Bursać Dejan, Lithgow Trevor
Department of Biochemistry & Molecular Biology, Monash University, Clayton, Australia.
FEBS Lett. 2009 Sep 3;583(17):2954-8. doi: 10.1016/j.febslet.2009.08.005. Epub 2009 Aug 13.
J-proteins are a class of molecular chaperones that serve to stimulate the activity of Hsp70s and are often located to recruit Hsp70 to a particular cellular function. Protein degradation associated with the endoplasmic reticulum (ERAD) is one such cellular process that requires Hsp70 on both faces of the endoplasmic reticulum. At least five J-proteins, including Jid1 (DnaJ protein Involved in ER-associated Degradation), have been implicated in controlling ERAD. Here we show that Jid1 is confined within the mitochondrial matrix - Jid1 has the same topology as the J-proteins Pam18 and Mdj2, which stimulate mitochondrial Hsp70 to drive protein import into the mitochondrial matrix. The location of Jid1 within mitochondria makes it unavailable to participate directly in the regulation of ERAD.
J蛋白是一类分子伴侣，可刺激热休克蛋白70（Hsp70）的活性，并且常定位在特定细胞功能中招募Hsp70。与内质网相关的蛋白降解（ERAD）就是这样一种细胞过程，在内质网的两侧都需要Hsp70。至少有五种J蛋白，包括Jid1（参与内质网相关降解的DnaJ蛋白），与控制ERAD有关。我们在此表明Jid1局限于线粒体基质内——Jid1与J蛋白Pam18和Mdj2具有相同的拓扑结构，后者刺激线粒体Hsp70以驱动蛋白质导入线粒体基质。Jid1在线粒体内的位置使其无法直接参与ERAD的调节。
