How to grow a filament: Lessons from the RAD51 paralogs toolbox.

In this issue of Molecular Cell, Koo et al.1 describe how the yeast Rad55-Rad57-SHU complex dynamically nucleates Rad51 filaments on DNA. Functional coupling between Rad55-Rad57 and Rad51 on ssDNA seeds filament growth, whilst ATP hydrolysis promotes complex turnover.