DIMERIZATION OF A PROTEIN TYROSINE PHOSPHATASE CD45 INDUCED BY CYSTEINE OXIDATIO

半胱氨酸氧化诱导的蛋白质酪氨酸磷酸酶 CD45 二聚化

• 批准号: 7370511
• 负责人: HIROTSUGU TSURUTA
• 金额: $ 0.24万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7370511
• 关键词: DIMERIZATION; PROTEIN; TYROSINE; PHOSPHATASE; CD45

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. CD45 is a protein tyrosine phosphatase (PTP) prevalent in most of hematopoietic cells. It is a common leukocyte antigen, and involved in triggering auto-immune response. Recent studies have suggested that reactive oxygen species (ROS) are generated during the activation of tyrosine kinase growth factor receptors and by antigen receptors in lymphocytes. Accumulating evidence suggests that PTPs are regulated by such oxidation and one crystal structural study of PTP1b suggests that major conformational changes may occur in response to oxidation. Thus, ROS generated in lymphocytes may oxidize cysteine residues in CD45 and induce conformational changes. By titrating CD45 by a small amount of hydrogen peroxide to just exceed the reducing capacity of the DTT used in the protein preparation, we have seen a dramatic alteration in the radius of gyration and with approximately 20% of the molecules forming dimers. In the optimized condition, the radius of gyration increases from 33 ¿¿to 52 ¿¿ accompanied by a 2-fold increase in the forward scattered intensity, providing the clear evidence of dimerization. These affects are quite specific and we see no evidence of non-specific aggregation larger than the dimmer even at high protein concentrations as high as 20 mg/ml.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。CD 45是一种蛋白酪氨酸磷酸酶（PTP），广泛存在于造血细胞中。它是一种常见的白细胞抗原，参与触发自身免疫反应。最近的研究表明，活性氧（ROS）的产生过程中酪氨酸激酶生长因子受体和抗原受体在淋巴细胞。越来越多的证据表明，PTPs受到这种氧化的调节，PTP 1b的一项晶体结构研究表明，氧化可能会发生主要的构象变化。因此，在淋巴细胞中产生的ROS可以氧化CD 45中的半胱氨酸残基并诱导构象变化。通过用少量过氧化氢滴定CD 45，使其刚好超过蛋白质制备中使用的DTT的还原能力，我们已经看到回转半径发生了显著变化，大约20%的分子形成了二聚体。在优化条件下，回转半径从33增加到52，伴随着前向散射强度的2倍增加，提供了二聚化的明确证据。这些影响是相当特异性的，我们没有看到比二聚体更大的非特异性聚集的证据，即使在高达20 mg/ml的高蛋白浓度下。