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Identification of tyrosine autophosphorylation sites of Arabidopsis MEKK 1 and their involvement in the regulation of kinase activity
Author(s) -
Matsuoka Daisuke,
Furuya Tomoyuki,
Iwasaki Tetsushi,
Nanmori Takashi
Publication year - 2018
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13242
Subject(s) - autophosphorylation , map kinase kinase kinase , protein tyrosine phosphatase , map2k7 , mitogen activated protein kinase kinase , tyrosine phosphorylation , biochemistry , microbiology and biotechnology , phosphorylation , chemistry , biology , cyclin dependent kinase 2 , protein kinase a
The MEKK 1 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 MEKK 1, expressed in both mammalian HEK 293 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 MEKK 1. Tyrosine to phenylalanine mutations decrease phosphorylation of the substrate MKK 1, suggesting the important role of this residue in the regulation of MEKK 1 kinase activity. The present study is the first to show that plant MAPKKK s are regulated by tyrosine phosphorylation.