This purified mouse anti-Claudin-4 monoclonal antibody (mAb) is specific to human, rat, and canine Claudin-4. Mouse anti-Claudin-4 mAb recognizes the expressed product of the CLDN4 gene. Claudin-4 is the first to confer ionic selectivity to paracellular transport, leading to the prediction that the combination of different claudins defines the overall selectivity of different junctions. Mouse anti-Claudin-4 mAb can be used in applications such as western blotting, immunohistochemistry (FFPE) and immunofluorescence.
• Applications: Validated applications for mouse anti-Claudin-4 monoclonal antibody are western blotting, immunohistochemistry (FFPE), and immunofluorescence.
• Host Species and Isotype: The host species and isotype of Claudin-4 monoclonal antibody is mouse IgG1.
• Clone ID of Monoclonal Antibody (mAb): The mouse anti-Claudin-4 monoclonal antibody clone is 3E2C1.
• Reactivity: Reacts with human, rat, and canine Claudin-4.
• Product Size: Mouse anti-Claudin-4 monoclonal 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.
Several peripheral membrane proteins are associated with tight junctions including ZO-1, ZO-2, ZO-3, cingulin, the 7H6 antigen, Rab-3b, and symplekin. Suggested roles for these proteins include involvement in tight junction assembly and maintenance, signal transduction, and the regulation of tight junction permeability. A growing body of evidence suggests that actin filaments play a major role in regulating tight junction permeability.
Until recently, the only transmembrane protein known to be associated with tight junctions was occludin, a ~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 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.
The overexpression of claudin-4 was found to decrease paracellular electrical conductance due to a selective decrease in Na+ ion permeability, with no significant change for Cl- ions. Claudin-4 is the first to confer ionic selectivity to paracellular transport, leading to the prediction that the combination of different claudins defines the overall selectivity of different junctions. Thus, claudin-4 expression form channels through the tight junctions that discriminate against Na+ ions, but are indifferent to Cl- ions.