Enzymatic Cleavage of Branched Peptides for Targeting Mitochondria

摘要

Most of the reported mitochondria targeting molecules are lipophilic and cationic, which may become cytotoxic with accumulation. Here we show enzymatic cleavage of branched peptides that carry negative charges for targeting mitochondria. Conjugating a well-established protein tag (i.e., FLAG-tag) to self-assembling motifs affords the precursors that form micelles. Enzymatic cleavage of the hydrophilic FLAG motif (DDDDK) by enterokinase (ENTK) turns the micelles to nanofibers. After being taken up by cells, the micelles, upon the action of intracellular ENTK, turns into nanofibers to locate mainly at mitochondria. The micelles of the precursors are able to deliver cargos (either small molecules or proteins) into cells, largely to mitochondria and within two hours. Preventing ENTK proteolysis diminishes mitochondria targeting. As the first report of using enzymatic self-assembly for targeting mitochondria and delivery cargos to mitochondria, this work illustrates a fundamentally new way to target subcellular organelles for biomedicine.