TRAF1, also known as TNF receptor-associated factor 1, belongs to TNF receptor superfamily. This protein and TRAF2 form a heterodimeric complex, which is required for TNF-alpha-mediated activation of MAPK8/JNK and NF-kappaB. The complex also interacts with inhibitor-of-apoptosis proteins (IAPs), and thus mediates the anti-apoptotic signals from TNF receptors. Recombinant human TRAF1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.