Related Experiment Video

Updated: Feb 9, 2026

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation
08:47

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation

Published on: March 5, 2018

9.5K

Dimer-specific immunoprecipitation of active caspase-2 identifies TRAF proteins as novel activators

Alexander C Robeson1, Kelly R Lindblom1, Jeffrey Wojton1

  • 1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.

The EMBO Journal
|June 8, 2018
PubMed

Insights

Tumor necrosis factor receptor-associated factor 2 (TRAF2) directly binds and ubiquitylates caspase-2, stabilizing the active dimer. This TRAF2-dependent ubiquitylation is crucial for initiating apoptosis in response to cellular stress.

Area of Science:

  • Cellular Biology
  • Molecular Mechanisms of Cell Death
  • Apoptosis Signaling

Background:

  • Caspase-2 initiates apoptosis but upstream activators are unclear.
  • Understanding caspase-2 activation is key to cell death research.

Purpose of the Study:

  • To elucidate the molecular mechanisms regulating caspase-2 activation.
  • To identify proteins interacting with active caspase-2 dimers.

Main Methods:

  • Utilized a caspase-2 bimolecular fluorescence complementation (BiFC) system.
  • Employed fluorophore-specific immunoprecipitation to isolate active caspase-2 dimers.
  • Investigated protein interactions and ubiquitylation patterns.

Main Results:

  • Identified direct binding of tumor necrosis factor receptor-associated factor 2 (TRAF2), TRAF1, and TRAF3 to active caspase-2 dimers.
  • Demonstrated TRAF2 is essential for caspase-2 activation during apoptosis.
  • Showed TRAF2-dependent ubiquitylation of caspase-2 at specific lysine residues (K15, K152, K153) stabilizes the active dimer and enhances its apoptotic function.

Conclusions:

  • TRAF2 positively regulates caspase-2 activation and subsequent apoptosis.
  • TRAF2-mediated ubiquitylation stabilizes the active caspase-2 dimer, promoting cell death commitment.
Keywords:
Caspase‐2TRAFapoptosisdimer purificationubiquitylation

More Related Videos

Measuring Caspase Activity Using a Fluorometric Assay or Flow Cytometry05:29

Measuring Caspase Activity Using a Fluorometric Assay or Flow Cytometry

Published on: March 24, 2023

5.6K
In Vivo Biosensor Tracks Non-apoptotic Caspase Activity in Drosophila13:21

In Vivo Biosensor Tracks Non-apoptotic Caspase Activity in Drosophila

Published on: November 27, 2016

9.5K

Related Concept Videos

Eukaryotic Transcription Activators02:42

Eukaryotic Transcription Activators

Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
12.9K
Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high...
11.6K
Co-activators and Co-repressors02:04

Co-activators and Co-repressors

Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
8.7K
Activation Energy01:26

Activation Energy

Activation energy is the minimum amount of energy necessary for a chemical reaction to move forward. The higher the activation energy, the slower the rate of the reaction. However, adding heat to the reaction will increase the rate, since it causes molecules to move faster and increase the likelihood that molecules will collide. The collision and breaking of bonds represents the uphill phase of a reaction and generates the transition state. The transition state is an unstable high-energy state...
86.8K
tRNA Activation02:26

tRNA Activation

Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
23.0K
Secondary Active Transport01:55

Secondary Active Transport

One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
138.1K