{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T18:29:15Z","timestamp":1787077755251,"version":"build-2736575974"},"reference-count":34,"publisher":"National Academy of Sciences","issue":"34","license":[{"start":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T00:00:00Z","timestamp":1787011200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000050","name":"HHS | NIH | National Heart, Lung, and Blood Institute","doi-asserted-by":"publisher","award":["R01-HL131403"],"award-info":[{"award-number":["R01-HL131403"]}],"id":[{"id":"10.13039\/100000050","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000050","name":"HHS | NIH | National Heart, Lung, and Blood Institute","doi-asserted-by":"publisher","award":["R01-NS081320"],"award-info":[{"award-number":["R01-NS081320"]}],"id":[{"id":"10.13039\/100000050","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000968","name":"American Heart Association","doi-asserted-by":"publisher","award":["24PRE1188958"],"award-info":[{"award-number":["24PRE1188958"]}],"id":[{"id":"10.13039\/100000968","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2026,8,25]]},"abstract":"<jats:p>\n                    The\n                    <jats:italic toggle=\"yes\">human ether-\u00e0-go-go related gene<\/jats:italic>\n                    (\n                    <jats:italic toggle=\"yes\">hERG<\/jats:italic>\n                    ) encodes a potassium channel essential for cardiac repolarization and neuronal excitability. In the heart, heteromeric assemblies of hERG1a and hERG1b subunits produce cardiac I\n                    <jats:sub>Kr<\/jats:sub>\n                    , and mutations in either subunit are associated with long QT syndrome. Although hERG1a and 1b contain identical transmembrane and C-terminal cytosolic domains, they differ in N-terminal cytosolic domains, with hERG1b harboring an arginine-based endoplasmic reticulum (ER) retention\/retrieval motif that limits its surface expression in the absence of hERG1a. While the association of hERG1a and 1b subunits is known to influence channel function, the stoichiometry of heteromeric hERG channels and mechanisms that regulate it have remained unresolved. Here, using single molecule photobleaching step analysis in HeLa cells, we show that heteromeric hERG1a\/1b channels assemble predominantly with a fixed 2:2 stoichiometry. Mutation of the hERG1b ER retention motif disrupts this bias, resulting in a broader, near-random distribution of subunit compositions. Independent functional assays using dominant-negative pore mutants in Xenopus oocytes yielded quantitative current suppression consistent with a 2:2 assembly and similarly revealed loss of stoichiometric bias upon RXR mutation. Together, these results establish the oligomeric composition of hERG1a\/1b channels and identify ER retention as a previously unrecognized determinant of heteromeric stoichiometry.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2605305123","type":"journal-article","created":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T17:59:27Z","timestamp":1787075967000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":0,"title":["An ER retention motif controls the heteromeric stoichiometry of hERG1a\/1b channels"],"prefix":"10.1073","volume":"123","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0460-0068","authenticated-orcid":false,"given":"Sudharsan","family":"Kannan","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01y2jtd41","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison","place":["Madison"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-9801-1712","authenticated-orcid":false,"given":"Liliana R.","family":"Ernandez","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01y2jtd41","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison","place":["Madison"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4694-5790","authenticated-orcid":false,"given":"Gail A.","family":"Robertson","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01y2jtd41","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison","place":["Madison"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2026,8,18]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.91.8.3438"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/0092-8674(95)90340-2"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.7604285"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/0092-8674(95)90358-5"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1002\/ana.24596"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1038\/nm.1962"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1161\/01.RES.81.5.870"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1414945111"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M408344200"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCRESAHA.108.185249"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1128\/MCB.23.6.1856-1862.2003"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1161\/01.RES.81.5.719"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0092-8674(00)81635-9"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M708999200"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M117.816488"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.yjmcc.2015.06.008"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0900180106"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jbc.2022.102233"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0123951"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.pbiomolbio.2016.01.002"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2500218122"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1038\/nmeth1024"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cell.2017.03.048"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.str.2020.12.007"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1521577113"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.93.5.2208"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M610875200"},{"key":"e_1_3_4_28_2","doi-asserted-by":"crossref","unstructured":"L. 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