ATTACHMENT OF RIBOSOMES TO MICROSOMAL MEMBRANES

这个项目的长期目标是了解生物遗传学 负责特定亚细胞分布的机制 膜和细胞器中的蛋白质。几种化合物的生物合成 具有不同目的地的模型蛋白质，包括内质 网状结构(如细胞色素P-450及其还原酶)、质膜 (例如，红细胞带3、钠钾ATPase和病毒包膜 糖蛋白)、溶酶体(如组织蛋白酶D和b-葡萄糖醛酸苷酶)和 将对线粒体(如细胞色素C和细胞色素氧化酶)进行研究。 对于在结合的多聚体中合成的蛋白质，服务于 作为它们共翻译插入内质网的信号或停止 多肽在体内的载体释放和滞留 膜将被识别。这将通过体外实验完成。 添加微粒体膜的蛋白质合成系统及其分析 来自蛋白质化学和cDNA的初级氨基酸序列 测序研究。据预计，这一数字和位置 膜多肽中的插入和停止转移信号将解释 因为它的跨膜处理。对以下流程进行排序 将多肽共翻译插入内质网，确保其 将对细胞内的分布进行调查。细胞化学研究的新进展 高尔基体膜将被用来关联高尔基体极性 它在理清机制方面的作用是复杂的。一个人的生命之路 多肽将使用干扰转移的试剂进行研究 细胞内细胞器间产物与体外重建 将开发用于这一转移的系统。分配一个特定的 多肽片段在插入、停止转移或分选中的作用 这些过程将由重组DNA程序辅助构建修饰的 以及将被引入培养细胞的嵌合基因 其表达产物的分布情况。翻译后 多肽与线粒体的结合也将被研究。 为了研究寻址信号的作用机制，它是 在细胞色素C中识别，并指导该多肽的摄取 进入细胞器。

The long-term objective of this project is to understand the biogenetic mechanisms responsible for the subcellular distribution of specific proteins within membranes and organelles. The biosynthesis of several model proteins with diverse destinations, including the endoplasmic reticulum (e.g., cytochrome P-450 and its reductase), plasma membrane (e.g., erythrocyte band 3, the sodium-potassium ATPase and viral envelope glycoproteins), lysosomes (e.g., cathepsin D and b-glucuronidase) and mitochondria (e.g., cytochrome C and cytochrome oxidase) will be studied. For proteins which are synthesized in bound polysomes, features which serve as signals for their cotranslational insertion into the ER or which halt the vectorial discharge and lead to retention of polypeptides within the membranes will be identified. This will be accomplished using in vitro protein synthesis systems with added microsomal membranes and by analysis of the primary amino acid sequences derived from protein chemistry and cDNA sequencing studies. It is expected that the number and location of insertion and halt transfer signals in a membrane polypeptide will account for its transmembrane disposition. Sorting out processes which, following cotranslational insertion of a polypeptide into the ER, ensure its distribution within the cell will be investigated. Cytochemical studies on Golgi membranes will be carried out to relate the polarity of the Golgi complex to its role in sorting out mechanisms. The pathway of a polypeptide will be stutied using agents which perturb the transfer of products between organelles within cells and in vitro reconstruction systems for this transfer will be developed. The assignment of a specific role to polypeptide segments in the insertion, halt transfer or sorting processes will be aided by recombinant DNA procedures to construct modified and chimeric genes which will be introduced into cultural cells to follow the distribution of the products of their expression. Post-translational incorporation of polypeptides into mitochondria will also be investigated to study the mechanism of action of an addressing signal which was identified within cytochrome C and directs the uptake of this polypeptide into the organelle.