Abstract
Type IV pili are long polymers located on the surface of a wide variety of bacterial cells, including the pathogen Neisseria meningitidis. They are responsible for a diverse range of functions, including adhesion, motility and natural transformation. In this issue of The EMBO Journal, Imhaus and Duménil show that two minor pilins, PilX and PilV, exert some of their effects by changing mean surface pilus number and that this modulates different pilus-dependent functions.