Identification of apoptosis inhibitor produced by bacteria species

细菌种类产生的凋亡抑制剂的鉴定

基本信息

批准号：
10557018
负责人：
YAMAMURA Hirohei
金额：
$ 8.32万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

We have investigated the role of Syk protein-tyrosine kinase (PTK) in the intracellular signaling mechanism in variety of cells. In particular, our recent works have shown that PTKs play important roles in the regulatory mechanism of a B lymphocyte apoptosis mediated by the oxidative stress. On the other hand, we found that bacteria such as accidental actinomyces secreted unknown factor (s) which blocked apoptosis of B cells mediated by the oxidative stress. In this study, we have identified this factor as bacterial phospholipase D (PLD) which catalyzes phosphatidylcholine hydrolysis to choline and phosphatidic acid. Therefore, it is highly possible that phosphatidic acid blocked apoptosis of B cells mediated by the oxidative stress. To further understand the regulatory mechanism of PLD action on apoptosis signaling, we first examined the role and signaling pathway of endogenous PLD.We provide biochemical and genetic evidence that cross-linking of the B cell receptor (BCR) induces rapid activation of PLD through a Syk, Btk and phospholipase C (PLC)-gamma2 dependent pathway in DT40 B cells. In addition, we have shown that Syk, Btk and PLC-gamma2 pathway is required for phorbol ester-induced PLD activation in DT40 cells. Although we are now investigating the role of PLD action on apoptosis signaling, the exact molecular mechanism is still unknown. We are currently attempting to establish a PLD-deficient cell line by gene targeting in DT40 B cells. The genetic analysis of this mutant will provide a major tool in the physiological investigation of the functions of PLD.

我们研究了 Syk 蛋白酪氨酸激酶 (PTK) 在多种细胞的细胞内信号传导机制中的作用。特别是，我们最近的工作表明，PTKs 在氧化应激介导的 B 淋巴细胞凋亡的调节机制中发挥着重要作用。另一方面，我们发现诸如意外放线菌之类的细菌会分泌未知因子，阻止氧化应激介导的 B 细胞凋亡。在这项研究中，我们将这种因子鉴定为细菌磷脂酶 D (PLD)，它能催化磷脂酰胆碱水解为胆碱和磷脂酸。因此，磷脂酸很可能阻断氧化应激介导的B细胞凋亡。为了进一步了解PLD对细胞凋亡信号传导的调节机制，我们首先检查了内源性PLD的作用和信号通路。我们提供了生化和遗传学证据，表明B细胞受体（BCR）的交联通过a诱导PLD的快速激活。 DT40 B 细胞中的 Syk、Btk 和磷脂酶 C (PLC)-gamma2 依赖性途径。此外，我们还发现 Syk、Btk 和 PLC-gamma2 途径是佛波酯诱导 DT40 细胞中 PLD 激活所必需的。尽管我们现在正在研究PLD作用对细胞凋亡信号传导的作用，但确切的分子机制仍然未知。我们目前正尝试通过 DT40 B 细胞中的基因靶向建立 PLD 缺陷细胞系。该突变体的遗传分析将为 PLD 功能的生理学研究提供主要工具。