Analysis of post-lysosomal compartments
Analysis of post-lysosomal compartments
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DOI：
10.1016/j.bbrc.2003.12.092
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发表时间：
2004-02-06
影响因子：
3.1
通讯作者：
Tanaka, Y
中科院分区：
文献类型：
--
作者：
Hirota, Y;Masuyama, N;Tanaka, Y
溶酶体是酸性的细胞内隔室，被认为是内吞途径的降解物和终点。在这里，我们提供了在NRK细胞中产生酸性水解酶贫乏和非酸性溶酶体后隔室的证据，这些NRK细胞在溶酶体中积累了不可消化的大分子德州红-葡聚糖(tr-Dex)。当tr-Dex进入细胞6h后，内化的tr-dex大部分与溶酶体酶组织蛋白酶D共定位，但随着追逐时间的延长，内化的tr-dex逐渐积累在组织蛋白酶D阴性的小泡中。这些小泡对溶酶体膜蛋白LGP85呈阳性反应，U18666A处理细胞后其形成受到抑制，从而阻碍了膜运输出晚期的内小体/溶酶体室，从而表明这些小泡来自溶酶体源。有趣的是，根据潮湿染色的判断，这些隔室是非酸性的。因此，结果表明，不可消化的大分子在溶酶体内的过度积累导致了酸性水解酶贫乏和非酸性溶酶体后隔室的形成。溶酶体亲和胺或微管解聚剂处理细胞的事实进一步表明，溶酶体后隔室的形成依赖于溶酶体的酸化和微管的机化。此外，这些结果表明溶酶体和溶酶体后的隔室之间存在双向的膜转运，这意味着后者不是静止的隔室。(C)2003 Elsevier Inc.保留所有权利。
Lysosomes are acidic intracellular compartments and are regarded as degradative and the end point, of the endocytic pathway. Here we provide evidence for the generation of acid hydrolase poor and non-acidic post-lysosomal compartments in NRK cells that have accumulated non-digestible macromolecules, Texas red-dextran (TR-Dex), within lysosomes. When TR-Dex was fed to the cells for 6 h, most of the internalized TR-Dex colocalized with a lysosomal enzyme, cathepsin D. With an increase in the chase period, however, the internalized TR-Dex gradually accumulated in cathepsin D-negative vesicles. These vesicles were positive for a lysosomal membrane protein, LGP85, and their formation was inhibited by treatment of the cells with U18666A, which impairs membrane transport out of late endosomal/lysosomal compartments, thereby suggesting that the vesicles are derived from lysosomes. Interestingly, these compartments are non-acidic as judged for the DAMP staining. The results, therefore, suggest that the excess accumulation of non-digestible macromolecules within lysosomes induces the formation of acid hydrolase poor and non-acidic post-lysosomal compartments. The fact that treatment of the cells with lysosomotropic amines or a microtubule-depolymerization agent resulted in extensive colocalization of TR-Dex with cathepsin D further indicates that the formation of the post-lysosomal compartments depends on the lysosomal acidification and microtubule organization. Furthermore, these results suggest bi-directional membrane transport between lysosomes and the post-lysosomal compartments, which implies that the latter are not resting compartments. (C) 2003 Elsevier Inc. All rights reserved.