This purified rabbit anti-Claudin-1 polyclonal antibody (pAb) recognizes claudin-1. Specific for ~22kDa Claudin-1 protein, rabbit anti-Claudin-1 pAb does not cross-react with Claudin-3. Rabbit anti-Claudin-1 pAb can be used in applications such as western blotting, ELISA, immunohistochemistry and immunocytochemistry/immunofluorescence.

Antibody Specifications:

• Applications: Validated applications for rabbit anti-Claudin-1 polyclonal antibody are western blotting, ELISA, immunohistochemistry (FFPE) and immunocytochemistry/immunofluorescence.
• Host Species and Isotype: The host species and isotype of the antibody is rabbit IgG.
• Purification: Epitope affinity purified.
• Reactivity: Reacts to human, chicken, canine, and rat Claudin-1.
• Product Size: Rabbit anti-Claudin-1 polyclonal antibody is available in a 100 µg pack size.

Tight junctions are specialized regions of cell-cell contact that are particularly abundant in luminal epithelial cell sheets. In freeze-fracture electron micrographs, tight junctions are visualized as belt-like bands of anastomosing sealing strands (TJ strands) that completely encircle the lateral surfaces of each cell. TJ strands on adjacent cells interact with each other to form a "molecular gasket" that prevents ions, water and other molecules from leaking between cells (ie. from one side of the sheet to the other). In addition to this "barrier" function, the "fence" function of tight junctions plays an important role in maintaining epithelial cell-polarity by blocking the diffusion of membrane proteins between apical (luminal) and basolateral cell surfaces.

Until recently, the only transmembrane protein known to be associated with tight junctions was occludin, an ~65 kDa protein with four transmembrane domains. Despite widespread expectation, a critical structural role for occludin in TJ strands was ruled out by the observation of apparently normal tight junctions formed between cells disrupted at both occludin alleles. A closer examination of isolated tight junctions uncovered two related ~22 kDa, four-transmembrane domain proteins, claudin-1 and claudin-2, with no similarity to occludin. In contrast to occludin, which induces only a small number of short strands at cell-cell contact sites when introduced into fibroblasts lacking tight junctions, claudin-1 and -2 induce networks of strands that are characteristic of true tight junctions. Though inconclusive, these findings suggest that claudin-1 and -2 are major structural components of TJ strands and that occludin plays some other accessory role. Excitement in the tight junction field continues to rise following the recent discovery of claudins -3, -4, -5, -6, -7, and -8 and experiments suggesting that tight junctions in different tissues are comprised of different sets of claudin family proteins.