title: Structure of the second RRM domain of Nrd1, a fission yeast MAPK target RNA binding protein, and implication for its RNA recognition and regulation.
abstract: Negative regulator of differentiation 1 (Nrd1) is known as a negative regulator of sexual differentiation in fission yeast. Recently, it has been revealed that Nrd1 also regulates cytokinesis, in which physical separation of the cell is achieved by a contractile ring comprising many proteins including actin and myosin. Cdc4, a myosin II light chain, is known to be required for cytokinesis. Nrd1 binds and stabilizes Cdc4 mRNA, and thereby suppressing the cytokinesis defects of the cdc4 mutants. Interestingly, Pmk1 MAPK phosphorylates Nrd1, resulting in markedly reduced RNA binding activity. Furthermore, Nrd1 localizes to stress granules in response to various stresses, and Pmk1 phosphorylation enhances the localization. Nrd1 consists of four RRM domains, although the mechanism by which Pmk1 regulates the RNA binding activity of Nrd1 is unknown. In an effort to delineate the relationship between Nrd1 structure and function, we prepared each RNA binding domain of Nrd1 and examined RNA binding to chemically synthesized oligo RNA using NMR. The structure of the second RRM domain of Nrd1 was determined and the RNA binding site on the second RRM domain was mapped by NMR. A plausible mechanism pertaining to the regulation of RNA binding activity by phosphorylation is also discussed.
authors.affiliation: Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397, Japan.
authors.forename: Ayaho
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Teppei
authors.initials: T
authors.lastname: Kanaba
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Satoh
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ito
authors.forename: Reiko
authors.initials: R
authors.lastname: Sugiura
authors.forename: Masaki
authors.initials: M
authors.lastname: Mishima
mesh_terms: D001665:Binding Sites; D009682:Magnetic Resonance Spectroscopy; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012331:RNA, Fungal / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry* / Q000378:metabolism*; D012996:Solutions; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship
chemical_list: D012331:RNA, Fungal; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029702:Schizosaccharomyces pombe Proteins; D012996:Solutions; C491210:nrd1 protein, S pombe; D020928:Mitogen-Activated Protein Kinases
keywords: GST; HSQC; IPTG; MAPK; NOE; NOE spectroscopy; NOESY; Nrd1; Phosphorylation; RNA recognition motif; RRM; TCEP; TOCSY; glutathione S-transferase; heteronuclear single quantum correlation spectroscopy; isopropyl β-d-1-thiogalactopyranoside; nuclear Overhauser effect; total correlation spectroscopy; tris(2-carboxyethyl)phosphine