Fig. 1

Schematic representation of the spliceosome pathway and the function of the DExD/H-box proteins involved. The spliceosome pathway can be divided into four phases: spliceosome assembly, spliceosome activation, catalytic steps and spliceosome disassembly. Two DExD/H-box proteins are required for each phase of the pathway, and their functions are shown. a Sub2 is implicated in the removal of BBP/Mud2 from binding to the branch site. b Prp5 is implicated in the removal of Cus2 from U2 snRNP and converts U2 snRNA into a functional form. c Prp28 is implicated in the removal of U1C or destabilization of U1 snRNA from the 5’ splice site to promote U1/U6 switch at the 5’ splice site. d Brr2 catalyzes U4/U6 unwinding to release U4. e Prp2 is required for remodeling of the spliceosome structure by destabilization of SF3a/b. Prp2 binds to the pre-mRNA in a region downstream of the branch site and translocates in a 3’-to’5’ direction to destabilize SF3a/b. f Prp16 is required for the release of Yju2/Cwc25. g Prp22 mediates the release mature mRNA, and h Prp43 mediates spliceosome disassembly. Prp22 binds to the mature mRNA in a region downstream of the splice junction and translocates in a 3’-to’5’ direction to destabilize mRNA from the spliceosome