CLDN1

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]

Claudin 1

Claudins function as major constituents of the tight junction complexes that regulate the permeability of epithelia. While some claudin family members play essential roles in the formation of impermeable barriers, others mediate the permeability to ions and small molecules. Often, several claudin family members are coexpressed and interact with each other, and this determines the overall permeability. CLDN1 is required to prevent the paracellular diffusion of small molecules through tight junctions in the epidermis and is required for the normal barrier function of the skin. Required for normal water homeostasis and to prevent excessive water loss through the skin, probably via an indirect effect on the expression levels of other proteins, since CLDN1 itself seems to be dispensable for water barrier formation in keratinocyte tight junctions (PubMed:23407391).

(Microbial infection) Acts as a co-receptor for hepatitis C virus (HCV) in hepatocytes (PubMed:17325668, PubMed:20375010, PubMed:24038151).

Associates with CD81 and the CLDN1-CD81 receptor complex is essential for HCV entry into host cell (PubMed:20375010).

Acts as a receptor for dengue virus (PubMed:24074594).

Aging Source: Ensembl
Bicellular tight junction assembly Source: UniProtKB
Calcium-independent cell-cell adhesion via plasma membrane cell-adhesion molecules Source: UniProtKB
Cell adhesion Source: GO_Central
Cell-cell junction organization Source: MGI
Cell junction maintenance Source: ARUK-UCL
Cellular response to butyrate Source: Ensembl
Cellular response to interferon-gamma Source: Ensembl
Cellular response to lead ion Source: Ensembl
Cellular response to transforming growth factor beta stimulus Source: Ensembl
Cellular response to tumor necrosis factor Source: Ensembl
Establishment of blood-nerve barrier Source: Ensembl
Establishment of endothelial intestinal barrier Source: Ensembl
Establishment of skin barrier Source: UniProtKB
Hyperosmotic salinity response Source: Ensembl
Liver regeneration Source: Ensembl
Maintenance of blood-brain barrier Source: ARUK-UCL
Positive regulation of bicellular tight junction assembly Source: Ensembl
Positive regulation of cell migration Source: ARUK-UCL
Positive regulation of epithelial cell proliferation involved in wound healing Source: ARUK-UCL
Positive regulation of wound healing Source: ARUK-UCL
Protein complex oligomerization Source: ARUK-UCL
Response to dexamethasone Source: Ensembl
Response to ethanol Source: Ensembl
Response to interleukin-18 Source: Ensembl
Response to lipopolysaccharide Source: Ensembl
Response to toxic substance Source: Ensembl
Xenobiotic transport across blood-nerve barrier Source: Ensembl

Cell membrane; Basolateral cell membrane; Tight junction. Associates with CD81 and the CLDN1-CD81 complex localizes to the basolateral cell membrane.

Ichthyosis-sclerosing cholangitis neonatal syndrome (NISCH):
A rare autosomal recessive complex ichthyosis syndrome characterized by scalp hypotrichosis, scarring alopecia, mild diffuse ichthyosis, sclerosing cholangitis and leukocyte vacuolization.

Cytoplasmic: 1-7
Helical: 8-28
Extracellular: 29-81
Helical: 82-102
Cytoplasmic: 103-115
Helical: 116-136
Extracellular: 137-163
Helical: 164-184
Cytoplasmic: 185-211