The signal sequence receptor (SSR) is a glycosylated endoplasmic reticulum (ER) membrane receptor associated with protein translocation across the ER membrane. The SSR consists of 2 subunits, a 34-kD glycoprotein encoded by this gene and a 22-kD glycoprotein. This gene generates several mRNA species as a result of complex alternative polyadenylation. This gene is unusual in that it utilizes arrays of polyA signal sequences that are mostly non-canonical. Recombinant human SSR1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.