Claudin-1 Protein-VLP, Human (HEK293)

CLDN1 protein, a member of the claudin family, plays a crucial role as a major constituent of tight junction complexes that regulate the permeability of epithelial barriers. While certain claudin family members contribute to the formation of impermeable barriers, others modulate the permeability to ions and small molecules. The interaction among various claudin family members, often coexpressed, determines the overall permeability of tight junctions. CLDN1 is specifically essential in preventing the paracellular diffusion of small molecules through tight junctions in the epidermis, crucial for maintaining the normal barrier function of the skin and ensuring water homeostasis. Interestingly, while CLDN1 appears dispensable for water barrier formation in keratinocyte tight junctions, it indirectly influences water loss, potentially through the regulation of other protein expression levels. Moreover, CLDN1 acts as a co-receptor for hepatitis C virus (HCV) in hepatocytes, forming a receptor complex with CD81 that is vital for HCV entry into host cells, and it also functions as a receptor for dengue virus. These diverse roles underscore the significance of CLDN1 in both physiological barrier functions and viral infection processes.