Construct and method for the internalization of cargo molecules into a cell

The present invention relates to the delivery of molecules into cells. Especially, it relates to a carrier complex comprising (i) a molecule comprising a receptor peptide and a peptide which is capable of penetrating a host cell; and (ii) a second molecule comprising a ligand peptide and a cargo molecule of interest. In a preferred embodiment, the carrier complex comprises (i) a fusion protein between the TAT-peptide of HIV I and streptactin, a streptavidin mutant; and (ii) a conjugate or a fusion protein between the Strep-tag II, a streptavidin-binding peptide, and the cargo molecule to be delivered.