Figure 9. XB15 Dephosphorylates the XA21 Kinase Domain.

(A) Immobilized GST-XA21K668 was autophosphorylated with [γ-³²P] ATP in kinase buffer. After washing, activated GST-XA21K668 was incubated with HIS-XB15ΔN (1 μg) at 37 °C for the indicated time (0, 1, 5, and 20 min). The samples were subsequently boiled in the presence of 2× sample buffer, separated by SDS-PAGE, stained with Coomassie brilliant blue R250 and destained (Coomassie). For the autoradiography, the dried gel was exposed to an image plate (Autorad).

(B) Activated GST-XA21K668 was incubated with 1 μg (+) or 10 μg (++) of HIS-XB15ΔN at 37 °C for 5 min. The samples were subsequently boiled in the presence of 2× sample buffer, separated by SDS-PAGE, stained with Coomassie brilliant blue R250 and destained (Coomassie). For the autoradiography, the dried gel was exposed to an image plate (Autorad).