IMMUNOCYTOCHEMICAL LOCALIZATION OF HEAT-SHOCK PROTEIN-60-RELATED PROTEIN IN BETA-CELL SECRETORY GRANULES AND ITS ALTERED DISTRIBUTION IN NONOBESE DIABETIC MICE
IMMUNOCYTOCHEMICAL LOCALIZATION OF HEAT-SHOCK PROTEIN-60-RELATED PROTEIN IN BETA-CELL SECRETORY GRANULES AND ITS ALTERED DISTRIBUTION IN NONOBESE DIABETIC MICE
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DOI：
10.1007/bf00401198
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发表时间：
1992-04-01
期刊：
影响因子：
8.2
通讯作者：
GUPTA, RS
中科院分区：
文献类型：
--
作者：
BRUDZYNSKI, K;MARTINEZ, V;GUPTA, RS
应用免疫电镜技术观察了正常和非肥胖糖尿病小鼠胰腺β细胞中60 kDa热休克蛋白（HSP 60）的细胞分布。在从对照小鼠制备的薄切片中，哺乳动物HSP 60的抗体与位于线粒体和分泌颗粒的蛋白质发生交叉反应。特别是，观察到抗体与成熟胰岛素分泌颗粒的胰岛素核心的显著结合。相比之下，很少的免疫反应性观察到与未成熟的分泌颗粒或高尔基体。正常小鼠血清或无关血清均未观察到与分泌颗粒或线粒体的结合。在Western印迹上，HSP 60抗体特异性地与单个62kDa胰岛细胞蛋白相互作用。这些结果表明，在β细胞的成熟分泌颗粒中存在一个新的位置与HSP 60相关的蛋白。在糖尿病前期非肥胖糖尿病小鼠的β细胞中，HSP 60相关蛋白与胰岛素核心的优先关联逐渐丧失，并且与胰岛炎的进展相关。HSP 60抗体颗粒结合的减少伴随着细胞质染色的增加，并且伴随着胰岛素核心直径的显著扩张。糖尿病前期小鼠HSP 60相关蛋白分布的改变，以及我们观察到未成熟的分泌颗粒在这些动物中积累，表明分泌颗粒中HSP 60相关蛋白的存在可能与β细胞的分泌功能有关。
Immuno-electron microscopy technique was employed to investigate the cellular distribution of 60 kDa heat-shock protein (HSP60) in pancreatic Beta cells of control and non-obese diabetic mice. In thin sections prepared from control mice, antibody to mammalian HSP60 cross-reacted with protein(s) located to mitochondria and secretory granules. In particular, prominent binding of the antibody was seen to the insulin core of the mature insulin-secreting granules. In comparison, very little immunoreactivity was observed with immature secretory granules or with the Golgi apparatus. No binding to secretory granules or mitochondria was observed with normal mouse serum or with unrelated sera. On Western blots, HSP60 antibody specifically interacted with a single 62 kDa islet cell protein. These results suggest the existence of an HSP60-related protein with a novel location in mature secretory granules of Beta cells. The preferential association of the HSP60-related protein with the insulin core was gradually lost in Beta cells of pre-diabetic non-obese diabetic mice, and correlated with the progression of insulitis. The decrease in the granular binding of the HSP60 antibody was accompanied by an increase in cytoplasm staining, and was concomitant with a significant expansion of the insulin core diameter. The altered distribution of the HSP60-related protein in pre-diabetic mice, together with our observation that immature secretory granules accumulate in these animals indicate that the presence of HSP60-related protein in secretory granules might be associated with the secretory function of Beta cells.