The role of collagen-specific molecular chaperone HSP47

胶原蛋白特异性分子伴侣HSP47的作用

基本信息

批准号：
06044125
负责人：
NAGATA Kazuhiro
金额：
$ 5.44万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044125/
关键词：
stress protein HSP47 procollagen molecular chaperone コラーゲン細胞内輸送

项目摘要

HSP47 was originally identified as a collagen-specific stress protein located in the endoplasmic reticulum (ER). HSP47 binds to procollagen in the ER immediately after the nascent chain of procollagen enters the ER and dissociates from it in the cis-Golgi network. Binding affinity of HSP47 to various types of collagens including types I to V was revealed to be similar using BIAcore biosensor. The expression of HSP47 closely correlates with that of collagens including types I to IV in various cell lines and during the development of mouse embryos. Both HSP47 and types I and III collagens were also induced in some pathological conditions such as during the progression of liver fibrosis caused by the administration of carbon tetrachrolide into rats.We showed the results of the transfection of antisense RNA for HSP47 into BALB c/3T3 cells. We obtained several stable transfectants where the synthesis and accumulation of HSP47 were inhibited moderately and almost completely. The expression of procollagen was observed to be inhibited at levels of both protein synthesis and mRNA accumulation in the cells containing low level of HSP47. In addition to the inhibition of collagen synthesis, the secretion of procollagen was inhibited in these cells although the inhibition was not so evident because of the low level of collagen synthesis. Next, we tried to transfect the cDNA encoding al chain of type I collagen into the HSP47-antisense transfected cells. In this double transfectants, the level of HSP47 was low while the amount of procollagen al chain was comparable with that of control cells. In these cells, we found that procollagen was recovered in the detergent-insoluble fraction, indicating that HSP47 is involved in the solubility of a chains of procollagen in the ER.

HSP47 最初被鉴定为位于内质网 (ER) 中的胶原蛋白特异性应激蛋白。在原胶原新生链进入内质网后，HSP47 立即与内质网中的原胶原结合，并在顺式高尔基体网络中与其解离。使用 BIAcore 生物传感器发现 HSP47 与各种类型胶原蛋白（包括 I 型至 V 型）的结合亲和力相似。 HSP47的表达与各种细胞系和小鼠胚胎发育过程中的I型至IV型胶原蛋白的表达密切相关。 HSP47 以及 I 型和 III 型胶原蛋白也在某些病理条件下被诱导，例如在大鼠四氯化碳引起的肝纤维化进展过程中。我们展示了 HSP47 反义 RNA 转染至 BALB c/3T3 的结果细胞。我们获得了几种稳定的转染子，其中HSP47的合成和积累受到适度和几乎完全的抑制。在含有低水平 HSP47 的细胞中，观察到前胶原蛋白的表达在蛋白质合成和 mRNA 积累水平上均受到抑制。除了抑制胶原蛋白合成外，这些细胞中原胶原蛋白的分泌也受到抑制，尽管由于胶原蛋白合成水平低，抑制作用并不那么明显。接下来，我们尝试将编码I型胶原α1链的cDNA转染到HSP47反义转染的细胞中。在该双转染子中，HSP47的水平较低，而前胶原α1链的量与对照细胞相当。在这些细胞中，我们发现在去污剂不溶性部分中回收了原胶原，这表明 HSP47 参与了内质网中原胶原链的溶解度。