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dc.contributor.authorClarke, Alison L.
dc.contributor.authorPetrou, Steven
dc.contributor.authorWalsh, John V. Jr.
dc.contributor.authorSinger, Joshua J.
dc.date2022-08-11T08:09:31.000
dc.date.accessioned2022-08-23T16:34:03Z
dc.date.available2022-08-23T16:34:03Z
dc.date.issued2002-11-01
dc.date.submitted2007-12-21
dc.identifier.citationAm J Physiol Cell Physiol. 2003 Mar;284(3):C607-19. Epub 2002 Oct 30. <a href="http://dx.doi.org/10.1152/ajpcell.00364.2002">Link to article on publisher's site</a>
dc.identifier.issn0363-6143 (Print)
dc.identifier.doi10.1152/ajpcell.00364.2002
dc.identifier.pmid12409285
dc.identifier.urihttp://hdl.handle.net/20.500.14038/38245
dc.description.abstractFatty acids and other negatively charged single-chain lipids increase large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel activity, whereas sphingosine and other positively charged single-chain lipids suppress activity. Because these molecules are effective on both inside-out and outside-out patches and because they can flip across the bilayer, the location of their site of action is unclear. To identify the site of action of charged lipids on this channel, we used two compounds that are unlikely to flip across the lipid bilayer. Palmitoyl coenzyme A (PCoA) was used to identify the site of action of negatively charged lipids, and a positively charged myristoylated pentapeptide (myr-KPRPK) was used to investigate the site of action of positively charged lipids. The effect of these compounds on channel activity was studied in excised patches using patch-clamp techniques. In "normal" ionic strength solutions and in experiments where high-ionic strength solutions were used to shield membrane surface charge, PCoA increased channel activity only when applied to outside-out patches, suggesting that the site of action of negatively charged lipids is located on the outer surface of the membrane. A decrease in activity, similar to that of other positively charged lipids, was observed only when myr-KPRPK was applied to outside-out patches, suggesting that positively charged lipids suppress activity by also acting on the outer membrane surface. Some channel blockade effects of myr-KPRPK and KPRPK are also described. The sidedness of action suggests that modulation of channel activity by single-chain lipids can occur by their interaction with the channel protein.
dc.language.isoen_US
dc.relation<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12409285&dopt=Abstract ">Link to article in PubMed</a>
dc.relation.urlhttp://dx.doi.org/10.1152/ajpcell.00364.2002
dc.subjectAmines
dc.subjectAnions
dc.subjectArteries
dc.subjectCell Membrane
dc.subjectCells, Cultured
dc.subjectDose-Response Relationship, Drug
dc.subjectFatty Acids
dc.subject*Lipid Metabolism
dc.subjectLipids
dc.subjectMembrane Potentials
dc.subjectMuscle, Smooth, Vascular
dc.subjectMyocytes, Smooth Muscle
dc.subjectPalmitoyl Coenzyme A
dc.subjectPeptide Fragments
dc.subjectPotassium Channels, Calcium-Activated
dc.subjectQuaternary Ammonium Compounds
dc.subjectTrimethyl Ammonium Compounds
dc.subjectLife Sciences
dc.subjectMedicine and Health Sciences
dc.titleSite of action of fatty acids and other charged lipids on BKCa channels from arterial smooth muscle cells
dc.typeJournal Article
dc.source.journaltitleAmerican journal of physiology. Cell physiology
dc.source.volume284
dc.source.issue3
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/112
dc.identifier.contextkey407407
html.description.abstract<p>Fatty acids and other negatively charged single-chain lipids increase large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel activity, whereas sphingosine and other positively charged single-chain lipids suppress activity. Because these molecules are effective on both inside-out and outside-out patches and because they can flip across the bilayer, the location of their site of action is unclear. To identify the site of action of charged lipids on this channel, we used two compounds that are unlikely to flip across the lipid bilayer. Palmitoyl coenzyme A (PCoA) was used to identify the site of action of negatively charged lipids, and a positively charged myristoylated pentapeptide (myr-KPRPK) was used to investigate the site of action of positively charged lipids. The effect of these compounds on channel activity was studied in excised patches using patch-clamp techniques. In "normal" ionic strength solutions and in experiments where high-ionic strength solutions were used to shield membrane surface charge, PCoA increased channel activity only when applied to outside-out patches, suggesting that the site of action of negatively charged lipids is located on the outer surface of the membrane. A decrease in activity, similar to that of other positively charged lipids, was observed only when myr-KPRPK was applied to outside-out patches, suggesting that positively charged lipids suppress activity by also acting on the outer membrane surface. Some channel blockade effects of myr-KPRPK and KPRPK are also described. The sidedness of action suggests that modulation of channel activity by single-chain lipids can occur by their interaction with the channel protein.</p>
dc.identifier.submissionpathoapubs/112
dc.contributor.departmentDepartment of Physiology
dc.source.pagesC607-19


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