Protein expression

A method for producing a recombinant protein or polypeptide of interest comprising the steps of:

• providing a genetically modified yeast cell comprising
• a) an expression secretion cassette comprising a recombinant nucleic acid molecule encoding a protein or polypeptide of interest and
• b) at least one recombinant promoter operably linked to at least one gene naturally occurring in the genome of the yeast cell and encoding a polypeptide or protein supporting the biosynthesis of polypeptides or proteins within said cell, said at least one gene being located at the native genomic locus of the genetically unmodified wild-type yeast cell, wherein the naturally occurring promoter of the at least one gene encoding the biosynthesis supporting polypeptide or protein is inactivated by at least one mutation within said naturally occurring promoter,
• cultivating said genetically modified yeast cell in a culture medium under conditions that allow for expression of the protein or polypeptide of interest and the at least one gene encoding the biosynthesis supporting polypeptide or protein and
• isolating the protein or polypeptide of interest from the culture medium.