TACSTD1, also known as tumor-associated calcium signal transducer 1, is a membrane glycoprotein expressed on adenomatous and simple epithelia, where it is involved in homophilic adhesion at the basolateral membrane. It may act as a physical homophilic interaction molecule between intestinal epithelial cells (IECs) and intraepithelial lymphocytes (IELs) at the mucosal epithelium for providing immunological barrier as a first line of defense against mucosal infection. It plays a role in embryonic stem cells proliferation and differentiation. Recombinant human TACSTD1, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.