title: Different modes of interaction by TIAR and HuR with target RNA and DNA.
abstract: TIAR and HuR are mRNA-binding proteins that play important roles in the regulation of translation. They both possess three RNA recognition motifs (RRMs) and bind to AU-rich elements (AREs), with seemingly overlapping specificity. Here we show using SPR that TIAR and HuR bind to both U-rich and AU-rich RNA in the nanomolar range, with higher overall affinity for U-rich RNA. However, the higher affinity for U-rich sequences is mainly due to faster association with U-rich RNA, which we propose is a reflection of the higher probability of association. Differences between TIAR and HuR are observed in their modes of binding to RNA. TIAR is able to bind deoxy-oligonucleotides with nanomolar affinity, whereas HuR affinity is reduced to a micromolar level. Studies with U-rich DNA reveal that TIAR binding depends less on the 2'-hydroxyl group of RNA than HuR binding. Finally we show that SAXS data, recorded for the first two domains of TIAR in complex with RNA, are more consistent with a flexible, elongated shape and not the compact shape that the first two domains of Hu proteins adopt upon binding to RNA. We thus propose that these triple-RRM proteins, which compete for the same binding sites in cells, interact with their targets in fundamentally different ways.
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia.
authors.forename: Henry S
authors.initials: HS
authors.lastname: Kim
authors.forename: Matthew C J
authors.initials: MC
authors.lastname: Wilce
authors.forename: Yano M K
authors.initials: YM
authors.lastname: Yoga
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Pendini
authors.forename: Menachem J
authors.initials: MJ
authors.lastname: Gunzburg
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Cowieson
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Wilson
authors.forename: Bryan R G
authors.initials: BR
authors.lastname: Williams
authors.forename: Myriam
authors.initials: M
authors.lastname: Gorospe
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Wilce
mesh_terms: D000225:Adenine / Q000032:analysis; D000954:Antigens, Surface / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D007700:Kinetics; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D012313:RNA / Q000737:chemistry* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D053838:Scattering, Small Angle; D014498:Uracil / Q000032:analysis; D014961:X-Ray Diffraction
chemical_list: D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D016601:RNA-Binding Proteins; D014498:Uracil; D012313:RNA; D004247:DNA; D000225:Adenine