Synaptotagmin II expression partially rescues the growth defect of the yeast sec15 secretory mutant.
Synaptotagmin II expression partially rescues the growth defect of the yeast sec15 secretory mutant.
复制标题
突触结合蛋白 II 的表达部分挽救了酵母 sec15 分泌突变体的生长缺陷。
DOI：
10.1016/s0248-4900(97)86831-1
复制
发表时间：
1996
影响因子：
2.7
通讯作者：
Creutz,CE
中科院分区：
文献类型：
--
作者：
Damer,CK;Creutz,CE
synaptotagmins是一个钙和磷脂结合蛋白家族，与细胞胞吐功能有关。Synaptotagmins I和Synaptotagmins II是神经表达蛋白，被认为参与神经元的神经递质释放。我们已经在几种对温度敏感的酿酒酵母分泌突变体中表达了大鼠synaptotagmin II，这些突变体在高尔基体对质膜囊泡运输中存在缺陷。Synaptotagmin II的表达能够部分修复一个特定突变体sec15的生长缺陷。synaptotagmin II在1、sec2、sec4、sec5、sec6、sec8、sec9、sec14、sec17、sec18中表达时未见抑制作用。两个synaptotagmin II缺失突变体也在昆虫中表达，并进行了抑制筛选。单独表达synaptotagmin的胞质结构域不能抑制这些生长缺陷。此外，缺少胞质结构域下半部分（包括第二个C2结构域）的synaptotagmin II片段的表达不抑制sec15。我们从表达synaptotagmin II的asec15菌株中分离出富含高尔基后囊泡的膜组分，并发现synaptotagmin II与该组分共纯化，这表明大鼠synaptotagmin II是针对酵母膜的。sec15p形成一个大的多亚基蛋白复合物，包括Sec6p和Sec8p。这种蛋白复合物被认为在酵母的胞吐后期起作用。在哺乳动物细胞中已鉴定出Sec6p和Sec8p同源物。我们的研究表明，synaptotagmin可能是哺乳动物细胞中该复合体的一部分或调节其功能。
Summry—Synaptotagmins are a family of calcium‐ and phospholipid‐binding proteins implicated in the function of cell exocytosis. Synaptotagmins I and II are neurally expressed proteins thought to be involved in neurotransmitter release from neurons. We have expressed rat synaptotagmin II in severalSaccharomyces cerevisiaetemperature‐sensitive secretory mutants that are defective in Golgi to plasma membrane vesicular transport. Synaptotagmin II expression was able to partially rescue the growth defect in one particular mutant,sec15. No suppression was observed when synaptotagmin II was expressed insec1, sec2, sec4, sec5, sec6, sec8, sec9, sec14, sec17, orsec18. Two synaptotagmin II deletion mutants were also expressed insec15and screened for suppression. The expression of the cytoplasmic domain of synaptotagmin alone was not able to suppress thesec15growth defect. In addition, the expression of a synaptotagmin II fragment lacking the second half of the cytoplasmic domain including the second C2 domain did not suppresssec15. We have isolated a membrane fraction enriched in post‐Golgi vesicles from asec15strain expressing synaptotagmin II and found that synaptotagmin II co‐purifies with this fraction, suggesting that the rat synaptotagmin II is targeted to membranes in yeast. Sec 15p forms a large multisubunit protein complex that includes Sec6p and Sec8p. This protein complex is thought to function in a late stage of exocytosis in yeast. Sec6p and Sec8p homologs have been identified in mammalian cells. Our studies suggest that synaptotagmin may be a part of this complex or regulate its function in mammalian cells.