Biotechnology: A targeted protein delivery device

A protein delivery system, which uses a bacterial ‘syringe’ that has been designed to inject proteins into human cells, is reported in Nature. The approach may have useful applications for future biomedical therapies in humans, such as gene therapy and cancer therapy.

The delivery of selected proteins into specific cell types has potential in the treatment of diseases. Some bacteria have evolved delivery systems to interface with host cells — for example, small syringe-like mechanisms that inject proteins into cells by driving a spike through the cell membrane. However, whether these delivery systems can function in human cells, and the mechanism that these systems use to recognize target cells, remain poorly understood.

Feng Zhang and colleagues used AlphaFold to predict the structure of a suitable bacterial protein that usually targets insect cells and modified this protein to target cultured human cells. They found that the system could be used to deliver diverse protein types into human cells with high efficiency. The authors also adapted the system to target mouse cells in live mice, demonstrating that the system could be used to introduce proteins into living organisms.

The authors suggest that this system could potentially be used as a delivery tool for human therapies in the future.