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dc.contributor.authorLau, Sze-Yi
dc.contributor.authorProcko, Erik
dc.contributor.authorGaudet, Rachelle
dc.date.accessioned2013-07-05T20:41:32Z
dc.date.issued2012
dc.identifier.citationLau, Sze-Yi, Erik Procko, and Rachelle Gaudet. 2012. Distinct properties of \(Ca^{2+}\)-calmodulin binding to N- and C-terminal regulatory regions of the TRPV1 channel. Journal of General Physiology 140(5): 541-555.en_US
dc.identifier.issn0022-1295en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:10860184
dc.description.abstractTransient receptor potential (TRP) vanilloid 1 (TRPV1) is a molecular pain receptor belonging to the TRP superfamily of nonselective cation channels. As a polymodal receptor, TRPV1 responds to heat and a wide range of chemical stimuli. The influx of calcium after channel activation serves as a negative feedback mechanism leading to TRPV1 desensitization. The cellular calcium sensor calmodulin (CaM) likely participates in the desensitization of TRPV1. Two CaM-binding sites are identified in TRPV1: the N-terminal ankyrin repeat domain (ARD) and a short distal C-terminal (CT) segment. Here, we present the crystal structure of calcium-bound CaM \((Ca^{2+}–CaM)\) in complex with the TRPV1-CT segment, determined to \(1.95-\mathring{A}\) resolution. The two lobes of \(Ca^{2+}–CaM\) wrap around a helical TRPV1-CT segment in an antiparallel orientation, and two hydrophobic anchors, W787 and L796, contact the C-lobe and N-lobe of \(Ca^{2+}–CaM\), respectively. This structure is similar to canonical \(Ca^{2+}–CaM\)-peptide complexes, although TRPV1 contains no classical CaM recognition sequence motif. Using structural and mutational studies, we established the TRPV1 C terminus as a high affinity \(Ca^{2+}–CaM\)-binding site in both the isolated TRPV1 C terminus and in full-length TRPV1. Although a ternary complex of CaM, TRPV1-ARD, and TRPV1-CT had previously been postulated, we found no biochemical evidence of such a complex. In electrophysiology studies, mutation of the \(Ca^{2+}–CaM\)-binding site on TRPV1-ARD abolished desensitization in response to repeated application of capsaicin, whereas mutation of the \(Ca^{2+}–CaM\)-binding site in TRPV1-CT led to a more subtle phenotype of slowed and reduced TRPV1 desensitization. In summary, our results show that the TRPV1-ARD is an important mediator of TRPV1 desensitization, whereas TRPV1-CT has higher affinity for CaM and is likely involved in separate regulatory mechanisms.en_US
dc.description.sponsorshipMolecular and Cellular Biologyen_US
dc.language.isoen_USen_US
dc.publisherRockefeller University Pressen_US
dc.relation.isversionofdoi:10.1085/jgp.201210810en_US
dc.relation.hasversionhttp://www.ncbi.nlm.nih.gov/pubmed/23109716en_US
dash.licenseOAP
dc.subjectcalciumen_US
dc.subjectcalmodulinen_US
dc.subjectdesensitizationen_US
dc.subjectTRPV1en_US
dc.subjectTRP channelen_US
dc.titleDistinct Properties of \(Ca^{2+}\)-Calmodulin Binding to N- and C-Terminal Regulatory Regions of the TRPV1 Channelen_US
dc.typeJournal Articleen_US
dc.description.versionAuthor's Originalen_US
dc.relation.journalJournal of General Physiologyen_US
dash.depositing.authorGaudet, Rachelle
dc.date.available2013-07-05T20:41:32Z
dc.identifier.doi10.1085/jgp.201210810*
dash.contributor.affiliatedGaudet, Rachelle


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