Collagen is the most abundant protein in mammals. A unique feature of collagen is its triple-helical structure formed by the Gly-Xaa-Yaa repeats. Three single chains of procollagen make a trimer, and the triple-helical structure is then folded in the endoplasmic reticulum (ER). This unique structure is essential for collagen's functions in vivo, including imparting bone strength, allowing signal transduction, and forming basement membranes. The triple-helical structure of procollagen is stabilized by posttranslational modifications and intermolecular interactions, but collagen is labile even at normal body temperature. Heat shock protein 47 (Hsp47) is a collagen-specific molecular chaperone residing in the ER that plays a pivotal role in collagen biosynthesis and quality control of procollagen in the ER. Mutations that affect the triple-helical structure or result in loss of Hsp47 activity cause the destabilization of procollagen, which is then degraded by autophagy. In this review, we present the current state of the field regarding quality control of procollagen. Expected final online publication date for the Annual Review of Biochemistry, Volume 90 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

中文翻译：

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细胞中原胶原的质量控制。

胶原蛋白是哺乳动物中最丰富的蛋白质。胶原蛋白的独特功能是由Gly-Xaa-Yaa重复序列形成的三螺旋结构。前胶原的三条单链构成三聚体，然后将三螺旋结构折叠在内质网（ER）中。这种独特的结构对于胶原蛋白在体内的功能至关重要，包括赋予骨骼强度，允许信号转导和形成基底膜。前胶原的三螺旋结构通过翻译后修饰和分子间相互作用而稳定，但胶原即使在正常体温下也不稳定。热休克蛋白47（Hsp47）是驻留在ER中的胶原蛋白特异性分子伴侣，在ER中胶原蛋白的生物合成和前胶原的质量控制中起着关键作用。影响三螺旋结构或导致Hsp47活性降低的突变会导致原胶原不稳定，然后被自噬降解。在这篇综述中，我们介绍了有关胶原蛋白质量控制领域的现状。《生物化学年度评论》第90卷的最终最终在线发布日期为2021年6月。请参阅http://www.annualreviews.org/page/journal/pubdates以获取修订的估算值。