Tic40 is important for reinsertion of proteins from the chloroplast stroma into the inner membrane.
Tic40 is important for reinsertion of proteins from the chloroplast stroma into the inner membrane.
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DOI：
10.1111/j.1365-313x.2008.03638.x
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发表时间：
2008-12
期刊：
影响因子：
--
通讯作者：
Li HM
中科院分区：
文献类型：
--
作者：
Chiu CC;Li HM
叶绿体内膜蛋白Tic 40和Tic 110首先从细胞质输入到叶绿体基质中，随后从基质重新插入到内膜中。然而，重新安置的机制仍不清楚。在这里，我们表明Tic 40本身参与了这个重新插入过程。当前体的Tic 40或Tic 110 C-末端截短，tpTic 110-Tic 110 N，进口到叶绿体分离的tic 40无效突变体，可溶性Tic 40和Tic 110 N中间积累在基质中的tic 40突变体叶绿体，由于重新插入的速度较慢。我们进一步表明，大量的可溶性Tic 21中间体也积累在基质中的tic 40突变体叶绿体。相比之下，磷酸丙糖/磷酸转运蛋白的内膜插入不受tic 40突变的影响。我们的数据表明，叶绿体内膜蛋白的插入存在多种途径。
Chloroplast inner-membrane proteins Tic40 and Tic110 are first imported from the cytosol into the chloroplast stroma, and subsequently reinserted from the stroma into the inner membrane. However, the mechanism of reinsertion remains unclear. Here we show that Tic40 itself is involved in this reinsertion process. When precursors of either Tic40 or a Tic110 C-terminal truncate, tpTic110-Tic110N, were imported into chloroplasts isolated from a tic40-null mutant, soluble Tic40 and Tic110N intermediates accumulated in the stroma of tic40-mutant chloroplasts, due to a slower rate of reinsertion. We further show that a larger quantity of soluble Tic21 intermediates also accumulated in the stroma of tic40-mutant chloroplasts. In contrast, inner-membrane insertion of the triose-phosphate/phosphate translocator was not affected by the tic40 mutation. Our data suggest that multiple pathways exist for the insertion of chloroplast inner-membrane proteins.