TAP Binding Protein Like Protein (TAPBPL)

TAPBPL is a member of the Ig superfamily that is localized on chromosome 12p13.3, a region somewhat paralogous to the MHC.The deduced 468-amino acid protein is 22% identical to TAPBP. It contains an N-terminal signal sequence, a region weakly similar to an Ig-like or fibronectin (FN1)-like domain, an IgV domain, an IgC1 domain, a transmembrane region, and a 42-residue cytoplasmic tail with no ER retention motif. Unlike TAPBP, TAPBPR does not have a conserved class I molecule-binding region in its N terminus. RT-PCR analysis detected wide expression in mouse tissues, with raised levels in kidney, adipose tissue, salivary gland, placenta, ovary, and gut tissue. Fluorescence microscopy demonstrated expression primarily in the ER, but also on the cell surface.