Fig. 1.

Analysis of thylakoid protein dephosphorylation. (A) Dephosphorylation of thylakoid proteins. Twelve-day-old Col0 wild-type seedlings grown under white light were exposed to far-red light or transferred to the dark for the indicated times to induce a transition from state 2 to state 1. Seedlings treated with far red for 1 h were then exposed to blue light to induce the reverse transition from state 1 to state 2. Total protein was extracted and was analyzed by SDS/PAGE and immunoblotting with antiphosphothreonine antibodies. (B) The pph1 mutants are deficient in LHCII dephosphorylation under far-red light. Seedlings of the Col0 wild-type (WT), of pph1-1, and of pph1-2 were treated with far-red light and analyzed as in A. The same blot was decorated with antibody against the PsaA subunit of PSI as a control. (C) The pph1 mutants are deficient in dark-induced LHCII dephosphorylation. Four hours after the onset of the light period, mature leaves were collected and the plants were transferred to the dark for 5 h. Total protein was extracted and analyzed as in A. Note that the defect in dephosphorylation is more pronounced in pph1-3 than in pph1-1, which is a leaky allele containing residual amounts of PPH1 mRNA (Fig. S5).