Analysis of New NAD-cleavage Enzymes Involved in Signal Transduction System

信号转导系统中涉及的新型 NAD 裂解酶的分析

基本信息

批准号：
08458193
负责人：
KATADA Toshiaki
金额：
$ 4.35万
依托单位：
The University of Tokyo (Faculty of Pharmaceutical Sciences)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458193/
关键词：
NAD Cyclic ADP-ribose NADase G proteins CD38 Tyrosine phosphorylation Signal transduction 環状ADPリボース

项目摘要

The human cell surface antigen CD38, which has an amino acid sequence homologous to Aplysia ADP-ribosyl cyclase, is a 46-kDa type II glycoprotein with a single-transmembrane domain. We previously demonstrated that the extracellular domain of CD38 exhibits NAD^+ glycohydrolase (NADase) activity and that the ecto-form NADase activity induced by all-trans retinoic acid (RA) in HL-60 cells is due to CD38. CD38 catalyzes not only the hydrolysis of NAD^+ but also the formation and hydrolysis of cyclic ADP-ribose, which is a novel candidate that mediates Ca^<2+> release from intracellular Ca^<2+> stores. In the present study, we obtained the following findings. 1. Stimulation of RA-differentiated HL-60 cells with anti-CD38 monoclonal antibodies (mAbs) induced rapid tyrosine phosphorylation of cellular proteins with the molecular weights of 120,000,87,000 and 77,000. One of the prominent phosphorylated proteins was identified as the c-cbl proto-oncogene product, p120^<c-cbl>.2. Superoxide formation in response to formyl-Met-Leu-Phe was markedly enhanced by the anti-CD38 mAbs in the differentiated HL-60 cells. 3. The epitopes recognized by these agonistic mAbs stimulating protein tyrosine phosphorylation were all mapped on the same carboxyl-terminal sequence of CD38, and the same sequence was also required for its ecto-NADase activity. 4. Fcgamma-II receptors appeared to be involved in the signal transduction pathway mediated through the agonistic anti-CD38 mAb-induced tyrosine phosphorylation of cellular proteins. 5. The expression of CD38 mRNA was mediated through nuclear RA receptors ; a RA receptor-responsive element was present in the first intron of CD38 gene.

人细胞表面抗原 CD38 具有与海兔 ADP-核糖基环化酶同源的氨基酸序列，是一种具有单跨膜结构域的 46 kDa II 型糖蛋白。我们之前证明CD38的胞外结构域表现出NAD^+糖水解酶(NADase)活性，并且HL-60细胞中全反式视黄酸(RA)诱导的外型NADase活性是由于CD38所致。 CD38不仅催化NAD^+的水解，而且还催化环状ADP-核糖的形成和水解，这是介导细胞内Ca^2+储存的Ca^2+释放的新候选者。在本研究中，我们获得了以下发现。 1.用抗CD38单克隆抗体(mAb)刺激RA分化的HL-60细胞，诱导分子量为120,000、87,000和77,000的细胞蛋白快速酪氨酸磷酸化。一种重要的磷酸化蛋白被鉴定为 c-cbl 原癌基因产物 p120^<c-cbl>.2。在分化的 HL-60 细胞中，抗 CD38 mAb 显着增强了对甲酰基 Met-Leu-Phe 反应的超氧化物形成。 3.这些激动性单克隆抗体刺激蛋白酪氨酸磷酸化所识别的表位都定位在CD38的相同羧基末端序列上，并且其胞外NAD酶活性也需要相同的序列。 4. Fcgamma-II 受体似乎参与通过激动性抗 CD38 mAb 诱导的细胞蛋白酪氨酸磷酸化介导的信号转导途径。 5. CD38 mRNA的表达是通过核RA受体介导的； CD38基因的第一个内含子中存在RA受体反应元件。