Format

Send to:

Choose Destination
See comment in PubMed Commons below
EMBO J. 2013 Oct 16;32(20):2697-707. doi: 10.1038/emboj.2013.192. Epub 2013 Aug 27.

Blm10 facilitates nuclear import of proteasome core particles.

Author information

  • 11] Department of Biochemistry, University of Toronto, One King's College Circle, Toronto, Ontario, Canada [2] Institute of Biochemistry, University of Stuttgart, Stuttgart, Germany.

Abstract

Short-lived proteins are degraded by proteasome complexes, which contain a proteolytic core particle (CP) but differ in the number of regulatory particles (RPs) and activators. A recently described member of conserved proteasome activators is Blm10. Blm10 contains 32 HEAT-like modules and is structurally related to the nuclear import receptor importin/karyopherin β. In proliferating yeast, RP-CP assemblies are primarily nuclear and promote cell division. During quiescence, RP-CP assemblies dissociate and CP and RP are sequestered into motile cytosolic proteasome storage granuli (PSG). Here, we show that CP sequestration into PSG depends on Blm10, whereas RP sequestration into PSG is independent of Blm10. PSG rapidly clear upon the resumption of cell proliferation and proteasomes are relocated into the nucleus. Thereby, Blm10 facilitates nuclear import of CP. Blm10-bound CP serves as an import receptor-cargo complex, as Blm10 mediates the interaction with FG-rich nucleoporins and is dissociated from the CP by Ran-GTP. Thus, Blm10 represents the first CP-dedicated nuclear import receptor in yeast.

PMID:
23982732
[PubMed - indexed for MEDLINE]
PMCID:
PMC3801435
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk