Progesterone Receptor Membrane Component 1 (PGRMC1)

The sole biochemical function of PGRMC1 is heme-binding. PGRMC1 shares key structural motifs with cytochrome b₅. PGRMC1 binds and activates P450 proteins, which are important in drug, hormone and lipid metabolism. PGRMC1 also binds to PAIR-BP1 (plasminogen activator inhibitor RNA-binding protein-1). However, its expression outside of the reproductive tract and in males suggests multiple functions for the protein. These may include binding to Insig (insulin-induced gene),which regulates cholesterol synthesis.

PGRMC1 is highly expressed in the liver and kidney in humans with lower expression in the brain, lung, heart, skeletal muscle and pancreas. In rodents, PGRMC1 is found in the liver, lung, kidney and brain.