Native signal peptide of human ERp57 disulfide isomerase mediates secretion of active native recombinant ERp57 protein in yeast Saccharomyces cerevisiae.

Human ERp57 protein is disulfide isomerase, facilitating proper folding of glycoprotein precursors in the concert with ER lectin chaperones calreticulin and calnexin. Growing amount of data also associates ERp57 with many different functions in subcellular locations outside the ER. Analysis of protein functions requires substantial amounts of correctly folded, biologically active protein, and in this study we introduce yeast Saccharomyces cerevisiae as a perfect host for production of human ERp57. Our data suggest that native signal peptide of human ERp57 protein is recognized and correctly processed in the yeast cells, which leads to protein secretion. Secreted recombinant ERp57 protein possesses native amino acid sequence and is biologically active. Moreover, secretion allows simple one-step purification of recombinant ERp57 protein with the yields reaching up to 10mg/L.