Abstract
Here, we report that the calcium ionophore ionomycin induces a massive Ca2+-dependent apoptosis in wildtype DT-40 chicken B lymphoma cells, as well as in BTK-deficient, PLCgamma2-deficient and IP3 receptor-deficient DT-40 cells, but not in LYN- or SYK-deficient DT-40 cells. Notably, the deficiency of CSK, a negative regulator of Src-family PTK, promoted ionomycin-induced apoptosis of DT-40 cells. Reconstitution of SYK-deficient cells with wild-type SYK restored the apoptotic response of the cells to ionomycin, but the expression of FYN or LCK in LYN-deficient cells did not restore the apoptotic response of LYN-deficient cells. Taken together, our data suggests that both LYN and SYK, but not BTK, FYN or LCK, are crucial mediators of BCR-independent Ca2+-induced apoptosis in DT-40 lymphoma B cells.
MeSH terms
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Agammaglobulinaemia Tyrosine Kinase
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Animals
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Apoptosis*
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B-Lymphocytes / pathology
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Calcium / physiology*
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Chickens
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Enzyme Precursors / physiology*
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Intracellular Signaling Peptides and Proteins
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Ionomycin / pharmacology
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
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Lymphoma, B-Cell / pathology*
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Protein-Tyrosine Kinases / physiology*
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-fyn
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Receptors, Antigen, B-Cell
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Syk Kinase
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Tumor Cells, Cultured
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src-Family Kinases / physiology*
Substances
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Enzyme Precursors
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Intracellular Signaling Peptides and Proteins
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Proto-Oncogene Proteins
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Receptors, Antigen, B-Cell
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Ionomycin
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Protein-Tyrosine Kinases
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Agammaglobulinaemia Tyrosine Kinase
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
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Proto-Oncogene Proteins c-fyn
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Syk Kinase
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lyn protein-tyrosine kinase
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src-Family Kinases
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Calcium