Immunocytochemistry of calciosomes in liver and pancreas.
Immunocytochemistry of calciosomes in liver and pancreas.
复制标题
肝脏和胰腺中钙化的免疫细胞化学。
DOI：
10.1083/jcb.107.6.2523
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发表时间：
1988-12
影响因子：
7.8
通讯作者：
Meldolesi, J
中科院分区：
文献类型：
--
作者：
Hashimoto, S;Bruno, B;Lew, D P;Pozzan, T;Volpe, P;Meldolesi, J
钙小体是一种小的细胞质液泡，存在于各种非肌肉细胞类型中，其蛋白质含量与肌浆网（SR）的钙固蛋白（CS）相似。这些实体被解释为SR的“原始”对应物，并被认为是肌醇1,4,5-三磷酸作用的细胞器靶点（Volpe， P.， K. H. Krause， S. Hashimoto， F. Zorzato， T. Pozzan， J. Meldolesi和D. P. Lew）。Proc。国家的。学会科学。美国。85:1091 - 1095)。利用抗肌CS抗体在大鼠肝细胞和胰腺腺泡细胞的厚、超薄冷冻切片中进行免疫过氧化物酶和免疫金实验，发现特异性标记广泛分布于整个细胞质中，细胞核呈阴性。单个钙小体表现为小的（105nm）膜结合液泡，与内质网池和线粒体混合在一起。其他钙小体散布在高尔基区、酶原颗粒之间和质膜下。经测定，cs阳性细胞器的累积体积分别占肝脏和胰腺细胞细胞质的0.8%和0.45%。钙小体室的实际总容积预计约为其两倍大。在肝细胞中，类似cs阳性钙小体的结构被肌肉SR的Ca2+ atp酶抗体修饰，而内质网池没有。通过双重标记，53.6%的细胞器显示共定位，37.6%的细胞器仅为atp酶阳性。CS优先局限于含量，Ca2+ atp酶优先局限于细胞器的轮廓。结果表明，这两种抗原的部分分离，让人想起它们在肌肉sr中众所周知的分离。另外的双标记实验表明，肝钙小体既不表达两种内质网标记物（细胞色素p450和nadh细胞色素b5还原酶），也不表达内溶酶体标记物，腔酸性（由3-[2,4-二硝基苯胺]-3′-氨基- n -甲基二丙胺显示）。钙小体是一种独特的细胞学实体，理想地在非肌肉细胞中快速控制无细胞质Ca2+中发挥作用。
Calciosomes are small cytoplasmic vacuoles identified in various nonmuscle cell types by their content of protein(s) similar to calsequestrin (CS), the Ca2+ storage protein of the muscle sarcoplasmic reticulum (SR). These entities have been interpreted as the "primitive" counterpart of the SR, and suggested to be the organelle target of inositol-1,4,5-triphosphate action (Volpe, P., K. H. Krause, S. Hashimoto, F. Zorzato, T. Pozzan, J. Meldolesi, and D. P. Lew. Proc. Natl. Acad. Sci. USA. 85:1091-1095). Immunoperoxidase and immunogold experiments carried out in both thick and ultrathin cryosections of rat hepatocytes and pancreatic acinar cells by using antimuscle CS antibodies revealed a specific labeling widely distributed in the entire cytoplasm, while nuclei were negative. Individual calciosomes appeared as small (105 nm) membrane-bound vacuoles intermingled with, and often apposed to ER cisternae and mitochondria. Other calciosomes were scattered in the Golgi area, in between zymogen granules and beneath the plasma membrane. The cumulative volume of the CS-positive organelles was measured to account for the 0.8 and 0.45% of the cytoplasm in liver and pancreas cells, respectively. The real total volume of the calciosome compartment is expected to be approximately twice as large. In hepatocytes, structures similar to CS-positive calciosomes were decorated by antibodies against the Ca2+ ATPase of muscle SR, while ER cisternae were not. By dual labeling, colocalization was revealed in 53.6% of the organelles, with 37.6% positive for the ATPase only. CS appeared preferentially confined to the content, and the Ca2+ ATPase to the contour of the organelle. The results suggested a partial segregation of the two antigens, reminiscent of their well-known segregation in muscle SR. Additional dual-label experiments demonstrated that hepatic calciosomes express neither two ER markers (cytochrome-P450 and NADH-cytochrome b5 reductase) nor the endolysosome marker, luminal acidity (revealed by 3- [2,4-dinitroanilino]-3'-amino-N-methyl dipropylamine). Calciosomes appear as unique cytological entities, ideally equipped to play a role in the rapid-scale control of the cytosolic-free Ca2+ in nonmuscle cells.