DnaK and DnaJ heat shock proteins participate in protein export in Escherichia coli.
DnaK and DnaJ heat shock proteins participate in protein export in Escherichia coli.
复制标题
DnaK 和 DnaJ 热休克蛋白参与大肠杆菌中的蛋白质输出。
DOI：
10.1101/gad.6.7.1165
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发表时间：
1992
影响因子：
10.5
通讯作者：
Gross,CA
中科院分区：
文献类型：
--
作者：
Wild,J;Altman,E;Yura,T;Gross,CA
在大肠杆菌中，分泌的蛋白质在跨细胞质膜转运之前必须保持在有输出能力的状态。这种功能是由一组称为伴侣蛋白的蛋白质执行的。SecB是在前体蛋白分泌之前与其相互作用的主要伴侣。我们报告的结果表明，DnaK和DnaJ热休克蛋白也参与了几种蛋白质的出口，最有可能是作为他们的伴侣。转移的碱性磷酸酶，SecB-独立的蛋白质，被抑制在dnaK-和dnaJ-突变株，这表明该蛋白质的出口可能涉及DnaK和DnaJ。此外，DnaK和DnaJ在缺乏SecB的菌株中起关键作用。它们对于在secB无效菌株中观察到的SecB依赖性蛋白LamB和麦芽糖结合蛋白（MBP）的活力和残留加工都是必需的。此外，DnaK和DnaJ的过量生产允许缺乏SecB的菌株在丰富的培养基中生长，并加速LamB和MBP的加工。这些结果表明，在SecB成为限制的条件下，DnaK和DnaJ可能取代SecB和促进蛋白质输出。这为细胞提供了一种机制，以克服由前体蛋白库突然扩增引起的分泌过程中的暂时不平衡。
In Escherichia coli secreted proteins must be maintained in an export-competent state before translocation across the cytoplasmic membrane. This function is carried out by a group of proteins called chaperones. SecB is the major chaperone that interacts with precursor proteins before their secretion. We report results indicating that the DnaK and DnaJ heat shock proteins are also involved in the export of several proteins, most likely by acting as their chaperones. Translocation of alkaline phosphatase, a SecB-independent protein, was inhibited in dnaK- and dnaJ- mutant strains, suggesting that export of this protein probably involves DnaK and DnaJ. In addition, DnaK and DnaJ play a critical role in strains lacking SecB. They are required both for viability and for the residual processing of the SecB-dependent proteins LamB and maltose-binding protein (MBP) seen in secB null strains. Furthermore, overproduction of DnaK and DnaJ permits strains lacking SecB to grow in rich medium and accelerates the processing of LamB and MBP. These results suggest that under conditions where SecB becomes limiting, DnaK and DnaJ probably substitute for SecB and facilitate protein export. This provides the cell with a mechanism to overcome a temporary imbalance in the secretion process caused by an abrupt expansion in the pool of precursor proteins.