Ribosome biogenesis; co-translational regulation; Saccharomyces cerevisiae; yeast genetics; chaperones; ribosomal proteins
Mitterer Valentin, Shayan Ramtin, Ferreira-Cerca Sébastien, Murat Guillaume, Enne Tanja, Rinaldi Dana, Weigl Sarah, Omanic Hajrija, Gleizes Pierre-Emmanuel, Kressler Dieter, Plisson-Chastang Celia, Pertschy Brigitte (2019), Conformational proofreading of distant 40S ribosomal subunit maturation events by a long-range communication mechanism, in Nature Communications
, 10(1), 2754-2754.
Martín‐Villanueva Sara, Fernández‐Pevida Antonio, Fernández‐Fernández José, Kressler Dieter, de la Cruz Jesús (2019), Ubiquitin release from eL 40 is required for cytoplasmic maturation and function of 60S ribosomal subunits in Saccharomyces cerevisiae, in The FEBS Journal
, 287(2), 345-360.
Martín-Villanueva Sara, Fernández-Pevida Antonio, Kressler Dieter, de la Cruz Jesús (2019), The Ubiquitin Moiety of Ubi1 Is Required for Productive Expression of Ribosomal Protein eL40 in Saccharomyces cerevisiae, in Cells
, 8(8), 850-850.
Rössler Ingrid, Embacher Julia, Pillet Benjamin, Murat Guillaume, Liesinger Laura, Hafner Jutta, Unterluggauer Julia Judith, Birner-Gruenberger Ruth, Kressler Dieter, Pertschy Brigitte (2019), Tsr4 and Nap1, two novel members of the ribosomal protein chaperOME, in Nucleic Acids Research
, 47(13), 6984-7002.
Thoms Matthias, Mitterer Valentin, Kater Lukas, Falquet Laurent, Beckmann Roland, Kressler Dieter, Hurt Ed (2018), Suppressor mutations in Rpf2–Rrs1 or Rpl5 bypass the Cgr1 function for pre-ribosomal 5S RNP-rotation, in Nature Communications
, 9(1), 4094-4094.
The process of ribosome biogenesis is evolutionarily conserved among eukaryotes and constitutes a main cellular activity. Most of our current knowledge about this complicated process comes from studies with the yeast Saccharomyces cerevisiae. Research over the last 30 years has revealed that numerous biogenesis factors (>200), including many energy-consuming enzymes and quality-controlling checkpoint factors, are required for the accurate and efficient maturation of pre-ribosomal particles as they travel from the nucleolus to the cytoplasm. Fueled by recent advances in cryo-electron microscopy, a structural view of ribosome assembly has begun to emerge with the first, near-atomic snapshots of different assembly intermediates. Moreover, we have only recently learnt that dedicated chaperones, which in many cases already capture their client in a co-translational manner, selectively protect and facilitate the assembly of individual ribosomal proteins (r-proteins). Despite the enormous progress in understanding how this gigantic molecular jigsaw puzzle is put together, the precise role of a large number of biogenesis factors and the molecular mechanisms driving ribosome assembly have remained in many instances largely elusive.The aim of this proposal is to provide molecular insight into selected aspects of eukaryotic ribosome biogenesis. To this end, we combine unique and extremely powerful yeast genetic approaches with biochemical, cell biological, and, in the framework of collaborations, structural methods.Specifically, I propose the following projects:1) Investigation of early pre-60S maturation eventsThe early steps of pre-60S maturation, partly owing to the lack of structural information, are still poorly understood. We have previously shown that the AAA-type ATPase Rix7 is required for the release of Nsa1 from a nucleolar pre-60S particle. By performing an ‘in vivo structure probing’ approach, based on the isolation of suppressor mutations that bypass the requirement for the essential Nsa1, we have identified several early-acting pre-60S biogenesis factors. Here, we propose to decipher their functional and physical interaction network and to unveil the assembly alterations that compensate for the lack of Nsa1 recruitment in order to illuminate the early phase of pre-60S formation and maturation.2) Identification and characterization of novel dedicated chaperones of r-proteinsSo far only eight of the 79 r-proteins have been shown to be associated with dedicated chaperones. Anticipating a more widespread requirement for dedicated chaperones, we propose to identify novel dedicated chaperones and to subsequently define their relevance for the life cycle of their r-protein client. By determining the co-translational capturing potential and the structural basis of the interaction, we expect to obtain insight into the timing and mode of r-protein recognition as well as the mechanism of r-protein assembly into pre-ribosomes.3) Co-translational regulation of Rpl4 expressionWe have previously shown that Acl4 is a dedicated chaperone of Rpl4. Our analysis of ?acl4 suppressors revealed an unexpected connection between the ribosome-associated chaperone NAC and the Ccr4/Not complex for the regulation of Rpl4 expression. With this project, we aim to provide detailed insight into this co-translational control mechanism by investigating how the regulatory module is recruited to the RPL4 mRNA and how it affects its translation and degradation. Moreover, we will determine the subset of mRNAs that are regulated by this quality control mechanism.