Nair Devi M, Purdue P Edward, Lazarow Paul B
Mount Sinai School of Medicine, New York, NY 10029, USA.
J Cell Biol. 2004 Nov 22;167(4):599-604. doi: 10.1083/jcb.200407119. Epub 2004 Nov 15.
Pex7p is the soluble receptor responsible for importing into peroxisomes newly synthesized proteins bearing a type 2 peroxisomal targeting sequence. We observe that appending GFP to Pex7p's COOH terminus shifts Pex7p's intracellular distribution from predominantly cytosolic to predominantly peroxisomal in Saccharomyces cerevisiae. Cleavage of the link between Pex7p and GFP within peroxisomes liberates GFP, which remains inside the organelle, and Pex7p, which exits to the cytosol. The reexported Pex7p is functional, resulting in import of thiolase into peroxisomes and improved growth of the yeast on oleic acid. These results support the "extended shuttle" model of peroxisome import receptor function and open the way to future studies of receptor export.
Pex7p是一种可溶性受体，负责将带有2型过氧化物酶体靶向序列的新合成蛋白质导入过氧化物酶体。我们观察到，在酿酒酵母中，将绿色荧光蛋白（GFP）附加到Pex7p的COOH末端会使Pex7p的细胞内分布从主要位于胞质溶胶转变为主要位于过氧化物酶体。过氧化物酶体内Pex7p与GFP之间的连接被切割后，会释放出留在细胞器内的GFP和进入胞质溶胶的Pex7p。重新输出的Pex7p具有功能，可导致硫解酶导入过氧化物酶体，并改善酵母在油酸上的生长。这些结果支持了过氧化物酶体导入受体功能的“扩展穿梭”模型，并为未来受体输出的研究开辟了道路。
