A RanGTP-independent Mechanism Allows Ribosomal Protein Nuclear Import for Ribosome Assembly
Schubert, Olga T.
Panse, Vikram G.
- Journal Article
Rights / licenseCreative Commons Attribution 4.0 International
Within a single generation time a growing yeast cell imports ∼14 million ribosomal proteins (r-proteins) into the nucleus for ribosome production. After import, it is unclear how these intrinsically unstable and aggregation-prone proteins are targeted to the ribosome assembly site in the nucleolus. Here, we report the discovery of a conserved nuclear carrier Tsr2 that coordinates transfer of the r-protein eS26 to the earliest assembling pre-ribosome, the 90S. In vitro studies revealed that Tsr2 efficiently dissociates importin:eS26 complexes via an atypical RanGTP-independent mechanism that terminates the import process. Subsequently, Tsr2 binds the released eS26, shields it from proteolysis, and ensures its safe delivery to the 90S pre-ribosome. We anticipate similar carriers—termed here escortins—to securely connect the nuclear import machinery with pathways that deposit r-proteins onto developing pre-ribosomal particles Show more
Journal / serieseLife
Pages / Article No.
PublishereLife Sciences Publications
Organisational unit03884 - Panse, Vikram G. (SNF-Professur) (ehemalig)
260676 - Dissecting the biogenesis of eukaryotic ribosomal subunits (EC)
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