Ryals P E, Bae S, Patterson C E
Department of Biochemistry and Molecular Biology, Mississippi State University 39762, USA.
J Eukaryot Microbiol. 1999 Jan-Feb;46(1):77-83. doi: 10.1111/j.1550-7408.1999.tb04587.x.
The mechanism of stomatin-induced differentiation of Tetrahymena vorax was investigated by in vivo protease degradation of cell surface proteins, the direct measurement of products formed from the activation of phospholipase C, and the use of an array of signal transduction inhibitors/activators. The data indicate that a surface-exposed protein is required for stomatin to signal the cells to differentiate and that the cells are committed to the differentiation pathway within two hours after exposure to stomatin. Analysis of radiolabeled polyphosphoinositols and inositol lipids from control and stomatin-treated populations in the presence of 10 mM LiCl were consistent with a rapid activation of phospholipase C. Within five min following addition of stomatin, this resulted in an increase in polyphosphoinositols and a concomitant decrease in the relative amounts of phosphatidylinositol bisphosphate and phosphatidylinositol trisphosphate.
通过对细胞表面蛋白进行体内蛋白酶降解、直接测量磷脂酶C激活产生的产物以及使用一系列信号转导抑制剂/激活剂，研究了口前叶四膜虫中气孔蛋白诱导分化的机制。数据表明，气孔蛋白向细胞发出分化信号需要一种表面暴露蛋白，并且细胞在暴露于气孔蛋白后两小时内就会进入分化途径。在10 mM LiCl存在的情况下，对对照和经气孔蛋白处理的群体中的放射性标记多磷酸肌醇和肌醇脂质进行分析，结果与磷脂酶C的快速激活一致。添加气孔蛋白后五分钟内，这导致多磷酸肌醇增加，同时磷脂酰肌醇二磷酸和磷脂酰肌醇三磷酸的相对量减少。
