INHIBITION OF PHOSPHATIDYLINOSITOL 3-KINASE ACTIVITY BY ASSOCIATION WITH 14-3-3-PROTEINS IN T-CELLS
INHIBITION OF PHOSPHATIDYLINOSITOL 3-KINASE ACTIVITY BY ASSOCIATION WITH 14-3-3-PROTEINS IN T-CELLS
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DOI：
10.1073/pnas.92.22.10142
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发表时间：
1995-10-24
影响因子：
11.1
通讯作者：
ALTMAN, A
中科院分区：
文献类型：
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作者：
BONNEFOYBERARD, N;LIU, YC;ALTMAN, A
14-3-3家族的蛋白质可以与几种原癌基因和癌基因产物结合和/或调节它们的活性，因此涉及信号传导途径的调节。我们报道14-3-3与另一种重要的转导酶磷脂酰肌醇3-激酶（PI 3-K）相关。重组14-3-3融合蛋白结合几个酪氨酸磷酸化蛋白从抗原受体刺激的T淋巴细胞。PI 3-K通过免疫印迹和酶测定被鉴定为静息或活化细胞中的14-3-3结合蛋白之一。此外，内源性14-3-3和PI 3-K从完整的T细胞共免疫沉淀。用重组14- 3-3融合蛋白对凝胶纯化、免疫沉淀的PI 3-K进行远蛋白质印迹，显示14-3-3与PI 3-K的催化亚基（p110）直接结合。最后，来自激活的14-3-3过表达细胞的抗磷酸酪氨酸免疫沉淀物比来自对照细胞的类似免疫沉淀物含有更低的PI 3-K酶活性。这些发现表明，14-3-3与造血（和可能的其他）细胞中的PI 3-K的关联在受体启动的信号转导期间调节PI 3-K的酶活性。
Proteins of the 14-3-3 family can associate with, and/or modulate the activity of, several protooncogene and oncogene products and, thus, are implicated in regulation of signaling pathways. We report that 14-3-3 is associated with another important transducing enzyme, phosphatidylinositol 3-kinase (PI3-K). A recombinant 14-3-3 fusion protein bound several tyrosine-phosphorylated proteins from antigen receptor-stimulated T lymphocytes. PI3-K was identified by immunoblotting and enzymatic assays as one of the 14-3-3-binding proteins in resting or activated cells. Moreover, endogenous 14-3-3 and PI3-K were coimmunoprecipitated from intact T cells. Far-Western blots of gel-purified, immunoprecipitated PI3-K with a recombinant 14-3-3 fusion protein revealed direct binding of 14-3-3 to the catalytic subunit (p110) of PI3-K. Finally, anti-phosphotyrosine immunoprecipitates from activated, 14-3-3-overexpressing cells contained lower PI3-K enzymatic activity than similar immunoprecipitates from control cells. These findings suggest that association of 14-3-3 with PI3-K in hematopoietic (and possibly other) cells regulates the enzymatic activity of PI3-K during receptor-initiated signal transduction.