Claudin 16 (Paracellin 1, CLDN16) Antibody from MyBioSource.com

Claudin 16, also known as Paracellin-1, is a renal tight junction protein required for paracellular magnesium resorption. It is localized in the intercellular junctions of the epithelial cells of the thick ascending limb of Henle's loop (TAL), the distal tubule, and the collecting duct(6). Antibodies against Tamm-Horsfall protein (THP) (a TAL marker) are used to localize this specific structure of nephrons in kidney sections(1). Mg2+ resorption occurs in TAL(2), and Claudin 16 is required for this paracellular function(3). Failure in renal 'handling' of magnesium can result in hypermagnesemia, whose major direct toxicity implications are cardiovascular as well as renal failure. Recent studies have shown that the lack of Claudin-16 proteins contributes to the dysfunction of paracellular renal transport systems(5). 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 are presumed to interact with each other to form a sort of "molecular gasket" that prevents ions, water and other molecules from leaking between cells and thus, from one side of the sheet to the other. In addition to this so-called "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. Claudin proteins have been shown to be major integral membrane proteins localized at tight junctions