CLDN2 Gene: Claudin-2
Tight junction protein involved in paracellular ion transport and disease
Gene Information Card
| Symbol | CLDN2 |
|---|---|
| Full Name | Claudin 2 |
| Gene Type | protein-coding |
| Chromosomal Location | Xq22.3 |
| NCBI Gene ID | 9075 ncbi.nlm.nih.gov/gene/9075 |
| Ensembl ID | ENSG00000187912 |
| UniProt ID | P57739 |
| OMIM ID | 300520 |
| HGNC ID | 2041 |
| Aliases | SPM, claudin-2 |
Description
CLDN2 encodes claudin-2, a member of the claudin family of tight junction proteins. Claudin-2 forms paracellular channels selective for small cations (e.g., Na+, K+) and water, playing a critical role in ion and fluid transport across epithelia, particularly in kidney proximal tubules and liver bile ducts. Its expression is regulated by various signaling pathways and is implicated in renal and hepatic diseases.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Chronic kidney disease | Altered claudin-2 expression disrupts paracellular Na+ and water reabsorption in proximal tubules, contributing to hypertension and kidney function decline. | PMID: 25655767 |
| Primary biliary cholangitis | CLDN2 downregulation in bile duct epithelial cells impairs tight junction integrity, leading to bile leakage and cholestasis. | PMID: 29220509 |
| Colorectal cancer | CLDN2 overexpression enhances paracellular permeability and promotes tumor cell invasion and metastasis. | PMID: 23934199 |
| Nephrolithiasis (kidney stones) | CLDN2 dysfunction alters ion transport, contributing to hypercalciuria and stone formation. | PMID: 27066841 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 89.3 | High |
| Liver | 45.6 | Medium |
| Small intestine | 32.1 | Medium |
| Colon | 18.7 | Low |
| Pancreas | 12.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 78.5 | High expression in transfected cells |
| Caco-2 | 55.2 | Intestinal epithelial cell line |
| HK-2 | 42.0 | Proximal tubule epithelial cells |
| HepG2 | 28.3 | Hepatocellular carcinoma cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.200C>T (p.Thr67Ile) | Missense | <0.1% | Reduced ion selectivity; associated with kidney disease |
| c.341G>A (p.Arg114His) | Missense | <0.1% | Altered tight junction assembly; reported in primary biliary cholangitis |
| c.487_489del (p.Phe163del) | Deletion | <0.1% | Loss of function; impaired paracellular transport |
Mutation functional classification
Loss of Function (LOF)
Deletion mutations (e.g., p.Phe163del) disrupt tight junction integrity and reduce paracellular ion permeability.
Gain of Function (GOF)
Missense mutations (e.g., p.Thr67Ile) may enhance cation selectivity or channel activity.
Dominant Negative (DN)
Some missense variants (e.g., p.Arg114His) can interfere with wild-type claudin-2 assembly, disrupting barrier function.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005923 - bicellular tight junction | • GO:0005254 - chloride channel activity |
| • GO:0016328 - lateral plasma membrane | • GO:0030324 - lung development |
| • GO:0070830 - bicellular tight junction assembly |
Pathways
• Tight junction pathway (KEGG: hsa04530)
• Paracellular ion transport (Reactome: R-HSA-420029)
Protein Summary
Claudin-2 is a 230-amino acid transmembrane protein with four membrane-spanning domains, two extracellular loops, and intracellular N- and C-termini. It forms paracellular channels selective for small cations and water, primarily expressed in kidney proximal tubules and liver bile ducts. The protein is essential for maintaining epithelial barrier function and ion homeostasis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CLDN2 Knockout HEK293 Cell Line | EDJ-KQ6451 | Human | 9075 | Details Get a Quote |
| CLDN23 Knockout HEK293 Cell Line | EDJ-KQ9387 | Human | 137075 | Details Get a Quote |
| CLDN20 Knockout HEK293 Cell Line | EDJ-KQ10654 | Human | 49861 | Details Get a Quote |
| CLDN24 Knockout HEK293 Cell Line | EDJ-KQ12930 | Human | 100132463 | Details Get a Quote |
| CLDN25 Knockout HEK293 Cell Line | EDJ-KQ12931 | Human | 644672 | Details Get a Quote |
| CLDN23 Knockout A-549 Cell Line | EDJ-KQ36035 | Human | 137075 | Details Get a Quote |
| CLDN23 Knockout HCT 116 Cell Line | EDJ-KQ36036 | Human | 137075 | Details Get a Quote |
| CLDN23 Knockout HeLa Cell Line | EDJ-KQ36037 | Human | 137075 | Details Get a Quote |
| CLDN2 Knockout A-549 Cell Line | EDJ-KQ30525 | Human | 9075 | Details Get a Quote |
| CLDN2 Knockout HCT 116 Cell Line | EDJ-KQ30526 | Human | 9075 | Details Get a Quote |
| CLDN22 Knockout HEK293 Cell Line | EDJ-KQ51356 | Human | 53842 | Details Get a Quote |
| CLDN2 Knockout HeLa Cell Line | EDJ-KQ55074 | Human | 9075 | Details Get a Quote |
| CLDN20 Knockout HeLa Cell Line | EDJ-KQ56163 | Human | 49861 | Details Get a Quote |
| CLDN22 Knockout HeLa Cell Line | EDJ-KQ56387 | Human | 53842 | Details Get a Quote |
| CLDN25 Knockout HeLa Cell Line | EDJ-KQ60573 | Human | 644672 | Details Get a Quote |
Displaying Records 1 To 15 Of 24 Records
