PAS domain

The PAS domain is a protein domain contained in many signaling proteins where it functions as a signal sensor. PAS domains are found in a large number of organisms from bacteria to humans. The PAS domain was named after the three proteins in which it was first discovered:

• Per – period circadian protein
• Arnt – aryl hydrocarbon receptor nuclear translocator protein
• Sim – single-minded protein

Many PAS-domain proteins detect their signal by way of an associated cofactor such as heme. Proteins that contain a PAS domain include Hypoxia-inducible factors.