FIGURE 2. In vivo phosphorylation of AvrPtoB_1–307 in plant cells.

AvrPtoB_1–307 with a C-terminal HA epitope tag was expressed in tomato RG-prf3 protoplasts by polyethylene glycol-mediated transformation in the presence of [³²P]orthophosphate. AvrPtoB_1–307-HA was immunoprecipitated with anti-HA affinity matrix, followed by SDS-PAGE separation and autoradiography. AvrPtoB_1–307-HA incorporated [³²P]phosphate (top panel). The identity of AvrPtoB_1–307-HA band was confirmed by Western blotting (WB) with an anti-HA antibody using a small amount of lysate before immunoprecipitation (bottom panel).