CLDN1

Protein identityUniProt · HPA

UniProt accession

O95832

Gene

CLDN1

Ensembl

ENSG00000163347

Chromosome

3

Canonical length

211 aa

Protein class

Disease related genes, Human disease related genes, Potential drug targets, Predicted membrane proteins, Transporters

Quaternary structure

Homopolymer

OverviewNCBI Gene

Tight junctions represent one mode of cell-to-cell adhesion in epithelial or endothelial cell sheets, forming continuous seals around cells and serving as a physical barrier to prevent solutes and water from passing freely through the paracellular space. These junctions are comprised of sets of continuous networking strands in the outwardly facing cytoplasmic leaflet, with complementary grooves in the inwardly facing extracytoplasmic leaflet. The protein encoded by this gene, a member of the claudin family, is an integral membrane protein and a component of tight junction strands. Loss of function mutations result in neonatal ichthyosis-sclerosing cholangitis syndrome. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

211 residues, UniProt reviewed canonical sequence.

>O95832|CLDN1
     1  MANAGLQLLG FILAFLGWIG AIVSTALPQW RIYSYAGDNI VTAQAMYEGL WMSCVSQSTG
    61  QIQCKVFDSL LNLSSTLQAT RALMVVGILL GVIAIFVATV GMKCMKCLED DEVQKMRMAV
   121  IGGAIFLLAG LAILVATAWY GNRIVQEFYD PMTPVNARYE FGQALFTGWA AASLCLLGGA
   181  LLCCSCPRKT TSYPTPRPYP KPAPSSGKDY V

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CLDN1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability

Cell surface

Secreted

No

Transmembrane segments

4

Mean surface accessibility (rSASA)

0.35

Highest tissue expression

290 nTPM

Expression across tissuesHPA

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CLDN1.

Disease | AllUniProt

Conditions CLDN1 is implicated in, by any mechanism.

• Ichthyosis-sclerosing cholangitis neonatal syndrome (NISCH) MIM:607626

Disease | GeneticClinVar

8 pathogenic / likely-pathogenic of 120 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

• Neonatal ichthyosis-sclerosing cholangitis syndrome

ReferencesPubMed · IEDB

Publications for CLDN1 from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. IEDB — curated epitope assays from the Immune Epitope Database (Vita et al., Nucleic Acids Research 2019). Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)

1.18

gnomAD pLI

0

gnomAD missense Z

0.03

DepMap mean gene effect

0.01

DepMap dependency class

selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

• bicellular tight junction assembly
• calcium-independent cell-cell adhesion via plasma membrane cell-adhesion molecules
• cell adhesion
• cell junction maintenance
• cell-cell junction organization
• cellular response to butyrate
• cellular response to lead ion
• cellular response to transforming growth factor beta stimulus
• cellular response to tumor necrosis factor
• cellular response to type II interferon
• establishment of blood-nerve barrier
• establishment of endothelial intestinal barrier
• establishment of skin barrier
• liver regeneration
• maintenance of blood-brain barrier
• positive regulation of bicellular tight junction assembly
• positive regulation of cell migration
• positive regulation of epithelial cell proliferation involved in wound healing
• positive regulation of wound healing
• protein complex oligomerization
• response to dexamethasone
• response to ethanol
• response to interleukin-18
• response to lipopolysaccharide
• response to toxic substance
• xenobiotic transport across blood-nerve barrier

Molecular functions

• identical protein binding
• structural molecule activity
• virus receptor activity

Cellular components

• apical plasma membrane
• basolateral plasma membrane
• bicellular tight junction
• lateral plasma membrane
• membrane
• plasma membrane
• protein-containing complex
• tight junction

Protein domainsUniProt · Pfam · InterPro

• PMP-22/EMP/MP20/Claudin
• Claudin
• Claudin, conserved site
• PMP-22/EMP/MP20/Claudin family
• Claudin-1

KeywordsUniProt

• Cell junction
• Cell membrane
• Disulfide bond
• Host cell receptor for virus entry
• Host-virus interaction
• Ichthyosis
• Membrane
• Receptor
• Tight junction
• Transmembrane
• Transmembrane helix

InteractionsUniProt · HPA

Protein binding partners of CLDN1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• CD81
• CLDN4
• CLDN6
• CLDN9
• MPDZ
• OCLN
• PATJ