Functional Analysis of BiP as a Plant Molecular Chaperone

该提案涉及玉米储存蛋白（zeins），它以称为蛋白体的球形聚集体的形式储存在内质网膜内。一种分子伴侣子已被分离并鉴定，它在核发育过程中积累，并可能在蛋白质体内蛋白质的有序沉积中起关键作用。这种分子伴侣子是BiP，是一种75 kD的多肽，存在于内质网和蛋白体内。虽然这种蛋白的确切作用尚不清楚，但在原生物和真核生物中都发现了BiP同源物。该提案的目标是表征在正常和突变胚乳转运到内质网过程中BiP和靶蛋白之间的相互作用；探讨fl2、De-B30和Mc突变体发育中胚乳蛋白体形态改变的分子基础；并确定翻译后修饰是否与植物中的BiP功能相关。本提案中概述的研究将增加我们对重要储存储备的运输和积累的调节过程的了解。它们对于设计引进新基因产品的新策略以改善植物生长和质量也是必不可少的。＊＊＊

9317303 Boston The proposal concerns the maize storage proteins (zeins), that are stored within ER membranes as spherical aggregates called protein bodies. A molecular chaperon has been isolated and characterized that accumulates during kernel development and may play a critical role in the ordered deposition of the proteins within protein bodies. This molecular chaperon is BiP, and is a 75 kD polypeptide that is found within the ER and the protein bodies. Although the exact role of this protein is not known, BiP homologues are found in both prokayotes and eukaryotes. The goals of the proposal are to characterize the interactions between BiP and target proteins during translocation to the ER of normal and mutant endosperm; to investigate the molecular basis of altered protein body morphology in developing endosperm of fl2,De-B30 and Mc mutants; and to determine if post translational modifications are correlated with BiP function in plants. %%% The studies outlined in this proposal will increase our knowledge of the processes regulating transport and accumulation of the important storage reserves. They are also essential for devising new strategies for introducing new gene products to improve plant growth and quality. ***