CYP8B1 Gene
Cytochrome P450 Family 8 Subfamily B Member 1
Gene Information Card
| Symbol | CYP8B1 |
|---|---|
| Full Name | Cytochrome P450 Family 8 Subfamily B Member 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 3p22.1 |
| NCBI Gene ID | 1582 ncbi.nlm.nih.gov/gene/1582 |
| Ensembl ID | ENSG00000163631 |
| UniProt ID | Q9UNU6 |
| OMIM ID | 602172 |
| HGNC ID | 2648 |
| Aliases | CP8B, CYP12, sterol 12-alpha-hydroxylase |
Description
CYP8B1 encodes a member of the cytochrome P450 superfamily of enzymes, specifically sterol 12α-hydroxylase. This enzyme catalyzes the 12α-hydroxylation of 7α-hydroxy-4-cholesten-3-one, a critical step in the synthesis of cholic acid, the primary bile acid in humans. CYP8B1 activity determines the ratio of cholic acid to chenodeoxycholic acid in bile, influencing cholesterol homeostasis and bile acid pool composition. The gene is predominantly expressed in the liver and regulated by bile acid feedback via the FXR-SHP pathway.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cholestasis, progressive familial intrahepatic 1 | Reduced CYP8B1 activity alters bile acid composition, contributing to cholestatic liver injury | PMID: 23541340 |
| Gallstone disease | Altered cholic acid/chenodeoxycholic acid ratio promotes cholesterol supersaturation in bile | PMID: 17661428 |
| Hypertriglyceridemia | CYP8B1 deficiency may affect lipid metabolism via altered bile acid signaling | PMID: 21518877 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 32.5 | High |
| Small intestine | 1.2 | Low |
| Kidney | 0.8 | Low |
| Adrenal gland | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 15.3 | Hepatocellular carcinoma cell line |
| Huh-7 | 12.8 | Hepatoma cell line |
| Primary hepatocytes | 28.1 | Normal liver cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | <0.01% | Loss of start codon, likely loss of function |
| c.334C>T (p.Arg112Trp) | Missense | <0.01% | Reduced enzyme activity in vitro |
| c.1072G>A (p.Gly358Ser) | Missense | <0.01% | Unknown functional effect |
Mutation functional classification
Loss of Function (LOF)
Mutations affecting the start codon or catalytic residues (e.g., p.Met1?) are predicted to abolish enzyme activity, leading to altered bile acid composition.
Gain of Function (GOF)
No gain-of-function mutations have been reported for CYP8B1.
Dominant Negative (DN)
No dominant-negative mutations have been described for CYP8B1.
View complete mutation data：
Gene Ontology (GO)
| • sterol 12-alpha-hydroxylase activity | • iron ion binding |
| • heme binding | • oxidoreductase activity |
| • acting on paired donors | • with incorporation or reduction of molecular oxygen |
| • bile acid biosynthetic process | • cholesterol homeostasis |
Pathways
• Bile acid biosynthesis (KEGG: hsa00120)
• Metabolism of lipids and lipoproteins (Reactome: R-HSA-556833)
Protein Summary
CYP8B1 is a 500-amino acid microsomal cytochrome P450 enzyme (UniProt Q9UNU6) localized to the endoplasmic reticulum in hepatocytes. It catalyzes the 12α-hydroxylation of 7α-hydroxy-4-cholesten-3-one to form 7α,12α-dihydroxy-4-cholesten-3-one, a committed step in cholic acid synthesis. The enzyme contains a conserved heme-binding domain and requires NADPH-cytochrome P450 reductase for activity. Its expression is tightly regulated by bile acid receptor FXR via SHP-mediated repression.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CYP8B1 Knockout HEK293 Cell Line | EDJ-KQ4411 | Human | 1582 | Details Get a Quote |
| CYP8B1 Knockout HeLa Cell Line | EDJ-KQ53057 | Human | 1582 | Details Get a Quote |
| CYP8B1 Knockout A-549 Cell Line | EDJ-KQ61522 | Human | 1582 | Details Get a Quote |
| CYP8B1 Knockout HCT 116 Cell Line | EDJ-KQ70014 | Human | 1582 | Details Get a Quote |
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