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Acylation targets emdothelial nitric-oxide synthase to plasmalemmal caveolae
P W Shaul1, E J Smart, L J Robinson
1Departmemt of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235, USA.
The Journal of Biological Chemistry
|March 15, 1996
Summary
Endothelial nitric-oxide synthase (eNOS) localizes to caveolae, specialized membrane domains, through acylation. This positioning optimizes nitric oxide production and release in endothelial cells.
Area of Science:
- Cell Biology
- Biochemistry
- Physiology
Background:
- Endothelial nitric-oxide synthase (eNOS) produces nitric oxide (NO), a crucial signaling molecule.
- eNOS responds to hormonal and mechanical cues.
- Caveolae are plasmalemmal microdomains involved in signal transduction.
Purpose of the Study:
- To investigate the localization of eNOS within endothelial cells.
- To determine if eNOS is targeted to caveolae.
Main Methods:
- Detergent-free isolation of endothelial cell plasma membrane fractions.
- Immunoblot analysis to detect eNOS protein.
- Assay of NOS enzymatic activity.
- Immunoelectron microscopy.
- Transfection of COS-7 cells with eNOS cDNA and mutants.
Main Results:
- eNOS protein and activity were significantly enriched in isolated caveolar membrane fractions.
- eNOS was heavily localized to endothelial caveolae visualized by immunoelectron microscopy.
- Myristoylation and palmitoylation of eNOS were essential for its targeting to caveolae.
Conclusions:
- Acylation directs eNOS to plasmalemmal caveolae.
- Localization to caveolae likely enhances eNOS activation and nitric oxide release.
- This microdomain targeting is critical for eNOS function in endothelial cells.