Production of Heterologous Proteins in Yeast With the Aid of the Hsp150 Carrier

Proper folding, and consequently exit from the endoplasmic reticulum (ER) and secretion of heterologous exocytic proteins in yeast can be rescued by fusing the proteins to certain yeast-derived polypeptides. Biologically active mammalian glycoproteins can be produced in Saccharomyces cerevisiae and Pichia pastoris by joining them to a fragment of a natural secretory glycoprotein of S. cerevisiae , Hsp150Δ. The performance of the Hsp150Δ carrier in both yeasts appears to exceed that of the MFα leader, which is widely used in industrial protein production. Here we describe the use of the Hsp150Δ carrier in P. pastoris in both shake flask and fermentor cultivations. As a reporter protein we use the periplasmic disulfide-bonded Escherichia coli enzyme β-lactamase.