RT Journal Article
SR Electronic
T1 Blocking a dead-end assembly pathway creates a point of regulation for the DEAD-box ATPase Has1 and prevents platform misassembly
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.09.06.459192
DO 10.1101/2021.09.06.459192
A1 Xin Liu
A1 Haina Huang
A1 Katrin Karbstein
YR 2021
UL http://biorxiv.org/content/early/2021/09/06/2021.09.06.459192.abstract
AB Assembly of ribosomal subunits occurs via parallel pathways, which accelerate the process and render it more robust. Nonetheless, in vitro analyses have also demonstrated that some assembly pathways are dead-ends, presumably due to rRNA misfolding. If and how these non-productive pathways are avoided during assembly in vivo remains unknown. Here we use a combination of biochemical, genetic, proteomic and structural analyses to demonstrate a role for assembly factors in biasing the folding landscape away from non-productive intermediates. By binding Rrp36, Rrp5 is prevented from forming a premature interaction with the platform, which leads to a dead-end intermediate, and a misassembled platform that is functionally defective. The DEAD-box ATPase Has1 separates Rrp5 and Rrp36, allowing Rrp5 to reposition to the platform, thereby promoting ribosome assembly and enabling rRNA processing. Thus, Rrp36 establishes an ATP-dependent regulatory point that ensures correct platform assembly by opening a new folding channel that avoids funnels to misfolding.Competing Interest StatementThe authors have declared no competing interest.