Elgersma Y, Kwast L, Klein A, Voorn-Brouwer T, van den Berg M, Metzig B, America T, Tabak H F, Distel B
Department of Biochemistry, Academic Medical Centre, Amsterdam, The Netherlands.
J Cell Biol. 1996 Oct;135(1):97-109. doi: 10.1083/jcb.135.1.97.
We identified a Saccharomyces cerevisiae peroxisomal membrane protein, Pex13p, that is essential for protein import. A point mutation in the COOH-terminal Src homology 3 (SH3) domain of Pex13p inactivated the protein but did not affect its membrane targeting. A two-hybrid screen with the SH3 domain of Pex13p identified Pex5p, a receptor for proteins with a type I peroxisomal targeting signal (PTS1), as its ligand. Pex13p SH3 interacted specifically with Pex5p in vitro. We determined, furthermore, that Pex5p was mainly present in the cytosol and only a small fraction was associated with peroxisomes. We therefore propose that Pex13p is a component of the peroxisomal protein import machinery onto which the mobile Pex5p receptor docks for the delivery of the selected PTS1 protein.
我们鉴定出一种酿酒酵母过氧化物酶体膜蛋白Pex13p，它对于蛋白质输入至关重要。Pex13p羧基末端Src同源结构域3（SH3）中的一个点突变使该蛋白失活，但不影响其膜靶向。用Pex13p的SH3结构域进行的双杂交筛选确定Pex5p，一种具有I型过氧化物酶体靶向信号（PTS1）的蛋白质的受体，为其配体。Pex13p SH3在体外与Pex5p特异性相互作用。此外，我们确定Pex5p主要存在于细胞质中，只有一小部分与过氧化物酶体相关。因此，我们提出Pex13p是过氧化物酶体蛋白质输入机制的一个组成部分，移动的Pex5p受体停靠在该机制上以递送选定的PTS1蛋白。
