Activation-dependent phosphorylation of the T-lymphocyte surface receptor CD28 and associated proteins.
Activation-dependent phosphorylation of the T-lymphocyte surface receptor CD28 and associated proteins.
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DOI：
10.1073/pnas.91.8.3260
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发表时间：
1994-04
影响因子：
11.1
通讯作者：
J. Hutchcroft;Barbara E. Bierer
中科院分区：
文献类型：
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作者：
J. Hutchcroft;Barbara E. Bierer
CD 28是一种共刺激受体，可提供T细胞活化所需的第二信号，并通过T细胞抗原受体/CD 3复合物响应刺激发挥功能。我们发现，一个独特的阵列的蛋白质被磷酸化的酪氨酸刺激后，与抗CD 28单克隆抗体，免疫复合物激酶检测。体外激酶活性的抗CD 28刺激是去污剂依赖性的，发生在用Brij 96而不是Nonidet P-40制备的免疫复合物中。用低浓度佛波酯预处理细胞增加了CD 28免疫复合物中蛋白质的活化非依赖性磷酸化。再免疫沉淀研究表明，细胞质蛋白酪氨酸激酶Lck和Fyn与CD 28。通过非还原/还原SDS/PAGE分析检测，CD 28本身在体外和体内均以激活依赖性方式磷酸化。活化刺激的CD 28磷酸化可能在通过该受体的信号传导中起关键作用。
CD28 is a costimulatory receptor that can provide the second signal necessary for T-cell activation and function in response to stimulation through the T-cell antigen receptor/CD3 complex. We found that a distinct array of proteins was phosphorylated on tyrosine following stimulation with anti-CD28 monoclonal antibody, as detected by immune-complex kinase assays. Anti-CD28 stimulation of in vitro kinase activity was detergent-dependent, occurring in immune complexes prepared with Brij 96 but not Nonidet P-40. Pretreatment of cells with low concentrations of phorbol ester increased the activation-independent phosphorylation of proteins in CD28 immune complexes. Reimmunoprecipitation studies indicated that the cytoplasmic protein-tyrosine kinases Lck and Fyn were associated with CD28. CD28 itself was phosphorylated both in vitro and in vivo in an activation-dependent manner, as detected by nonreducing/reducing SDS/PAGE analyses. The activation-stimulated phosphorylation of CD28 may play a key role in signaling through this receptor.