Arabidopsis MAP kinase phosphatase 1 is phosphorylated and activated by its substrate AtMPK6

作者：Park Hyeong Cheol; Song Eun Hyeon; Xuan Canh Nguyen; Lee Kyunghee; Kim Kyung Eun; Kim Ho Soo; Lee Sang Min; Kim Sun Ho; Bae Dong Won; Yun Dae Jin; Chung Woo Sik^*

来源：Plant Cell Reports, 2011, 30(8): 1523-1531.

DOI：10.1007/s00299-011-1064-4

• Arabidopsis
• Calmodulin
• Mitogen-activated protein kinase (MPK)
• Mitogen-activated protein kinase phosphatase (MKP)
• Phosphorylation

Arabidopsis MAP kinase phosphatase 1 (AtMKP1) is a member of the mitogen-activated protein kinase (MPK) phosphatase family, which negatively regulates AtMPKs. We have previously shown that AtMKP1 is regulated by calmodulin (CaM). Here, we examined the phosphorylation of AtMKP1 by its substrate AtMPK6. Intriguingly, AtMKP1 was phosphorylated by AtMPK6, one of AtMKP1 substrates. Four phosphorylation sites were identified by phosphoamino acid analysis, TiO(2) chromatography and mass spectrometric analysis. Site-directed mutation of these residues in AtMKP1 abolished the phosphorylation by AtMPK6. In addition, AtMKP1 interacted with AtMPK6 as demonstrated by the yeast two-hybrid system. Finally, the phosphatase activity of AtMKP1 increased approximately twofold following phosphorylation by AtMPK6. By in-gel kinase assays, we showed that AtMKP1 could be rapidly phosphorylated by AtMPK6 in plants. Our results suggest that the catalytic activity of AtMKP1 in plants can be regulated not only by Ca(2+)/CaM, but also by its physiological substrate, AtMPK6.

• 出版日期2011-8