BASIS FOR STRESS TOLERANCE IN OSTEOLIGAMENT CELLS

描述：（改编自申请人摘要）假设 本申请书所依据的译文- α 1（I）前胶原链的移位是由 转位子（内质网的多跨膜糖蛋白 内质网）和内质网（ER）驻留分子伴侣。 此外，前胶原与单个易位子的关联 蛋白质和一系列分子伴侣遵循以下原则： 连续动作。 根据申请人的研究，候选人 与前胶原的这种连续相互作用被认为可能 包括translocon相关蛋白（TRAP），易位链- 相关膜蛋白（TRAM），SEC 61 p的哺乳动物同系物， Hsp 47（一种特异性胶原结合蛋白）、Grp 78和Grp 94。 据推测，转位子蛋白可介导 参与合成前胶原的核糖体， 通过信号识别颗粒及其受体作用于内质网膜。 随着新生链的移位进行，它们被屏蔽， 膜的疏水性核心通过易位子成分。 的 新生的原胶原链随后被交给一组连续的 分子伴侣，Hsp 47，Grp 78和Grp 94，它们促进了 通过减少不正确的折叠， 以确保以高保真度发生易位。这 在韧带细胞中，蛋白质-蛋白质相互作用的级联确保了 正常时期前胶原的组成性合成， 应力 将通过完成以下内容来检验该假设 具体目标。 具体目标1将验证易位子包含 易位链相关膜蛋白（TRAM）和SEC 61 p 存在于韧带细胞和成纤维细胞的内质网中， 原胶原I 具体目标2将确定哺乳动物 结合翻译α 1（I）的核糖体的内质网 前胶原mRNA，并与α（I）易位相关 原胶原新生链。 具体重点将放在TRAM， SEC 61 p和HSP 47。 具体目标3将试图证明， 一个连续的协会之间的个别易位蛋白，ER 常驻分子伴侣和原胶原蛋白。 利用交联 和重建方法，将确定Hsp 47是否是 第一个ER驻留分子伴侣， 前胶原链，并确定前胶原合成点， 与Grp 78、Grp 94和其他ER驻留蛋白相关。

DESCRIPTION: (Adapted from the applicant's abstract) The hypothesis upon which this application is based is that the translation- translocation of alpha1(I) procollagen chains is facilitated by a translocon (multispaning membrane glycoproteins of the endoplasmic reticulum), and endoplasmic reticulum (ER) resident molecular chaperons. Further, the association of procollagen with individual translocon proteins and a series of molecular chaperons follows the principle of successive action. Based on the studies of the applicant, candidates for this consecutive interaction with procollagen are seen to possibly include the translocon-associated protein (TRAP), translocating chain- associating membrane protein (TRAM), the mammalian homolog of SEC61p, Hsp47 (a specific collagen binding protein), Grp78, and Grp94. Translocon proteins are proposed to act to mediate the binding of ribosomes engaged in synthesizing procollagen that has been targeted to the ER membrane by the signal recognition particle and its receptor. As translocation of the nascent chains proceeds, they are shielded from the hydrophobic core of the membrane by translocon components. The nascent chains of procollagen are then handed to a successive group of molecular chaperons, Hsp47, Grp78, and Grp94, that facilitate the translation-translocation process by reducing incorrect folding, thus insuring that translation-translocation occur with high fidelity. This cascade of protein-protein interactions ensures, in ligament cells, the constitutive synthesis of procollagen during periods of normalcy and stress. This hypothesis will be tested by completion of the following specific aims. Specific Aim 1 will verify that a translocon comprised of translocating chain associating membrane protein (TRAM) and SEC61p exists in the ER of ligament cells and fibroblasts that produce procollagen I. Specific Aim 2 will identify components of the mammalian endoplasmic reticulum that bind ribosomes which translate alpha1(I) procollagen mRNA, and are associated with translocation of alpha(I) procollagen nascent chains. Specific focus will be directed to TRAM, SEC61p and HSP47. Specific Aim 3 will attempt to prove that there is a successive association between individual translocon proteins, ER resident molecular chaperons and procollagen. Utilizing crosslinking and reconstitution methods it will be determined whether Hsp47 is the first ER resident molecular chaperone to interact with evolving procollagen chains and determine the point of procollagen synthesis that is associated with Grp78, Grp94 and other ER resident proteins.