Selective effects of calcium chelators on anterograde and retrograde protein transport in the cell
Selective effects of calcium chelators on anterograde and retrograde protein transport in the cell
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DOI：
10.1074/jbc.m204157200
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发表时间：
2002-09-20
影响因子：
4.8
通讯作者：
Stamnes, M
中科院分区：
文献类型：
--
作者：
Chen, JL;Ahluwalia, JP;Stamnes, M
钙在细胞内蛋白质运输的几个方面起着调节作用。添加钙螯合剂可以抑制囊泡融合和囊泡形成。由于钙螯合剂的作用主要是在无细胞系统中研究的，因此尚不清楚分泌途径中的哪些转运步骤对钙水平敏感。在这方面，我们已经研究了钙螯合剂对整个细胞中蛋白质的顺行和逆行转运的影响。利用细胞化学和生化分析，我们发现，水泡性口炎病毒G蛋白的顺行定向出口和滋贺毒素从高尔基体的逆行定向出口都被钙螯合抑制。水泡性口炎病毒G从前高尔基体隔室的排出和滋贺毒素从内体隔室的排出对膜渗透性钙螯合剂1，2-双（2-氨基苯氧基）乙烷-N，N，N '，N'-四乙酸-四（乙酰氧基甲基酯）（BAPTA-AM）敏感。相比之下，内质网出口和胞吞内化从质膜不受BAPTA。总之，我们的数据表明，细胞中的一些（但不是全部）运输步骤可能受钙调节。这些研究为更详细地分析钙在蛋白质转运过程中作为调节剂的作用提供了一个框架。
Calcium plays a regulatory role in several aspects of protein trafficking in the cell. Both vesicle fusion and vesicle formation can be inhibited by the addition of calcium chelators. Because the effects of calcium chelators have been studied predominantly in cell-free systems, it is not clear exactly which transport steps in the secretory pathway are sensitive to calcium levels. In this regard, we have studied the effects of calcium chelators on both anterograde and retrograde protein transport in whole cells. Using both cytochemical and biochemical analyses, we find that the anterograde-directed exit of vesicular stomatitis virus G protein and the retrograde-directed exit of Shiga toxin from the Golgi apparatus are both inhibited by calcium chelation. The exit of vesicular stomatitis virus G from a pre-Golgi compartment and the exit of Shiga toxin from an endosomal compartment are sensitive to the membrane-permeant calcium chelator 1,2-bis(2-amino phenoxy)ethane-N,N,N',N'-tetraacetic acid-tetrakis (acetoxymethyl ester) (BAPTA-AM). By contrast, endoplasmic reticulum exit and endocytic internalization from the plasma membrane are not affected by BAPTA. Together, our data show that some, but not all, trafficking steps in the cell may be regulated by calcium. These studies provide a framework for a more detailed analysis of the role of calcium as a regulatory agent during protein transport.