Recombinant Human TJP1 protein

**Background of TJP1 Recombinant Protein**

TJP1 (Tight Junction Protein 1), also known as Zonula Occludens-1 (ZO-1), is a pivotal scaffolding protein localized at cellular tight junctions (TJs). These junctions are critical for maintaining cell polarity, regulating paracellular permeability, and facilitating cell-cell adhesion in epithelial and endothelial tissues. TJP1 belongs to the membrane-associated guanylate kinase (MAGUK) family, characterized by its multidomain structure, including PDZ, SH3. and guanylate kinase (GUK) domains. These domains enable TJP1 to interact with transmembrane TJ proteins (e.g., claudins, occludin) and cytoskeletal components, thereby stabilizing junctional complexes and linking them to the actin cytoskeleton.

Recombinant TJP1 protein is engineered through molecular cloning and expression systems (e.g., *E. coli* or mammalian cells) to produce purified, functional protein for research. It retains key structural and functional domains, allowing studies on TJ assembly, signaling, and dysregulation in diseases. For instance, disrupted TJP1 expression or mutations are linked to impaired barrier function in conditions like inflammatory bowel disease, cancer metastasis, and neurological disorders. Researchers utilize recombinant TJP1 to investigate its role in cell-cell communication, drug delivery across biological barriers (e.g., blood-brain barrier), and therapeutic targeting.

Additionally, recombinant TJP1 serves as a tool for developing assays to screen TJ-modulating compounds or antibodies. Its applications extend to structural studies (e.g., crystallography) to map interaction interfaces and mechanistic insights into TJ dynamics. By enabling precise control over protein variants (e.g., domain deletions, phosphorylation mimics), recombinant TJP1 advances our understanding of epithelial/endothelial biology and pathological mechanisms, offering potential avenues for restoring barrier integrity in disease states.