OCLN (Occludin) Gene: Structure, Function, and Clinical Significance
A comprehensive overview of the OCLN gene, encoding occludin, a key tight junction protein involved in barrier function and associated with human diseases.
Gene Information Card
| Symbol | OCLN |
|---|---|
| Full Name | occludin |
| Gene Type | protein coding |
| Chromosomal Location | 5q13.2 |
| NCBI Gene ID | 100506658 ncbi.nlm.nih.gov/gene/100506658 |
| Ensembl ID | ENSG00000197822 |
| UniProt ID | Q16625 |
| OMIM ID | 602876 |
| HGNC ID | 8104 |
| Aliases | BLCPMG |
Description
The OCLN gene encodes occludin, a 522-amino acid integral membrane protein that is a critical component of tight junctions. Tight junctions regulate paracellular permeability and maintain cell polarity in epithelial and endothelial cells. Occludin interacts with other tight junction proteins (e.g., claudins, ZO-1) and is involved in signal transduction, cell adhesion, and barrier function. Mutations in OCLN cause band-like calcification with simplified gyration and polymicrogyria (BLCPMG), a rare autosomal recessive neurological disorder.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Band-like calcification with simplified gyration and polymicrogyria (BLCPMG) | Loss-of-function mutations in OCLN disrupt tight junction integrity in the brain, leading to abnormal neuronal migration and calcification. | Multiple homozygous and compound heterozygous mutations reported in affected families (OMIM, PubMed). |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Medium |
| Liver | 8.2 | Low |
| Kidney | 15.3 | Medium |
| Lung | 6.1 | Low |
| Intestine | 20.4 | High |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Caco-2 | 25.3 | Intestinal epithelial cell line, high expression |
| HUVEC | 18.7 | Endothelial cell line, moderate expression |
| HepG2 | 9.8 | Liver carcinoma cell line, low expression |
| A549 | 7.2 | Lung carcinoma cell line, low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.597C>A (p.Cys199Ter) | Nonsense | Rare | Loss of function, premature truncation |
| c.803G>A (p.Arg268His) | Missense | Rare | Likely loss of function, disrupts protein structure |
| c.1123delC (p.Leu375TrpfsTer3) | Frameshift | Rare | Loss of function, truncated protein |
Mutation functional classification
Loss of Function (LOF)
Most OCLN mutations are loss-of-function, leading to reduced or absent occludin protein, disrupting tight junction formation.
Gain of Function (GOF)
No gain-of-function mutations have been reported for OCLN.
Dominant Negative (DN)
No dominant-negative mutations have been characterized; the disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • protein binding | • identical protein binding |
| • cell-cell junction | • tight junction |
| • plasma membrane | • integral component of membrane |
| • cell adhesion | • regulation of paracellular permeability |
Pathways
• Tight junction pathway (KEGG hsa04530)
• Adherens junction pathway (KEGG hsa04520)
• Leukocyte transendothelial migration (KEGG hsa04670)
Protein Summary
Occludin is a 522-amino acid protein with four transmembrane domains, two extracellular loops, and cytoplasmic N- and C-termini. It localizes to tight junctions and interacts with ZO-1, claudins, and other scaffolding proteins. Occludin plays a role in barrier function, cell polarity, and signal transduction. Its C-terminal domain is essential for localization and function. Mutations causing BLCPMG typically result in truncated or misfolded proteins, leading to loss of tight junction integrity in the brain.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| OCLN Knockout HEK293 Cell Line | EDJ-KQ12122 | Human | 100506658 | Details Get a Quote |
| OCLN Knockout A-549 Cell Line | EDJ-KQ40811 | Human | 100506658 | Details Get a Quote |
| OCLN Knockout HCT 116 Cell Line | EDJ-KQ40812 | Human | 100506658 | Details Get a Quote |
| OCLN Knockout HeLa Cell Line | EDJ-KQ40813 | Human | 100506658 | Details Get a Quote |
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