Table of Contents
SRX Biology
Volume 2010, Article ID 606391, 10 pages
http://dx.doi.org/10.3814/2010/606391
Research Article

Stimulation of p53 Transactivation Ability by Nicastrin in Mouse Fibroblasts

1Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8670, Japan
2Department of Molecular and Tumor Pathology, Graduate School of Medicine, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8670, Japan

Received 14 July 2009; Revised 14 September 2009; Accepted 27 September 2009

Copyright © 2010 Toshifumi Koshida et al. 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.

Abstract

Nicastrin (NCSTN), a component of the γ-secretase complex, is involved in the p53-dependent apoptosis of neurons, although its mechanism remains unclear. We analyzed the effects of NCSTN transfection on the transactivity of p53 in ras-NIH3T3 mouse fibroblasts with a luciferase assay. Luciferase activity was elevated after transfection, suggesting the stimulation of p53 transactivation ability. In addition, the protein levels of endogenous mouse p53 and transfected human p53 increased. The effects of NCSTN appeared to be independent of γ-secretase activity because it was not inhibited by the γ-secretase inhibitor DAPT. The functional domains of NCSTN were further examined with NCSTN deletion mutants. Activation of the p53-responsive promoter was completely diminished in a NCSTN mutant lacking the amino acid residues between 306 and 360. Since this domain is a γ-secretase-substrate-recognition site, the activation of p53 by NCSTN may be mediated by γ-secretase-substrate-like molecules.