TJP3 (Tight Junction Protein 3)
A component of tight junctions involved in epithelial barrier function and cell polarity.
Gene Information Card
| Symbol | TJP3 |
|---|---|
| Full Name | Tight junction protein 3 |
| Gene Type | protein-coding |
| Chromosomal Location | 19p13.3 |
| NCBI Gene ID | 27134 ncbi.nlm.nih.gov/gene/27134 |
| Ensembl ID | ENSG00000105290 |
| UniProt ID | O95049 |
| OMIM ID | 610066 |
| HGNC ID | 11828 |
| Aliases | ZO-3, ZO3 |
Description
TJP3 (tight junction protein 3) encodes a member of the membrane-associated guanylate kinase (MAGUK) family, also known as ZO-3. This protein localizes to tight junctions of epithelial and endothelial cells and interacts with other tight junction proteins (e.g., ZO-1, occludin) to regulate paracellular permeability and cell polarity.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hereditary hemorrhagic telangiectasia (HHT)-like syndrome | Disruption of tight junction integrity leading to vascular malformations | ClinVar: pathogenic variants in TJP3 associated with HHT-like phenotype |
| Cancer (general) | Altered expression may affect cell adhesion and invasion | COSMIC: somatic mutations found in various cancers; loss of tight junction function promotes metastasis |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | Medium |
| Liver | 8.3 | Low |
| Lung | 15.2 | Medium |
| Small intestine | 20.1 | High |
| Colon | 18.7 | High |
| Heart | 6.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Caco-2 (colon adenocarcinoma) | 22.3 | High expression; used as model for tight junction studies |
| HepG2 (hepatocellular carcinoma) | 9.1 | Moderate expression |
| A549 (lung carcinoma) | 14.8 | Moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1234C>T (p.Arg412*) | Nonsense | <0.1% | Loss of function; truncated protein disrupts tight junction assembly |
| c.567G>A (p.Gly189Arg) | Missense | 0.2% | Unknown; may alter protein interaction with ZO-1 |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations that truncate the protein or disrupt the PDZ domain impair tight junction formation.
Gain of Function (GOF)
Not reported for TJP3.
Dominant Negative (DN)
Missense mutations in the SH3 domain may interfere with wild-type ZO-3 function, acting in a dominant-negative manner.
View complete mutation data：
Gene Ontology (GO)
| • tight junction | • cell-cell junction |
| • protein binding | • guanylate kinase activity |
| • cell polarity | • paracellular transport |
Pathways
• Tight junction (KEGG: hsa04530)
• Adherens junction (KEGG: hsa04520)
• Cell adhesion molecules (CAMs) (KEGG: hsa04514)
Protein Summary
TJP3 (ZO-3) is a 903-amino acid protein with three PDZ domains, one SH3 domain, and one guanylate kinase (GUK) domain. It localizes to tight junctions and links transmembrane proteins (e.g., claudins, occludin) to the actin cytoskeleton via ZO-1 and ZO-2. It is essential for maintaining epithelial barrier integrity and cell polarity.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TJP3 Knockout HEK293 Cell Line | EDJ-KQ8691 | Human | 27134 | Details Get a Quote |
| TJP3 Knockout A-549 Cell Line | EDJ-KQ34903 | Human | 27134 | Details Get a Quote |
| TJP3 Knockout HCT 116 Cell Line | EDJ-KQ34904 | Human | 27134 | Details Get a Quote |
| TJP3 Knockout HeLa Cell Line | EDJ-KQ56010 | Human | 27134 | Details Get a Quote |
