title: RNA chaperones, RNA annealers and RNA helicases.
abstract: RNA molecules face difficulties when folding into their native structures. In the cell, proteins can assist RNAs in reaching their functionally active states by binding and stabilizing a specific structure or, in a quite opposite way, by interacting in a non-specific manner. These proteins can either facilitate RNA-RNA interactions in a reaction termed RNA annealing, or they can resolve non-functional inhibitory structures. The latter is defined as "RNA chaperone activity" and is the main topic of this review. Here we define RNA chaperone activity in a stringent way and we review those proteins for which RNA chaperone activity has been clearly demonstrated. These proteins belong to quite diverse families such as hnRNPs, histone-like proteins, ribosomal proteins, cold shock domain proteins and viral nucleocapsid proteins. DExD/H-box containing RNA helicases are discussed as a special family of enzymes that restructure RNA or RNPs in an ATP-dependent manner. We further address the different mechanisms RNA chaperones might use to promote folding including the recently proposed theory of protein disorder as a key element in triggering RNA-protein interactions. Finally, we present a new website for proteins with RNA chaperone activity which compiles all the information on these proteins with the perspective to promote the understanding of their activity.
authors.affiliation: Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.
authors.forename: Lukas
authors.initials: L
authors.lastname: Rajkowitsch
authors.forename: Doris
authors.initials: D
authors.lastname: Chen
authors.forename: Sabine
authors.initials: S
authors.lastname: Stampfl
authors.forename: Katharina
authors.initials: K
authors.lastname: Semrad
authors.forename: Christina
authors.initials: C
authors.lastname: Waldsich
authors.forename: Oliver
authors.initials: O
authors.lastname: Mayer
authors.forename: Michael F
authors.initials: MF
authors.lastname: Jantsch
authors.forename: Robert
authors.initials: R
authors.lastname: Konrat
authors.forename: Udo
authors.initials: U
authors.lastname: Bläsi
authors.forename: Renée
authors.initials: R
authors.lastname: Schroeder
mesh_terms: D000818:Animals; D006801:Humans; D018832:Molecular Chaperones / Q000737:chemistry* / Q000145:classification / Q000502:physiology*; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology; D020365:RNA Helicases / Q000737:chemistry* / Q000145:classification / Q000502:physiology*
chemical_list: D018832:Molecular Chaperones; D012313:RNA; D020365:RNA Helicases