The unconventional biogenesis of Kv7.1-KCNE1 complexes

• Published in: Science advances Vol. 6; no. 14; p. eaay4472
• Main Authors: Oliveras, Anna, Serrano-Novillo, Clara, Moreno, Cristina, de la Cruz, Alicia, Valenzuela, Carmen, Soeller, Christian, Comes, Núria, Felipe, Antonio
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01-04-2020
• Subjects: Biological Transport; Biomarkers; Cell Biology; Cellular Neuroscience; Fluorescent Antibody Technique; Genes, Reporter; Humans; Ion Channel Gating; KCNQ1 Potassium Channel - metabolism; Multiprotein Complexes - metabolism; Myocytes, Cardiac - metabolism; Physiology; Potassium Channels, Voltage-Gated - metabolism; Protein Binding; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aay4472

The potassium channel Kv7.1 associates with the KCNE1 regulatory subunit to trigger cardiac
currents. Although the Kv7.1/KCNE1 complex has received much attention, the subcellular compartment hosting the assembly is the subject of ongoing debate. Evidence suggests that the complex forms either earlier in the endoplasmic reticulum or directly at the plasma membrane. Kv7.1 and KCNE1 mutations, responsible for long QT syndromes, impair association and traffic, thereby altering
currents. We found that Kv7.1 and KCNE1 do not assemble in the first stages of their biogenesis. Data support an unconventional secretory pathway for Kv7.1-KCNE1 that bypasses Golgi. This route targets channels to endoplasmic reticulum-plasma membrane junctions, where Kv7.1-KCNE1 assemble. This mechanism helps to resolve the ongoing controversy about the subcellular compartment hosting the association. Our results also provide new insights into
channel localization at endoplasmic reticulum-plasma membrane junctions, highlighting an alternative anterograde trafficking mechanism for oligomeric ion channels.