Activation of Arabidopsis MAPK kinase kinase (AtMEKK1) and induction of AtMEKK1-AtMEK1 pathway by wounding.
We have constructed a series of deletion mutants of Arabidopsis MAPK kinase kinase (AtMEKK1) and obtained a constitutively active mutant, AtMEKK1Delta166, which lacks in self-inhibitory sequence of N-terminal 166 amino acids but still has substrate specificity. AtMEKK1Delta166 predominantly phosphorylates AtMEK1, an Arabidopsis MAPKK, but not its double mutant (AtMEK1T218A/S224E), suggesting that Thr-218 and Ser-224 are the phosphorylation sites. In wounded seedlings, AtMEKK1 was activated and phosphorylated its downstream AtMEK1. Furthermore, analysis using anti-AtMEKK1 and anti-AtMEK1 antibodies revealed that the interaction between the two proteins was signal dependent. These results suggest the presence of AtMEKK1-AtMEK1 pathway induced by wounding.
Hadiarto
Toto
T
Graduate School of Science and Technology, Kobe University, Rokkodai-cho, Nada-ku, Japan.
Nanmori
Takashi
T
Matsuoka
Daisuke
D
Iwasaki
Tetsushi
T
Sato
Ken-Ichi
K
Fukami
Yasuo
Y
Azuma
Tetsushi
T
Yasuda
Takeshi
T
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D018506:Gene Expression Regulation, Plant; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048728:MAP Kinase Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010935:Plant Diseases; D018515:Plant Leaves / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism
D029681:Arabidopsis Proteins; C436292:AtMPK4 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; D048369:MAP Kinase Kinase 1; C458515:MEK1 protein, Arabidopsis