Steroid receptor RNA activator 1, also known as SRA1, exists as both a RNA transcript and as stably expressed proteins. Also this protein mediates transcriptional coactivation of steroid receptors ligand-dependently through the steroid-binding domain (AF-2). SRA1 enhances cellular proliferation and differentiation and promotes apoptosis in vivo. It may play a role in tumorigenesis. Recombinant human SRA1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.