Synaptotagmin III is a novel isoform of rat synaptotagmin expressed in endocrine and neuronal cells.
Synaptotagmin III is a novel isoform of rat synaptotagmin expressed in endocrine and neuronal cells.
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Synaptotagmin III 是一种在内分泌和神经细胞中表达的大鼠突触结合蛋白的新型亚型。
DOI：
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发表时间：
1994
影响因子：
4.8
通讯作者：
Susumu Seino
中科院分区：
文献类型：
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作者：
M. Mizuta;Nobuya Inagaki;Y. Nemoto;S. Matsukura;Masami Takahashi;Susumu Seino
突触结合蛋白（Synaptotagmin，p65）是突触囊泡的一种膜蛋白，参与突触囊泡的胞吐作用。在这里，我们报告的克隆和组织分布的一种新的亚型的突触结合蛋白，指定突触结合蛋白III。编码突触结合蛋白III的cDNA克隆已从大鼠脑cDNA文库中分离出来。大鼠突触结合蛋白III是一种588个氨基酸的蛋白质，分别与大鼠突触结合蛋白I、大鼠突触结合蛋白II和o-p65-C（海洋鳐的第三种突触结合蛋白同种型）具有40.5%、38.3%和64.0%的同一性。与蛋白激酶C的调节结构域（C2结构域）同源的两个内部重复序列的区域在突触结合蛋白I、II和III之间高度保守。RNA印迹研究表明，synaptotagmin III mRNA表达在脑，各种内分泌组织，和神经分泌克隆细胞。这些结果表明，大鼠synaptotagmin III是一个哺乳动物的同源物的o-p65-C，并参与Ca（2+）依赖性胞吐的分泌囊泡在内分泌细胞，以及在神经元。
Synaptotagmin (p65), an integral membrane protein of synaptic vesicles, is thought to be involved in calcium-dependent exocytosis of synaptic vesicles. Here, we report the cloning and tissue distribution of a novel isoform of synaptotagmin, designated synaptotagmin III. The cDNA clones encoding synaptotagmin III have been isolated from a rat brain cDNA library. Rat synaptotagmin III is a protein of 588 amino acids having 40.5, 38.3, and 64.0% identity with rat synaptotagmin I, rat synaptotagmin II, and o-p65-C, a third synaptotagmin isoform of marine ray Discopyge ommata, respectively. The region of the two internal repeats homologous to the regulatory domain (C2 domain) of protein kinase C is highly conserved among synaptotagmin I, II, and III. RNA blotting studies reveal that synaptotagmin III mRNA is expressed in brain, various endocrine tissues, and hormone-secreting clonal cells. These results suggest that rat synaptotagmin III is a mammalian homolog of o-p65-C and is involved in Ca(2+)-dependent exocytosis of secretory vesicles in endocrine cells, as well as in neurons.