ZF5.3 is a mini-protein that escapes endosomes efficiently. Work to understand the underlying mechanism now reveals that ZF5.3 unfolds at pH values lower than 5.5 through protonation of Zn(II)-bound His residues. Unfolding promotes pH-dependent interactions with a unique lipid present in late endolysosomal membranes and is essential for endosomal escape.
- Jonathan Giudice
- Daniel D. Brauer
- Alanna Schepartz