Jones Jacob M, Morrell James C, Gould Stephen J
Dept. of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
J Cell Biol. 2004 Jan 5;164(1):57-67. doi: 10.1083/jcb.200304111.
Integral peroxisomal membrane proteins (PMPs) are synthesized in the cytoplasm and imported posttranslationally. Here, we demonstrate that PEX19 binds and stabilizes newly synthesized PMPs in the cytosol, binds to multiple PMP targeting signals (mPTSs), interacts with the hydrophobic domains of PMP targeting signals, and is essential for PMP targeting and import. These results show that PEX19 functions as both a chaperone and an import receptor for newly synthesized PMPs. We also demonstrate the existence of two PMP import mechanisms and two classes of mPTSs: class 1 mPTSs, which are bound by PEX19 and imported in a PEX19-dependent manner, and class 2 mPTSs, which are not bound by PEX19 and mediate protein import independently of PEX19.
完整的过氧化物酶体膜蛋白（PMPs）在细胞质中合成并在翻译后导入。在此，我们证明PEX19在细胞质中结合并稳定新合成的PMPs，与多个PMP靶向信号（mPTSs）结合，与PMP靶向信号的疏水结构域相互作用，并且对于PMP的靶向和导入至关重要。这些结果表明，PEX19作为新合成PMPs的伴侣蛋白和导入受体发挥作用。我们还证明了存在两种PMP导入机制和两类mPTSs：第1类mPTSs，由PEX19结合并以PEX19依赖的方式导入；第2类mPTSs，不被PEX19结合并独立于PEX19介导蛋白质导入。
