日本电鳐电器官突触前神经末梢的一种钙通道包含一个非N型α2δ亚基。

A calcium channel from the presynaptic nerve terminal of the Narke japonica electric organ contains a non-N-type alpha 2 delta subunit.

作者信息

Tokumaru H, Shojaku S, Takehara H, Hirashima N, Abe T, Saisu H, Kirino Y

机构信息

Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.

出版信息

J Neurochem. 1995 Aug;65(2):831-6. doi: 10.1046/j.1471-4159.1995.65020831.x.

DOI:10.1046/j.1471-4159.1995.65020831.x

PMID:7616242

Abstract

A monoclonal antibody (MCC-1) that recognizes the alpha 2 delta subunit complex of L-type calcium channels from rabbit skeletal muscle membranes partially inhibited the evoked release of acetylcholine from synaptosomes isolated from the electric organ of the marine electric ray, Narke japonica. Digitonin extracts of synaptosomal plasma membranes were subjected to immunoaffinity column chromatography on MCC-1-Sepharose. The purified fraction contained a 170-kDa protein that reacts with MCC-1 and dissociates into smaller polypeptides under reducing conditions. In addition, immunoblotting analysis revealed the existence of syntaxin in the purified fraction, suggesting that the calcium channel forms a complex with syntaxin. However, MCC-1 did not immunoprecipitate an omega-conotoxin GVIA-binding protein. These findings indicate that the 170-kDa protein may be the alpha 2 delta subunit of a calcium channel that is distinct from the omega-conotoxin GVIA-sensitive N-type calcium channel and partially responsible for the calcium influx that triggers the evoked release of acetylcholine.

摘要

一种单克隆抗体（MCC - 1）可识别兔骨骼肌膜中L型钙通道的α2δ亚基复合体，该抗体可部分抑制从日本电鳐（Narke japonica）电器官分离出的突触体中乙酰胆碱的诱发释放。突触体质膜的洋地黄皂苷提取物在MCC - 1 - 琼脂糖上进行免疫亲和柱层析。纯化后的组分含有一种170 kDa的蛋白质，它能与MCC - 1反应，并在还原条件下解离成较小的多肽。此外，免疫印迹分析显示纯化后的组分中存在 syntaxin，这表明钙通道与syntaxin形成了复合体。然而，MCC - 1并未免疫沉淀ω-芋螺毒素GVIA结合蛋白。这些发现表明，170 kDa的蛋白质可能是一种钙通道的α2δ亚基，它不同于ω-芋螺毒素GVIA敏感的N型钙通道，并且部分负责触发乙酰胆碱诱发释放的钙内流。