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Regulation of Kv1.2 redox-sensitive gating by the transmembrane lectin LMAN2.
Lamothe, Shawn M; Das, Damayantee; Wong, Anson A; Hao, Yubin; Maguire, Aislinn D; Kerr, Bradley J; Baronas, Victoria A; Kurata, Harley T.
Afiliação
  • Lamothe SM; Dept. of Pharmacology, Alberta Diabetes Institute, University of Alberta, 9-70 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada.
  • Das D; Dept. of Pharmacology, Alberta Diabetes Institute, University of Alberta, 9-70 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada.
  • Wong AA; Dept. of Pharmacology, Alberta Diabetes Institute, University of Alberta, 9-70 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada.
  • Hao Y; Dept. of Pharmacology, Alberta Diabetes Institute, University of Alberta, 9-70 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada.
  • Maguire AD; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
  • Kerr BJ; Dept. of Pharmacology, Alberta Diabetes Institute, University of Alberta, 9-70 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada.
  • Baronas VA; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
  • Kurata HT; Dept. of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada.
Function (Oxf) ; 2024 Sep 11.
Article em En | MEDLINE | ID: mdl-39264045
ABSTRACT
Kv1.2 potassium channels influence excitability and action potential propagation in the nervous system. Unlike closely-related Kv1 channels, Kv1.2 exhibits highly variable voltage-dependence of gating, attributed to regulation by unidentified extrinsic factors. Variability of Kv1.2 gating is strongly influenced by the extracellular redox potential, and we demonstrate that Kv1.2 currents in dorsal root ganglion sensory neurons exhibit similar variability and redox sensitivity as observed when the channel is heterologously expressed in cell lines. We used a functional screening approach to test the effects of candidate regulatory proteins on Kv1.2 gating, using patch clamp electrophysiology. Among 52 candidate genes tested, we observed that co-expression with the transmembrane lectin LMAN2 led to a pronounced gating shift of Kv1.2 activation to depolarized voltages in CHO and L(tk-) cell lines, accompanied by deceleration of activation kinetics. Overexpression of LMAN2 promoted a slow gating mode of Kv1.2 that mimics the functional outcomes of extracellular reducing conditions, and enhanced sensitivity to extracellular reducing agents. In contrast, shRNA-mediated knockdown of endogenous LMAN2 in cell lines reduced Kv1.2 redox sensitivity and gating variability. Kv1.2 sensitivity to LMAN2 is abolished by mutation of neighboring residues F251 and T252 in the intracellular S2-S3 linker, and these also abolish redox-dependent gating changes, suggesting that LMAN2 influences the same pathway as redox for Kv1.2 modulation. In conclusion, we identified LMAN2 as a candidate regulatory protein that influences redox-dependent modulation of Kv1.2, and clarified the structural elements of the channel that are required for sensitivity.
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Texto completo: 1 Base de dados: MEDLINE Idioma: En Ano de publicação: 2024 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Idioma: En Ano de publicação: 2024 Tipo de documento: Article