title: mRNA helicases: the tacticians of translational control.
abstract: The translation initiation step in eukaryotes is highly regulated and rate-limiting. During this process, the 40S ribosomal subunit is usually recruited to the 5' terminus of the mRNA. It then migrates towards the initiation codon, where it is joined by the 60S ribosomal subunit to form the 80S initiation complex. Secondary structures in the 5' untranslated region (UTR) can impede binding and movement of the 40S ribosome. The canonical eukaryotic translation initiation factor eIF4A (also known as DDX2), together with its accessory proteins eIF4B and eIF4H, is thought to act as a helicase that unwinds secondary structures in the mRNA 5' UTR. Growing evidence suggests that other helicases are also important for translation initiation and may promote the scanning processivity of the 40S subunit, synergize with eIF4A to 'melt' secondary structures or facilitate translation of a subset of mRNAs.
authors.affiliation: Department of Biochemistry and Goodman Cancer Research Centre, Faculty of Medicine, McGill University, Montreal, Quebec H3A 1A3, Canada.
authors.forename: Armen
authors.initials: A
authors.lastname: Parsyan
authors.forename: Yuri
authors.initials: Y
authors.lastname: Svitkin
authors.forename: David
authors.initials: D
authors.lastname: Shahbazian
authors.forename: Christos
authors.initials: C
authors.lastname: Gkogkas
authors.forename: Paul
authors.initials: P
authors.lastname: Lasko
authors.forename: William C
authors.initials: WC
authors.lastname: Merrick
authors.forename: Nahum
authors.initials: N
authors.lastname: Sonenberg
mesh_terms: D000818:Animals; D018387:Codon, Initiator / Q000235:genetics*; D039601:Eukaryotic Initiation Factor-4A / Q000378:metabolism; D039642:Eukaryotic Initiation Factors / Q000378:metabolism; D006801:Humans; D008957:Models, Genetic; D014176:Protein Biosynthesis / Q000235:genetics*; D020365:RNA Helicases / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism
chemical_list: D018387:Codon, Initiator; C111495:EIF4H protein, human; D039642:Eukaryotic Initiation Factors; D012333:RNA, Messenger; C031799:eIF-4B; D039601:Eukaryotic Initiation Factor-4A; D020365:RNA Helicases