Recombinant protein production remains a central component of many biotechnological projects. As mammalian proteins frequently require extensive post-translational modification, mammalian cells are often used for recombinant protein production instead of yeast and bacteria. Intuitively, a protein will be best expressed in its native cell type under physiological conditions, where a multitude of
molecular systems work together for efficient production and quality control at various stages, including synthesis and folding, post-translational modifications and subcellular targeting. However, as mammalian cell culture is costly and establisment of efficiently producing cell lines can be a lengthy procedure, productivity is an important determinant.