Related Experiment Video
Updated: Mar 22, 2026
Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
p46Shc Inhibits Thiolase and Lipid Oxidation in Mitochondria
Alexey Tomilov1, Natalia Tomilova1, Yuxi Shan1
1Department of ‡Molecular Biosciences, University of California Davis, California 95616.
Abstract:
Although the p46Shc isoform has been known to be mitochondrially localized for 11 years, its function in mitochondria has been a mystery. We confirmed p46Shc to be mitochondrially localized and showed that the major mitochondrial partner of p46Shc is the lipid oxidation enzyme 3-ketoacylCoA thiolase ACAA2, to which p46Shc binds directly and with a strong affinity. Increasing p46Shc expression inhibits, and decreasing p46Shc stimulates enzymatic activity of thiolase in vitro Thus, we suggest p46Shc to be a negative mitochondrial thiolase activity regulator, and reduction of p46Shc expression activates thiolase. This is the first demonstration of a protein that directly binds and controls thiolase activity. Thiolase was thought previously only to be regulated by metabolite balance and steady-state flux control. Thiolase is the last enzyme of the mitochondrial fatty acid beta-oxidation spiral, and thus is important for energy metabolism. Mice with reduction of p46Shc are lean, resist obesity, have higher lipid oxidation capacity, and increased thiolase activity. The thiolase-p46Shc connection shown here in vitro and in organello may be an important underlying mechanism explaining the metabolic phenotype of Shc-depleted mice in vivo.
Insights
The p46Shc protein directly binds and inhibits mitochondrial 3-ketoacylCoA thiolase ACAA2. Reducing p46Shc activates thiolase, leading to leaner mice with higher lipid oxidation, revealing a novel regulator of energy metabolism.
Area of Science:
- Mitochondrial biology
- Metabolic regulation
- Protein-protein interactions
Background:
- The p46Shc protein isoform is known to localize to mitochondria, but its function there remains unclear.
- Mitochondrial fatty acid beta-oxidation is crucial for energy metabolism, with thiolase (ACAA2) as its final enzyme.
Purpose of the Study:
- To elucidate the function of the mitochondrial p46Shc isoform.
- To identify the interaction partners and regulatory mechanisms of mitochondrial thiolase ACAA2.
Main Methods:
- Confirmation of p46Shc mitochondrial localization.
- In vitro biochemical assays to assess p46Shc and ACAA2 interaction and thiolase activity.
- Analysis of metabolic phenotypes in mice with reduced p46Shc expression.
Main Results:
- p46Shc directly binds to and inhibits the enzymatic activity of mitochondrial thiolase ACAA2.
- Reduced p46Shc expression leads to increased thiolase activity, higher lipid oxidation capacity, and a lean phenotype in mice.
- This study identifies p46Shc as the first known direct protein regulator of thiolase activity.
Conclusions:
- p46Shc acts as a negative regulator of mitochondrial thiolase ACAA2 activity.
- The p46Shc-thiolase interaction provides a novel mechanism for controlling fatty acid oxidation and energy metabolism.
- Understanding this interaction may explain the metabolic benefits observed in p46Shc-deficient mice.
More Related Videos
07:16Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
08:39Experimental Protocol for Detecting Mitochondrial Function in Hepatocytes Exposed to Organochlorine Pesticides
Published on: September 16, 2020
Related Concept Videos
01:30The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q...
01:24Peroxisomes
01:46Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
01:20Sulfur Assimilation
01:19Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
01:27Protein Import into the Peroxisomes
Peroxisomal Protein Import:
Peroxisomes lack the genetic machinery required to code for their own proteins. Hence, most peroxisomal membrane, lumenal and transmembrane proteins are synthesized in the cytoplasm or ER and transported to the peroxisome...