Hill P E, Walton P A
Department of Anatomy and Cell Biology, McGill University, Montreal, Canada.
J Cell Sci. 1995 Apr;108 ( Pt 4):1469-76. doi: 10.1242/jcs.108.4.1469.
Peroxisomes import virtually all of their membrane and matrix proteins post-translationally. It is presently unknown whether, in mammalian cells, their exists a pool of mature peroxisomes which have received their complement of proteins and are import-incompetent. Previous work has shown that fibroblasts are capable of importing microinjected peroxisomal proteins into peroxisomes. This report describes the import of a hybrid peroxisomal protein into virtually all peroxisomes of the microinjected cell. The peroxisomal import was uniform in both short and long incubations. Pretreatment of the cells with cycloheximide did not affect the import of the peroxisomal protein, nor was there any difference in the distribution of the imported protein. Sequential microinjection experiments demonstrated that peroxisomes that had imported luciferase were capable of importing another peroxisomal protein injected 24 hours later. These results suggest that, in fibroblasts, all peroxisomes have associated protein-import machinery; this evidence does not support the hypothesis that there exists a pool of import-incompetent peroxisomes.
过氧化物酶体几乎所有的膜蛋白和基质蛋白都是在翻译后导入的。目前尚不清楚在哺乳动物细胞中是否存在一群已接收其蛋白质补充且无导入能力的成熟过氧化物酶体。先前的研究表明，成纤维细胞能够将显微注射的过氧化物酶体蛋白导入过氧化物酶体。本报告描述了一种杂交过氧化物酶体蛋白几乎导入到显微注射细胞的所有过氧化物酶体中。在短期和长期孵育中，过氧化物酶体的导入都是均匀的。用环己酰亚胺预处理细胞不会影响过氧化物酶体蛋白的导入，导入蛋白的分布也没有任何差异。连续显微注射实验表明，已导入荧光素酶的过氧化物酶体能够导入24小时后注射的另一种过氧化物酶体蛋白。这些结果表明，在成纤维细胞中，所有过氧化物酶体都具有相关的蛋白导入机制；这一证据不支持存在一群无导入能力的过氧化物酶体这一假说。
