Fusion proteins

Abstract

A single chain, polypeptide fusion protein, comprising: a non-cytotoxic protease, or a fragment thereof, which protease or protease fragment can cleave a protein of the exocytic fusion apparatus of a nociceptive sensory afferent; a Targeting Moiety that can bind to a Binding Site on the nociceptive sensory afferent, which Binding Site can undergo endocytosis to be incorporated into an endosome within the nociceptive sensory afferent; a protease cleavage site at which site the fusion protein is cleavable by a protease, which is located between the non-cytotoxic protease and the Targeting Moiety; and a translocation domain that can translocate the protease or protease fragment from within an endosome, across the endosomal membrane and into the cytosol of the nociceptive sensory afferent; wherein the Targeting Moiety is BAM, β-endorphin, bradykinin, substance P, dynorphin and/or nociceptin. Nucleic acid sequences encoding the fusion proteins, methods of preparing same and uses thereof are also described.