Cycling across the membrane

In a Nature Chemistry study, a German team has shown that nanobodies coupled to cyclic peptides rich in arginine can target intracellular proteins with antibody-like precision and even deliver extracellular proteins to the cytosol.

Delivering proteins across the plasma membrane often relies on endocytosis, which means providing it with a means to escape the endosome before it is degraded. Cell-penetrating peptides like the HIV tat protein (HIV tat) bypass endocytosis by directly crossing the membrane, but their ability to transport therapeutics into cells is limited by the size of the cargo, and potential for interfering with the cargo's normal function. ...