FIGURE 5.
In vitro thiophosphorylation assay of MPK3/6. (A) Thiophosphorylation assays of GST-tagged wild type (Wt)- and analog-sensitive (AS)-MPK3 in the presence of Bn-ATPγS as cofactor. Tested StrepII-tagged substrates (SUB, e.g., eYFP, VQ4, HON5, DRP2B, WRKY6, CLMP1, MKK2, and NOT2/3/5) were purified from cell-free in vitro transcription-translation reactions using tobacco BY-2 cell lysates. Western blotting analysis, and immunodetection with specific antibodies was performed to check equal amounts of kinase (α-GST) and substrate (α-STREP) in each reaction and to examine phosphorylation of substrates (α-TPE). (B) Same as in (A) but using Wt- and AS-MPK6.