Recombinant Human CLDN5 protein

Claudin-5 (CLDN5) is a key component of tight junction complexes, predominantly expressed in endothelial and epithelial cells. As a member of the claudin family, it plays a critical role in maintaining cell polarity and regulating paracellular permeability, particularly in the blood-brain barrier (BBB). Structurally, CLDN5 consists of four transmembrane domains, two extracellular loops, and intracellular N- and C-termini. The extracellular loops mediate homophilic or heterophilic interactions with adjacent claudins, forming selective barriers that control ion and solute transport. Dysregulation of CLDN5 is implicated in neurological disorders (e.g., stroke, Alzheimer’s disease) and cancer metastasis due to BBB leakage or loss of epithelial integrity.

Recombinant CLDN5 protein is produced using expression systems like Escherichia coli or mammalian cells, often tagged with affinity markers (e.g., His-tag) for purification. Its applications span structural studies, antibody development, and functional assays to investigate tight junction dynamics. Researchers use it to model BBB permeability in vitro, screen drugs targeting barrier integrity, or study pathogenic mechanisms of neurotropic viruses that exploit CLDN5 for entry. Notably, CLDN5 overexpression or knockdown models help validate its role in disease progression. However, challenges persist in preserving its native conformation during recombinant production, as post-translational modifications (e.g., phosphorylation) in eukaryotic systems may influence functionality. Despite this, CLDN5 recombinant proteins remain vital tools for advancing vascular biology and therapeutic strategies for barrier-related pathologies.