Back to Search Start Over

A mechano-and heat-gated two-pore domain K+ channel controls excitability in adult zebrafish skeletal muscle.

Authors :
Idoux, Romane
Exbrayat-Héritier, Chloé
Sohm, Frédéric
Jaque-Fernandez, Francisco
Vaganay, Elisabeth
Berthier, Christine
Bretaud, Sandrine
Jacquemond, Vincent
Ruggiero, Florence
Allard, Bruno
Source :
Proceedings of the National Academy of Sciences of the United States of America; 11/7/2023, Vol. 120 Issue 45, p1-11, 14p
Publication Year :
2023

Abstract

TRAAK channels are mechano-gated two-pore-domain K+ channels. Up to now, activity of these channels has been reported in neurons but not in skeletal muscle, yet an archetype of tissue challenged by mechanical stress. Using patch clamp methods on isolated skeletal muscle fibers from adult zebrafish, we show here that single channels sharing properties of TRAAK channels, i.e., selective to K+ ions, of 56 pS unitary conductance in the presence of 5 mM external K+, activated by membrane stretch, heat, arachidonic acid, and internal alkaline pH, are present in enzymatically isolated fast skeletal muscle fibers from adult zebrafish. The kcnk4b transcript encoding for TRAAK channels was cloned and found, concomitantly with activity of mechano-gated K+ channels, to be absent in zebrafish fast skeletal muscles at the larval stage but arising around 1 mo of age. The transfer of the kcnk4b gene in HEK cells and in the adult mouse muscle, that do not express functional TRAAK channels, led to expression and activity of mechano-gated K+ channels displaying properties comparable to native zebrafish TRAAK channels. In whole-cell voltage-clamp and current-clamp conditions, membrane stretch and heat led to activation of macroscopic K+ currents and to acceleration of the repolarization phase of action potentials respectively, suggesting that heat production and membrane deformation associated with skeletal muscle activity can control muscle excitability through TRAAK channel activation. TRAAK channels may represent a teleost-specific evolutionary product contributing to improve swimming performance for escaping predators and capturing prey at a critical stage of development. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00278424
Volume :
120
Issue :
45
Database :
Complementary Index
Journal :
Proceedings of the National Academy of Sciences of the United States of America
Publication Type :
Academic Journal
Accession number :
173580445
Full Text :
https://doi.org/10.1073/pnas.2305959120