OCA2 Gene
OCA2 melanosomal transmembrane protein
Gene Information Card
| Symbol | OCA2 |
|---|---|
| Full Name | OCA2 melanosomal transmembrane protein |
| Gene Type | protein-coding |
| Chromosomal Location | 15q12-q13.1 |
| NCBI Gene ID | 4948 ncbi.nlm.nih.gov/gene/4948 |
| Ensembl ID | ENSG00000104044 |
| UniProt ID | Q04671 |
| OMIM ID | 611409 |
| HGNC ID | 8101 |
| Aliases | P, D15S12, BEY, EYCL2, EYCL3, PED |
Description
The OCA2 gene encodes the melanosomal transmembrane protein, also known as the P protein, which is involved in the maturation of melanosomes and the regulation of melanin synthesis. It is primarily expressed in melanocytes and retinal pigment epithelium. Mutations in OCA2 are the most common cause of oculocutaneous albinism type II (OCA2), and common polymorphisms are associated with normal variation in human eye color.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Oculocutaneous albinism type II (OCA2) | Loss-of-function mutations in OCA2 impair melanosomal pH regulation and tyrosine transport, reducing melanin synthesis. | ClinVar, OMIM |
| Brown oculocutaneous albinism (BOCA) | Specific missense variants (e.g., p.Pro743Leu) cause partial loss of function leading to a milder albinism phenotype. | OMIM, PubMed |
| Eye color variation (brown/blue) | Common intronic and regulatory SNPs (e.g., rs1800407, rs12913832) modulate OCA2 expression, affecting iris pigmentation. | NCBI, GWAS Catalog |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin | 12.5 | Medium |
| Retina | 8.3 | Medium |
| Brain (cerebellum) | 2.1 | Low |
| Testis | 1.8 | Low |
| Lung | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SK-MEL-28 (melanoma) | 15.2 | High expression |
| MNT-1 (melanoma) | 14.8 | High expression |
| HEK293 (embryonic kidney) | 0.3 | Very low/not detected |
| ARPE-19 (retinal pigment epithelium) | 9.1 | Medium expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1327G>A (p.Val443Ile) | Missense | 0.1% in general population | Reduced melanosomal pH regulation; associated with OCA2 |
| c.1045-15T>G | Splice site | 0.05% | Aberrant splicing; loss of function; OCA2 |
| c.2T>C (p.Met1Thr) | Start loss | <0.01% | Complete loss of protein; severe OCA2 |
| rs1800407 (c.1256G>A, p.Arg419Gln) | Missense | ~20% in Europeans | Moderate effect on eye color (blue/brown) |
Mutation functional classification
Loss of Function (LOF)
Nonsense, frameshift, and splice-site mutations that truncate or abolish OCA2 protein function cause oculocutaneous albinism type II.
Gain of Function (GOF)
No gain-of-function mutations are currently described in the literature or curated databases.
Dominant Negative (DN)
No dominant-negative mutations have been reported for OCA2; the condition is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • integral component of membrane (GO:0016021) | • plasma membrane (GO:0005886) |
| • melanosome (GO:0042470) | • melanosome membrane (GO:0032402) |
| • pigmentation (GO:0043473) | • developmental pigmentation (GO:0048066) |
| • amino acid transmembrane transporter activity (GO:0015171) |
Pathways
• ['Melanin biosynthesis (Reactome: R-HSA-5668599)']
• ['Melanosome maturation (KEGG: hsa04916)']
Protein Summary
The OCA2 protein (P protein) is a 12-pass transmembrane protein localized to the melanosome membrane. It functions as a chloride/anion transporter that regulates melanosomal pH, which is critical for proper tyrosinase activity and melanin synthesis. The protein is 838 amino acids long and is highly conserved in vertebrates.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| OCA2 Knockout HEK293 Cell Line | EDJ-KQ2431 | Human | 4948 | Details Get a Quote |
| OCA2 Knockout HeLa Cell Line | EDJ-KQ54037 | Human | 4948 | Details Get a Quote |
| OCA2 Knockout A-549 Cell Line | EDJ-KQ62525 | Human | 4948 | Details Get a Quote |
| OCA2 Knockout HCT 116 Cell Line | EDJ-KQ70996 | Human | 4948 | Details Get a Quote |
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