Claudin-11 (E7E9U) Rabbit mAb #38062

Tight junctions, or zonula occludens, form a continuous barrier to fluids across the epithelium and endothelium. They function in regulation of paracellular permeability and in the maintenance of cell polarity, blocking the movement of transmembrane proteins between the apical and the basolateral cell surfaces. Tight junctions are composed of claudin and occludin proteins, which join the junctions to the cytoskeleton (1,2). The claudin family is composed of 23 integral membrane proteins, and their expression, which varies among tissue types, may determine both the strength and properties of the epithelial barrier. Alteration in claudin protein expression pattern is associated with several types of cancer (2,3). Claudin-1 is expressed primarily in keratinocytes (4) and normal mammary epithelial cells, but is absent or reduced in breast carcinomas and breast cancer cell lines (5,6).

Claudin-11, originally identified as oligodendrocyte specific protein (OSP), is a transmembrane protein member of the claudin family that is abundantly expressed by oligodendrocytes and within tight junctions of central nervous system myelin (7,8). Mouse models lacking claudin-11 fail to assemble these tight junctions, leading to altered neurotransmitter levels and significant loss of function behavioral changes (9).