Lck-interacting transmembrane adapter 1 precursor, also known as LIME1, was previously characterized as a transmembrane adaptor protein mediating TCR-dependent T cell activation. LIME1 becomes tyrosine phosphorylated after cross-linking of the CD4 or CD8 coreceptors. Phospho-LIME1 associates with the Src family kinase Lck and its negative regulator, Csk. Recombinant human LIME1 protein, fused to His-tag at N-terminus, was expressed in E.coli.