Nuclear Transport of Yeast Proteasomes

Biomolecules

卷:4

Cordula Enenkel¹ 

[1] Department of Biochemistry, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON M5S 1A8, Canada;

关键词: proteasome;    nuclear transport;    protein degradation;   

DOI  :  10.3390/biom4040940

来源: DOAJ

【 摘 要 】

Proteasomes are conserved protease complexes enriched in the nuclei of dividing yeast cells, a major site for protein degradation. If yeast cells do not proliferate and transitto quiescence, metabolic changes result in the dissociation of proteasomes into proteolytic core and regulatory complexes and their sequestration into motile cytosolic proteasome storage granuli. These granuli rapidly clear with the resumption of growth, releasing the stored proteasomes, which relocalize back to the nucleus to promote cell cycle progression. Here, I report on three models of how proteasomes are transported from the cytoplasminto the nucleus of yeast cells. The first model applies for dividing yeast and is based onthe canonical pathway using classical nuclear localization sequences of proteasomal subcomplexes and the classical import receptor importin/karyopherin αβ. The second model applies for quiescent yeast cells, which resume growth and use Blm10, a HEAT-like repeat protein structurally related to karyopherin β, for nuclear import of proteasome core particles. In the third model, the fully-assembled proteasome is imported into the nucleus. Our still marginal knowledge about proteasome dynamics will inspire the discussionon how protein degradation by proteasomes may be regulated in different cellular compartments of dividing and quiescent eukaryotic cells.

【 授权许可】

Unknown