YidC is strictly required for membrane insertion of Subunits a and c of the F1F0ATP synthase and SecE of the SecYEG translocase
YidC is strictly required for membrane insertion of Subunits a and c of the F1F0ATP synthase and SecE of the SecYEG translocase
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DOI：
10.1021/bi034309h
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发表时间：
2003-09-09
期刊：
影响因子：
2.9
通讯作者：
Dalbey, RE
中科院分区：
文献类型：
--
作者：
Yi, L;Jiang, FL;Dalbey, RE
YidC先前被发现在将独立于sec的M13原衣和Pf3原衣噬菌体蛋白插入大肠杆菌内膜中起关键作用。为了确定是否有任何内源性大肠杆菌蛋白的膜蛋白插入绝对需要YidC，我们研究了一些有代表性的膜蛋白。基于蛋白酶定位和免疫印迹分析，我们发现F(1)F(0)ATP合成酶的F-0区膜亚基和SecYEG转位酶的SecE蛋白高度依赖于YidC进行膜插入。我们发现，在膜插入过程中，SecE依赖于YidC，这与观察结果并不矛盾，即在37度时，YidC的耗尽不会阻断secyeg依赖蛋白的输出。YidC耗竭不会将SecE水平降低到足以阻止出口的37度。相反，我们发现在25℃时，当YidC耗尽时，OmpA的蛋白质输出严重受阻，这可能是由于SecE水平下降所致，因为SecE水平下降50%会严重影响蛋白质在低温下的输出[Schatz， P. J, Bieker， K. L., Ottemann， K. M., Silhavy， T. J, and Beckwith， J.（1991）植物学报，10,1749-57]。本文报道的这些研究证实了YidC的生理底物包括ATP合酶和SecYEG转位酶的亚基，这表明YidC在细菌内源性膜蛋白插入中起着至关重要的作用。
YidC was previously discovered to play a critical role for the insertion of the Sec-independent M13 procoat and Pf3 coat phage proteins into the Escherichia coli inner membrane. To determine whether there is an absolute requirement of YidC for membrane protein insertion of any endogenous E. coli proteins, we investigated a few representative membrane proteins. We found that membrane subunits of the F-0 sector of the F(1)F(0)ATP synthase and the SecE protein of the SecYEG translocase are highly dependent on YidC for membrane insertion, based on protease mapping and immunoblot analysis. We found that the SecE dependency on YidC for membrane insertion does not contradict the observation that depletion of YidC does not block SecYEG-dependent protein export at 37 degreesC. YidC depletion does not decrease the SecE level low enough to block export at 37 degreesC. In contrast, we found that protein export of OmpA is severely blocked at 25 degreesC when YidC is depleted, which may be due to the decreased SecE level, as a 50% decrease in the SecE levels drastically affects protein export at the cold temperature [Schatz, P. J., Bieker, K. L., Ottemann, K. M., Silhavy, T. J., and Beckwith, J. (1991) EMBO J. 10, 1749-57]. These studies reported here establish that physiological substrates of YidC include subunits of the ATP synthase and the SecYEG translocase, demonstrating that YidC plays a vital role for insertion of endogenous membrane proteins in bacteria.