SHP-1 regulates Lck-induced phosphatidylinositol 3-kinase phosphorylation and activity
SHP-1 regulates Lck-induced phosphatidylinositol 3-kinase phosphorylation and activity
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DOI：
10.1074/jbc.274.39.27583
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发表时间：
1999-09-24
影响因子：
4.8
通讯作者：
Mills, GB
中科院分区：
文献类型：
--
作者：
Cuevas, B;Lu, YL;Mills, GB
T细胞抗原受体（TCR）的连接激活Src家族酪氨酸激酶p56 Lck，其继而磷酸化多种细胞内底物。磷脂酰肌醇3-激酶（PI 3 K）和酪氨酸磷酸酶SHP-1是两种与TGR信号传导有关的Lck底物。在这项研究中，我们证明了SHP-1与Jurkat T细胞中PI 3 K的p85调节亚基共免疫沉淀，并且这种关联通过TCR复合物的连接而增加。在COS 7细胞中SHP-1和具有组成性激活形式的Lck的PI 3 K的GO表达证明了PI 3 K的羧基末端SH 2结构域与全长SHP-1蛋白可诱导地缔合。相反，缺少Lck磷酸化位点（Tyr（564））的截短的SHP-1突变体不能结合p85。野生型但非催化失活的SHP-1诱导p85的去磷酸化。此外，SHP-1的表达降低了抗磷酸酪氨酸免疫沉淀物中的PI 3 K酶活性和Akt中丝氨酸473的磷酸化，这是一个依赖于PI 3 K活性的过程。这些结果表明PI 3 K和SHP-1之间存在功能性相互作用，并表明PI 3 K信号传导，这已经涉及细胞增殖，凋亡，细胞骨架重组，和许多其他生物活性，可以调节由SHP-1在T淋巴细胞。
Ligation of the T cell antigen receptor (TCR) activates the Src family tyrosine kinase p56 Lck, which, in turn, phosphorylates a variety of intracellular substrates. The phosphatidylinositol 3-kinase (PI3K) and the tyrosine phosphatase SHP-1 are two Lck substrates that have been implicated in TGR signaling. In this study, we demonstrate that SHP-1 co-immunoprecipitates with the p85 regulatory subunit of PI3K in Jurkat T cells, and that this association is increased by ligation of the TCR complex. Go-expression of SHP-1 and PI3K with a constitutively activated form of Lck in COS7 cells demonstrated the carboxyl-terminal SH2 domain of PI3K to inducibly associate with the full-length SHP-1 protein. By contrast, a truncated SHP-1 mutant lacking the Lck phosphorylation site (Tyr(564)) failed to bind p85. Wild-type but not catalytically inactive SHP-1 induced dephosphorylation of p85, Furthermore, expression of SHP-1 decreased PI3K enzyme activity in anti-phosphotyrosine immunoprecipitates and phosphorylation of serine 473 in Akt, a process dependent on PI3K activity. These results indicate the presence of a functional interaction between PI3K and SHP-1 and suggest that PI3K signaling, which has been implicated in cell proliferation, apoptosis, cytoskeletal reorganization, and many other biological activities, can be regulated by SHP-1 in T lymphocytes.