Yeast is an established industrial fermentation system and supports high-level recombinant protein production. Yeasts are attractive hosts for the production of heterologous proteins. Unlike prokaryotic systems, their eukaryotic subcellular organization enables them to carry out many of the post-translational folding, processing and modification events required to produce "authentic" and bioactive mammalian proteins. In addition, they retain the advantages of a unicellular microorganism, with respect to rapid growth and ease of genetic manipulation. Aside from the baker's yeast Saccharomyces cerevisiae, an increasing number of alternative non-Saccharomyces yeast species are used as expression systems in basic research and for industrial application. These include Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, Schizosaccharomyces pombe, Schwanniomyces occidentalis and Yarrowia lipolytica. Since the profit margin available on exogenously expressed proteins is dependent on protein yield, there is an ongoing search for yeast strains which show improved protein production. Two possibilities exist for increasing production: engineering a protein to make it more amenable to production, or understanding the host response in order to engineer improved strains.

Scientists at Aston University have discovered that BMS1 upregulation can significantly improve the production of recombinant proteins in eukaryotic cells. In particular, proteins that are produced at low level in wildtype yeast gain a boost, and all proteins investigated to date have an increase in yield of between 5 to 80 fold. This increased yield of recombinant protein may lead to significant cost and efficiency savings for industrial producers of recombinant proteins.