CLDN1
CLDN1 (claudin 1, also known as SEMP1 and ILVASC) is an integral membrane protein of the claudin family and a component of tight junction strands. It helps seal epithelial and endothelial cell sheets, and also acts as a host co-receptor for hepatitis C virus. Browse Assay Genie's current range of CLDN1 research reagents below, or read on for the biology behind the target.
Tight junctions are one mode of cell-to-cell adhesion in epithelial and endothelial cell sheets. They form continuous seals around cells and act as a physical barrier, preventing solutes and water from passing freely through the paracellular space. CLDN1 is an integral membrane protein and a component of the tight junction strands that make up these seals. The strands form continuous networks in the outwardly facing cytoplasmic leaflet of the membrane, with complementary grooves in the inwardly facing extracytoplasmic leaflet.
Beyond its structural role, CLDN1 has a well-described function in viral infection. It acts as a co-receptor for hepatitis C virus (HCV) in hepatocytes. CLDN1 associates with CD81, and the CLDN1-CD81 receptor complex is essential for HCV entry into the host cell. CLDN1 has also been described as a receptor for dengue virus.
The CLDN1 gene encodes the claudin-1 protein, which UniProt assigns to the claudin family; HGNC lists it in the Claudins gene group. It localises to the tight junction, the cell membrane and the basolateral cell membrane. Loss of function mutations in the gene result in neonatal ichthyosis-sclerosing cholangitis syndrome, linking CLDN1 to both skin and bile duct biology. Mouse and rat orthologs are both named Cldn1, which allows comparative work in standard rodent models. Researchers studying CLDN1 by antibody-based methods or by ELISA often do so to examine junction organisation, epithelial barrier function or viral entry.
CLDN1 is a component of tight junction strands that seal epithelial and endothelial sheets and restrict paracellular passage of solutes and water.
CLDN1 acts as a co-receptor for HCV in hepatocytes, and the CLDN1-CD81 complex is essential for viral entry into the host cell.
CLDN1 has been described as a receptor for dengue virus, making it relevant to studies of how the virus engages host cells.
Loss of function mutations in CLDN1 cause neonatal ichthyosis-sclerosing cholangitis syndrome, a disorder affecting skin and bile ducts.
CLDN1 is an integral membrane protein of the claudin family and a component of tight junction strands. These strands form seals between epithelial and endothelial cells, creating a barrier to paracellular passage of solutes and water. It also serves as a co-receptor for hepatitis C virus in hepatocytes.
The HGNC full name is claudin 1, and UniProt lists the protein as Claudin-1. Aliases and previous symbols include SEMP1 and ILVASC. The gene belongs to the HGNC Claudins group, alongside related members such as CLDN2, CLDN3 and CLDN4.
Loss of function mutations in CLDN1 result in neonatal ichthyosis-sclerosing cholangitis syndrome. The protein also acts as a host factor for hepatitis C virus entry. Mouse and rat both carry a Cldn1 ortholog; check the datasheet of any product for its validated reactivity.
Other claudin family members that form tight junction strands, with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt O95832; product specifications from Assay Genie datasheets.