The invention provides compositions for intracellular delivery of
biotinylated cargo. The compositions comprise a complex formed between
(a) a fusion protein comprising a protein transduction domain linked to
streptavidin and (b) a biotinylated cargo for intracellular delivery. In
some embodiments, the protein transduction domain comprises the protein
transduction domain of the Human Immunodeficiency Virus type 1 (HIV-1)
TAT protein. The complex may further comprise a biotinylated endosomal
releasing polymer, such as a poly(propylacrylic acid) polymer. The
invention also provides methods for obtaining intracellular delivery of
biotinylated cargo and methods for obtaining cytoplasmic delivery of
biotinylated cargo.