PGRMC1
Domain
The cytochrome b5 heme-binding domain lacks the conserved iron-binding His residues at positions 107 and 131.
Function
Component of a progesterone-binding protein complex (PubMed:28396637). Binds progesterone (PubMed:25675345). Has many reported cellular functions (heme homeostasis, interaction with CYPs). Required for the maintenance of uterine histoarchitecture and normal female reproductive lifespan (By similarity). Intracellular heme chaperone. Regulates heme synthesis via interactions with FECH and acts as a heme donor for at least some hemoproteins (PubMed:27599036). Forms a ternary complex with TMEM97 receptor and low density lipid receptor/LDLR, which increases LDLR-mediated LDL lipoprotein internalization (PubMed:30443021).
Post-translational modifications
O-glycosylated; contains chondroitin sulfate attached to Ser-54. Ser-54 is in the cytoplasmic domain but the glycosylated form was detected in urine, suggesting that the membrane-bound form is cleaved, allowing for production of a secreted form which is glycosylated.
Sequence Similarities
Belongs to the cytochrome b5 family. MAPR subfamily.
Tissue Specificity
Detected in urine (at protein level) (PubMed:36213313, PubMed:37453717). Expressed by endometrial glands and stroma (at protein level) (PubMed:23793472). Widely expressed, with highest expression in liver and kidney.
Cellular localization
- Microsome membrane
- Single-pass membrane protein
- Smooth endoplasmic reticulum membrane
- Single-pass membrane protein
- Mitochondrion outer membrane
- Single-pass membrane protein
- Extracellular side
- Secreted
- Localized at cell membrane, probably in lipid rafts, in serum-starved conditions.
Alternative names
HPR6.6, PGRMC, PGRMC1, Membrane-associated progesterone receptor component 1, mPR, Dap1, IZA