Design rules for efficient endosomal escape.

The results described in this paper provide new insights into how protein delivery works and how it can be best utilized in the future. Although intracellular protein delivery has been studied for decades, this paper describes the first interrogation of why certain protein cargos are privileged for efficient endosomal escape. These results represent a fundamental advance in the long-awaited goal of efficient protein delivery and provide design rules to overcome one of the most significant challenges for the future of biotechnology.