APOB Gene: Apolipoprotein B - Function, Mutations, and Associated Diseases
Comprehensive biomedical overview of the APOB gene, including genomic context, protein function, disease associations, expression patterns, and mutation landscape.
Gene Information Card
| Symbol | APOB |
|---|---|
| Full Name | Apolipoprotein B |
| Gene Type | Protein-coding |
| Chromosomal Location | 2p24.1 |
| NCBI Gene ID | 338 ncbi.nlm.nih.gov/gene/338 |
| Ensembl ID | ENSG00000084674 |
| UniProt ID | P04114 |
| OMIM ID | 107730 |
| HGNC ID | 603 |
| Aliases | FLDB, LDLCQ4, apoB-100, apoB-48 |
Description
The APOB gene encodes apolipoprotein B, the primary structural protein of chylomicrons, VLDL, and LDL particles. It exists in two main isoforms: apoB-48 (produced in the intestine) and apoB-100 (produced in the liver). APOB plays a critical role in lipid metabolism, cholesterol transport, and the regulation of plasma lipid levels. Mutations in APOB are associated with familial hypercholesterolemia (due to defective LDL receptor binding) and familial hypobetalipoproteinemia (leading to reduced LDL levels).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Familial hypercholesterolemia | Loss-of-function mutations in the LDL receptor-binding domain of apoB-100 impair LDL clearance, leading to elevated plasma LDL cholesterol. | ClinVar, OMIM |
| Familial hypobetalipoproteinemia | Nonsense or frameshift mutations causing truncated apoB proteins reduce LDL production and plasma cholesterol levels. | ClinVar, OMIM |
| Hypercholesterolemia, autosomal dominant, type B | Specific missense mutations (e.g., p.Arg3527Gln) disrupt LDL receptor binding, causing autosomal dominant hypercholesterolemia. | OMIM, ClinVar |
| Coronary artery disease | APOB variants affecting LDL levels contribute to atherosclerosis risk. | ClinVar, NCBI |
| Gallbladder disease | APOB polymorphisms may influence cholesterol gallstone formation. | ClinVar, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | High (nTPM ~ 200) | High expression; primary site of apoB-100 synthesis. |
| Small intestine | Moderate (nTPM ~ 50) | Expression of apoB-48 in enterocytes. |
| Kidney | Low (nTPM ~ 10) | Minimal expression. |
| Adipose tissue | Low (nTPM ~ 5) | Low expression. |
| Testis | Low (nTPM ~ 3) | Low expression. |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | High | Hepatocellular carcinoma cell line; robust APOB expression. |
| Caco-2 | Moderate | Colorectal adenocarcinoma cells; express apoB-48 upon differentiation. |
| Huh7 | High | Hepatoma cell line; used for lipoprotein studies. |
| A549 | Low | Lung carcinoma; minimal expression. |
| MCF7 | Low | Breast cancer; minimal expression. |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| p.Arg3527Gln (R3500Q) | Missense | 0.1-0.2% in general population; higher in FH cohorts | Disrupts LDL receptor binding, causing familial hypercholesterolemia. |
| p.Arg3527Trp (R3500W) | Missense | Rare | Similar effect to R3500Q; impairs LDL clearance. |
| p.Arg463Lys | Missense | Rare | Associated with hypobetalipoproteinemia. |
| c.10580G>A (splice site) | Splice variant | Rare | Causes exon skipping and truncated protein. |
| p.Leu343Val | Missense | Rare | Potential effect on LDL binding. |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations (e.g., truncations) reduce apoB production, leading to hypobetalipoproteinemia with low LDL levels.
Gain of Function (GOF)
Gain-of-function mutations are not well-defined; most pathogenic variants are loss-of-function or dominant-negative.
Dominant Negative (DN)
Missense mutations in the LDL receptor-binding domain (e.g., R3500Q) act in a dominant-negative manner by producing apoB that cannot bind LDL receptor, impairing LDL clearance.
View complete mutation data：
Gene Ontology (GO)
| • lipid binding | • cholesterol transporter activity |
| • lipoprotein particle binding | • low-density lipoprotein particle receptor binding |
| • extracellular matrix structural constituent | • protein homodimerization activity |
Pathways
• Lipoprotein metabolism
• Chylomicron-mediated lipid transport
• VLDL/LDL metabolism
• Reverse cholesterol transport
• PPAR signaling pathway
Protein Summary
Apolipoprotein B (apoB) is a large amphipathic glycoprotein that serves as the main scaffold for atherogenic lipoproteins. ApoB-100 (4563 amino acids) is synthesized in the liver and is the sole protein component of LDL. ApoB-48 (2152 amino acids) is produced in the intestine via mRNA editing and is essential for chylomicron assembly. The protein contains LDL receptor-binding domains that mediate clearance of LDL from circulation. Defects in these domains lead to familial hypercholesterolemia, while truncating mutations cause hypobetalipoproteinemia.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| APOBEC3G Knockout HEK293 Cell Line | EDJ-KQ1894 | Human | 60489 | Details Get a Quote |
| APOB Knockout HEK293 Cell Line | EDJ-KQ2190 | Human | 338 | Details Get a Quote |
| APOBEC3A Knockout HEK293 Cell Line | EDJ-KQ3561 | Human | 200315 | Details Get a Quote |
| APOBEC1 Knockout HEK293 Cell Line | EDJ-KQ4070 | Human | 339 | Details Get a Quote |
| APOBEC3F Knockout HEK293 Cell Line | EDJ-KQ4453 | Human | 200316 | Details Get a Quote |
| APOBEC3B Knockout HEK293 Cell Line | EDJ-KQ6646 | Human | 9582 | Details Get a Quote |
| APOBEC2 Knockout HEK293 Cell Line | EDJ-KQ7217 | Human | 10930 | Details Get a Quote |
| APOBEC3D Knockout HEK293 Cell Line | EDJ-KQ9783 | Human | 140564 | Details Get a Quote |
| APOBEC4 Knockout HEK293 Cell Line | EDJ-KQ11694 | Human | 403314 | Details Get a Quote |
| APOBEC3A_B Knockout HEK293 Cell Line | EDJ-KQ11872 | Human | 100913187 | Details Get a Quote |
| APOBEC3H Knockout HEK293 Cell Line | EDJ-KQ12133 | Human | 164668 | Details Get a Quote |
| APOBEC3G Knockout HCT 116 Cell Line | EDJ-KQ23159 | Human | 60489 | Details Get a Quote |
| APOBEC3F Knockout A-549 Cell Line | EDJ-KQ27007 | Human | 200316 | Details Get a Quote |
| APOBEC3F Knockout HCT 116 Cell Line | EDJ-KQ27008 | Human | 200316 | Details Get a Quote |
| APOBEC3B Knockout A-549 Cell Line | EDJ-KQ30924 | Human | 9582 | Details Get a Quote |
Displaying Records 1 To 15 Of 52 Records
- 1
- 2
- Next Page »
