Expression, Purification And Activity Determination Of Human Type I T Cell Immunoglobulin - 1 (Tim - 1)

TTM-1(T cell immunoglobulin domain and mucin domain protein-1), the first member of the family, is also known as hHAVCR-1(human hepatitis A virus receptor) or KIM-1(kidney injury molecule1). TIM-1is expressed on activated but not naive CD4+T cells and provides a costimulatory signal for T cell proliferation and differentiation. TIM-1genes encode type I cell-surface glycoproteins with common structural features including an N-terminal immunoglobulin (Ig)-like domain, a mucin domain with O-linked glycosylations and with N-linked glycosylations close to the membrane, a single transmembrane domain, and a cytoplasmic region with tyrosine phosphorylation motif.A number of protein ligands has been discovered for TIM-1including TIM-4, HAV,IgA, PtdSer and TIM-1. Tim-1regulates the occurrence and development of some autoimmune diseases,like MS、SLE、EAE、RA etc. Therefore,Timl protein may provide a novel target for therapeutic intervention autoimmune diseases.In a humanized SCID model of experimental asthma, treatment with mAbs directed to the IgV domain of TIM-1can suppresses T cell proliferation and ablate the pathogenic responses. So, Wo speculate the binding site with ligand for Tim-1is the N-terminal immunoglobulin (Ig)-like domain(IgV).We have successfully expressed recombinant Tim-1comprising its N-terminal immunoglobulin (Ig)-like domain region in E.coli. The recombinant protein is expressed in the form of inclusion body protein. After washing, solubilization, purification and refolding of the inclusion body protein, their bioactivity was identified by CCK-8kit and the binding with PtdSer. We provide experimental base for further study for Timl as a novel target for therapeutic intervention autoimmune diseases.