The present invention provides new tools useful for controlling the post-translational modifications of recombinant polypeptides. These tools are particular
signal peptides allowing the targeting of recombinant polypeptides during their synthesis in a host
cell to specific sub-cellular compartments and a specific designing of said recombinant polypeptides within said sub-cellular compartments. These
signal peptides are SEQ ID no 1 to SEQ ID no 31 disclosed herein. The present invention relates therefore also to a process for producing a recombinant polypeptide, in particular to a post-translationally modified polypeptide comprising the steps of transfecting or transforming a
cell with at least one numleic acid vector encoding a recombinant
protein which is the polypeptide before being post-translationally modified or a recombinant
protein different to said polypeptide, said recombinant
protein comprising
a peptide signal according to the present invention; growing the transfected
cell; and harvesting the post-translationally modified polypeptide; wherein, when said recombinant protein is different to said polypeptide, the method also comprises a step of transfecting said cell with at least one vector encoding said polypeptide. The present invention allows advantageously, for example, to increase the yield of production of recombinant polypeptides, to prevent
immunogenicity if recombinant polypeptides and to obtain therapeutically active recombinant polypeptides that are the exact copy of their natural counterpart. This invention relates particularly to the field of reorientation of plants made pharmaceuticals (PMP).