title: The DEAD-box helicase eIF4A: paradigm or the odd one out?
abstract: DEAD-box helicases catalyze the ATP-dependent unwinding of RNA duplexes. They share a helicase core formed by two RecA-like domains that carries a set of conserved motifs contributing to ATP binding and hydrolysis, RNA binding and duplex unwinding. The translation initiation factor eIF4A is the founding member of the DEAD-box protein family, and one of the few examples of DEAD-box proteins that consist of a helicase core only. It is an RNA-stimulated ATPase and a non-processive helicase that unwinds short RNA duplexes. In the catalytic cycle, a series of conformational changes couples the nucleotide cycle to RNA unwinding. eIF4A has been considered a paradigm for DEAD-box proteins, and studies of its function have revealed the governing principles underlying the DEAD-box helicase mechanism. However, as an isolated helicase core, eIF4A is rather the exception, not the rule. Most helicase modules in other DEAD-box proteins are modified, some by insertions into the RecA-like domains, and the majority by N- and C-terminal appendages. While the basic catalytic function resides within the helicase core, its modulation by insertions, additional domains or a network of interaction partners generates the diversity of DEAD-box protein functions in the cell. This review summarizes the current knowledge on eIF4A and its regulation, and discusses to what extent eIF4A serves as a model DEAD-box protein.
authors.affiliation: University of Muenster, Institute for Physical Chemistry, Muenster, Germany.
authors.forename: Alexandra Z
authors.initials: AZ
authors.lastname: Andreou
authors.forename: Dagmar
authors.initials: D
authors.lastname: Klostermeier
mesh_terms: D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000378:metabolism*; D039601:Eukaryotic Initiation Factor-4A / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D012313:RNA / Q000378:metabolism
chemical_list: D012313:RNA; D039601:Eukaryotic Initiation Factor-4A; D053487:DEAD-box RNA Helicases