Molecules and Cells

, Volume 27, Issue 3, pp 359–363

Nuclear localization of Chfr is crucial for its checkpoint function

  • Young Eun Kwon
  • Ye Seul Kim
  • Young Mi Oh
  • Jae Hong Seol
Article

DOI: 10.1007/s10059-009-0046-7

Cite this article as:
Kwon, Y.E., Kim, Y.S., Oh, Y.M. et al. Mol Cells (2009) 27: 359. doi:10.1007/s10059-009-0046-7

Abstract

Chfr, a checkpoint with FHA and RING finger domains, plays an important role in cell cycle progression and tumor suppression. Chfr possesses the E3 ubiquitin ligase activity and stimulates the formation of polyubiquitin chains by Ub-conjugating enzymes, and induces the proteasome-dependent degradation of a number of cellular proteins, including Plk1 and Aurora A. While Chfr is a nuclear protein that functions within the cell nucleus, how Chfr is localized in the nucleus has not been clearly demonstrated. Here, we show that nuclear localization of Chfr is mediated by nuclear localization signal (NLS) sequences. To reveal the signal sequences responsible for nuclear localization, a short lysine-rich stretch (KKK) at amino acid residues 257–259 was replaced with alanine, which completely abolished nuclear localization. Moreover, we show that nuclear localization of Chfr is essential for its checkpoint function but not for its stability. Thus, our results suggest that NLS-mediated nuclear localization of Chfr leads to its accumulation within the nucleus, which may be important in the regulation of Chfr activation and Chfr-mediated cellular processes, including cell cycle progression and tumor suppression.

Keywords

Chfr nuclear localization signal (NLS) sequence ubiquitination Ub-ligase 

Copyright information

© The Korean Society for Molecular and Cellular Biology and Springer Netherlands 2009

Authors and Affiliations

  • Young Eun Kwon
    • 1
  • Ye Seul Kim
    • 1
  • Young Mi Oh
    • 1
  • Jae Hong Seol
    • 1
  1. 1.School of Biological Sciences, Research Center for Functional CellulomicsSeoul National UniversitySeoulKorea

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