DOLICHOL PHOSPHATE METABOLISM AND GLYCOPROTEIN SYNTHESIS

B淋巴细胞(B细胞)的激活导致 膜结合型和分泌型糖蛋白的合成。这 应用展望N-糖基化调控的研究进展 膜糖蛋白合成受刺激时的活性 细菌诱导静息B细胞增殖的实验研究 脂多糖(LPS)。N-糖基化的控制也将 在人B淋巴母细胞系(CESS)中的研究 刺激分化和分泌大量的 暴露于B细胞分化因子的免疫球蛋白 (BCDF)。N-糖基化反应活性的变化 诱导B细胞增殖或分化将是 与Dolichyl相关的几种酶的变化 磷酸(DO1-P)代谢与二羟苯二酚的合成 低聚糖。Dol-ol激酶与Dol-P磷酸酶活性 将在体外进行检测，以确定Dol-P水平是否可以 通过改变磷酸化中的平衡来改变- B细胞增殖过程中的去磷酸化机制 流水线的分化。从头开始的要求 多酚或Dol-P在增殖期和发育期的合成 将通过代谢物标记来探索差异性变化 用(~3H)甲氧基丙交酯进行实验，并用外源性 提供Dolicol和Capactin，HMG的竞争性抑制物- 辅酶A还原酶。钙离子动员的可能参与 和蛋白激酶C在激活过程中的作用将被探索 通过对离子霉素和佛波酯的细胞研究。这个 拟议中的实验可能会为控制空气中的 在B细胞中的N-糖基化装置，并延长电流 了解生物化学过程中发生的事件 B淋巴细胞的增殖和分化。

The activation of B-lymphocytes (B-cells) leads to increased synthesis of membrane-bound and secretory glycoproteins. This application proposes studies on the regulation of N-glycosylation activity when membrane glycoprotein synthesis is stimulated in resting B-cells induced to proliferate by bacterial lipopolysaccharide (LPS). The control of N-glycosylation will also be investigated in the human B lymphoblastoid cell line (CESS) stimulated to differentiate and secrete large amounts of immunoglobulins by exposure to B-cell differentiation factor (BCDF). Changes in N-glycosylation activity in response to the induction of proliferation or differentiation of the B-cells will be correlated with changes in several enzymes involved in dolichyl phosphate (Do1-P) metabolism and the synthesis of dolichol-linked oligosaccharides. Dolichol kinase and Dol-P phosphatase activity will be assayed in vitro to determine if Dol-P levels could be altered by shifting the balance in a phosphorylation- dephosphorylation scheme during the proliferation of B-cells or the differentiation of the CESS line. The requirement for de novo synthesis of dolichol or Dol-P during the proliferative and differentiative changes will be explored by metabolic labeling experiments with (3H)mevalonate, and studies with exogenously supplied dolichol and capactin, the competitive inhibitor of HMG- CoA reductase. The possible involvement of Ca++-mobilization and protein kinase C in the activation processes will be explored by cellular studies with ionomycin and phorbol diesters. The proposed experiments could shed new light on the control of the N-glycosylation apparatus in B-cells, and extend the current knowledge of the biochemical events occurring during the proliferation and differentiation of B-lymphocytes.