MOLECULAR STUDIES OF EUKARYOTIC CELL SURFACE GROWTH

真核细胞表面生长的分子研究

• 批准号: 3274175
• 负责人: RANDY W. SCHEKMAN
• 金额: $ 32.01万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-07-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3274175
• 关键词: Saccharomyces; acid phosphatase; beta fructofuranosidase; carbohydrate structure; electron microscopy; enzyme structure; eukaryote; fungal genetics; glycoproteins; immunochemistry; membrane reconstitution /synthesis; radiotracer; secretion; secretory protein; temperature sensitive mutant

We have isolated a series of yeast secretory mutants (sec mutants) that are temperature-sensitive for cell surface growth, division, and secretion. Most of these mutants accumulate secretory proteins in an intracellular pool which can be released when cells are returned to a permissive temperature. At least 23 gene products have been implicated in the process of delivering membrane and secretory proteins to the cell surface. Electron microscope analysis has revealed three distinct membrane-bounded organelles that accumulate in different mutants. Ten of the mutants produce vesicles, nine of the mutants produce endoplasmic reticulum, and two of the mutants produce Golgi body-like structures which we have called Berkely bodies. We have also identified nine genes that contrrl the earliest steps in the cell surface growth pathway. Mutations in these genes result in a failure to synthesize active secretory protein, in spite of a normal rate of overall protein synthesis. Two of the mutants are also defective in the production of a membrane permease activity. The secretory mutants are now being used to identify some of the molecular events involved in cell-surface growth. In higher eukaryotic cells, glycoproteins are glycosylated in stages during their transit to the cell surface and thus if a secretory mutant blocks passage from one stage to another, incompletely glycosylated forms may accumulate. We have detected at least two stages in oligosaccharide assembly on the secretory enzyme invertase. The secretory mutants that accumulate endoplasmic reticulum at a nonpermissive temperature produce an incompletely glycosylated form of invertase.

我们已经隔离了一系列酵母分泌突变体（SEC突变体） 温度敏感细胞表面生长，分裂和分泌。 大多数 这些突变体在细胞内积累分泌蛋白，可以 当细胞返回允许温度时，可以释放。 至少23 基因产品与传递膜的过程有关 分泌蛋白到细胞表面。 电子显微镜分析有 揭示了三个不同的膜结合的细胞器，它们积聚在不同的 突变体。 十个突变体产生囊泡，其中九个突变体产生 内质网和两个突变体产生类似高尔基体的结构 我们称之为伯基身体。 我们还确定了九个基因，这些基因符合细胞中最早的步骤 表面生长途径。 这些基因的突变导致无法 尽管总体速率正常，但合成活性分泌蛋白 蛋白质合成。 两个突变体在生产中也有缺陷 膜渗透活性。 分泌突变体现在被用来识别一些分子 细胞表面生长涉及的事件。 在较高的真核细胞中， 糖蛋白在过渡到细胞的过程中分阶段被糖基化 表面，因此，如果一个分泌突变体阻止从一个阶段传递到另一个阶段， 可能会积累不完全糖基化的形式。 我们已经检测到了至少两个 分泌酶转化酶的寡糖组件中的阶段。 这 分泌突变体在非监禁处积累内质网 温度产生不完全糖基化形式的转化酶。