ATPase-dependent role of the atypical kinase Rio2 on the evolving pre-40S ribosomal subunit

作者：Ferreira Cerca Sebastien; Sagar Vatsala; Schaefer Thorsten; Diop Momar; Wesseling Anne Maria; Lu Haiyun; Chai Eileen; Hurt Ed^*; LaRonde LeBlanc Nicole

来源：Nature Structural & Molecular Biology, 2012, 19(12): 1316-+.

DOI：10.1038/nsmb.2403

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-Mg2+ complex. The active site contains ADP-Mg2+ and a phosphoaspartate intermediate typically found in Na+, K+ and Ca2+ 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.

• 出版日期2012-12