A composition for delivering cargo molecules across biological membranes is provided comprising (i) a peptide comprising consecutive amino acid residues having the sequence set forth in SEQ ID NO 1 for the transport of a cargo molecule across a biological membrane and (ii) the cargo molecule, wherein the cargo molecule is not a peptide comprising amino acid residues having the sequence set forth in SEQ ID NO 4. Methods of delivering cargo molecules across biological membranes are also provided. Methods of treating a tumor, cancer, a metabolic disorder, and a cardiovascular disorder are also provided.