6g04

Publication Abstract from PubMed

Disordered extensions at the termini and short internal insertions distinguish eukaryotic ribosomal proteins (r-proteins) from their anucleated archaeal counterparts. Here, we report an NMR structure of such a eukaryotic-specific segment (ESS) in the r-protein eS26 in complex with the escortin Tsr2. The structure reveals how ESS attracts Tsr2 specifically to importin:eS26 complexes entering the nucleus in order to trigger non-canonical RanGTP-independent disassembly. Tsr2 then sequesters the released eS26 and prevents rebinding to the importin, providing an alternative allosteric mechanism to terminate the process of nuclear import. Notably, a Diamond-Blackfan anemia-associated Tsr2 mutant protein is impaired in binding to ESS, unveiling a critical role for this interaction in human hematopoiesis. We propose that eS26-ESS and Tsr2 are components of a nuclear sorting system that co-evolved with the emergence of the nucleocytoplasmic barrier and transport carriers.

Molecular basis for disassembly of an importin:ribosomal protein complex by the escortin Tsr2.,Schutz S, Michel E, Damberger FF, Oplova M, Pena C, Leitner A, Aebersold R, Allain FH, Panse VG Nat Commun. 2018 Sep 10;9(1):3669. doi: 10.1038/s41467-018-06160-x. PMID:30201955^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.