Barry M A, Eastman A
Department of Pharmacology, Dartmouth Medical School, Hanover, NH 03755-3835.
Biochem Biophys Res Commun. 1992 Jul 31;186(2):782-9. doi: 10.1016/0006-291x(92)90814-2.
An axiom of apoptosis is that increases in cytosolic Ca2+ activate a Ca2+/Mg(2+)-dependent endonuclease. However, when HL-60 human promyelocytic leukemia cells were incubated with the Ca2+ ionophore ionomycin in varied extracellular Ca2+, DNA digestion was independent of extracellular Ca2+. Under these conditions, intracellular Ca2+ concentrations did not correlate with the observed DNA digestion. In contrast, intracellular acidification correlated well with DNA digestion. These data indicate that increased intracellular Ca2+ is not the primary signal for endonuclease activation in all forms of apoptosis, but that intracellular acidification may be involved. The observed intracellular acidification is consistent with the involvement of deoxyribonuclease II in apoptosis.
细胞凋亡的一个公理是，胞质Ca2+的增加会激活一种Ca2+/Mg(2+)依赖性核酸内切酶。然而，当HL-60人早幼粒细胞白血病细胞在不同的细胞外Ca2+条件下与Ca2+离子载体离子霉素一起孵育时，DNA消化与细胞外Ca2+无关。在这些条件下，细胞内Ca2+浓度与观察到的DNA消化不相关。相反，细胞内酸化与DNA消化密切相关。这些数据表明，细胞内Ca2+增加并非所有形式细胞凋亡中核酸内切酶激活的主要信号，而细胞内酸化可能参与其中。观察到的细胞内酸化与脱氧核糖核酸酶II参与细胞凋亡一致。
