Lysine 263 residue of NPM/B23 is essential for regulating ATP binding and B23 stability

Choi, Joung Woo; Lee, Sang Bae; Kim, Chung Kwon; Lee, Kyung-Hoon; Cho, Sung-Woo; Ahn, Jee-Yin

doi:10.1016/j.febslet.2008.02.059

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Volume 582, Issue 7 , Pages 1073-1080, 2 April 2008

Lysine 263 residue of NPM/B23 is essential for regulating ATP binding and B23 stability

Edited by Noboru Mizushima

Joung Woo Choi
- Departments of Molecular Cell Biology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
- These authors contributed equally to this work.
Sang Bae Lee
- Departments of Molecular Cell Biology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
- These authors contributed equally to this work.
Chung Kwon Kim
- Departments of Molecular Cell Biology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
Kyung-Hoon Lee
- Departments of Anatomy, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan, College of Medicine, Seoul 138-736, Republic of Korea
Jee-Yin Ahn
- Departments of Molecular Cell Biology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
- Corresponding author. Fax: +82 31 299 6139.

Received 23 January 2008; received in revised form 22 February 2008; accepted 25 February 2008. published online 04 March 2008.

Abstract

Here, we show that Nucleophsomin/B23 provides lysine 263 as a critical binding site for ATP. Mutagenesis of lysine 263 to asparagine (K263N) disrupts B23 from ATP binding. While B23 WT exclusively localizes to the nucleolus, the B23-K263N is redistributed from the nucleolus to the nucleoplam. Notably, the K263N mutant is unstable, and displayed rapid degradation. Alteration of K263 induced B23 instability through increased ubiquitination and proteaosomal degradation. Moreover, mutation of K263 impedes the mitogenic effect of B23 in PC12 cells. Thus, K263 is a critical site for ATP binding and required for B23 stability, confining B23 in the nucleolus.

Keywords: Nucleolus/Nucleoplasm, Protein stability, Ubiquitination, Proliferation, Apoptosis