Related Experiment Video

Updated: Jul 14, 2026

Exploring Caspase Mutations and Post-Translational Modification by Molecular Modeling Approaches
05:56

Exploring Caspase Mutations and Post-Translational Modification by Molecular Modeling Approaches

Published on: October 13, 2022

Caspase-3-mediated cleavage of Akt: involvement of non-consensus sites and influence of phosphorylation

Arezu Jahani-Asl1, Ajoy Basak, Benjamin K Tsang

  • 1Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa, Canada.

FEBS Letters
|June 5, 2007
PubMed

Insights

This study identifies novel caspase-3 cleavage sites on Akt1, revealing that phosphorylation regulates Akt1 cleavage. This finding is crucial for understanding cell survival mechanisms involving Akt1.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Signaling

Background:

  • Akt1 is a key regulator of cell survival and proliferation.
  • Caspase-3 is a critical executioner caspase involved in apoptosis.
  • Understanding Akt1 cleavage is essential for elucidating its role in cell fate determination.

Purpose of the Study:

  • To identify and characterize novel caspase-3 cleavage sites on Akt1.
  • To investigate the impact of Akt1 phosphorylation on its cleavage.
  • To elucidate the regulatory mechanisms of Akt1 activity in cell survival.

Main Methods:

  • In vitro cleavage assays using purified Akt1 and caspase-3.
  • Site-directed mutagenesis to identify non-consensus cleavage sites.
  • Phosphorylation of Akt1 using kinases.
  • Analysis of cleavage products using mass spectrometry.

Main Results:

  • Identified DQDD(456) as a consensus caspase-3 cleavage site in Akt1.
  • Discovered novel non-consensus caspase-3 cleavage sites: QEEE(116), MD(117), EEMD(119), TPPD(453), and DAKE(398).
  • Demonstrated that phosphorylation of Akt1 confers resistance to cleavage at the DAKE(398) site, located within the kinase domain.

Conclusions:

  • Akt1 is cleaved by caspase-3 at both consensus and novel non-consensus sites.
  • Phosphorylation-dependent regulation of Akt1 cleavage, particularly at the DAKE(398) site, offers a mechanism to modulate its anti-apoptotic function.
  • These findings are significant for biological models dependent on Akt1 for cell survival.

More Related Videos

Caspase-3 Activity in the Rat Amygdala Measured by Spectrofluorometry After Myocardial Infarction08:41

Caspase-3 Activity in the Rat Amygdala Measured by Spectrofluorometry After Myocardial Infarction

Published on: January 12, 2016

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

Related Concept Videos

Caspases01:24

Caspases

Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...