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Optogenetic apoptosis: light-triggered cell death

Robert M Hughes1, David J Freeman2, Kelsey N Lamb2

  • 1Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599 (USA). rhughes@email.unc.edu.

Angewandte Chemie (International Ed. in English)
|September 30, 2015
PubMed

Insights

Researchers developed optogenetic Bax to control cell death using light. This engineered protein triggers apoptosis by localizing to mitochondria, leading to cell death, and can be modulated to prevent unintended cell death.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biotechnology

Background:

  • Apoptosis, or programmed cell death, is a critical biological process.
  • Bax is a key protein in the intrinsic apoptosis pathway, regulating mitochondrial outer membrane permeabilization.
  • Controlling apoptosis with precision is essential for understanding cellular mechanisms and developing therapeutics.

Purpose of the Study:

  • To design and validate an optogenetic Bax protein for light-inducible apoptosis.
  • To investigate the mechanism of optogenetic Bax-mediated cell death.
  • To identify strategies for mitigating background apoptosis caused by Bax overexpression.

Main Methods:

  • Genetically engineered a light-responsive Bax protein.
  • Utilized microscopy to track mitochondrial recruitment and protein release.
  • Assessed caspase-3 cleavage, cellular morphology changes, and cell viability.
  • Employed mutagenesis and small molecule inhibitors to explore apoptotic pathways.

Main Results:

  • Mitochondrial recruitment of optogenetic Bax induced apoptosis, evidenced by protein release, caspase activation, and cell death.
  • Mutations at a key phosphorylatable residue or C-terminus modification reduced dark-dependent apoptosis.
  • Optogenetic Bax formed a mitochondrial channel similar to endogenous Bax, as confirmed by mechanistic studies.

Conclusions:

  • Optogenetic Bax provides a novel tool for precisely controlling apoptosis with light.
  • The engineered protein mimics endogenous Bax function in initiating the mitochondrial cell death pathway.
  • Modifications to optogenetic Bax can enhance its specificity and reduce off-target effects.
Keywords:
apoptosisoptogeneticsphotochemistryprotein engineeringsynthetic biology

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