Next Article in Journal / Special Issue
Spatiotemporal Regulation of Nuclear Transport Machinery and Microtubule Organization
Previous Article in Journal
Autophagy and Neurodegeneration: Insights from a Cultured Cell Model of ALS
Previous Article in Special Issue
Misdelivery at the Nuclear Pore Complex—Stopping a Virus Dead in Its Tracks
Article Menu

Export Article

Open AccessReview
Cells 2015, 4(3), 387-405;

Nuclear Import of Yeast Proteasomes

Biochemistry Department, University of Toronto, Toronto, ON M5S 1A8, Canada
Author to whom correspondence should be addressed.
Academic Editor: Birthe Fahrenkrog
Received: 21 June 2015 / Accepted: 28 June 2015 / Published: 7 August 2015
(This article belongs to the Special Issue Nucleocytoplasmic Transport)
Full-Text   |   PDF [1084 KB, uploaded 7 August 2015]   |  


Proteasomes are highly conserved protease complexes responsible for the degradation of aberrant and short-lived proteins. In highly proliferating yeast and mammalian cells, proteasomes are predominantly nuclear. During quiescence and cell cycle arrest, proteasomes accumulate in granules in close proximity to the nuclear envelope/ER. With prolonged quiescence in yeast, these proteasome granules pinch off as membraneless organelles, and migrate as stable entities through the cytoplasm. Upon exit from quiescence, the proteasome granules clear and the proteasomes are rapidly transported into the nucleus, a process reflecting the dynamic nature of these multisubunit complexes. Due to the scarcity of studies on the nuclear transport of mammalian proteasomes, we summarised the current knowledge on the nuclear import of yeast proteasomes. This pathway uses canonical nuclear localisation signals within proteasomal subunits and Srp1/Kap95, and the canonical import receptor, named importin/karyopherin αβ. Blm10, a conserved 240 kDa protein, which is structurally related to Kap95, provides an alternative import pathway. Two models exist upon which either inactive precursor complexes or active holo-enzymes serve as the import cargo. Here, we reconcile both models and suggest that the import of inactive precursor complexes predominates in dividing cells, while the import of mature enzymes mainly occurs upon exit from quiescence. View Full-Text
Keywords: proteasome; nuclear transport; importin; karyopherin; Blm10; proteasome granules proteasome; nuclear transport; importin; karyopherin; Blm10; proteasome granules

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Burcoglu, J.; Zhao, L.; Enenkel, C. Nuclear Import of Yeast Proteasomes. Cells 2015, 4, 387-405.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Cells EISSN 2073-4409 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top