Cryptochrome-1 (CRY1), Cryptochrome-2 (CRY2) (CRY1, CRY2)

Cryptochrome-1 and Cryptochrome-2 are highly conserved flavoproteins that serve as core components of the circadian clock in mammals, functioning mainly as transcriptional repressors of CLOCK-BMAL1 activity. They evolved from photolyase enzymes responsible for DNA repair and retain a similar fold and FAD-binding domain. CRY1 and CRY2 regulate the timing and amplitude of circadian gene expression, with distinct but overlapping effects on behavior and physiology: CRY1 is a stronger repressor and more directly implicated in cell cycle regulation and DNA repair, while CRY2 is mainly nuclear-localized and impacts rhythm synchrony. Genetic variation in these proteins can cause sleep and metabolic disorders, and dysregulation of their expression or function is associated with cancer and other diseases. As such, cryptochromes are considered emerging therapeutic targets for diseases involving circadian rhythm dysfunction and related cellular processes.

Other names

CRY1CRY2Circadian clock protein CRY1Circadian clock protein CRY2Blue light photoreceptor

Transcriptional repression: drugs or molecules that target cryptochrome typically aim to modulate its ability to repress CLOCK-BMAL1-mediated transcription, thereby altering circadian rhythm outputs. Protein-protein interaction inhibition or stabilization: by binding cryptochrome or its complexes, drugs may influence its nuclear localization or interaction with other clock proteins.