Kragler F, Langeder A, Raupachova J, Binder M, Hartig A
Institut für Biochemie und Molekulare Zellbiologie, Universität Wien, Austria.
J Cell Biol. 1993 Feb;120(3):665-73. doi: 10.1083/jcb.120.3.665.
In contrast to many other peroxisomal proteins catalase A contains at least two peroxisomal targeting signals each sufficient to direct reporter proteins to peroxisomes. One of them resides at the extreme carboxy terminus constituting a new variant of this signal, -SSNSKF, not active in monkey kidney cells (Gould, S. J., G. A. Keller, N. Hosken, J. Wilkinson, and S. Subramani 1989. J. Cell Biol. 108:1657-1664). However, this signal is completely dispensable for import of catalase A itself. In its amino-terminal third this protein contains another peroxisomal targeting signal sufficient to direct reporter proteins into microbodies. This internal signal depends on the context. The nature of this targeting signal might be a short defined sequence or a structural feature recognized by import factors. In addition, we have demonstrated that the carboxy-terminal seven amino acids of citrate synthase of Saccharomyces cerevisiae encoded by CIT2 and containing the canonical -SKL represents a targeting signal sufficient to direct reporter proteins to peroxisomes.
与许多其他过氧化物酶体蛋白不同，过氧化氢酶A至少含有两个过氧化物酶体靶向信号，每个信号都足以将报告蛋白导向过氧化物酶体。其中一个位于极端羧基末端，构成了该信号的一种新变体——-SSNSKF，在猴肾细胞中无活性（古尔德，S. J.，G. A. 凯勒，N. 霍斯肯，J. 威尔金森，和S. 苏布拉马尼，1989年。《细胞生物学杂志》108:1657 - 1664）。然而，这个信号对于过氧化氢酶A自身的导入完全是可有可无的。在其氨基末端三分之一区域，该蛋白含有另一个过氧化物酶体靶向信号，足以将报告蛋白导入微体。这个内部信号取决于上下文。这个靶向信号的性质可能是一个短的特定序列或一个被导入因子识别的结构特征。此外，我们已经证明，酿酒酵母柠檬酸合酶由CIT2编码的羧基末端七个氨基酸，包含典型的-SKL，代表一个足以将报告蛋白导向过氧化物酶体的靶向信号。
