Mechanism of spliceosome remodeling by the ATPase/helicase Prp2 and its coactivator Spp2

Remodeling an RNA processing machine Splicing of precursor messenger RNA (pre-mRNA) is carried out by the spliceosome, a highly dynamic, supramolecular complex that undergoes assembly, activation, catalysis, and disassembly. These essential spliceosome remodeling events are driven by a conserved family of adenosine triphosphatase (ATPase)/helicases. In the presence of its coactivator Spp2, the ATPase/helicase Prp2 associates with the activated spliceosome and translocates the single-stranded pre-mRNA toward its 3′ end. Bai et al. now report the cryo–electron microscopy structures of Prp2 both before and after recruitment into the activated spliceosome. These structures and the associated biochemical analysis reveal how Prp2 remodels the activated spliceosome and how Spp2 safeguards the function of Prp2. Science , this issue p. eabe8863