Presequence Recognition by the Tom40 Channel Contributes to Precursor Translocation into the Mitochondrial Matrix
Presequence Recognition by the Tom40 Channel Contributes to Precursor Translocation into the Mitochondrial Matrix
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DOI：
10.1128/mcb.00433-14
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发表时间：
2014-09-01
影响因子：
5.3
通讯作者：
Rehling, Peter
中科院分区：
文献类型：
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作者：
Melin, Jonathan;Schuiz, Christian;Rehling, Peter
超过70%的线粒体蛋白利用N-末端前序列作为靶向信号。与线粒体外膜（TOM）的易位酶的冗余胞质受体结构域的前序列相互作用是很好地建立的。然而，在前序列进入蛋白传导Tom 40通道后，在导致前序列与内膜结合受体接合的反式侧发生的识别事件不太清楚。使用修饰的前序列肽的光亲和标记方法，我们确定Tom 40作为TOM复合物的前序列相互作用。利用质谱分析，我们将Tom 40的前序列相互作用区域映射到β桶的两侧。前序列相互作用区域之一内的磷酸化位点的分析揭示改变易位动力学沿着前序列途径。我们的分析评估之间的关系，确定的前序列结合区域的Tom 40和膜间空间域的Tom 22。所确定的Tom 40前序列相互作用区域能够在基质导入期间独立于所建立的反式作用TOM前序列结合结构域发挥作用。
More than 70% of mitochondrial proteins utilize N-terminal presequences as targeting signals. Presequence interactions with redundant cytosolic receptor domains of the translocase of the outer mitochondrial membrane (TOM) are well established. However, after the presequence enters the protein-conducting Tom40 channel, the recognition events that occur at the trans side leading up to the engagement of the presequence with inner membrane-bound receptors are less well defined. Using a photoaffinity-labeling approach with modified presequence peptides, we identified Tom40 as a presequence interactor of the TOM complex. Utilizing mass spectrometry, we mapped Tom40's presequence-interacting regions to both sides of the beta-barrel. Analysis of a phosphorylation site within one of the presequence-interacting regions revealed altered translocation kinetics along the presequence pathway. Our analyses assess the relation between the identified presequence-binding region of Tom40 and the intermembrane space domain of Tom22. The identified presequence-interacting region of Tom40 is capable of functioning independently of the established trans-acting TOM presequence-binding domain during matrix import.