SAMSN1, also known as HACS1, is a member of putative adaptors and scaffold proteins containing SH3 and SAM (sterile alpha motif) domains. This protein is up-regulated by IL-4 in activated B cells and strongly expressed in dendritic cells. It may have a function analogous to other adaptor proteins that link signaling molecules in signal transduction cascades.Recombinant human SAMSN1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.