N enhances nuclear AMPK activity and phosphorylates and destabilizes nuclear CRY1. (A) Nuclear AMPK activity (N-kinase activity), nuclear AMPK protein level (N-AMPK), and total cellular AMPK protein level (T-AMPK) of WT plants grown under 1/20 LN, NN, or HN conditions over a 24-h period. Autoradiographs are marked with red boxes. (B) Nuclear phosphorylated CRY1 (N-pCRY1), nuclear CRY1 protein level (N-CRY1), and total cellular CRY1 protein level (T-CRY1) of WT plants grown under LN, NN, and HN conditions over a 24-h period. (C) ACTIN1 served as a loading control for total cellular proteins. (D) HISTONE3 served as a loading control for nuclear proteins.