Peroxisomal matrix protein import is facilitated by cycling receptors that recognize their cargo proteins in the cytosol by peroxisomal targeting sequences (PTS). In the following, the assembled receptor-cargo complex is targeted to the peroxisomal membrane where it docks to the docking-complex as part of the peroxisomal translocation machinery. The docking-complex is composed of Pex13p, Pex14p and in yeast also Pex17p, whose function is still elusive. In order to characterize the function of Pex17p, we compared the composition and size of peroxisomal receptor-docking complexes from wild-type and pex17Δ cells. Our data demonstrate that the deficiency of Pex17p affects the stoichiometry of the constituents of an isolated 600kDa complex and that pex17Δ cells lack a high molecular weight complex (>900kDa) of unknown function. We identified the dynein light chain protein Dyn2p as an additional core component of the Pex14p/Pex17p-complex. Both, Pex14p and Pex17p interact directly with Dyn2p, but in vivo, Pex17p turned out to be prerequisite for an association of Dyn2p with Pex14p. Finally, like pex17Δ also dyn2Δ cells lack the high molecular weight complex. As dyn2Δ cells also display reduced peroxisomal function, our data indicate that Dyn2p-dependent formation of the high molecular weight Pex14p-complex is required to maintain peroxisomal function on wild-type level.

中文翻译：

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过氧化物酶体蛋白导入机制的Pex14p / Dyn2p-亚复合物的Pex17p依赖性组装。

通过过氧化物酶体靶向序列（PTS）循环识别细胞质中其货物蛋白的受体，可以促进过氧化物酶体基质蛋白的导入。在下文中，组装的受体-货物复合物靶向过氧化物酶体膜，在其中它作为过氧化物酶体转运机制的一部分对接至对接复合物。对接复合体由Pex13p，Pex14p以及酵母中的Pex17p组成，其功能仍然难以捉摸。为了表征Pex17p的功能，我们比较了野生型和pex17Δ细胞的过氧化物酶体受体对接复合物的组成和大小。我们的数据表明，Pex17p的缺乏会影响分离的600kDa复合物成分的化学计量，并且pex17Δ细胞缺乏未知功能的高分子量复合物（> 900kDa）。我们确定了动力蛋白轻链蛋白Dyn2p是Pex14p / Pex17p-复合物的另一个核心组件。Pex14p和Pex17p都直接与Dyn2p相互作用，但是在体内，Pex17p成为Dyn2p与Pex14p缔合的前提。最后，像pex17Δ一样，dyn2Δ细胞也缺乏高分子量复合物。由于dyn2Δ细胞还显示出降低的过氧化物酶体功能，我们的数据表明，高分子量Pex14p复合体的Dyn2p依赖性形成是维持野生型水平的过氧化物酶体功能所必需的。像pex17Δ一样，dyn2Δ细胞也缺乏高分子量复合物。由于dyn2Δ细胞还显示出降低的过氧化物酶体功能，我们的数据表明，高分子量Pex14p复合体的Dyn2p依赖性形成是维持野生型水平上的过氧化物酶体功能所必需的。像pex17Δ一样，dyn2Δ细胞也缺乏高分子量复合物。由于dyn2Δ细胞还显示出降低的过氧化物酶体功能，我们的数据表明，高分子量Pex14p复合体的Dyn2p依赖性形成是维持野生型水平的过氧化物酶体功能所必需的。