Fig. 2.

The CIB1 protein is degraded in the absence of blue light by the 26S proteasome. (A and B) Immunoblot showing the inhibition of CIB1 degradation by the proteasome inhibitor MG132. Plants were grown in CW for 3 wk, and leaves were excised and incubated with MG132 (50 µmol/L) or mock solution (0.1% DMSO) in darkness (A) or white light (B) for the indicated time before sample collection. (C) Immunoblot showing the CIB1 protein in cytosolic and nuclear fractions. LD [16-h light/8-h dark (16hL/8hD)]-grown plants were transferred to dark for 16 h and then transferred to blue light (35 μmol⋅m⁻²⋅s⁻¹) for 60 min. Total protein, cytosolic protein, and nuclear proteins were extracted, fractionated by 10% SDS/PAGE, blotted, and probed by the anti-Myc (CIB1), anti-histone H3 (nuclear marker), and anti-HSP90 (cytosol marker) antibodies.