Roles of Dynamin-Related Protein 1 in the Regulation of Mitochondrial Fission and Apoptosis in Response to uv Stimuli

摘要

Mitochondria are dynamic structures that frequently divide and fuse with one another to form interconnecting network. This network disintegrates into punctiform organelles during apoptosis. However, it remains unclear whether this event has a significant impact on the rate of cell death or only accompanies apoptosis as an epiphenomenon. In this study, we investigate the role of dynamin-related protein 1 (Drpl), a large GTPase that mediates outer mitochondrial membrane fission, in mitochondrial morphology and apoptosis in response to UV irradiation in human lung adenocarcinoma cells (ASTC-a-1) and HeLa cells. Using time-lapse fluorescent imaging, we find that Drpl primarily distributes in cytosol under physiological conditions. After UV treatment, Drpl translocates from cytosol to mitochondria, indicating the enhancement of Drpl mitochondrial accumulation. Down-regulation of Drpl by shRNA inhibits UV-induced apoptosis. Our results suggest that Drpl is involved in the regulation of transition from a reticulo-tubular to a punctiform mitochondrial phenotype and mitochondrial fission plays an important role in UV-induced apoptosis.