Intracellular Ca2+ stores of rat cerebellum: heterogeneity within and distinction from endoplasmic reticulum.
Intracellular Ca2+ stores of rat cerebellum: heterogeneity within and distinction from endoplasmic reticulum.
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大鼠小脑细胞内 Ca2 储存：内质网内的异质性及其区别。
DOI：
10.1042/bj2910199
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Volpe,P
中科院分区：
文献类型：
--
作者：
Nori,A;Villa,A;Podini,P;Witcher,DR;Volpe,P
用等比线状蔗糖(20-42%)密度梯度对大鼠小脑微粒体进行细分。用生化和免疫学方法研究了内质网(ER)标志物(RNA、信号序列受体α、钙调素、钙网蛋白、免疫球蛋白结合蛋白Bip)和细胞内快速交换钙离子通道[对Ins(1，4，5)P3或ryanodine敏感的钙通道]的分布。比较表明：(A)带有InsP3受体的囊泡与带有ryanodine受体的囊泡是分开的；(B)ER标记物，即Bip，calnexin，信号序列受体α，RNA，没有像InsP3或ryanodine受体那样沉积；(C)calreticrin，一种腔内低亲和力的高容量钙结合蛋白，广泛分布，与Bip和calnexin相似，存在于Purkinje神经元、颗粒神经元、高尔基神经元和星状神经元中，小脑皮质冷冻免疫荧光标记表明。目前的结果表明，内质网不是一个均一的实体，而且由于InsP3受体和兰诺定受体是分离的，无论是到离散的细胞内细胞器还是到专门的内质网亚室，钙离子储存都是不同的。
Rat cerebellum microsomes were subfractionated on isopycnic linear sucrose (20-42%)-density gradients. The distribution of endoplasmic reticulum (ER) markers (RNA, signal-sequence receptor alpha, calnexin, calreticulin, the immunoglobulin-binding protein Bip) and markers of intracellular rapidly exchanging Ca2+ stores [Ca2+ channels sensitive to either Ins(1,4,5)P3 or ryanodine) was investigated biochemically and immunologically. The comparison indicates that: (a) vesicles bearing the InsP3 receptor were separated from those bearing the ryanodine receptor; (b) ER markers, i.e. Bip, calnexin, signal-sequence receptor alpha, RNA, did not sediment as either InsP3 or ryanodine receptors did; (c) calreticulin, an intralumenal low-affinity high-capacity Ca(2+)-binding protein, had a widespread distribution, similar to that of Bip and calnexin, and was present in Purkinje, granule, Golgi and stellate neurons, as indicated by immunofluorescent labelling of cerebellum cortex cryosections. The present results show that the ER is not a homogeneous entity, and that Ca2+ stores are heterogeneous insofar as InsP3 receptors and ryanodine receptors are segregated, either to discrete intracellular organelles or to specialized ER subcompartments.