Hsp47 and the translation-translocation machinery cooperate in the production of alpha 1(I) chains of type I procollagen.
Hsp47 and the translation-translocation machinery cooperate in the production of alpha 1(I) chains of type I procollagen.
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DOI：
10.1016/s0021-9258(17)41724-8
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发表时间：
1994-02
期刊：
影响因子：
--
通讯作者：
J. Sauk;T. Smith;K. Norris;L. Ferreira
中科院分区：
文献类型：
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作者：
J. Sauk;T. Smith;K. Norris;L. Ferreira
Hsp 47是一种内质网驻留蛋白，具有明胶结合和前胶原结合特性，并被假设为在调节前胶原折叠和/或组装中起分子伴侣的作用。在这份报告中，我们进一步调查的相互作用，热休克蛋白47与多核糖体相关的α 1（I）前胶原链的反义治疗后的3 T6细胞。对于这些研究，我们采用了针对Hsp 47的前五个密码子的硫代磷酸寡脱氧核苷酸，这些密码子跨越小鼠Hsp 47的预测翻译起始位点。观察到以这种方式耗尽Hsp 47的细胞产生减少量的完全伸长的新生α 1（I）前胶原，同时积累与肽基-tRNA相关的较短的前胶原肽。脉冲标记细胞与[35 S]蛋氨酸，然后用嘌呤霉素和免疫沉淀与抗HSP 47和抗前胶原抗体的治疗表明，HSP 47与α 1（I）前胶原在一个非常早期的点在易位的新生前胶原链。虽然热休克蛋白47似乎具有类似grp 78/BiP的性质，热休克蛋白47结合早期易位有利于一个更专门的具体功能相对于链选择或完成稳定的折叠在I型前胶原。
Hsp47, an endoplasmic reticulum resident protein, has gelatin-binding and procollagen-binding properties and has been hypothesized to function as a molecular chaperone in regulating procollagen folding and/or assembly. In this report, we further investigate the interaction of Hsp47 with polysome-associated alpha 1(I) procollagen chains following antisense treatment of 3T6 cells. For these studies, we employed phosphorothioate oligodeoxynucleotides directed to the first five codons of Hsp47 that straddle the predicted translation initiation site of mouse Hsp47. Cells depleted of Hsp47 in this manner were observed to produce diminished amounts of fully elongated nascent alpha 1(I) procollagen while accumulating shorter procollagen peptides associated with peptidyl-tRNA. Pulse-labeling of cells with [35S]methionine followed by treatment with puromycin and immunoprecipitation with anti-Hsp47 and anti-procollagen antibodies revealed that Hsp47 is associated with alpha 1(I) procollagen at a very early point during translocation of the nascent procollagen chains. Although Hsp47 appears to possess properties similar to grp78/BiP, Hsp47 binding early during translocation favors a more specialized specific function relative to chain selection or completion of stable folding in type I procollagen.