title: Architecture of the Rix1-Rea1 checkpoint machinery during pre-60S-ribosome remodeling.
abstract: Ribosome synthesis is catalyzed by ∼200 assembly factors, which facilitate efficient production of mature ribosomes. Here, we determined the cryo-EM structure of a Saccharomyces cerevisiae nucleoplasmic pre-60S particle containing the dynein-related 550-kDa Rea1 AAA(+) ATPase and the Rix1 subcomplex. This particle differs from its preceding state, the early Arx1 particle, by two massive structural rearrangements: an ∼180° rotation of the 5S ribonucleoprotein complex and the central protuberance (CP) rRNA helices, and the removal of the 'foot' structure from the 3' end of the 5.8S rRNA. Progression from the Arx1 to the Rix1 particle was blocked by mutational perturbation of the Rix1-Rea1 interaction but not by a dominant-lethal Rea1 AAA(+) ATPase-ring mutant. After remodeling, the Rix1 subcomplex and Rea1 become suitably positioned to sense correct structural maturation of the CP, which allows unidirectional progression toward mature ribosomes.
authors.affiliation: Gene Center, University of Munich, Munich, Germany.
authors.forename: Clara
authors.initials: C
authors.lastname: Barrio-Garcia
authors.affiliation: Heidelberg University Biochemistry Center, Heidelberg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Thoms
authors.affiliation: Heidelberg University Biochemistry Center, Heidelberg, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Flemming
authors.affiliation: Gene Center, University of Munich, Munich, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Kater
authors.affiliation: Gene Center, University of Munich, Munich, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Berninghausen
authors.affiliation: Heidelberg University Biochemistry Center, Heidelberg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Baßler
authors.affiliation: Gene Center, University of Munich, Munich, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Beckmann
authors.affiliation: Heidelberg University Biochemistry Center, Heidelberg, Germany.
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism*; D020285:Cryoelectron Microscopy; D008958:Models, Molecular; D001678:Organelle Biogenesis; D054683:Ribosome Subunits, Large, Eukaryotic / Q000378:metabolism* / Q000648:ultrastructure*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: C496539:Rix1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C496538:MDN1 protein, S cerevisiae; D000074183:ATPases Associated with Diverse Cellular Activities