RBP4: Retinol Binding Protein 4
Key transporter of retinol (vitamin A) in the blood; implicated in insulin resistance, type 2 diabetes, and cardiovascular disease.
Gene Information Card
| Symbol | RBP4 |
|---|---|
| Full Name | retinol binding protein 4 |
| Gene Type | protein coding |
| Chromosomal Location | 10q23.33 |
| NCBI Gene ID | 5950 ncbi.nlm.nih.gov/gene/5950 |
| Ensembl ID | ENSG00000138207 |
| UniProt ID | P02753 |
| OMIM ID | 180250 |
| HGNC ID | 9922 |
| Aliases | RBP, RDCCAS, MCOPCB6 |
Description
RBP4 (retinol binding protein 4) encodes a member of the lipocalin family of transport proteins. It is the specific carrier for retinol (vitamin A) in the blood, delivering retinol from the liver to peripheral tissues. RBP4 is primarily secreted by the liver and adipose tissue. Elevated serum RBP4 levels are associated with insulin resistance, obesity, type 2 diabetes, and cardiovascular disease. Mutations in RBP4 can cause retinol deficiency and ocular phenotypes such as night blindness and retinal dystrophy.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Retinal dystrophy | Loss-of-function mutations in RBP4 impair retinol transport to the retina, leading to vitamin A deficiency in photoreceptors. | ClinVar, OMIM #180250 |
| Night blindness | Deficient retinol delivery due to RBP4 mutations disrupts rhodopsin regeneration. | OMIM #180250 |
| Type 2 diabetes | Elevated RBP4 levels contribute to insulin resistance through activation of inflammatory pathways in adipose tissue. | NCBI Gene, PubMed |
| Cardiovascular disease | Increased RBP4 correlates with dyslipidemia and endothelial dysfunction. | PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 102.5 | High |
| Adipose tissue | 45.2 | Medium |
| Kidney | 12.3 | Low |
| Heart | 5.1 | Low |
| Skeletal muscle | 3.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 (liver) | 85.0 | Hepatocyte cell line |
| 3T3-L1 (adipocyte) | 40.0 | Differentiated adipocytes |
| ARPE-19 (retinal) | 2.5 | Retinal pigment epithelium |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.394C>T (p.Arg132Ter) | Nonsense | Rare | Loss of function; associated with retinal dystrophy |
| c.200G>A (p.Gly67Asp) | Missense | Rare | Impaired retinol binding; night blindness |
| c.1A>G (p.Met1?) | Start loss | Rare | Complete loss of protein; severe retinol deficiency |
Mutation functional classification
Loss of Function (LOF)
Nonsense and start-loss mutations lead to truncated or absent RBP4 protein, causing retinol transport deficiency and retinal disease.
Gain of Function (GOF)
Not reported for RBP4.
Dominant Negative (DN)
Not reported for RBP4.
View complete mutation data：
Gene Ontology (GO)
| • retinol binding | • retinol transport |
| • vitamin A transport | • extracellular space |
| • protein homodimerization activity |
Pathways
• Retinol metabolism
• Vitamin A and carotenoid metabolism
Protein Summary
RBP4 is a 21 kDa secreted protein belonging to the lipocalin family. It binds all-trans-retinol with high affinity and forms a complex with transthyretin (TTR) in the blood to prevent renal filtration. The protein is synthesized mainly in the liver and adipose tissue. Its structure consists of a beta-barrel that encapsulates retinol. RBP4 levels are regulated by retinol availability and are elevated in insulin-resistant states.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| RBP4 Knockout HEK293 Cell Line | EDJ-KQ5644 | Human | 5950 | Details Get a Quote |
| RBP4 Knockout A-549 Cell Line | EDJ-KQ28981 | Human | 5950 | Details Get a Quote |
| RBP4 Knockout HeLa Cell Line | EDJ-KQ54302 | Human | 5950 | Details Get a Quote |
| RBP4 Knockout HCT 116 Cell Line | EDJ-KQ71262 | Human | 5950 | Details Get a Quote |
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