ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: To examine the correlation between the structure of Bcl-2and its inhibitory function of c-Jun N-terminal kinase (JNK) and caspaseactivity, we established a dopaminergic neuronal cell line, MN9Doverexpressing Bcl-2 (MN9D/Bcl-2) or its structural mutants. The mutantscomprised a point mutation in the BH1 (G145A; MN9D/BH1) or BH2 (W188A;MN9D/BH2) domain and a deletion mutation in the C-terminal (MN9D/C22), BH3(MN9D/BH3), or BH4 (MN9D/BH4) domain. As determined by the TUNEL (terminaldeoxynucleotidyltransferase nick end-labeling) and MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] reductionassay, apoptotic death of MN9D/Neo cells reached 80-90% within 24 h inresponse to 1 μM staurosporine. Upon staurosporine treatment, JNK activity increased six- to sevenfold over the basal level within 2-4 h. Treatment of MN9D/Neo with both staurosporine and a caspase inhibitor, Z-VAD, attenuated cell death without suppressing JNK activation. Both staurosporine-induced cell death and JNK activation were attenuated in MN9D/Bcl-2. As determined by cleavage of poly(ADP-ribose) polymerase into 85 kDa, Bcl-2 blocked caspase activity as well. When cells overexpressing one of the Bcl-2 mutants were treated with staurosporine, death was attenuated in MN9D/BH1, MN9D/BH2, and MN9D/C22 but not in MN9D/BH3 and MN9D/BH4. Similarly, both JNK and caspase activation were blocked in MN9D/BH1, MN9D/BH2, and MN9D/C22, whereas they were not suppressed in MN9D/BH3 and MN9D/BH4. Taken together, our data indicate that there exists a close structural and functional correlation of Bcl-2 to JNK and caspase activity in staurosporine-induced dopaminergic neuronal cell death.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.2000.0741621.x
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