Lysosome Biogenesis Mediated by vps-18 Affects Apoptotic Cell Degradation in C. elegans
    作者: Hui Xiao,Didi Chen,Zhou Fang,Jing Xu,Xiaojuan Sun,Song Song,Jiajia Liu,and Chonglin Yang
    刊物名称: Molecular Biology of the Cell
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    摘要:
    Appropriate clearance of apoptotic cells (cell corpses) is an important step of programmed cell death. Although genetic and biochemical studies have identified several genes that regulate the engulfment of cell corpses, how these are degraded after being internalized in engulfing cell remains elusive. Here we show that VPS-18, the C. elegans homolog of yeast Vps18p, is critical to cell corpse degradation. VPS-18 is expressed and functions in engulfing cells. Deletion of vps-18 leads to significant accumulation of cell corpses that are not degraded properly. Furthermore, vps-18 mutation causes strong defects in the biogenesis of endosomes and lysosomes, thus affecting endosomal/lysosomal protein degradation. Importantly, we demonstrate that phagosomes containing internalized cell corpses are unable to fuse with lysosomes in vps-18 mutants. Our findings thus provide direct evidence for the important role of endosomal/lysosomal degradation in proper clearance of apoptotic cells during programmed cell death.