title: Structure and function of the N-terminal nucleolin binding domain of nuclear valosin-containing protein-like 2 (NVL2) harboring a nucleolar localization signal.
abstract: The N-terminal regions of AAA-ATPases (ATPase associated with various cellular activities) often contain a domain that defines the distinct functions of the enzymes, such as substrate specificity and subcellular localization. As described herein, we have determined the solution structure of an N-terminal unique domain isolated from nuclear valosin-containing protein (VCP)-like protein 2 (NVL2(UD)). NVL2(UD) contains three α helices with an organization resembling that of a winged helix motif, whereas a pair of β-strands is missing. The structure is unique and distinct from those of other known type II AAA-ATPases, such as VCP. Consequently, we identified nucleolin from a HeLa cell extract as a binding partner of this domain. Nucleolin contains a long (∼300 amino acids) intrinsically unstructured region, followed by the four tandem RNA recognition motifs and the C-terminal glycine/arginine-rich domain. Binding analyses revealed that NVL2(UD) potentially binds to any of the combinations of two successive RNA binding domains in the presence of RNA. Furthermore, NVL2(UD) has a characteristic loop, in which the key basic residues RRKR are exposed to the solvent at the edge of the molecule. The mutation study showed that these residues are necessary and sufficient for nucleolin-RNA complex binding as well as nucleolar localization. Based on the observations presented above, we propose that NVL2 serves as an unfoldase for the nucleolin-RNA complex. As inferred from its RNA dependence and its ATPase activity, NVL2 might facilitate the dissociation and recycling of nucleolin, thereby promoting efficient ribosome biogenesis.
authors.affiliation: Division of Structural Biology, Graduate School of Medicine, Kobe University, 7-5-1 Kusunokicho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Natsuko
authors.initials: N
authors.lastname: Goda
authors.forename: Naoko
authors.initials: N
authors.lastname: Iwaya
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tenno
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shirakawa
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Hiroaki
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000737:chemistry*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002466:Cell Nucleolus / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D010750:Phosphoproteins / Q000737:chemistry*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D000097796:Nucleolin
chemical_list: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases; D005982:Glutathione Transferase; D019913:Nuclear Localization Signals; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D000097796:Nucleolin; C500249:NVL protein, human