Forward genetics reveals a conserved CNBHD-CNBHD interface that restrains EAG channel activation to regulate sleep
4 affiliations
- 1Department of Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- 2Genetics Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- 3Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- 4Neuroscience Training Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
Abstract
KCNH voltage-gated potassium channels regulate neuronal excitability, yet how their hallmark cyclic nucleotide-binding homology domains (CNBHDs) influence channel gating to regulate behavior remains unclear. Using an unbiased forward genetic screen in Caenorhabditis elegans, we identified a gain-of-function mutation in the EAG-subfamily KCNH channel EGL-2 that suppresses sleep. The mutation (G574E) alters a highly conserved glycine residue at the interface between CNBHDs of adjacent channel subunits. EGL-2 functions cell-autonomously in the central sleep-promoting neuron ALA. In vivo calcium imaging showed that the gain-of-function mutation suppresses sleep by inhibiting ALA neuronal activity, consistent with enhanced potassium channel activity. Genetic analysis demonstrated that the sleep-suppressing phenotype of G574E requires both an intact potassium selectivity filter and the intrinsic ligand-occupied CNBHD. A second substitution at the same glycine (G574R), which introduces a positively charged side chain in contrast to the negatively charged side chain in G574E, similarly suppresses sleep, indicating that perturbation of the CNBHD-CNBHD interface, rather than the specific amino acid change, underlies the phenotype. Moreover, mutations at the corresponding residue in the ERG-subfamily KCNH channels C. elegans UNC-103 and human hERG also produce gain-of-function effects, and electrophysiological analysis showed that hERG(G749R) shifts voltage-dependent channel activation to more negative potentials and accelerates activation kinetics. These findings identify EGL-2 as an important sleep regulator and uncover a conserved gating mechanism by which the intersubunit CNBHD-CNBHD interface restrains KCNH channel activation to regulate neuronal excitability and behavior. Author summary: KCNH voltage-gated potassium channels are key regulators of neuronal excitability, but how their gating is controlled to influence neural circuit activity and behavior remains unclear. Here, through forward genetics and functional analyses, we identify gain-of-function mutations in EGL-2, an EAG-subfamily KCNH potassium channel in C. elegans. These mutations suppress sleep by directly inhibiting a central sleep-promoting neuron and disrupt the intersubunit interface between adjacent cyclic nucleotide-binding homology domains (CNBHDs). Analogous mutations increase channel activity across multiple KCNH family members. These findings uncover an important role of EAG channels in sleep regulation and identify the intersubunit CNBHD-CNBHD interface as a previously unrecognized, conserved structural element that restrains KCNH channel activation.
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BibTeX
@article{huang2026forward,
title = {{Forward genetics reveals a conserved CNBHD-CNBHD interface that restrains EAG channel activation to regulate sleep}},
author = {Xinyu Huang and Sudharsan Kannan and Gail A. Robertson and Han Wang},
journal = {PLOS Genetics},
year = {2026},
month = oct,
doi = {10.1371/journal.pgen.1012255},
url = {https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1012255},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Forward genetics reveals a conserved CNBHD-CNBHD interface that restrains EAG channel activation to regulate sleep
AU - Xinyu Huang
AU - Sudharsan Kannan
AU - Gail A. Robertson
AU - Han Wang
PY - 2026
DA - 2026/10/01
JO - PLOS Genetics
DO - 10.1371/journal.pgen.1012255
UR - https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1012255
AB - KCNH voltage-gated potassium channels regulate neuronal excitability, yet how their hallmark cyclic nucleotide-binding homology domains (CNBHDs) influence channel gating to regulate behavior remains unclear. Using an unbiased forward genetic screen in Caenorhabditis elegans, we identified a gain-of-function mutation in the EAG-subfamily KCNH channel EGL-2 that suppresses sleep. The mutation (G574E) alters a highly conserved glycine residue at the interface between CNBHDs of adjacent channel subunits. EGL-2 functions cell-autonomously in the central sleep-promoting neuron ALA. In vivo calcium imaging showed that the gain-of-function mutation suppresses sleep by inhibiting ALA neuronal activity, consistent with enhanced potassium channel activity. Genetic analysis demonstrated that the sleep-suppressing phenotype of G574E requires both an intact potassium selectivity filter and the intrinsic ligand-occupied CNBHD. A second substitution at the same glycine (G574R), which introduces a positively charged side chain in contrast to the negatively charged side chain in G574E, similarly suppresses sleep, indicating that perturbation of the CNBHD-CNBHD interface, rather than the specific amino acid change, underlies the phenotype. Moreover, mutations at the corresponding residue in the ERG-subfamily KCNH channels C. elegans UNC-103 and human hERG also produce gain-of-function effects, and electrophysiological analysis showed that hERG(G749R) shifts voltage-dependent channel activation to more negative potentials and accelerates activation kinetics. These findings identify EGL-2 as an important sleep regulator and uncover a conserved gating mechanism by which the intersubunit CNBHD-CNBHD interface restrains KCNH channel activation to regulate neuronal excitability and behavior. Author summary: KCNH voltage-gated potassium channels are key regulators of neuronal excitability, but how their gating is controlled to influence neural circuit activity and behavior remains unclear. Here, through forward genetics and functional analyses, we identify gain-of-function mutations in EGL-2, an EAG-subfamily KCNH potassium channel in C. elegans. These mutations suppress sleep by directly inhibiting a central sleep-promoting neuron and disrupt the intersubunit interface between adjacent cyclic nucleotide-binding homology domains (CNBHDs). Analogous mutations increase channel activity across multiple KCNH family members. These findings uncover an important role of EAG channels in sleep regulation and identify the intersubunit CNBHD-CNBHD interface as a previously unrecognized, conserved structural element that restrains KCNH channel activation.
SN - 1553-7404
ER -