Identification of tyrosine autophosphorylation sites of Arabidopsis MEKK1 and their involvement in the regulation of kinase activity
Identification of tyrosine autophosphorylation sites of Arabidopsis MEKK1 and their involvement in the regulation of kinase activity
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DOI：
10.1002/1873-3468.13242
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发表时间：
2018-09
期刊：
影响因子：
3.5
通讯作者：
D. Matsuoka;Tomoyuki Furuya;T. Iwasaki;T. Nanmori
中科院分区：
文献类型：
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作者：
D. Matsuoka;Tomoyuki Furuya;T. Iwasaki;T. Nanmori
MEKK1是拟南芥中逆境信号的关键调节因子；然而，对其活性的调控知之甚少。在此，我们发现在哺乳动物HEK293细胞和大肠杆菌中表达的重组MEKK1在SDS-PAGE中显示出迁移率的变化，免疫印迹检测到丝氨酸、苏氨酸和酪氨酸残基的磷酸化。N-末端缺失、定点突变和蛋白磷酸酶处理表明，这种迁移率的改变是由激酶域的自动磷酸化引起的。我们鉴定了MEKK1 N-末端的酪氨酸自磷酸化位点。酪氨酸到苯丙氨酸的突变降低了底物MKK1的磷酸化，表明该残基在调节MEKK1激酶活性中起着重要作用。本研究首次表明植物MAPKKK受酪氨酸磷酸化调控。
The MEKK1 kinase is a key regulator of stress signaling in Arabidopsis; however, little is known about the regulation of its kinase activity. Here, we found that recombinant MEKK1, expressed in both mammalian HEK293 cells and Escherichia coli, shows a mobility shift in SDS‐PAGE, and immunoblotting detected phosphorylation of serine, threonine, and tyrosine residues. N‐terminal deletions, site‐directed mutagenesis, and protein phosphatase treatment revealed that the mobility shift results from autophosphorylation of the kinase domain. We identified the tyrosine autophosphorylation sites in the N‐terminal region of MEKK1. Tyrosine to phenylalanine mutations decrease phosphorylation of the substrate MKK1, suggesting the important role of this residue in the regulation of MEKK1 kinase activity. The present study is the first to show that plant MAPKKKs are regulated by tyrosine phosphorylation.