Preferred Label : Circadian Rhythm Pathway BioCarta;
NCIt synonyms : BioCarta Circadian Rhythm Pathway;
NCIt related terms : Circadian Rhythms;
Alternative definition : BIOCARTA: Organisms from flies to humans have daily circadian rhythms entrained with
the 24-hour cycle of day and night that regulate many physiological systems. In mammals,
there appears to be a master regulator of circadian rhythms in the hypothalamus, as
well as additional peripheral mechanisms. The basic framework of the molecular pathways
in the cell that produce and maintain these daily rhythms has been elucidated. The
central feature of the circadian pathways are two transcription factors, Bmal1 and
Clock, that are expressed in a 24 hour cycle and that act together as a heterodimer
to regulate the expression of other genes involved in maintaining the circadian rhythm.
Bmal1 and Clock activate transcription of multiple Period (per) and Cryptochrome (Cry)
genes. When the activity of Bmal1 and Clock is maximal, Per and Cry genes are transcribed,
and then translated in the cytoplasm. The translated Per and Cry genes form a complex
in the cytoplasm that is transported back into the nucleus. In the nucleus, Per and
Cry form a feedback loop that inhibits transcriptional activation by Bmal1 and Clock,
lowering their own expression in the process. At the same time, Per and Cry increase
transcription of Bmal1 and Clock genes, to initiate the next phase of the cycle once
again. This cycle runs autonomously in the cell, causing jet lag during travel, but
can be regulated to retrain to changes in the light cycle. Factors that regulate the
cycle include casein kinase 1 epsilon (CK1e) that phosphorylates Per2 and induces
its degradation. Mutation of PER2 in humans has been genetically linked to changes
in human sleep patterns. Further exploration of the factors that regulate circadian
rhythms may enable manipulation of the system in sleep disorders. (This definition
may be outdated - see the DesignNote.);
NCIt note : The BIOCARTA Definition (ALT_DEFINITION) for this pathway concept was provided by
BioCarta. This property was not created by, nor is it maintained by the NCI Thesaurus
staff. Additionally, BioCarta is no longer updating its pathway data; thus, the BIOCARTA
Definition might be outdated or inaccurate. Please see the Terms and Conditions for
Use at http://www.biocarta.com/.;
Biocarta ID : h_circadianPathway;
Origin ID : C39030;
UMLS CUI : C1522722;
Automatic exact mappings (from CISMeF team)
- Semantic type(s)
- has_gene_product_element
- pathway_has_gene_element
