艾氏乳腺癌腹水细胞质膜NADH-铁氰化钾氧化还原酶质子泵活性诱导细胞与脂质体融合

MEMBRANE FUSION BETWEEN EHRLICH ASCITES OF MASTOCARCINOMA CELLS AND LIPOSOME INDUCED BY PROTON TRANSLOCATION OF TRANSPLASMA MEMBRANE NADH- FERRICYANIDE REDOX ENZYMES

在本文中,我们用荧光能量共振转移分析和荧光显微技术证明,小鼠艾氏乳腺癌腹水细胞质膜NADH-铁氰化钾氧化还原反应的电子传递所偶联的质子泵活性能诱导细胞与人工脂质体融合。糖酵解代谢的抑制剂碘乙酸能抑制融合,同时融合过程是吸取质子的。近几年来,我们实验室已报道了多种生物膜质子泵均具有诱导膜融合的功能。因此,质子泵诱导膜融合可能具有比较广泛的生理意义。并为细胞中存在有受能量代谢控制的驱动膜融合的生理机制提供了实验证据。

By using resonance energy transfer assay (RET) and fluorescence microscopy we show experimental evidence that mem -brane fusion of Ehrlich ascites of ma-stocarcinoma cells with liposomes could be induced by the proton translocation activity associated with NADH-ferricyani-de redox enzyme of transplasma membrane of cancer cells. The iodoacetate, an inhibitor of glycolysis, was found to be able to depress the proton translocation activity and also to inhibit the membrane fusion. It is suggested that NADH produced mainly by glycolysis is utilized as the substrate (electron donor) for transmem-brane ferricyanide reduction, and the proton pumping activity in the cancer cells is coupled to the transmembrane NADH-ferricyanide redox enzyme system. Experi-ments also show that membrane fusion extent of cancer cells with liposomes is proportional to the amount of H+ pumped out by the cells and membrane fusion process also exhibits a H+ consuming mode just as in fusion process of mitochondria with liposomes by redox enzyme proton pumps of respiratory chain. All of the results presented in this paper consists with recent reports of this laboratory, which indicated that various types of proton pumping system from different membrane system of cell have a new functon in membrane fusion . Therefore, the proton pumping induced membrane fusion may have a more general physiological importance in triggering and modulating fusion process of native membrane in vivo.