Figure 4.

Effects of physiological stimuli on phosphorylation level of the pT H⁺-ATPase in M. polymorpha. A, Light-induced phosphorylation of the H⁺-ATPase in thalli. Dark-adapted thalli were illuminated with white light for 3 h at 50 µmol m⁻² s⁻¹ (Lt) or kept in the dark (Dk). The thalli were then disrupted and the protein extracts subjected to SDS-PAGE. Phosphorylated H⁺-ATPase and the H⁺-ATPase were detected by immunoblot using anti-pThr and anti-H⁺-ATPase, respectively. B, Suc-induced phosphorylation of the H⁺-ATPase in thalli. Dark-adapted thalli were treated with 30 mm Suc or 30 mm mannitol for 30 min in the dark. Other procedures were the same as in A. Mannitol was used for osmotic control. C, Mannitol-induced phosphorylation of the H⁺-ATPase in thalli. Dark-adapted thalli were treated with 0, 100, or 200 mm mannitol for 30 min in the dark. Other procedures were the same as in A.