DUAL PHOSPHORYLATION AND AUTOPHOSPHORYLATION IN MITOGEN-ACTIVATED PROTEIN (MAP) KINASE ACTIVATION
DUAL PHOSPHORYLATION AND AUTOPHOSPHORYLATION IN MITOGEN-ACTIVATED PROTEIN (MAP) KINASE ACTIVATION
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DOI：
10.1042/bj2960025
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发表时间：
1993-11-15
影响因子：
4.1
通讯作者：
WEBER, MJ
中科院分区：
文献类型：
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作者：
HER, JH;LAKHANI, S;WEBER, MJ
p42mapk [丝裂原激活蛋白 (MAP) 激酶；细胞外信号调节蛋白激酶 (ERK)] 是一种丝氨酸/苏氨酸特异性蛋白激酶，可通过酪氨酸和苏氨酸双重磷酸化来激活，以响应不同的激动剂。酪氨酸和苏氨酸磷酸化对于完整的酶活性都是必需的。最近纯化和克隆的MAP激酶激活剂已被证明是一种蛋白激酶（MAP激酶激酶），能够在体外诱导MAP激酶在酪氨酸和苏氨酸调节位点上的双重磷酸化。在本文中，我们利用在调节性磷酸化位点上发生改变的 MAP 激酶突变体，在体内和体外表明，酪氨酸和苏氨酸的磷酸化可以彼此独立地发生，而无需磷酸化的顺序。我们还利用了 MAP 激酶的激酶缺陷型变体，该变体在 ATP 结合环或催化环中发生突变，并获得了表明 MAP 激酶催化环的活性或结构在其自身双重磷酸化中发挥重要作用的数据。
p42mapk [mitogen activated protein (MAP) kinase; extracellular signal-regulated protein kinase (ERK)] is a serine/threonine-specific protein kinase that is activated by dual tyrosine and threonine phosphorylation in response to diverse agonists. Both the tyrosine and threonine phosphorylations are necessary for full enzymic activity. A MAP kinase activator recently purified and cloned has been shown to be a protein kinase (MAP kinase kinase) that is able to induce the dual phosphorylation of MAP kinase on both the regulatory tyrosine and threonine sites in vitro. In the present paper we have utilized MAP kinase mutants altered in the sites of regulatory phosphorylation to show, both in vivo and in vitro, that phosphorylation of the tyrosine and the threonine can occur independently of one another, with no required order of phosphorylation. We also utilized kinase-defective variants of MAP kinase with mutations in either the ATP-binding loop or the catalytic loop, and obtained data suggesting that the activity or structure of the catalytic loop of MAP kinase plays an important role in its own dual phosphorylation.