title: The structure of the ARE-binding domains of Hu antigen R (HuR) undergoes conformational changes during RNA binding.
abstract: Human RNA-binding protein (HuR), a ubiquitously expressed member of the Hu protein family, plays an important role in mRNA degradation and has been implicated as a key post-transcriptional regulator. HuR contains three RNA-recognition motif (RRM) domains. The two N-terminal tandem RRM domains can selectively bind AU-rich elements (AREs), while the third RRM domain (RRM3) contributes to interactions with the poly-A tail of target mRNA and other ligands. Here, the X-ray structure of two methylated tandem RRM domains (RRM1/2) of HuR in their RNA-free form was solved at 2.9 Å resolution. The crystal structure of RRM1/2 complexed with target mRNA was also solved at 2.0 Å resolution; comparisons of the two structures show that HuR RRM1/2 undergoes conformational changes upon RNA binding. Fluorescence polarization assays (FPA) were used to study the protein-RNA interactions. Both the structure and the FPA analysis indicated that RRM1 is the primary ARE-binding domain in HuR and that the conformational changes induce subsequent contacts of the RNA substrate with the inter-domain linker and RRM2 which greatly improve the RNA-binding affinity of HuR.
authors.affiliation: School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Fuxing
authors.initials: F
authors.lastname: Zeng
authors.forename: Qiao
authors.initials: Q
authors.lastname: Liu
authors.forename: Huihui
authors.initials: H
authors.lastname: Liu
authors.forename: Zexian
authors.initials: Z
authors.lastname: Liu
authors.forename: Liwen
authors.initials: L
authors.lastname: Niu
authors.forename: Maikun
authors.initials: M
authors.lastname: Teng
authors.forename: Xu
authors.initials: X
authors.lastname: Li
mesh_terms: D063307:AU Rich Elements / Q000235:genetics; D000818:Animals; D018360:Crystallography, X-Ray; D019175:DNA Methylation / Q000235:genetics; D051959:ELAV Proteins / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D059372:Nucleotide Motifs / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D011487:Protein Conformation; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D020080:Tandem Repeat Sequences / Q000235:genetics
chemical_list: D051959:ELAV Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins
keywords: HuR; RNA binding; RRM; conformational change