FIGURE 7.

Turnover of Tic protein subunits in the inner envelope membranes. Degradation of the inner envelope membrane Tic subunits Tic110, Tic55, Tic 40, and Tic20 in chloroplasts of wild type Arabidopsis and clpP6 antisense lines or clpR1 knock-out mutant. Equal amounts of intact chloroplasts were incubated in the presence of light and ATP, with envelope membrane fractions isolated at 0 and 3 h. The two protein fractions were separated by denaturing-PAGE and each of the four Tic subunits were detected by immunoblotting with specific antibodies. The relative amount of the different Tic proteins was quantified at each time point and normalized to the 0 h control, which was set to 100%. Values shown are averages ± S.D. (n = 3).