Figure 2.

MKK4 is imported into the stroma of pea chloroplasts irrespective of the activation status of the kinase. In vitro-translated PsbO, MKK4 and CA-MKK4 were incubated with intact pea chloroplasts. After incubation, samples were treated with either thermolysin (B and D) or trypsin (A, C and E), re-isolated, washed, lysed, fractionated and analyzed by SDS-PAGE followed by autoradiography. Translation products (lanes T); washed chloroplast fraction (lanes C-); protease-treated chloroplast fraction (lanes C+). (E) + trypsin lanes show SDS-PAGE fractionation of in vitro-translated MKK4 and CA-MKK4 digested with trypsin.