cryptochrome 1 (CRY1)

Function

• blue light-dependent regulator of the circadian feedback
• component of the circadian core oscillator
• inhibits CLOCK|NPAS2-BMAL1 E box-mediated transcription via stabilizing unphosphorylated form of BMAL1
• acts, in conjunction with CRY2, in maintaining period length & circadian rhythmicity
• no photolyase activity
• translocates circadian clock core proteins, including PER proteins to the nucleus (putative)
• interacts directly with TIMELESS & the PER proteins
• interacts directly with PER1 & PER2 C-terminal domains
  • interaction with PER2 inhibits its ubiquitination & vice versa
• binds MAPK
• phosphorylation on Ser-247 by MAPK important for the inhibition of CLOCK-BMAL1-mediated transcriptional activity
• phosphorylation by CSNK1E requires interaction with PER1 or PER2

Cofactor:

• binds 1 FAD per subunit
• binds 1 5,10-methenyltetrahydrofolate non-covalently per subunit

Structure

• belongs to the DNA photolyase class-1 family
• contains 1 DNA photolyase domain

Compartment

• cytoplasm, nucleus
• translocated to the nucleus via interaction with other Clock proteins

Expression

• regulated by light & circadian rhythms.
• peak expression in the suprachiasma nucleus & eye at the day/night transition
• levels decrease with BMAL1-CLOCK inhibition as part of autoregulatory feedback loop

More general terms

• carrier protein (transporter)
• phosphoprotein

Component of

• circadian core oscillator

Database

• OMIM: https://mirror.omim.org/entry/601933
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=1407
• UniProt: http://www.uniprot.org/uniprot/Q16526.html