Insights into the Role of Circadian Rhythms in Bone Metabolism: A Promising Intervention Target?

Figure 1

Molecular clock machinery. The feedback loop of clock genes and proteins is comprised of 2 main branches: CLOCK/BMAL1-PERs/CRYs and the supplementary regulators REV-ERBs, RORs, DECs and DBP. Glucocorticoids and sympathetic signals regulate circadian oscillators by modulating transactivation of PER1. CLOCK, circadian locomotor output cycles kaput; BMAL1, brain and muscle ARNT-like 1; PER, period circadian clock; CRY, cryptochrome; DBP, D-site binding protein; RORs, retinoid-related orphan receptors; RORE, ROR response element; DEC, differentiated embryo-chondrocyte expressed gene; GC, glucocorticoid; GR, glucocorticoid receptor; AR, adrenergic receptor.