RGD Reference Report - Interaction with caveolin-1 modulates vascular ATP-sensitive potassium (KATP) channel activity. - Rat Genome Database

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Interaction with caveolin-1 modulates vascular ATP-sensitive potassium (KATP) channel activity.

Authors: Davies, LM  Purves, GI  Barrett-Jolley, R  Dart, C 
Citation: Davies LM, etal., J Physiol. 2010 Sep 1;588(Pt 17):3255-66. Epub 2010 Jul 12.
RGD ID: 6849299
Pubmed: PMID:20624795   (View Abstract at PubMed)
PMCID: PMC2976020   (View Article at PubMed Central)
DOI: DOI:10.1113/jphysiol.2010.194779   (Journal Full-text)

ATP-sensitive potassium channels (K(ATP) channels) of arterial smooth muscle are important regulators of arterial tone, and hence blood flow, in response to vasoactive transmitters. Recent biochemical and electron microscopic evidence suggests that these channels localise to small vesicular invaginations of the plasma membrane, known as caveolae, and interact with the caveolae-associated protein, caveolin. Here we report that interaction with caveolin functionally regulates the activity of the vascular subtype of K(ATP) channel, Kir6.1/SUR2B. Pinacidil-evoked recombinant whole-cell Kir6.1/SUR2B currents recorded in HEK293 cells stably expressing caveolin-1 (69.6 +/- 8.3 pA pF(1), n = 8) were found to be significantly smaller than currents recorded in caveolin-null cells (179.7 +/- 35.9 pA pF(1), n = 6; P < 0.05) indicating that interaction with caveolin may inhibit channel activity. Inclusion in the pipette-filling solution of a peptide corresponding to the scaffolding domain of caveolin-1 had a similar inhibitory effect on whole-cell Kir6.1/SUR2B currents as co-expression with full-length caveolin-1, while a scrambled version of the same peptide had no effect. Interestingly, intracellular dialysis of vascular smooth muscle cells with the caveolin-1 scaffolding domain peptide (SDP) also caused inhibition of pinacidil-evoked native whole-cell K(ATP) currents, indicating that a significant proportion of vascular K(ATP) channels are susceptible to block by exogenously applied SDP. In cell-attached recordings of Kir6.1/SUR2B single channel activity, the presence of caveolin-1 significantly reduced channel open probability (from 0.05 +/- 0.01 to 0.005 +/- 0.001; P < 0.05) and the amount of time spent in a relatively long-lived open state. These changes in kinetic behaviour can be explained by a caveolin-induced shift in the channel's sensitivity to its physiological regulator MgADP. Our findings thus suggest that interaction with caveolin-1 suppresses vascular-type K(ATP) channel activity. Since caveolin expression is regulated by cellular free cholesterol and plasma levels of low-density lipoprotein (LDL), this interaction may have implications in both the physiological and pathophysiological control of vascular function.



Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Cav1Ratnegative regulation of cation channel activity  IDA  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Cav1  (caveolin 1)


Additional Information