Molecular basis for disassembly of an importin: ribosomal protein complex by the escortin Tsr2

Autor: Schütz, Sabina, Michel, Erich, Damberger, Fred, Oplova, Michaela, Peña, Cohue, Leitner, Alexander, Aebersold, Ruedi, Allain, Frédéric H.-T., Panse, Vikram Govind
Jazyk: angličtina
Rok vydání: 2018
Zdroj: Nature Communications, 9
ISSN: 2041-1723
Popis: 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.
Nature Communications, 9
ISSN:2041-1723
Databáze: OpenAIRE