巴斯德毕赤酵母过氧化物酶体蛋白PAS8p是C末端三肽过氧化物酶体靶向信号的受体。

The Pichia pastoris peroxisomal protein PAS8p is the receptor for the C-terminal tripeptide peroxisomal targeting signal.

作者信息

Terlecky S R, Nuttley W M, McCollum D, Sock E, Subramani S

机构信息

Department of Biology, University of California-San Diego, La Jolla 92093-0322, USA.

出版信息

EMBO J. 1995 Aug 1;14(15):3627-34. doi: 10.1002/j.1460-2075.1995.tb00032.x.

The peroxisomal targeting signal 1 (PTS1), consisting of a C-terminal tripeptide (SKL and variants), directs polypeptides to the peroxisome matrix in evolutionarily diverse organisms. Previous studies in the methylotrophic yeast Pichia pastoris identified a 68 kDa protein, PAS8p, as a potential component of the PTS1 import machinery. We now report several new properties of this molecule which, taken together, show that it is the peroxisomal PTS1 receptor. (i) PAS8p is localized to and tightly associated with the cytoplasmic side of the peroxisomal membrane, (ii) peroxisomes of wild-type, but not of pas8 delta (null) mutant, P.pastoris cells bind a PTS1-containing peptide (CRYHLKPLQSKL), (iii) CRYHLKPLQSKL can be cross-linked to PAS8p after binding at the peroxisome membrane and (iv) purified PAS8p binds CRYHLKPLQSKL with high affinity (nanomolar dissociation constant). In addition, the tetratricopeptide repeat (TPR) domain of PAS8p is identified as the PTS1 binding region.

过氧化物酶体靶向信号1（PTS1）由一个C端三肽（SKL及其变体）组成，可将多肽导向进化上不同生物中的过氧化物酶体基质。先前在甲基营养型酵母巴斯德毕赤酵母中的研究确定了一种68 kDa的蛋白质PAS8p，它是PTS1导入机制的潜在组成部分。我们现在报告了该分子的几个新特性，综合起来表明它是过氧化物酶体PTS1受体。（i）PAS8p定位于过氧化物酶体膜的细胞质侧并与之紧密结合，（ii）野生型巴斯德毕赤酵母细胞的过氧化物酶体可结合含PTS1的肽（CRYHLKPLQSKL），而pas8δ（缺失）突变体的过氧化物酶体则不能，（iii）CRYHLKPLQSKL在过氧化物酶体膜上结合后可与PAS8p交联，（iv）纯化的PAS8p以高亲和力（纳摩尔解离常数）结合CRYHLKPLQSKL。此外，PAS8p的四肽重复（TPR）结构域被确定为PTS1结合区域。