Figure 5.

CPK18 Positively Regulates MPK5 Activity.

(A) MPK5-T32D, containing the T32A mutation to mimic phosphorylation, exhibited increased kinase activity toward MBP. The relative radioactivity is shown at the bottom.

(B) and (C) Detection of overall MAPK activity and MPK5 activity in CPK18-RI and wild-type plants using an in-gel kinase assay. Total protein (B) and immunoprecipitated MPK5 (C) were resolved on 10% SDS-PAGE gels containing MBP. The in-gel kinase assay was performed to analyze MAPK activity. The relative MAPK activity is shown at the bottom of (B). Protein loading is shown by Coomassie Brilliant Blue (CBB) staining.

(D) MPK5 protein level and overall MAPK TEY phosphorylation level in wild type and CPK18-RI lines. MPK5 and phos-TEY levels were examined by immunoblotting (WB) with anti-MPK5 and anti-phos-TEY antibodies, respectively.

(E) RT-qPCR examination of MPK4/5/6 expression in the wild type and CPK18-RI lines. Data are presented as means ± sd (n = 3).

[See online article for color version of this figure.]