A deficiency in Syk enhances ceramide-induced apoptosis in DT40 lymphoma B cells.
Syk deficiency significantly enhanced ceramide-induced apoptosis. Ectopic expression of wild-type or kinase-inactive Syk rendered Syk-negative cells resistant to ceramide-induced apoptosis. Furthermore, ceramide could not activate Syk, indicating that Syk protected DT40 cells from ceramide-induced apoptosis, via a mechanism independent of its activity. In addition, a deficiency in Lyn also resulted in the cells becoming susceptible to ceramide-induced apoptosis. However, no difference of Ara-C-induced apoptosis between wild-type and mutant cells was observed. c-Jun N-terminal kinases appeared not to be important in mediating the enhanced apoptosis, as they were still activated in mutant cells following ceramide treatment.
Qin
S
S
Department of Biochemistry, Kobe University School of Medicine, Japan.
Ding
J
J
Kurosaki
T
T
Yamamura
H
H
D017209:Apoptosis / Q000187:drug effects*; D002518:Ceramides / Q000494:pharmacology*; D004792:Enzyme Precursors / Q000172:deficiency* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D016393:Lymphoma, B-Cell / Q000473:pathology / Q000503:physiopathology*; D009363:Neoplasm Proteins / Q000172:deficiency*; D011505:Protein-Tyrosine Kinases / Q000172:deficiency* / Q000378:metabolism; D000072377:Syk Kinase; D019061:src-Family Kinases / Q000378:metabolism
D002518:Ceramides; D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases