Role of Pex19p in the targeting of PMP70 to peroxisome
Role of Pex19p in the targeting of PMP70 to peroxisome
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DOI：
10.1016/j.bbamcr.2005.10.006
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发表时间：
2005-12-15
影响因子：
5.1
通讯作者：
Imanaka, T
中科院分区：
文献类型：
--
作者：
Kashiwayama, Y;Asahina, K;Imanaka, T
Pex 19 p是过氧化物酶体膜合成所需的蛋白质。70 kDa的过氧化物酶体膜蛋白（PMP 70）是在游离的胞质核糖体上合成的，然后插入过氧化物酶体膜中。Pex 19 p在这一过程中发挥了重要作用。使用体外翻译系统，我们研究了Pex 19 p作为伴侣的作用，并确定了与Pex 19 p相互作用所需的PMP 70区域。当在纯化的Pex 19 p存在下翻译PMP 70时，大部分PMP 70以可溶形式存在，并与Pex 19 p共免疫沉淀。然而，在Pex 19 p的情况下，PMP 70在翻译过程中形成聚集体。为了鉴定与Pex 19 p相互作用的区域，在Pex 19 p存在下翻译各种截短的PMP 70并进行免疫共沉淀。的相互作用显着减少的NH 2-末端61个氨基酸或TMD 6周围的区域的删除。此外，我们在CHO细胞中表达了与绿色荧光蛋白融合的PMP 70的这些缺失构建体。缺乏这些Pex 19 p结合位点的融合蛋白不显示任何过氧化物酶体定位。这些结果表明，Pex 19 p与PMP 70共构象结合，并保持PMP 70作为合适的构象定位于过氧化物酶体。(c)2005 Elsevier B. V.保留所有权利。
Pex 19p is a protein required for the peroxisomal membrane synthesis. The 70-kDa peroxisomal membrane protein (PMP70) is synthesized on free cytosolic ribosomes and then inserted posttranslationally into peroxisomal membranes. Pex 19p has been shown to play an important role in this process. Using an in vitro translation system, we investigated the role of Pex 19p as a chaperone and identified the regions of PMP70 required for the interaction with Pex 19p. When PMP70 was translated in the presence of purified Pex 19p, a large part of PMP70 existed as soluble form and was co-immunoprecipitated with Pex 19p. However, in the absence of Pex 19p, PMP70 formed aggregates during translation. To identify the regions that interact with Pex 19p, various truncated PMP70 were translated in the presence of Pex 19p and subjected to co-immunoprecipitation. The interaction was markedly reduced by the deletion of the NH2-terminal 61 amino acids or the region around TMD6. Further, we expressed these deletion constructs of PMP70 in fusion with the green fluorescent protein in CHO cells. Fusion proteins lacking these Pex 19p binding sites did not display any peroxisomal localization. These results suggest that Pex 19p binds to PMP70 co-translationally and keeps PMP70 as a proper conformation for the localization to peroxisome. (c) 2005 Elsevier B.V. All rights reserved.