p56(lck), ZAP-70, SLP-76, and calcium-regulated effectors are involved in NF-kappaB activation by bisperoxovanadium phosphotyrosyl phosphatase inhibitors in human T cells.
This study investigates the second messengers involved in NF-kappaB activation by the bisperoxovanadium (bpV) phosphotyrosyl phosphatase inhibitors. We first initiated a time course analysis of bpV-mediated activation of the human immunodeficiency virus type-1 long terminal repeat- and NF-kappaB-driven reporter gene. Our results showed a slower and more transient activation of both kappaB-regulated luciferase-encoding vectors by bpV compounds when compared with the action of tumor necrosis factor-alpha (TNF). Time course analyses of NF-kappaB translocation by shift assay experiments further confirmed these results, hence implying distinct pathways of NF-kappaB activation for bpV compounds and TNF. Attempts to characterize the bpV-dependent signaling cascade revealed that the src family protein tyrosine kinase p56(lck) was critical for NF-kappaB induction by bpV. Furthermore, p56(lck) interaction with the intracytoplasmic tail of CD4 markedly enhanced such induction. Optimal activation of NF-kappaB following bpV treatment necessitated downstream effectors of p56(lck) such as the syk family protein tyrosine kinase ZAP-70 and the molecular adaptor SLP-76. Importantly, reduced NF-kappaB activation was observed when capacitative calcium entry was deficient but also upon pharmacological inhibition of calmodulin and calcineurin. Altogether, these results suggest that induction of NF-kappaB by phosphotyrosyl phosphatase bpV inhibitors necessitates both proximal and distal effectors of T cell activation.
Ouellet
M
M
Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire du Québec, Pavillon CHUL and Département de Biologie Médicale, Faculté de Médecine, Université Laval, Sainte-Foy Québec G1V 4G2, Canada.
Barbeau
B
B
Tremblay
M J
MJ
D048868:Adaptor Proteins, Signal Transducing; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism; D002460:Cell Line; D017930:Genes, Reporter; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D008156:Luciferases / Q000378:metabolism; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D017968:Vanadium Compounds / Q000037:antagonists & inhibitors*; D051746:ZAP-70 Protein-Tyrosine Kinase
D048868:Adaptor Proteins, Signal Transducing; D002147:Calmodulin; D016328:NF-kappa B; D010750:Phosphoproteins; D010835:Phytohemagglutinins; C092947:SLP-76 signal Transducing adaptor proteins; D014409:Tumor Necrosis Factor-alpha; D017968:Vanadium Compounds; D008156:Luciferases; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; D019703:Calcineurin; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium