Activation of a low pH-dependent nuclease by apoptotic agents
| Autor: | Konrad S. Famulski, Malcolm C. Paterson, Ewa Sikora, Dawn Macdonald |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Ceramide
Programmed cell death Ultraviolet Rays Apoptosis HL-60 Cells Ceramides HeLa chemistry.chemical_compound Humans Molecular Biology Transcription factor Caspase Etoposide Nuclease Deoxyribonucleases biology Cell Biology Hydrogen-Ion Concentration biology.organism_classification Cell biology Enzyme Activation Transcription Factor AP-1 Zinc chemistry biology.protein DNA |
| Zdroj: | Cell Death & Differentiation. 6:281-289 |
| ISSN: | 1476-5403 1350-9047 |
| Popis: | Intracellular acidification caused by agents such as UV(C), etoposide or ceramide accompanies the progression of apoptosis. It is suggested that cellular acidosis may set favorable conditions for a dormant, low pH-dependent (acidic) nuclease, which could be involved in intranucleosomal genome degradation, a hallmark of programmed cell death. Here we show that exposure of HL-60 cells to acidotic/apoptotic agents results in the several-fold activation of a novel low pH-dependent (acidic) nuclease activity, as revealed by zymography. Its activity, which resides in nuclei, is associated with four polypeptides with apparent Mr of 56, 48, 45 and 40 kDa. Treatment of HeLa cells with UV(C) or ceramide causes also the up-regulation of an acidic nuclease activity which is represented by 70 and 62 kDa polypeptides. These observations suggest that acidic nuclease activation can be induced by the same apoptotic agents in different cell types. In HL-60 cells, acidic nuclease up-regulation triggered by acidotic agents follows the induction of AP-1 transcription factor active complexes and accompanies the progression of apoptosis. Inhibition of AP-1 factor activity caused by either anti-caspase/anti-acidotic agent Zn2+ or curcumin, an inhibitor of AP-1 binding to DNA and c-jun synthesis, protects cells from genome destruction. Acidic nuclease activation, however, is only partially inhibited by these factors. We propose that (i) the up-regulation of an acidic nuclease activity is governed by a regulatory pathway different from that responsible for AP-1 factor induction, caspases activation and intracellular acidification, and (ii) activation of an acidic nuclease does not cause any deleterious effects when AP-1 transcription factor induction, caspases activation and intracellular acidification are down-regulated. Thus, the acidic nuclease up-regulation alone is not a sufficient prerequisite for apoptosis. |
| Databáze: | OpenAIRE |
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