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Updated: Jul 14, 2026
06:40
Mitochondrial Preparation from Microglia for Glycan Analysis
Published on: May 30, 2025
P-Glycoprotein is not present in mitochondrial membranes
Jill K Paterson1, Michael M Gottesman
1Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH/DHHS, Bethesda, MD 20892-4256, USA.
Experimental Cell Research
|May 22, 2007
Summary
P-glycoprotein is not found in mitochondria, contrary to previous assumptions. This study demonstrates its primary location is the plasma membrane, not involved in mitochondrial drug transport.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Recent reports suggested P-glycoprotein presence in mitochondrial membranes.
- This raised questions about its role in mitochondrial transport.
- P-glycoprotein is known to confer multidrug resistance.
Purpose of the Study:
- To investigate the actual localization of P-glycoprotein within cells.
- To determine if P-glycoprotein resides in mitochondrial membranes.
- To clarify the mechanism of P-glycoprotein's role in multidrug resistance.
Main Methods:
- Purification of mitochondria from P-glycoprotein overexpressing cell lines (KB-V1, MCF-7(ADR)).
- Western blot analysis using anti-P-glycoprotein antibody (C219) and organelle-specific antibodies.
- Confocal microscopy with anti-P-glycoprotein antibody (17F9).
Main Results:
- Crude mitochondrial fractions showed P-glycoprotein presence due to plasma membrane contamination.
- Further purified mitochondria lacked detectable P-glycoprotein.
- Confocal microscopy confirmed P-glycoprotein's primary localization to the plasma membrane, not mitochondria.
Conclusions:
- P-glycoprotein is not expressed in mitochondrial membranes.
- The presence in crude fractions was due to contamination with plasma membranes.
- P-glycoprotein confers multidrug resistance by reducing cellular drug accumulation at the plasma membrane, not within mitochondria.
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