This antibody reacts specifically with the ~22-23 kDa Claudin-2 protein. Reactivity has been confirmed with human, mouse, rat, and dog liver and kidney homogenates, as well MDCK and Caco-2 cell lysates, by western blotting and immunfluorescence. Reactivity has also been confirmed with formalin-fixed, paraffin-embedded (FFPE) human normal colon, spleen, and thyroid, and colon and breast cancer tissues by immunohistochemistry.
For best results in immunohistochemistry (1-2 µg/mL) with formalin-fixed, paraffin-embedded (FFPE) tissues, heat induced epitope retrieval (HIER) with EDTA buffer, pH 8.0, is required prior to staining. In western blotting a non-specific band at 27 kDa is observed in some lysates. In Caco-2 cells this band appears stronger than the correct band at 22 kDa. An alternative product, rabbit anti-Claudin-2 (Cat. No. 516100) may be used for western blotting of these lysates.
Mouse Claudin-2 was discovered in 1998 as a 230 amino acid protein localizing at tight junctions with an approximate molecular weight of 22.9 kDa. Claudin-1 and Claudin-2 are structurally related, and are 38% identical at the amino acid sequence level. Claudin-2 belongs to the claudin family of integral membrane proteins. Claudins are responsible for the formation of tight junction strands, and are connected to the actin cytoskeleton through ZO-1. Claudin-2 functions as a paracellular channel with cation (Na+) selectivity at tight junctions. The expression of Claudin-2 is restricted to the liver and kidney, with small amounts also found in the brain.Tight junctions (TJs) are specialized membrane domains that seal the intercellular spaces in epithelia and endothelia and thus contribute to the permeability barrier between lumenal and interstitial compartments. Tight junctions not only separate distinct physiological compartments, but they also confer selectivity to the transepithelial flux of molecules and ions through the intercellular spaces between the epithelial cells, the so-called paracellular pathway. In addition, tight junctions limit the diffusion of lipids between the apical and basolateral plasma membrane domain. Claudin and Occludin, the two types of four-transmembrane domain proteins, are the major integral membrane components of the mammalian tight junction. So far, 20 distinct claudins have been identified.
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Protein Aliases: Claudin-2; CLD2; CLDN2; integral membrane protein claudin-2; SP82
Gene Aliases: AL022813; CLDN2; PSEC0059; RGD1560247; SP82; UNQ705/PRO1356