Myxococcus xanthus Encapsulin as a Promising Platform for Intracellular Protein Delivery.

Introducing a new genetically encoded material containing a photoactivatable label as a model cargo protein, based on () encapsulin system stably expressed in human 293T cells. Encapsulin from is known to be a protein-based container for a ferritin-like cargo in its shell which could be replaced with an exogenous cargo protein, resulting in a modified encapsulin system. We replaced natural cargo with a foreign photoactivatable mCherry (PAmCherry) fluorescent protein and isolated encapsulins, containing PAmCherry, from 293T cells. Isolated encapsulin shells containing photoactivatable label can be internalized by macrophages, wherein the PAmCherry fluorescent signal remains clearly visible. We believe that a genetically encoded nanocarrier system obtained in this study, can be used as a platform for controllable delivery of protein/peptide therapeutics in vitro.