Receptor PTPs, Cell Contract and Signal Transduction

描述(由申请人提供)：该项目广泛的、长期的目标是表征蛋白质酪氨酸磷酸酶(PTP)家族的结构、调节和功能。蛋白酪氨酸激酶(PTKs)和蛋白酪氨酸激酶(PTPs)的协同和竞争作用在体内被整合，控制着生长、增殖、分化、存活、运动和新陈代谢等基本过程。此外，PTPs和PTKs之间微妙的平衡被破坏，这与人类疾病的病因学有关，包括癌症、糖尿病和炎症。因此，对PTPs的表征是全面了解正常和疾病条件下酪氨酸磷酸化的生理后果的先决条件。这种竞争性的更新集中在酪氨酸-磷酸化依赖的信号转导的新一层控制上，即通过可逆氧化来调节PTP功能。该提案的具体目的是：1)开发新的策略来检测PTPs的可逆氧化，并确定氧化对生理刺激的化学计量比。2)研究PTP氧化与pTyr依赖信号调控之间的相互作用。3)探讨刺激诱导的PTP氧化的特异性机制。4)研究受体PTPs中第二个PTP结构域作为氧化感受器的潜在功能。将开发新的检测方法来测量PTPs对生理刺激的可逆氧化反应。此外，这种氧化将被利用为一种“标记”特定的PTP的手段，这些PTP是由这些刺激启动的信号转导通路调节所不可或缺的。通过结合使用RNA干扰和底物捕获突变形式的PTPs，这些酶的信号功能将被确定。预计所产生的洞察力可能为人类疾病的治疗干预确定新的靶点，并可能为抑制PTP提出新的治疗策略。

DESCRIPTION (provided by applicant): The broad, long-term objectives of the project are to characterize the structure, regulation and function of the protein tyrosine phosphatase (PTP) family of enzymes. It is now apparent that the coordinated and competing actions of both protein tyrosine kinases (PTKs) and PTPs are integrated in vivo to control such fundamental processes as growth and proliferation, differentiation, survival, motility and metabolism. Furthermore, disruption of the delicate balance between the action of PTPs and PTKs has been implicated in the etiology of human diseases, including cancer, diabetes and inflammation. Therefore, characterization of the PTPs is a prerequisite to gaining a complete understanding of the physiological consequences of tyrosine phosphorylation under normal and diseased conditions. This competitive renewal focuses on a new tier of control of tyrosine-phosphorylation dependent signal transduction, the regulation of PTP function by reversible oxidation. The Specific Aims of the proposal are: 1) To develop new strategies to assay reversible oxidation of PTPs and to determine the stoichiometry of oxidation in response to physiological stimuli. 2) To investigate the interplay between PTP oxidation and the control of pTyr-dependent signaling. 3) To investigate mechanisms underlying the specificity of stimulus-induced PTP oxidation. 4) To investigate the potential function of the second PTP domain in Receptor PTPs as an oxidation sensor. New assays will be developed to measure the reversible oxidation of PTPs in response to physiological stimuli. Furthermore, such oxidation will be harnessed as a means of "tagging" the specific PTPs that are integral to the regulation of signal transduction pathways initiated by those stimuli. By combining the use of RNA interference with application of substrate trapping mutant forms of the PTPs, the signaling function of these enzymes will be defined. It is anticipated that the insights that are generated may identify novel targets for therapeutic intervention in human disease and may suggest new therapeutic strategies for PTP inhibition.