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The modifying enzyme Tsr3 establishes the hierarchy of Rio kinase binding in 40S ribosome assembly.
Huang, Haina; Parker, Melissa; Karbstein, Katrin.
Afiliação
  • Huang H; Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA.
  • Parker M; Skaggs Graduate School of Chemical and Biological Sciences at Scripps Research, Jupiter, Florida 33458, USA.
  • Karbstein K; Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA.
RNA ; 28(4): 568-582, 2022 04.
Article em En | MEDLINE | ID: mdl-35031584
ABSTRACT
Ribosome assembly is an intricate process, which in eukaryotes is promoted by a large machinery comprised of over 200 assembly factors (AFs) that enable the modification, folding, and processing of the ribosomal RNA (rRNA) and the binding of the 79 ribosomal proteins. While some early assembly steps occur via parallel pathways, the process overall is highly hierarchical, which allows for the integration of maturation steps with quality control processes that ensure only fully and correctly assembled subunits are released into the translating pool. How exactly this hierarchy is established, in particular given that there are many instances of RNA substrate "handover" from one highly related AF to another, remains to be determined. Here we have investigated the role of Tsr3, which installs a universally conserved modification in the P-site of the small ribosomal subunit late in assembly. Our data demonstrate that Tsr3 separates the binding of the Rio kinases, Rio2 and Rio1, with whom it shares a binding site. By binding after Rio2 dissociation, Tsr3 prevents rebinding of Rio2, promoting forward assembly. After rRNA modification is complete, Tsr3 dissociates, thereby allowing for recruitment of Rio1 into its functional site. Inactive Tsr3 blocks Rio1 function, which can be rescued using mutants that bypass the requirement for Rio1 activity. Finally, yeast strains lacking Tsr3 randomize the binding of the two kinases, leading to the release of immature ribosomes into the translating pool. These data demonstrate a role for Tsr3 and its modification activity in establishing a hierarchy for the function of the Rio kinases.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Alquil e Aril Transferases / Proteínas de Saccharomyces cerevisiae Tipo de estudo: Clinical_trials Idioma: En Ano de publicação: 2022 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Alquil e Aril Transferases / Proteínas de Saccharomyces cerevisiae Tipo de estudo: Clinical_trials Idioma: En Ano de publicação: 2022 Tipo de documento: Article