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Phosphorylated filamin A regulates actin-linked caveolae dynamics.
Olivia Muriel1, Asier Echarri, Christian Hellriegel
1Integrin Signaling Laboratory, Department of Vascular Biology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
Journal of Cell Science
|August 3, 2011
Summary
Filamin A (FLNa) is essential for caveolin-1 vesicle trafficking after cell detachment. FLNa anchors these vesicles to the cell membrane, a process critical for their inward movement toward recycling endosomes.
Area of Science:
- Cell biology
- Membrane trafficking
- Cytoskeletal dynamics
Background:
- Caveolae are vital membrane structures involved in signaling, lipid metabolism, and viral entry.
- Caveolae internalization is triggered by stimuli like cell detachment, but the underlying mechanisms remain unclear.
Purpose of the Study:
- To investigate the role of filamin A (FLNa) in regulating caveolin-1 vesicle trafficking after cell adhesion loss.
- To elucidate the molecular pathways governing caveolae internalization.
Main Methods:
- Total internal reflection fluorescence (TIRF) microscopy with high spatiotemporal resolution particle tracking of caveolin-1-GFP vesicles.
- Analysis of FLNa-depleted HeLa and FLNa-deficient M2-melanoma cells.
- Investigation of actin binding and PKCα-dependent phosphorylation of FLNa.
Main Results:
- Filamin A (FLNa) is crucial for the linear distribution and plasma membrane anchorage of caveolin-1 vesicles, dependent on F-actin.
- FLNa's ability to bind actin and its phosphorylation on Ser2152 by PKCα are required for caveolin-1 vesicle trafficking.
- Impaired inward trafficking of caveolin-1 vesicles was observed in cells lacking functional FLNa.
Conclusions:
- Filamin A acts as a key regulator of F-actin-dependent caveolin-1 vesicle trafficking and anchorage.
- FLNa-mediated processes are essential for the de-adhesion-induced internalization of caveolae towards recycling endosomes.
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