DOLICHOL PHOSPHATE METABOLISM AND GLYCOPROTEIN SYNTHESIS

B淋巴细胞（B细胞）的活化导致增加的 膜结合和分泌糖蛋白的合成。 这 应用提出了对N-糖基化的调节的研究 当膜糖蛋白合成被刺激时， 细菌诱导的静息B细胞增殖 脂多糖（LPS）。 N-糖基化的控制也将 在人B淋巴母细胞样细胞系（CESS）中进行研究 刺激分化并分泌大量的 B细胞分化因子免疫球蛋白 （BCDF）。 N-糖基化活性的变化， B细胞增殖或分化的诱导将是 与参与长叶醇合成的几种酶的变化相关 磷酸盐（Do1-P）代谢和合成多萜醇连接的 低聚糖。 Dolichol激酶和Dol-P磷酸酶活性 将在体外进行测定，以确定是否可以 通过改变磷酸化平衡而改变 B细胞增殖过程中的去磷酸化方案，或 CESS系列的差异化。 重新分类的要求 在增殖过程中合成多萜醇或Dol-P， 将通过代谢标记来探索分化变化 （3H）甲羟戊酸的实验，以及外源性 提供了多萜醇和capactin，HMG的竞争性抑制剂， CoA还原酶。 Ca ++动员的可能参与 和蛋白激酶C在激活过程中的作用 通过离子霉素和佛波醇二酯的细胞研究。 的 拟议的实验可以揭示新的光控制的 在B细胞中的N-糖基化装置，并延长电流 生物化学过程中发生的事件的知识 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.