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Analysis of the function of collagen-binding heat shock protein (hsp47)

胶原结合热休克蛋白（hsp47）的功能分析

基本信息

批准号：
63570159
负责人：
SAGA Shinsuke
金额：
$ 1.34万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

Heat shock protein of molecular weight 47,000 D, HSP47, binds to native and denatured collagen including type I, type III, or type IV. We examined the localization of HSP47 as well as collagen type I,II,III, and IV in various tissues from chicken embryos and adults by immunohistochemical and immuno- electronmicroscopical methods. In adult chicks, HSP47 is located on fibrocytes or fibroblasts in the connective tissue in various organs, chondrocytes in the cartilage, smooth muscle cells in the gastrointestinal tract and blood vessels, vitamin A storage cells in sinusoidal area of liver, and epithelial cells of renal glomeruli and tubules. These cells also co-express a certain type of collagen molecules. Further, in developing embryos the expression of HSP47 in periosteal fibroblasts surrounding vertebral bone or in chondrocytes within scleral cartilage is coupled to the expression of collagen type I or type II, respectively.When chick embryo fibroblasts (CEF) were cultured in the condition that the hydroxylation of pro-alpha chains of collagen was inhibited, such as deficiency of ascorbate or addition of 2-2'-dipyridyl, procollagen was retained within ER in the granular pattern because of inhibition of triple-helix formation, and HSP47 was co-localized with procollagen. Enough level of hydroxylation induced the formation of triple-helix and the transportation of procollagen molecules from ER to Golgi apparatus to change the distribution of HSP47 to reticular networks. Even if enough ascorbate was added to the cultures, heat shock treatment of the cells induced the retention of procollagen molecules in ER because the helix formation was inhibited at high temperature over melting point of procollagen. The distribution of HSP47 was also coincided to that of retained procollagen.These results indicate that HSP47 indeed binds to collagen molecules in vivo, and that it may play an important role in the transportation of procollagen molecules from ER to Golgi.

分子量为47，000 D的热休克蛋白HSP 47与天然和变性胶原蛋白结合，包括I型、III型或IV型。我们用免疫组织化学和免疫电镜方法研究了鸡胚和成年鸡各种组织中HSP 47和I、II、III、IV型胶原的定位。在成年鸡中，HSP 47位于各种器官的结缔组织中的纤维细胞或成纤维细胞、软骨中的软骨细胞、胃肠道和血管中的平滑肌细胞、肝窦区的维生素A储存细胞以及肾小球和肾小管的上皮细胞上。这些细胞还共同表达某种类型的胶原蛋白分子。此外，在发育中的胚胎中，HSP 47在椎骨周围的骨膜成纤维细胞或巩膜软骨内的软骨细胞中的表达分别与I型或II型胶原的表达偶联。由于抑制了三螺旋的形成，前胶原以颗粒模式保留在ER内，并且HSP 47与前胶原共定位。足够的羟化水平诱导三螺旋的形成和前胶原分子从ER到高尔基体的运输，改变HSP 47的分布到网状网络。即使足够的抗坏血酸被添加到培养物中，热休克处理的细胞诱导保留的前胶原分子在ER中，因为螺旋的形成被抑制在高温下超过熔点的前胶原。HSP47的分布也与滞留的前胶原的分布相一致，提示HSP47在体内确实与胶原分子结合，并可能在前胶原分子从内质网向高尔基体的转运中起重要作用。