The protein kinase C-inhibitor staurosporine, the immunosuppressants cyclosporin A and FK-506 and genistein, an inhibitor of tyrosine kinases, all inhibited esterase release triggered in intact cells by anti-T-cell receptor antibodies but not GTP gamma S-induced release from permeabilized cells. Cyclosporin A, FK-506 and genistein also blocked exocytosis triggered in intact cells by a combination of phorbolester and the calcium ionophore A23187. In addition, cytochalasin B, an inhibitor of actin polymerization, inhibited exocytosis in intact cells but enhanced exocytosis from permeabilized cells. These data show that the G-protein effecting exocytosis is localized distally in the cascade of events after T-cell activation.

AB - Human cloned CD8+ cytotoxic T lymphocytes permeabilized with alpha-toxin of Staphylococcus aureus can be triggered by the guanosine triphosphate (GTP) analogue GTP gamma S to release the contents of their granula by exocytosis. To localize the guanosine nucleotide-binding protein (G-protein) activated by GTP gamma S in the sequence of events after T-lymphocyte triggering we have used several inhibitors of T-cell activation that inhibit early stages in T-cell triggering. The protein kinase C-inhibitor staurosporine, the immunosuppressants cyclosporin A and FK-506 and genistein, an inhibitor of tyrosine kinases, all inhibited esterase release triggered in intact cells by anti-T-cell receptor antibodies but not GTP gamma S-induced release from permeabilized cells. Cyclosporin A, FK-506 and genistein also blocked exocytosis triggered in intact cells by a combination of phorbolester and the calcium ionophore A23187. In addition, cytochalasin B, an inhibitor of actin polymerization, inhibited exocytosis in intact cells but enhanced exocytosis from permeabilized cells. These data show that the G-protein effecting exocytosis is localized distally in the cascade of events after T-cell activation.

KW - Alkaloids

KW - Cells, Cultured

KW - Cyclosporine

KW - Exocytosis

KW - GTP-Binding Proteins

KW - Guanosine 5'-O-(3-Thiotriphosphate)

KW - Humans

KW - Lymphocyte Activation

KW - Protein Kinase C

KW - Protein-Tyrosine Kinases

KW - Staurosporine

KW - T-Lymphocytes, Cytotoxic

KW - Tacrolimus

M3 - SCORING: Journal article

C2 - 1383135

VL - 76

SP - 610

EP - 615

JO - IMMUNOLOGY

JF - IMMUNOLOGY

SN - 0019-2805

IS - 4

ER -