Fission yeast Schizosaccharomyces pombe as a producer and secretor of heterologous proteins

Microorganisms are widely used as producers of heterologous (foreign) proteins of medical or industrial interest. Bacteria are the most efficient producers, but they are not able to perform the posttranslational processing of eucaryotic proteins (folding, glycosylation, phosphorylation or removal of part of their initial sequence). Eucaryotic yeasts are able to do the post-translational processing and secrete heterologous eucaryotic proteins in their native, biologically functional form. Among yeasts, the fission yeast Schizosaccharomyces pombe has the advantage of being more similar to higher eucaryotes in many respects, but its heterologus protein production is still small compared to that of other yeasts such as Saccharomyces cerevisiae, Pichia pastoris or Kluyveromyces lactis. However, the good quality of proteins obtained so far makes fission yeast an interesting producer and efforts are being made by many researchers to modify the gemome of S. pombe in order to obtain better producers of proteins. This review presents these efforts up to date and describes expression systems, signaling peptides, posttranslational processing and secretion systems known in fission yeast, and the possible ways to increase their efficiency. The last paragraphs are dedicated to approaching methods and protocols of genomic modifications.