Mechanochemical Removal of Ribosome Biogenesis Factors from Nascent 60S Ribosomal Subunits
2009
Authors: Ulbrich C, Diepholz M, Bassler J, Kressler D, Pertschy B, Galani K, Böttcher B, Hurt E.
CellNetworks People: Hurt Ed
Journal: Cell. 2009 Sep 4;138(5):911-22

The dynein-related AAA ATPase Rea1 is a preribosomal factor that triggers an unknown maturation step in 60S subunit biogenesis. Using electron microscopy, we show that Rea1's motor domain is docked to the pre-60S particle and its tail-like structure, harboring a metal ion-dependent adhesion site (MIDAS), protrudes from the preribosome. Typically, integrins utilize a MIDAS to bind extracellular ligands, an interaction that is strengthened under applied tensile force. Likewise, the Rea1 MIDAS binds the preribosomal factor Rsa4, which is located on the pre-60S subunit at a site that is contacted by the flexible Rea1 tail. The MIDAS-Rsa4 interaction is essential for ATP-dependent dissociation of a group of non-ribosomal factors from the pre-60S particle. Thus, Rea1 aligns with its interacting partners on the preribosome to effect a necessary step on the path to the export-competent 60S subunit.