Chaudhuri B, Latham S E, Helliwell S B, Seeboth P
Department of Biotechnology, Ciba-Geigy Ltd., Basel, Switzerland.
Biochem Biophys Res Commun. 1992 Feb 28;183(1):212-9. doi: 10.1016/0006-291x(92)91630-9.
The prepro sequence of the yeast prepro-alpha-factor, usually referred to as the alpha-factor leader, has often been used for the efficient secretion of heterologous proteins from the yeast Saccharomyces cerevisiae. The alpha-factor leader consists of a 19-amino acid N-terminal pre or signal sequence followed by a 66-amino acid proregion. After removal of the signal sequence during membrane translocation, the proregion is cleaved from the precursor protein by the Kex2 endoprotease only in a late Golgi compartment. Here we report that a modified Kex2 enzyme, containing at the C-terminus the HDEL tetrapeptide, cleaves the proregion from the alpha-factor leader--human insulin like growth factor-1 fusion protein in the endoplasmic reticulum. The processing of pro-proteins earlier in the secretion pathway could be helpful in defining the cellular function of the proregions present naturally in various eucaryotic precursor proteins.
酵母前体α因子的前原序列，通常称为α因子前导序列，常被用于从酿酒酵母中高效分泌异源蛋白。α因子前导序列由一个19个氨基酸的N端前导或信号序列以及一个66个氨基酸的原区组成。在膜转运过程中信号序列被去除后，原区仅在高尔基体晚期区室中被Kex2内切蛋白酶从前体蛋白上切割下来。在此我们报道，一种在C端含有HDEL四肽的修饰型Kex2酶，在内质网中从α因子前导序列-人胰岛素样生长因子-1融合蛋白上切割下原区。在分泌途径中更早地加工前体蛋白，可能有助于确定各种真核生物前体蛋白中天然存在的原区的细胞功能。
