Figure 7From: Regulation of Arabidopsis defense responses against Spodoptera littoralisby CPK-mediated calcium signalingSubstrate targeting of CPK3 and CPK13. A. Auto-phosphorylation signals from each CPK protein. Recombinant CPK was pre-treated with BAPTA (2.5 mM; a calcium chelator) and then subjected to auto-phosphorylation assays with several concentrations of CaCl2. B. In vitro kinase assays of the CPK3 and CPK13 proteins with a suite of TFs and ATL2 (following cell-free protein synthesis and purification) revealed their substrate targets. In the presence (+) or absence (-) of BAPTA (500 μM), kinase assays were performed in the presence of CaCl2 (100 μM). The DHFR protein served as a control. Each experiment was performed two or three times, with similar results each time. See the quantitative values in Additional file 3.Back to article page