Fig. 1. Activation and phosphorylation of recombinant bacterially expressed PCTAIRE-1 in brain and testis extracts. (A) Bacterial lysates containing either wild-type or kinase-dead myc-tagged PCTAIRE-1 proteins were incubated in brain or testis extracts or buffer, and the bound material was assayed for protein kinase activity towards myelin basic protein (MBP). (top panel) Coomassie-blue-stained gel; (middle panel) autoradiograph at the position of PCTAIRE-1; (bottom panel) autoradiograph at the position of MBP. (B) Purified wild-type and truncated recombinant myc-tagged PCTAIRE-1 proteins were incubated in brain and testis extracts or buffer, immunoprecipitated, and incubated in the presence of [-³²P]ATP. (top panel) Coomassie-blue-stained gel; (bottom panel) autoradiograph at the position of PCTAIRE-1.