PROTEIN STORAGE IN POST GOLGI ORGANELLES

高尔基后细胞器中的蛋白质储存

基本信息

批准号：
6736965
负责人：
REGINA M KULIAWAT
金额：
$ 25.05万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-06-01 至 2007-05-31
项目状态：
已结题

项目摘要

In addition to its other functions in vesicle trafficking, the trans-Golgi network is the parent organelle from which components of secretory granules in neuroendocrine cells and melanosomes in melanocytes originate. These two specialized storage organelles have remarkable similarities that heretofore have been under-appreciated. In particular, the organization of both compartments hinges on the assembly of a luminal protein matrix that forms within a specialized ionic milieu, and this is hypothesized to serve as a fundamental mechanism for protein retention in such compartments. This application proposes to explore relationships in the biogenesis of these two post-Golgi storage organelles. Thus, new content proteins of the melansomal matrix will be identified, with the intent to ultimately characterize the importance of protein/protein interactions to storage. The cDNAs encoding these proteins will also be expressed in neuroendocrine secretory cells that maintain in storage granules a specialized lumenal environment highly analogous to that of melanosomes but with a very different protein content. I propose to initiate the heterologous expression studies immediately with MMP115, the one melanosomal cDNA that has so far been cloned which does not encode a single-spanning membrane protein, and is believed to reside entirely within the melanosome lumen. Moreover, I plan to develop an assay in which the de novo budding of immature melanosomes from the TGN is reconstituted in vitro using a permeabilized melanocyte cell system. I believe that the studies proposed in this application will provide important insights into general mechanisms of protein sorting and storage in post-Golgi compartments.

除了其在囊泡运输中的其他功能外，反式高尔基网络是母体细胞器，神经内分泌细胞中分泌颗粒的成分和黑色素细胞中黑素体的成分起源。这两个专门的存储器官具有迄今为止低估的显着相似性。特别是，两个隔室的组织取决于在专门的离子环境中形成的腔蛋白基质组装上，并且认为这是在此类隔室中蛋白质保留的基本机制。该应用建议探索这两个高尔基储存细胞器的生物发生中的关系。因此，将鉴定出黑色素基质的新含量蛋白质，目的是最终表征蛋白质/蛋白质相互作用对储存的重要性。编码这些蛋白质的cDNA也将在神经内分泌分泌细胞中表达，该细胞保持在储存颗粒中的特殊腔内环境，与黑色素体高度相似，但具有截然不同的蛋白质含量。我建议用MMP115立即启动异源表达研究，MMP115是一个黑色素体cDNA，它已经被克隆了，它没有编码单个跨膜蛋白，并且被认为完全驻留在黑色素体管中。此外，我计划开发一种测定法，其中使用透明的黑素细胞细胞系统在体外重构未成熟的黑素体的从头萌芽。我认为，本应用中提出的研究将为大加尔基后室中蛋白质分类和储存的一般机制提供重要的见解。