RNF125 is a ubiquitin-protein ligase that promotes p53 degradation.

Abstract

BACKGROUND/AIMS:

Although early studies show that Mdm2 is the primary E3 ubiquitin ligase for the p53 tumor suppressor, an increasing amount of data suggests that p53 ubiquitination and degradation are more complex than once thought. Here, we investigated the role of RNF125, a non-Mdm2 ubiquitin-protein ligase, in the regulation of p53.

METHODS AND RESULTS:

RNF125 physically interacted with p53 in exogenous/endogenous co-immunoprecipitation (IP) and GST-pull down assay, and a C72/75A mutation of RNF125 did not interfere with this interaction. Expression of RNF125 decreased the level of p53 in a dose-dependent manner, whereas knockdown of RNF125 by RNA interference increased the level of p53. As shown by Western blotting and ubiquitin assay, RNF125 ubiquitinated p53 and targeted it for proteasome degradation. Furthermore, RNF125 repressed p53 functions including p53-dependent transactivation and growth inhibition.

CONCLUSION:

Our data suggest that RNF125 negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation.

• Authors: Liuzhong Yang, Bing Zhou, Xiaorui Li, Zhihong Lu, Weiwei Li, Xiaoqing Huo, Zhanhui Miao
• Journal: Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (Cell Physiol Biochem) Vol. 35 Issue 1 Pg. 237-45 ( 2015) ISSN: 1421-9778 [Electronic] Germany
• PMID: 25591766 (Publication Type: Journal Article)
• Copyright: © 2015 S. Karger AG, Basel.

Chemical References

• Leupeptins
• RNA, Small Interfering
• Tumor Suppressor Protein p53
• RNF125 protein, human
• Ubiquitin-Protein Ligases
• Proteasome Endopeptidase Complex
• benzyloxycarbonylleucyl-leucyl-leucine aldehyde

Topics

• Amino Acid Substitution
• Cell Proliferation
• Down-Regulation
• HCT116 Cells
• HEK293 Cells
• Humans
• Immunoprecipitation
• Leupeptins (pharmacology)
• Proteasome Endopeptidase Complex (chemistry, metabolism)
• Protein Binding
• Proteolysis (drug effects)
• RNA Interference
• RNA, Small Interfering (metabolism)
• Transcriptional Activation
• Transfection
• Tumor Suppressor Protein p53 (chemistry, genetics, metabolism)
• Ubiquitin-Protein Ligases (antagonists & inhibitors, genetics, metabolism)
• Ubiquitination