Related Experiment Video
Updated: Sep 25, 2026
Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro
Published on: July 17, 2018
Identification and characterization of the cytoplasmic protein TRAF4 as a p53-regulated proapoptotic gene
Joanna K Sax1, Wafik S El-Deiry
1Laboratory of Molecular Oncology and Cell Cycle Regulation, Howard Hughes Medical Institute, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Abstract:
The role of p53 in tumor suppression partly relies on its ability to transcriptionally regulate target genes involved in the initiation of cell cycle arrest or the activation of programmed cell death. In recent years many genes have been identified as p53-regulated genes; however, no single target gene has been shown to be required for the full apoptotic effect. We have identified TRAF4 as a p53-regulated gene in a microarray screen using a Murine 11K Affymetrix GeneChip hybridized with cRNA from the p53 temperature-sensitive cell line, Vm10. TRAF4 is a member the TRAF family of adaptor proteins that mediate cellular signaling by binding to various members of the tumor necrosis family receptor superfamily and interleukin-1/Toll-like receptor super-family. In contrast to its other family members, TRAF4 has not been shown to bind to a member of the tumor necrosis factor receptor superfamily in vivo, nor has it been shown to regulate signaling pathways common to its other family members. Therefore the role of TRAF4 in a signaling pathway has not yet been established and requires further study. TRAF4 is specifically regulated by p53 in response to temperature sensitive p53, overexpression of p53 by use of an adenovirus, and stabilization of p53 in response to DNA damage. The murine TRAF4 promoter contains a functional p53 DNA-binding site approximately 1 kilobase upstream of the initiating methionine. TRAF4 localizes to the cytoplasm and appears to remain in the cytoplasm following DNA damage. Interestingly, the overexpression of TRAF4 induces apoptosis and suppresses colony formation. These data suggest a correlation that the orphan adaptor protein TRAF4 may play a role in p53-mediated proapoptotic signaling in the response to cellular stress.
Insights
The tumor suppressor protein p53 regulates genes for cell cycle arrest and apoptosis. Researchers identified TRAF4 as a p53-regulated gene that induces apoptosis when overexpressed, suggesting its role in p53-mediated stress responses.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- The tumor suppressor protein p53 plays a critical role in preventing cancer by regulating genes involved in cell cycle arrest and programmed cell death (apoptosis).
- While many p53 target genes have been identified, none have been definitively shown to be essential for the complete apoptotic response.
- The precise function of TRAF4 (TNF receptor-associated factor 4), an adaptor protein, remains unclear as it doesn't interact with known TNF receptor superfamily members in vivo.
Purpose of the Study:
- To identify novel p53-regulated genes involved in tumor suppression.
- To investigate the role of TRAF4 in p53-mediated cellular responses, particularly apoptosis.
- To characterize the regulation of TRAF4 by p53 and its functional consequences.
Main Methods:
- Microarray screening using a temperature-sensitive p53 murine cell line (Vm10) to identify p53-regulated genes.
- Analysis of the murine TRAF4 promoter for p53 DNA-binding sites.
- Cellular localization studies of TRAF4 following DNA damage.
- Overexpression studies of TRAF4 to assess its effect on apoptosis and colony formation.
Main Results:
- TRAF4 was identified as a novel p53-regulated gene.
- A functional p53 DNA-binding site was found in the murine TRAF4 promoter, indicating direct transcriptional regulation by p53.
- TRAF4 is specifically upregulated by p53 under various conditions, including temperature-sensitive p53, adenoviral p53 overexpression, and DNA damage-induced p53 stabilization.
- Overexpression of TRAF4 was found to induce apoptosis and suppress colony formation.
- TRAF4 localizes to the cytoplasm and remains there after DNA damage.
Conclusions:
- TRAF4 is a novel p53 target gene directly regulated by p53.
- TRAF4 plays a role in p53-mediated apoptosis and tumor suppression.
- The orphan adaptor protein TRAF4 may be a key mediator in the cellular stress response pathway governed by p53.
More Related Videos
04:56Detection of Aggregation-Prone Behavior in Mutant P53 V157F Breast Cancer Cells Using Multipoint Thioflavin T Fluorescence
Published on: December 30, 2025
13:54Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death
Published on: October 21, 2012
Related Concept Videos
02:23Abnormal Proliferation
01:31The Intrinsic Apoptotic Pathway
01:22PI3K/mTOR/AKT Signaling Pathway
01:23Negative Regulator Molecules
02:36DNA Damage can Stall the Cell Cycle
02:36DNA Damage Can Stall the Cell Cycle