Daily biological clock regulation by chemical modification of the BMAL1 protein

BMAL1 is SUMOylated on a conserved lysine residue (Lys259) in vivo, demonstrating a circadian pattern of modification.

• SUMOylation of BMAL1 correlates with its activation in the mouse liver.
• The process of SUMOylation is dependent on CLOCK, which partners with BMAL1.
• Ectopic expression of a SUMO-deficient BMAL1 suggests that SUMOylation is important for BMAL1's circadian expression.
• These findings indicate a new regulatory layer in the core mechanism of the circadian clock.

Simplified