The energetics of Pex5p-mediated peroxisomal protein import
The energetics of Pex5p-mediated peroxisomal protein import
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DOI：
10.1074/jbc.m305089200
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发表时间：
2003-10-10
影响因子：
4.8
通讯作者：
Azevedo, JE
中科院分区：
文献类型：
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作者：
Oliveira, ME;Gouveia, AM;Azevedo, JE
大多数新合成的过氧化物酶体基质蛋白通过过氧化物酶体循环受体 Pex5p 靶向细胞器。根据目前的过氧化物酶体生物发生模型，Pex5p 与细胞质中的货物蛋白相互作用并将其转运至过氧化物酶体膜。将过客蛋白递送至过氧化物酶体基质后，Pex5p 返回胞质溶胶以催化额外几轮的运输。显然，这样的循环途径必须需要能量，事实上，已经有数据证实了这种需要。然而，该循环中需要能量输入的确切步骤仍不清楚。在这里，我们提供的数据表明，将 Pex5p 插入过氧化物酶体膜不需要 ATP 水解。这一观察结果提出了一种可能性，即在过氧化物酶体膜上，蛋白质易位步骤的下游主要（如果不是全部）需要 ATP 来重置 Pex5p 介导的转运系统。
Most newly synthesized peroxisomal matrix proteins are targeted to the organelle by Pex5p, the peroxisomal cycling receptor. According to current models of peroxisomal biogenesis, Pex5p interacts with cargo proteins in the cytosol and transports them to the peroxisomal membrane. After delivering the passenger protein into the peroxisomal matrix, Pex5p returns to the cytosol to catalyze additional rounds of transportation. Obviously, such cyclic pathway must require energy, and indeed, data confirming this need are already available. However, the exact step(s) of this cycle where energy input is necessary remains unclear. Here, we present data suggesting that insertion of Pex5p into the peroxisomal membrane does not require ATP hydrolysis. This observation raises the possibility that at the peroxisomal membrane ATP is needed predominantly (if not exclusively) downstream of the protein translocation step to reset the Pex5p-mediated transport system.