Interaction with caveolin-1 modulates vascular ATP-sensitive potassium (KATP) channel activity
Lowri M Davies1, Gregor I Purves, Richard Barrett-Jolley
1Biosciences Building, School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
The Journal of Physiology
|July 14, 2010
Summary
Caveolin-1 interaction suppresses vascular ATP-sensitive potassium (K(ATP)) channel activity, impacting arterial tone regulation. This finding suggests a novel mechanism for controlling blood flow and has implications for cardiovascular health.
Area of Science:
- Molecular Biology
- Cardiovascular Physiology
- Ion Channel Function
Background:
- ATP-sensitive potassium (K(ATP)) channels in arterial smooth muscle regulate vascular tone and blood flow.
- Evidence suggests K(ATP) channels localize to caveolae and interact with caveolin.
- The functional consequence of this caveolin-K(ATP) channel interaction is not fully understood.
Purpose of the Study:
- To investigate the functional impact of caveolin interaction on vascular K(ATP) channel activity, specifically Kir6.1/SUR2B.
- To determine if caveolin binding inhibits or activates vascular K(ATP) channel function.
- To explore the implications of this interaction in native vascular smooth muscle cells.
Main Methods:
- Recombinant expression of Kir6.1/SUR2B and caveolin-1 in HEK293 cells.
- Electrophysiological recordings (whole-cell and cell-attached) to measure K(ATP) channel currents and activity.
- Application of caveolin-1 scaffolding domain peptide (SDP) in both cell-based assays and native vascular smooth muscle cells.
Main Results:
- HEK293 cells expressing caveolin-1 showed significantly smaller pinacidil-evoked Kir6.1/SUR2B currents compared to caveolin-null cells.
- Application of caveolin-1 SDP mimicked the inhibitory effect of caveolin co-expression on Kir6.1/SUR2B currents.
- Intracellular dialysis with SDP inhibited native K(ATP) currents in vascular smooth muscle cells, and cell-attached recordings revealed reduced channel open probability in the presence of caveolin-1.
Conclusions:
- Interaction with caveolin-1 suppresses the activity of vascular-type K(ATP) channels (Kir6.1/SUR2B).
- Caveolin-mediated inhibition involves altered channel kinetics and sensitivity to MgADP.
- This interaction may play a role in the physiological and pathophysiological regulation of vascular function, potentially influenced by cholesterol and LDL levels.
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