Type IVa pili are bacterial surface filaments that undergo extension and retraction powered by a protein machine that spans the cell envelope. Here, Treuner-Lange et al. show that a complex formed by PilY1 and minor pilins is an integral part of this machine and is necessary for pilus extension, adhesion and retraction termination.
- Anke Treuner-Lange
- Yi-Wei Chang
- Lotte Søgaard-Andersen
