Calsequestrin is a component of smooth muscles: the skeletal- and cardiac-muscle isoforms are both present, although in highly variable amounts and ratios.
Calsequestrin is a component of smooth muscles: the skeletal- and cardiac-muscle isoforms are both present, although in highly variable amounts and ratios.
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Calsequestrin 是平滑肌的组成部分：骨骼肌和心肌同工型均存在，但含量和比例存在很大差异。
DOI：
10.1042/bj3010465
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Meldolesi,J
中科院分区：
文献类型：
--
作者：
Volpe,P;Martini,A;Furlan,S;Meldolesi,J
calsequestrin （CS）是横纹肌肌浆网（SR）的低亲和力/高容量Ca（2+）结合蛋白，近年来在平滑肌细胞中的表达被研究，结果相互矛盾。在这里，我们报告了从大鼠输精管中纯化和表征两种CS亚型，第一种被认为是骨骼肌型，第二种是心脏型，因为它们的n端氨基酸和其他相关的生化和分子特性。与输精管相比，主动脉和胃的平滑肌按顺序表达的CS含量较低，而子宫和膀胱则未检测到CS蛋白。两种CS异构体的比例也不同，胃和主动脉主要表达骨骼肌型，输精管表达两种CS的数量大致相似。由于CSs不均匀地定位于骨骼肌SR管腔内，但根据其锚定膜蛋白的分布，该蛋白的表达表明平滑肌细胞中存在离散的内质网区域，专门负责快速交换Ca2+的储存和释放，从而控制包括平滑肌收缩在内的多种功能。
Expression by smooth-muscle cells of calsequestrin (CS), the low-affinity/high-capacity Ca(2+)-binding protein of striated-muscle sarcoplasmic reticulum (SR), has been investigated in recent years with conflicting results. Here we report the purification and characterization from rat vas deferens of two CS isoforms, the first deemed skeletal muscle, the second cardiac type, on account of their N-terminal amino acids and other relevant biochemical and molecular properties. Compared with vas deferens, the smooth muscles from aorta and stomach, in that order, were found to express lower amounts of CS, whereas in the uterus and bladder the protein was not detectable. The ratio between the two CS isoforms was also variable, with the stomach and aorta predominantly expressing the skeletal-muscle type and the vas deferens expressing the two CSs in roughly similar amount. Because of the property of CSs to localize within the skeletal-muscle SR lumen not uniformly, but according to the distribution of their anchorage membrane proteins, the expression of the protein suggests the existence in smooth-muscle cells of discrete endoplasmic-reticulum areas specialized in the rapidly exchanging Ca2+ storage and release, and thus in the control of a variety of functions, including smooth-muscle contraction.