RT Journal Article
SR Electronic
T1 An open interface in the pre-80S ribosome coordinated by ribosome assembly factors Tsr1 and Dim1 enables temporal regulation of Fap7
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 617910
DO 10.1101/617910
A1 Jay Rai
A1 Melissa D. Parker
A1 Haina Huang
A1 Stefan Choy
A1 Homa Ghalei
A1 Matthew C. Johnson
A1 Katrin Karbstein
A1 M. Elizabeth Stroupe
YR 2020
UL http://biorxiv.org/content/early/2020/10/26/617910.abstract
AB During their maturation, nascent 40S subunits enter a translation-like quality control cycle, where they are joined by mature 60S subunits to form 80S-like ribosomes. While these assembly intermediates are essential for maturation and quality control, how they form, and how their structure promotes quality control remains unknown. To address these questions, we determined the structure of an 80S-like ribosome assembly intermediate to an overall resolution of 3.4 Å. The structure, validated by biochemical data, resolves a large body of previously paradoxical data and illustrates how assembly and translation factors cooperate to promote the formation of an interface that lacks many mature subunit contacts but is stabilized by the universally conserved Dim1. We also show how Tsr1 enables this interface by blocking the canonical binding of eIF5B to 40S subunits, while maintaining its binding to 60S. The structure also shows how this interface leads to unfolding of the platform, which allows for temporal regulation of the ATPase Fap7, thus linking 40S maturation to quality-control during ribosome assembly.Competing Interest StatementThe authors have declared no competing interest.