Related Experiment Videos
Endothelial transcytotic machinery involves supramolecular protein-lipid complexes
S A Predescu1, D N Predescu, G E Palade
1Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla 92093, USA. spredescu@ucsd.edu
Molecular Biology of the Cell
|April 11, 2001
Summary
Endothelial caveolae facilitate protein transcytosis via N-ethylmaleimide-sensitive factor (NSF)-dependent mechanisms. These studies reveal novel NSF-associated protein complexes crucial for vesicle trafficking in endothelial cells.
Area of Science:
- Cell Biology
- Endothelial Cell Biology
- Vesicular Transport
Background:
- Plasmalemmal vesicles, or caveolae, in continuous microvascular endothelium act as carriers for protein molecules.
- Endothelial transcytosis is an N-ethylmaleimide-sensitive factor (NSF)-dependent process.
Purpose of the Study:
- Investigate NSF interactions with endothelial proteins.
- Determine if fusion and targeting proteins form multimolecular complexes in endothelium.
- Compare endothelial complexes to neuronal counterparts for specialized transcytosis roles.
Main Methods:
- Utilized myc-NSF, cultured pulmonary endothelial cells, and rat lung cytosol/membrane preparations.
- Employed co-immunoprecipitation with myc antibodies for detection.
- Applied velocity sedimentation and cross-linking for characterization.
Main Results:
- Identified cytosolic and membrane complexes containing NSF, soluble NSF attachment proteins (SNAPs), SNAREs, rab 5, dynamin, caveolin, and lipids.
- Detected myc-NSF, syntaxin, dynamin, caveolin, and endogenous NSF in these complexes via immunogold labeling and negative staining.
- Confirmed similar complexes formed by endogenous NSF.
Conclusions:
- Endothelial cells possess distinct protein-lipid complexes involving NSF.
- These complexes are implicated in the targeting, fusion, and fission of caveolae with the endothelial plasmalemma.
- Findings suggest a specialized mechanism for transcytosis in endothelial cells.