A network of assembly factors is involved in remodeling rRNA elements during preribosome maturation

• DOI: 10.1083/jcb.201408111
• Publication Date: 2014-11-18T02:58:17Z
• Authors: Jochen Baßler; Helge Paternoga; Iris Holdermann; Matthias Thoms; Sander Granneman; Clara Barrio-Garcia; Afua Nyarko; Woonghee Lee; Gunter Stier; Sarah A. Clark; Daniel Schraivogel; Martina Kallas; Roland Beckmann; David Tollervey; Elisar Barbar; Irmi Sinning; Ed Hurt
• Keywords: Adenosine Triphosphatases; Ribosomal Proteins; 0303 health sciences; Saccharomyces cerevisiae Proteins; Recombinant Fusion Proteins; Molecular Sequence Data; 500; Correction; RNA-Binding Proteins; Cell Biology; Saccharomyces cerevisiae; Ribosome Subunits, Large, Eukaryotic; Crystallography, X-Ray; Protein Structure, Tertiary; 03 medical and health sciences; RNA, Ribosomal; Escherichia coli; ATPases Associated with Diverse Cellular Activities; Amino Acid Sequence; /dk/atira/pure/subjectarea/asjc/1300/1307; Sequence Alignment; Research Articles

Eukaryotic ribosome biogenesis involves ∼200 assembly factors, but how these contribute to ribosome maturation is poorly understood. Here, we identify a network of factors on the nascent 60S subunit that actively remodels preribosome structure. At its hub is Rsa4, a direct substrate of the force-generating ATPase Rea1. We show that Rsa4 is connected to the central protuberance by binding to Rpl5 and to ribosomal RNA (rRNA) helix 89 of the nascent peptidyl transferase center (PTC) through Nsa2. Importantly, Nsa2 binds to helix 89 before relocation of helix 89 to the PTC. Structure-based mutations of these factors reveal the functional importance of their interactions for ribosome assembly. Thus, Rsa4 is held tightly in the preribosome and can serve as a “distribution box,” transmitting remodeling energy from Rea1 into the developing ribosome. We suggest that a relay-like factor network coupled to a mechano-enzyme is strategically positioned to relocate rRNA elements during ribosome maturation.