Fig. 3.

AtCPK5 is phosphorylated when expressed in planta or in vitro. The upper phase from two-phase partitioning of Arabidopsis membranes (left), cell-free wheat germ extract following in vitro expression of AtCPK5 (center), or cell-free wheat germ extract following expression of the AtCPK5-G2A mutant protein (right) were incubated with calf intestinal alkaline phosphatase (AP) and alkaline phosphatase inhibitor (API). The reaction products were separated by SDS-PAGE and AtCPK5 was detected by immunoblotting with AtCPK5 antibody