Phosphorylation of components of the ER translocation site
Phosphorylation of components of the ER translocation site
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DOI：
10.1046/j.1432-1327.1999.00215.x
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发表时间：
1999-03-01
期刊：
影响因子：
--
通讯作者：
Dobberstein, B
中科院分区：
文献类型：
--
作者：
Gruss, OJ;Feick, P;Dobberstein, B
在许多真核细胞中，蛋白质的分泌受细胞外信号分子的调节，细胞外信号分子导致细胞内钙离子增加，并激活激酶和磷酸酶。为了测试参与分泌的第一步--蛋白质跨内质网膜的转运--是否受钙依赖的磷酸化和去磷酸化的调节，我们研究了钙离子对粗面内质网相关的激酶的影响。利用纯化的狗胰腺粗微粒体，我们发现钙离子依赖的蛋白激酶C(PKC)亚型与蛋白质转位机制的粗面内质网和磷酸化的基本成分有关。在体外，PKCs对微粒体蛋白的磷酸化提高了蛋白质的转位效率。我们还发现，在完整的细胞中，转位机制的蛋白质发生了磷酸化。这表明，蛋白质跨ER膜的转运受到了更深层次的调控。
In many eukaryotic cells, protein secretion is regulated by extracellular signalling molecules giving rise to increased intracellular Ca2+ and activation of kinases and phosphatases. To test whether components involved in the first step of secretion, the translocation of proteins across the endoplasmic reticulum (ER) membrane, are regulated by Ca2+-dependent phosphorylation and dephosphorylation, we have investigated the effect of Ca2+ on kinases associated with the rough ER. Using purified rough microsomes from dog pancreas we found that Ca2+-dependent isoforms of protein kinase C (PKC) are associated with the rough ER and phosphorylate essential components of the protein translocation machinery. Phosphorylation of microsomal proteins by PKCs increased protein translocation efficiency in vitro. We also found that proteins of the translocation machinery became phosphorylated in intact cells. This suggests a further level of regulation of protein translocation across the ER membrane.