STAT RECRUITMENT BY TYROSINE-PHOSPHORYLATED CYTOKINE RECEPTORS - AN ORDERED REVERSIBLE AFFINITY-DRIVEN PROCESS
STAT RECRUITMENT BY TYROSINE-PHOSPHORYLATED CYTOKINE RECEPTORS - AN ORDERED REVERSIBLE AFFINITY-DRIVEN PROCESS
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DOI：
10.1016/1074-7613(95)90012-8
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发表时间：
1995-06-01
期刊：
影响因子：
32.4
通讯作者：
SCHREIBER, RD
中科院分区：
文献类型：
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作者：
GREENLUND, AC;MORALES, MO;SCHREIBER, RD
在此，我们证明纯化的 Stat1 以直接、特异性和可逆的方式结合到 IFN γ 受体 α 链上的酪氨酸磷酸化对接位点。使用表面等离子共振，我们确定了相互作用的亲和力 (K-D = 137 nM) 和特异性，并定义了受体介导的 Stat1 激活所需的最小亲和力。此外，我们还定量了纯化的 Stat1 与其他 Stat 蛋白上酪氨酸磷酸化结合位点相互作用的相对能力。最后，我们描述的实验表明，激活的 Stat1 从 IFN γ 受体单向释放反映了游离酪氨酸磷酸化 Stat1 单体倾向于形成高亲和力的互惠同源二聚体，而不是与受体结合位点重新结合。我们的结果表明，IFN γ 诱导的 Stat1 激活是一个有序且亲和力驱动的过程，我们建议该过程可以作为其他细胞因子受体激活 Stat 的范例。
Herein, we demonstrate that purified Stat1 binds to its tyrosine-phosphorylated docking site on the IFN gamma receptor alpha chain in a direct, specific, and reversible manner. Using surface plasmon resonance, we determine the affinity(K-D = 137 nM) and specificity of the interaction and define the minimum affinity needed for receptor-mediated Stat1 activation. In addition, we quantitate the relative ability of purified Stat1 to interact with tyrosine-phosphorylated binding sites on other Stat proteins. Finally, we describe experiments that Imply that the unidirectional release of activated Stat1 from the IFN gamma receptor reflects the preference of free tyrosine-phosphorylated Stat1 monomers to form high avidity reciprocal homodimers rather than reassociating with the receptor binding site. Our results demonstrate that IFN gamma-induced Stat1 activation is an ordered and affinity-driven process and we propose that this process may serve as a paradigm for Stat activation by other cytokine receptors.