Reactivity has been confirmed with rat, human and mouse Claudin-5 using rat lung, mouse kidney, mouse small intestine, mouse lung homogenates, human colon tissue, and CACO-2 human cell line. This antibody reacts specifically with the ~ 22-24 kDa endogenous Claudin-5 protein. Excitation/Peak Emission (nm): 495/519
Initially 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 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+ permeability, with no significant change for Cl-. 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 forms channels through the tight junctions that discriminate against Na+ ions and are indifferent to Cl- ions.
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Protein Aliases: AWAL; Brain endothelial cell clone 1 protein; Claudin-5; CPETRL1; Lung-specific membrane protein; TMDVCF; TMVCF; Transmembrane protein deleted in VCFS; transmembrane protein deleted in velocardiofacial syndrome
Gene Aliases: AI854493; AWAL; BEC1; CLDN5; CPETRL1; MBEC1; TMVCF