{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T08:59:14Z","timestamp":1774256354210,"version":"3.50.1"},"reference-count":44,"publisher":"Rockefeller University Press","issue":"2","license":[{"start":{"date-parts":[[2019,9,19]],"date-time":"2019-09-19T00:00:00Z","timestamp":1568851200000},"content-version":"vor","delay-in-days":967,"URL":"http:\/\/www.rupress.org\/terms\/"},{"start":{"date-parts":[[2017,8,7]],"date-time":"2017-08-07T00:00:00Z","timestamp":1502064000000},"content-version":"vor","delay-in-days":194,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["NS081320"],"award-info":[{"award-number":["NS081320"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["NS081293"],"award-info":[{"award-number":["NS081293"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["rupress.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2017,2,1]]},"abstract":"<jats:p>Channels in the ether-\u00e0-go-go or KCNH family of potassium channels are characterized by a conserved, C-terminal domain with homology to cyclic nucleotide\u2013binding homology domains (CNBhDs). Instead of cyclic nucleotides, two amino acid residues, Y699 and L701, occupy the binding pocket, forming an \u201cintrinsic ligand.\u201d The role of the CNBhD in KCNH channel gating is still unclear, however, and a detailed characterization of the intrinsic ligand is lacking. In this study, we show that mutating both Y699 and L701 to alanine, serine, aspartate, or glycine impairs human EAG1 channel function. These mutants slow channel activation and shift the conductance\u2013voltage (G\u2013V) relation to more depolarized potentials. The mutations affect activation and the G-V relation progressively, indicating that the gating machinery is sensitive to multiple conformations of the CNBhD. Substitution with glycine at both sites (GG), which eliminates the side chains that interact with the binding pocket, also reduces the ability of voltage prepulses to populate more preactivated states along the activation pathway (i.e., the Cole\u2013Moore effect), as if stabilizing the voltage sensor in deep resting states. Notably, deletion of the entire CNBhD (577\u2013708, \u0394CNBhD) phenocopies the GG mutant, suggesting that GG is a loss-of-function mutation and the CNBhD requires an intrinsic ligand to exert its functional effects. We developed a kinetic model for both wild-type and \u0394CNBhD mutant channels that describes all our observations on activation kinetics, the Cole\u2013Moore shift, and G-V relations. These findings support a model in which the CNBhD both promotes voltage sensor activation and stabilizes the open pore. The intrinsic ligand is critical for these functional effects.<\/jats:p>","DOI":"10.1085\/jgp.201611701","type":"journal-article","created":{"date-parts":[[2017,1,25]],"date-time":"2017-01-25T15:10:11Z","timestamp":1485357011000},"page":"249-260","update-policy":"https:\/\/doi.org\/10.1085\/jgp.crossmarkpolicy","source":"Crossref","is-referenced-by-count":32,"title":["The intrinsically liganded cyclic nucleotide\u2013binding homology domain promotes KCNH channel activation"],"prefix":"10.1085","volume":"149","author":[{"given":"Yaxian","family":"Zhao","sequence":"first","affiliation":[{"name":"Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 1"},{"name":"Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 2"}]},{"given":"Marcel P.","family":"Goldschen-Ohm","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 1"},{"name":"Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 2"}]},{"given":"Jo\u00e3o H.","family":"Morais-Cabral","sequence":"additional","affiliation":[{"name":"Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150 Porto, Portugal 3"},{"name":"Instituto de Investiga\u00e7\u00e3o e Inova\u00e7\u00e3o em Sa\u00fade, Universidade do Porto, 4150 Porto, Portugal 4"}]},{"given":"Baron","family":"Chanda","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 1"},{"name":"Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 2"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4694-5790","authenticated-orcid":true,"given":"Gail A.","family":"Robertson","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 1"},{"name":"Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 2"}]}],"member":"291","published-online":{"date-parts":[[2017,1,25]]},"reference":[{"key":"2023072623591643100_bib1","doi-asserted-by":"publisher","first-page":"18718","DOI":"10.1073\/pnas.0505766102","article-title":"Optical detection of rate-determining ion-modulated conformational changes of the ether-\u00e0-go-go K+ channel voltage sensor","volume":"102","author":"Bannister","year":"2005","journal-title":"Proc. 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