UMMS Affiliation

Department of Molecular, Cell and Cancer Biology

Date

7-14-2015

Document Type

Article

Medical Subject Headings

Ataxia Telangiectasia Mutated Proteins; Cell Division; Cell Line; DNA Damage; F-Box Proteins; Humans; Mutagens; Phosphorylation; Protein Processing, Post-Translational; Proteolysis; Proto-Oncogene Proteins c-mdm2; Tumor Suppressor Protein p53; Tumor Suppressor Proteins

Disciplines

Cancer Biology | Cell Biology | Molecular Biology | Molecular Genetics

Abstract

The tumor suppressor p53 plays a critical role in maintaining genomic stability. In response to genotoxic stress, p53 levels increase and induce cell-cycle arrest, senescence, or apoptosis, thereby preventing replication of damaged DNA. In unstressed cells, p53 is maintained at a low level. The major negative regulator of p53 is MDM2, an E3 ubiquitin ligase that directly interacts with p53 and promotes its polyubiquitination, leading to the subsequent destruction of p53 by the 26S proteasome. Following DNA damage, MDM2 is degraded rapidly, resulting in increased p53 stability. Because of the important role of MDM2 in modulating p53 function, it is critical to understand how MDM2 levels are regulated. Here we show that the F-box protein FBXO31, a candidate tumor suppressor encoded in 16q24.3 for which there is loss of heterozygosity in various solid tumors, is responsible for promoting MDM2 degradation. Following genotoxic stress, FBXO31 is phosphorylated by the DNA damage serine/threonine kinase ATM, resulting in increased levels of FBXO31. FBXO31 then interacts with and directs the degradation of MDM2, which is dependent on phosphorylation of MDM2 by ATM. FBXO31-mediated loss of MDM2 leads to elevated levels of p53, resulting in growth arrest. In cells depleted of FBXO31, MDM2 is not degraded and p53 levels do not increase following genotoxic stress. Thus, FBXO31 is essential for the classic robust increase in p53 levels following DNA damage.

Rights and Permissions

Citation: Proc Natl Acad Sci U S A. 2015 Jul 14;112(28):8632-7. doi: 10.1073/pnas.1510929112. Epub 2015 Jun 29.Link to article on publisher's site

Comments

Publisher PDF posted as allowed by the publisher's author rights policy at http://www.pnas.org/site/aboutpnas/authorfaq.xhtml.

Related Resources

Link to Article in PubMed

Keywords

DNA damage, FBXO31, MDM2, p53, tumor suppressor

PubMed ID

26124108

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.