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Farnesyl-diphosphate synthase is localized in peroxisomes
S K Krisans1, J Ericsson, P A Edwards
1Department of Biology, San Diego State University, California 92182.
The Journal of Biological Chemistry
|May 13, 1994
Summary
Farnesyl-diphosphate synthase (FPP synthase), previously thought cytoplasmic, is primarily located in peroxisomes. This finding suggests peroxisomes are key for FPP synthesis, impacting cholesterol and protein modification pathways.
Area of Science:
- Biochemistry
- Cell Biology
- Metabolic Pathways
Background:
- Farnesyl-diphosphate synthase (FPP synthase) produces farnesyl pyrophosphate (FPP), a precursor for vital molecules like cholesterol and heme a.
- FPP synthase was traditionally considered a cytoplasmic enzyme based on cell fractionation studies.
Purpose of the Study:
- To determine the precise subcellular localization of FPP synthase.
- To investigate the role of peroxisomes in isoprenoid synthesis.
Main Methods:
- Fractionation of rat liver cells to isolate subcellular components.
- Enzyme activity assays for FPP synthase and other isoprenoid synthesis enzymes.
- Immunofluorescent and immunoelectron microscopy to visualize FPP synthase localization.
- Analysis of liver tissue from patients with peroxisomal deficiency diseases.
Main Results:
- FPP synthase was unequivocally localized to peroxisomes in rat liver.
- Peroxisomal localization of FPP synthase and mevalonate kinase suggests peroxisomes are the primary site for FPP synthesis from mevalonate.
- Activities of key isoprenoid synthesis enzymes, including FPP synthase, were significantly reduced in patients with peroxisomal deficiency disorders.
Conclusions:
- FPP synthase is predominantly localized in peroxisomes, challenging previous assumptions.
- Peroxisomes play a central role in the synthesis of FPP, a critical isoprenoid intermediate.
- Dysfunction in peroxisomal isoprenoid synthesis may contribute to the pathology of peroxisomal deficiency diseases.