Reppe S, Smeland S, Moskaug J O, Blomhoff R
Institute for Medical Biochemistry, University of Oslo, Norway.
FEBS Lett. 1998 May 8;427(2):213-9. doi: 10.1016/s0014-5793(98)00428-1.
Retinol-binding protein (RBP) functions as a transporter for retinol (vitamin A) in plasma in higher eukaryotes. We have successfully expressed human RBP in Saccharomyces cerevisiae, and its secretion was found to be induced by retinol also in this lower eukaryote. Reduced induction of secretion by retinol in a temperature-sensitive sec18-1 mutant that is blocked in secretion at the restricted temperature suggests that as in mammalian cells, RBP can be released from the endoplasmic reticulum upon addition of retinol. Thus, the molecular mechanism involved in retinol-dependent secretion of RBP appears to be conserved in yeast, and this points to yeast as a putative model system for studying retinol-regulated secretion of RBP. RBP purified from yeast was found to be indistinguishable from RBP purified from human plasma in several functional assays.
视黄醇结合蛋白（RBP）在高等真核生物中作为血浆中视黄醇（维生素A）的转运蛋白发挥作用。我们已在酿酒酵母中成功表达了人RBP，并且发现在这种低等真核生物中视黄醇也可诱导其分泌。在温度敏感型sec18-1突变体中，视黄醇对分泌的诱导作用减弱，该突变体在限制温度下分泌受阻，这表明与哺乳动物细胞一样，添加视黄醇后RBP可从内质网释放。因此，RBP视黄醇依赖性分泌所涉及的分子机制在酵母中似乎是保守的，这表明酵母是研究视黄醇调节的RBP分泌的一个假定模型系统。在几种功能测定中，发现从酵母中纯化的RBP与从人血浆中纯化的RBP没有区别。
