Targeted Subcellular Protein Delivery Using Cleavable Cyclic Cell-Penetrating Peptide-Conjugates.

Proteins conjugated to cyclic cell-penetrating peptides (cCPPs) haAbstractve been shown to be effectively taken up by living cells. Conjugation of proteins to cCPPs in a cleavable manner leads to localization in the cytosol and immediate bioavailability of the protein after uptake. Here we describe how mCherry, a fluorescent protein, can be targeted to a membrane-bound compartment, the nucleus, and a subcellular structure like the actin cytoskeleton after cCPP-mediated uptake into living cells. Targeting peptides are genetically fused to the mCherry protein sequence and the protein is conjugated to the cCPP via a cleavable disulfide bond. Localization of mCherry in the nucleus or the actin skeleton respectively can be observed by live cell confocal fluorescence microscopy.