Huhse B, Rehling P, Albertini M, Blank L, Meller K, Kunau W H
Abteilung für Zellbiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum, Germany.
J Cell Biol. 1998 Jan 12;140(1):49-60. doi: 10.1083/jcb.140.1.49.
The Saccharomyces cerevisiae pex17-1 mutant was isolated from a screen to identify mutants defective in peroxisome biogenesis. pex17-1 and pex17 null mutants fail to import matrix proteins into peroxisomes via both PTS1- and PTS2-dependent pathways. The PEX17 gene (formerly PAS9; Albertini, M., P. Rehling, R. Erdmann, W. Girzalsky, J.A.K.W. Kiel, M. Veenhuis, and W.-H Kunau. 1997. Cell. 89:83-92) encodes a polypeptide of 199 amino acids with one predicted membrane spanning region and two putative coiled-coil structures. However, localization studies demonstrate that Pex17p is a peripheral membrane protein located at the surface of peroxisomes. Particulate structures containing the peroxisomal integral membrane proteins Pex3p and Pex11p are evident in pex17 mutant cells, indicating the existence of peroxisomal remnants ("ghosts"). This finding suggests that pex17 null mutant cells are not impaired in peroxisomal membrane biogenesis. Two-hybrid studies showed that Pex17p directly binds to Pex14p, the recently proposed point of convergence for the two peroxisomal targeting signal (PTS)-dependent import pathways, and indirectly to Pex5p, the PTS1 receptor. The latter interaction requires Pex14p, indicating the potential of these three peroxins to form a trimeric complex. This conclusion is supported by immunoprecipitation experiments showing that Pex14p and Pex17p coprecipitate with both PTS receptors in the absence of Pex13p. From these and other studies we conclude that Pex17p, in addition to Pex13p and Pex14p, is the third identified component of the peroxisomal translocation machinery.
酿酒酵母pex17 - 1突变体是从一个筛选中分离出来的，该筛选旨在鉴定过氧化物酶体生物发生缺陷的突变体。pex17 - 1和pex17缺失突变体无法通过PTS1和PTS2依赖途径将基质蛋白导入过氧化物酶体。PEX17基因（以前称为PAS9；Albertini, M., P. Rehling, R. Erdmann, W. Girzalsky, J.A.K.W. Kiel, M. Veenhuis, and W.-H Kunau. 1997. Cell. 89:83 - 92）编码一个由199个氨基酸组成的多肽，有一个预测的跨膜区域和两个假定的卷曲螺旋结构。然而，定位研究表明Pex17p是一种位于过氧化物酶体表面的外周膜蛋白。在pex17突变体细胞中，含有过氧化物酶体整合膜蛋白Pex3p和Pex11p的颗粒结构很明显，这表明存在过氧化物酶体残余物（“幽灵”）。这一发现表明pex17缺失突变体细胞在过氧化物酶体膜生物发生方面没有受损。双杂交研究表明，Pex17p直接与Pex14p结合，Pex14p是最近提出的两条过氧化物酶体靶向信号（PTS）依赖导入途径的汇聚点，并且间接与PTS1受体Pex5p结合。后一种相互作用需要Pex14p，表明这三种过氧化物酶形成三聚体复合物的可能性。免疫沉淀实验支持了这一结论，该实验表明在没有Pex13p的情况下，Pex14p和Pex17p与两种PTS受体共沉淀。从这些研究和其他研究中我们得出结论，除了Pex13p和Pex14p之外，Pex17p是过氧化物酶体转运机制中第三个被鉴定的成分。
