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XB-ART-56435
Elife January 1, 2019; 8

The mechanosensitive ion channel TRAAK is localized to the mammalian node of Ranvier.

Brohawn SG , Wang W , Handler A , Campbell EB , Schwarz JR , MacKinnon R .


Abstract
TRAAK is a membrane tension-activated K+ channel that has been associated through behavioral studies to mechanical nociception. We used specific monoclonal antibodies in mice to show that TRAAK is localized exclusively to nodes of Ranvier, the action potential propagating elements of myelinated nerve fibers. Approximately 80 percent of myelinated nerve fibers throughout the central and peripheral nervous system contain TRAAK in what is likely an all-nodes or no-nodes per axon fashion. TRAAK is not observed at the axon initial segment where action potentials are first generated. We used polyclonal antibodies, the TRAAK inhibitor RU2 and node clamp amplifiers to demonstrate the presence and functional properties of TRAAK in rat nerve fibers. TRAAK contributes to the ''leak'' K+ current in mammalian nerve fiber conduction by hyperpolarizing the resting membrane potential, thereby increasing Na+ channel availability for action potential propagation. We speculate on why nodes of Ranvier contain a mechanosensitive K+ channel.

PubMed ID: 31674909
PMC ID: PMC6824864
Article link: Elife
Grant support: [+]
Genes referenced: dlg4 drg1 krt8.1 nav1 nodal s100a1 thy1


Article Images: [+] show captions
References [+] :
Anishkin, Feeling the hidden mechanical forces in lipid bilayer is an original sense. 2014, Pubmed


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