title: The organization and contribution of helicases to RNA splicing.
abstract: Splicing is an essential step of gene expression. It occurs in two consecutive chemical reactions catalyzed by a large protein-RNA complex named the spliceosome. Assembled on the pre-mRNA substrate from five small nuclear proteins, the spliceosome acts as a protein-controlled ribozyme to catalyze the two reactions and finally dissociates into its components, which are re-used for a new round of splicing. Upon following this cyclic pathway, the spliceosome undergoes numerous intermediate stages that differ in composition as well as in their internal RNA-RNA and RNA-protein contacts. The driving forces and control mechanisms of these remodeling processes are provided by specific molecular motors called RNA helicases. While eight spliceosomal helicases are present in all organisms, higher eukaryotes contain five additional ones potentially required to drive a more intricate splicing pathway and link it to an RNA metabolism of increasing complexity. Spliceosomal helicases exhibit a notable structural diversity in their accessory domains and overall architecture, in accordance with the diversity of their task-specific functions. This review summarizes structure-function knowledge about all spliceosomal helicases, including the latter five, which traditionally are treated separately from the conserved ones. The implications of the structural characteristics of helicases for their functions, as well as for their structural communication within the multi-subunits environment of the spliceosome, are pointed out.
authors.affiliation: Macromolecular Crystallography Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Inessa
authors.initials: I
authors.lastname: De
authors.affiliation: Macromolecular Crystallography Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Schmitzová
authors.affiliation: Macromolecular Crystallography Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Pena
mesh_terms: D000818:Animals; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D006801:Humans; D011485:Protein Binding; D020365:RNA Helicases / Q000737:chemistry / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism*; D012326:RNA Splicing; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D012322:RNA Precursors; D017411:Ribonucleoproteins, Small Nuclear; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases