title: ATPase-dependent role of the atypical kinase Rio2 on the evolving pre-40S ribosomal subunit.
abstract: Ribosome synthesis involves dynamic association of ribosome-biogenesis factors with evolving preribosomal particles. Rio2 is an atypical protein kinase required for pre-40S subunit maturation. We report the crystal structure of eukaryotic Rio2-ATP-Mg(2+) complex. The active site contains ADP-Mg(2+) and a phosphoaspartate intermediate typically found in Na(+), K(+) and Ca(2+) ATPases but not protein kinases. Consistent with this finding, ctRio2 exhibits a robust ATPase activity in vitro. In vivo, Rio2 docks on the ribosome, with its active site occluded and its flexible loop positioned to interact with the pre-40S subunit. Moreover, Rio2 catalytic activity is required for its dissociation from the ribosome, a necessary step in pre-40S maturation. We propose that phosphoryl transfer from ATP to Asp257 in Rio2's active site and subsequent hydrolysis of the aspartylphosphate could be a trigger to power late cytoplasmic 40S subunit biogenesis.
authors.affiliation: Biochemistry Center, University of Heidelberg, Heidelberg, Germany.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Ferreira-Cerca
authors.forename: Vatsala
authors.initials: V
authors.lastname: Sagar
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schäfer
authors.forename: Momar
authors.initials: M
authors.lastname: Diop
authors.forename: Anne-Maria
authors.initials: AM
authors.lastname: Wesseling
authors.forename: Haiyun
authors.initials: H
authors.lastname: Lu
authors.forename: Eileen
authors.initials: E
authors.lastname: Chai
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
authors.forename: Nicole
authors.initials: N
authors.lastname: LaRonde-LeBlanc
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012270:Ribosomes
chemical_list: D017346:Protein Serine-Threonine Kinases; C542171:RIOK2 protein, human; D000251:Adenosine Triphosphatases