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Caspase-3 Activity in the Rat Amygdala Measured by Spectrofluorometry After Myocardial Infarction
Published on: January 12, 2016
Quantitative studies of caspase-3 catalyzed αII-spectrin breakdown.
1Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, MC 111, Chicago, IL 60607, USA.
Brain Research
|August 17, 2013
Summary
Caspase-3 cleaves alphaII-spectrin at D1185 and D1478, generating spectrin breakdown products (SBDPs) like SBDP150 and SBDP120. This quantitative study provides a foundation for understanding brain injury mechanisms and developing biomarkers.
Area of Science:
- Biochemistry
- Molecular Biology
- Neuroscience
Background:
- Spectrin breakdown products (SBDPs) are generated under physiological and pathological conditions.
- SBDP formation is physiologically relevant, regulated, and complex, but molecular mechanisms remain poorly understood.
- AlphaII-spectrin is a key component of the red blood cell cytoskeleton and is also found in the brain.
Purpose of the Study:
- To investigate the molecular mechanism of alphaII-spectrin breakdown by caspase-3.
- To identify specific cleavage sites of caspase-3 on alphaII-spectrin.
- To quantify the efficiency of these cleavage events.
Main Methods:
- Utilized gel electrophoresis, fluorescence, and mass spectrometry to analyze alphaII-spectrin breakdown by caspase-3.
- Designed model systems to study the reaction kinetics.
- Determined kinetic parameters (kcat/KM) for identified cleavage sites.
Main Results:
- Identified two primary caspase-3 cleavage sites on alphaII-spectrin: after residues D1185 and D1478.
- Demonstrated that cleavage at D1185 produces SBDP150, and cleavage at D1478 produces SBDP120.
- Found that cleavage at these sites is independent and that D1185 cleavage is highly efficient (40,000 M(-1)s(-1)) compared to D1478 (3000 M(-1)s(-1)).
Conclusions:
- Established a quantitative methodology for studying caspase-3 mediated spectrin proteolysis.
- The findings provide a molecular basis for understanding spectrin breakdown in various conditions, including brain injury.
- This research may facilitate the development of more precise and specific biomarkers for neurological conditions.
Keywords:
20mM piperazine-N,N′-bis-(2-ethanesulfonic acid) with 100mM NaCl, 10mM DTT, 1mM EDTA, 0.1% CHAPS, and 10% sucrose at pH 7.2Brain injury biomarkerCaspase-3D10-D11(w)(′)D10-D11(w-1)(')D10-D11(w-1)(′)D10-D11(w-2)(')D10–D11D10–D11 with all its tryptophan residues except W1106 and W1192 replaced with phenylalanine residuesD10–D11 with all its tryptophan residues except W1192 and W1215 replaced with phenylalanine residuesD10–D11 with all its tryptophan residues except W1192 replaced with phenylalanine residuesD10–D13D12–D13D13D13 with W1533F mutationD13(w)(′)Nonerythroid (brain) spectrinSBDPSBDP120SBDP150SBDP37Spectrin breakdown product[casp-3]a recombinant protein consisting of residues 1087–1344 of αII-spectrin plus GS as the first two residuesa recombinant protein consisting of residues 1087–1556 of αII-spectrin plus GS as the first two residuesa recombinant protein consisting of residues 1335–1556 of αII-spectrin plus GS as the first two residuesa recombinant protein consisting of residues 1441–1556 of αII-spectrin plus GS as the first two residuesa recombinant protein consisting of residues 780–1344 of αII-spectrin plus GS as the first two residuescaspase activity bufferspectrin breakdown productthe SBDP with an electrophoretic mass of 120kDathe SBDP with an electrophoretic mass of 150kDathe SBDP with an electrophoretic mass of 37kDathe concentration of recombinant caspase-3
