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Occludin regulates actin cytoskeleton in endothelial cells
H Kuwabara1, Y Kokai, T Kojima
1Department of Pathology, Sapporo Medical University School of Medicine, Japan.
Cell Structure and Function
|August 3, 2001
Summary
Occludin, a tight junction protein, was introduced into rat lung endothelial cells. Its expression correlated with the actin cytoskeleton, not barrier function, suggesting a role in regulating endothelial cell actin.
Area of Science:
- Cell Biology
- Endothelial Cell Biology
- Tight Junctions
Background:
- Occludin is a key component of endothelial tight junctions, but its precise function remains unclear.
- Rat lung endothelial (RLE) cells exhibit low occludin levels but express E-cadherin and ZO-1.
- Understanding occludin's role is crucial for endothelial barrier research.
Purpose of the Study:
- To investigate the functional role of occludin in endothelial cells.
- To determine if occludin expression impacts paracellular barrier function.
- To explore the relationship between occludin and the endothelial actin cytoskeleton.
Main Methods:
- Occludin was introduced into RLE cells via transfection.
- Paracellular barrier function was assessed using transepithelial electrical resistance and small molecule flux.
- Co-culture experiments and treatment with actin depolymerizing agent (mycalolide B) were performed.
Main Results:
- Transfected cells showed junctional occludin expression without significant changes in E-cadherin or ZO-1.
- Occludin expression did not enhance paracellular barrier function.
- Junctional occludin expression strongly correlated with cortical actin organization and was disrupted by actin depolymerization.
Conclusions:
- Junctional occludin expression in RLE cells is not directly linked to enhanced paracellular barrier function.
- Occludin plays a significant role in the regulation of the actin cytoskeleton in endothelial cells.
- Further research is needed to elucidate occludin's specific regulatory mechanisms involving actin.