Anti-Tapasin from rabbit

Tapasin (UniProt: Q9R233; also known as TPN, TPSN, TAP-associated protein, TAP-binding protein) is encoded by the Tapbp (also known as Tapa) gene (Gene ID: 21356) in the murine species. Tapasin is a single-pass type I membrane glycoprotein protein that is involved in the association of MHC class I with transporter associated with antigen processing (TAP) and in the assembly of MHC class I with peptide. It is synthesized with a signal peptide of 23 amino acids, which is subsequently cleaved to generate mature Tapasin. It assists in loading of antigenic peptides on to class I molecules in the endoplasmic reticulum (ER). It is also reported to support the binding of high-affinity peptides to MHC class I in conjunction with ERp57. Defects in Tapasin expression are linked to destabilization of the MHC class I loading complex and diminution in the expression of MHC molecules at the cell surface. Tapasin is reportedly down-regulated in several human carcinomas and its re-expression in Tapasin-deficient cancer cells restores the expression of MHC class I antigen complexes and augment cancer cell immunogenicity, which helps in longer survival in animals bearing metastatic tumors. (Ref.: Lou, Y et al. (2008). Clin Cancer Res. 14(5); 1494-1501).