Fig. 1.

BVR is a substrate for IRK. (a) Time course of BVR phosphorylation by IRK. Ten micrograms of purified wtBVR was incubated in 100 μl of kinase buffer (pH 8.0) containing 0.1 μg of IRK and [γ-³²P]ATP up to 4 h. At the indicated times, samples were subjected to 8% SDS/PAGE and transferred to PVDF, and phosphorylated proteins were visualized by autoradiography. (b) IRK phosphorylates BVR on tyrosine residues. Five micrograms of purified wtBVR was incubated in IRK phosphorylation buffer for 2 h. The reaction mixtures, with the indicated additions, were resolved as described above, blotted onto PVDF, and analyzed by using antiphosphotyrosine antibodies with the ECL detection system.