COSTIMULATION OF T LYMPHOCYTES OF CD28

描述：(根据申请者的抽象和具体目标改编。) T细胞对抗原的反应依赖于T细胞的刺激 T细胞抗原受体及其通过辅助T细胞传递的信号 细胞分子，如CD28。CD28结合B7(CD80)和B7-2(B70)， 由抗原提呈细胞表达的细胞表面分子。这个 目前的申请寻求定义CD28的结构基础- 传递信号，目的是让人们了解他们之间的关系 在信号通路和细胞反应之间。以前的研究 已经证明CD28的扰动诱导了它的酪氨酸 磷酸化。第一个具体目标是描述CD28的特征- 需要胞质酪氨酸残基的介导信号。CD28 带有Phe的Tyr替换的突变体将用于确定哪些 CD28需要酪氨酸残基才能引发特定的早期 信号传递事件，并调节某些细胞反应。此外, 与CD28相互作用需要这些Tyr残基的蛋白质将 被指认出来。此外，50kD的蛋白质在Tyr 170处与CD28结合，并 与磷脂酰肌醇密切相关的3‘-激酶P85 特色化的。第二个具体目标是确定 CD28与TEC成员p72itk/EMT相互作用的研究 家族蛋白酪氨酸激酶。第三个特定目标将使用 酵母菌双杂交系统用于鉴定能够与 CD28的胞浆结构域不依赖于其磷酸化。

DESCRIPTION: (Adapted from the applicant's abstract and Specific Aims.) T-cell activation in response to antigen depends upon stimulation of the T cell antigen receptor and upon signals delivered through accessory T cell molecules, such as CD28. CD28 binds B7 (CD80) and B7-2 (B70), cell-surface molecules expressed by antigen-presenting cells. The current application seeks to define the structural basis for CD28- mediated signaling, with the goal of shedding light on the relationships between signaling pathways and cellular responses. Previous studies have shown that perturbation of CD28 induces its tyrosine phosphorylation. The first specific aim is to characterize the CD28- mediated signals that require cytoplasmic tyrosine residues. CD28 mutants with Phe for Tyr substitutions will be used to determine which Tyr residues are required in order for CD28 to elicit particular early signaling events and to mediate certain cellular responses. In addition, proteins whose interaction with CD28 requires these Tyr residues will be identified. Also, a 50 kD protein that binds CD28 at Tyr 170 and is closely related to phosphatidylinositol 3'-kinase p85 will be characterized. The second specific aim is to determine the importance of the interaction of CD28 with p72itk/emt which is a member of the tec family protein tyrosine kinases. The third specific aim will use a yeast two hybrid system to identify proteins that can interact with the cytoplasmic domain of CD28 independently of its phosphorylation.