TREK Assays
Background of TREK
The TWIK-related potassium channel (TREK) was discovered in 1996 as the second mammalian K2P channel. TREK subfamily is comprised of three members named TREK1, TREK2, and TRAAK. The family of K2P channels shares a unique structure of two pore-forming domains in each channel subunit surrounded by four membrane-spanning helices and a large cap domain, which is formed by an extracellular linker connecting the first transmembrane domain with the first pore loop. The 15 members of the K2P family are expressed throughout the human body, where their dynamic and polymodal regulation determines cellular excitability.
Fig. 1. Proteins forming TREK channels have four transmembrane segments and two pore domains so that they assemble as dimers. (Lamas, 2019)
Distributions and Functions of TREK
Among the K2P channels, the three members of the TREK subfamily TREK-1, TRAAK, and TREK-2 share a unique feature: their currents are activated via membrane stretch, osmotic swelling or mechanical deformation of the cell. Further regulatory stimuli include temperature; arachidonic acid; phospho-, lysophospho-, and other lipids; anesthetics and other drugs; extracellular or intracellular pH; phosphorylation as well as G protein-coupled receptors; glycosylation and/or direct interaction with several putative partner proteins.
Subtypes and Mechanisms of TREK
- TREK-1
TREK1 is the most extensively studied K2P channel. It is predominantly expressed in the brain (GABA-containing neurons) and spinal cord, as well as in the prefrontal cortex, fetal brain, amygdala, and thalamus, but also peripheral tissues. Moreover, TREK1 was also found in prostate cancer and a role in the progression of ovarian cancer has been shown. TREK-1 channels have been proposed to be involved in multiple physiological and pathophysiological processes, such as anesthesia, epilepsy, depression, neuroprotection in ischemia, pain sensation, and the regulation of cardiac rhythm as well as hypertrophy and fibrosis.
- TREK-2
TREK-2 is a 538-amino acid protein and shares 65% amino acid sequence identity with TREK-1, has a short N terminus, an extended extracellular loop between M1 and P1, and a long C terminus, structural features typical of nearly all 4TM K+ channels. The genomic organization of TREK-2 is very close to the genomic organization of both TRAAK and TREK-1 channel genomic organizations. TREK-2 is involved in amount of pathologic processes such as acute cerebral ischemia. TREK-2 is greatly possible to associate with nociception according to its electrophysiological properties and tissue distribution.
- TRAAK
TRAAK expression appears to be essentially neuronally restricted. TRAAK currents showed a strong open-channel outward rectification when recorded in whole-cell configuration, and these currents increase strongly when the temperature rises (24 to 42℃). TRAAK has a low threshold for tension activation and is activated over the entire range of tension a membrane can experience. TREK channels have a similarly broad range of tension activation, but an apparently higher tension threshold for activation than TRAAK in studies of reconstituted channels.
Assay List of TREK Channel
Creative Biolabs can provide a range of assays of the TREK channel. You can choose the assay in the list or contact us for more information:
| Assay No. | Assay Name | Host Cell | Assay Type | Datasheet |
|---|---|---|---|---|
| S01YF-0722-KX243 | Magic™ Human KCNK2 In Vitro Electrophysiology Assay | Electrophysiology Assay |
Published Data
| Paper Title | Polymodal Mechanism for TWIK-Related K+ Channel Inhibition by Local Anesthetic |
| Journal | Anesth Analg |
| Published | 2019 |
| Abstract | Previous studies narrowed TREK-1 sensitivity of local anesthetics to a disordered loop in the channels C-terminal domain (CTD). Recently, inhaled anesthetics were shown to increase the binding of phospholipase D2 (PLD2) to the same C-terminal segment of TREK-1 identified for the sensitivity of local anesthetic. Inhaled anesthetics ejected PLD2 from nanoscale lipid domains causing PLD2 to translocate a very small distance to phosphatidylinositol 4,5-bisphosphate (PIP2) clusters that activated the enzyme. The localized production of phosphatidic acid (PA) by PLD2 then indirectly activated TREK-1 by binding to a lipid site in the channel transmembrane domain. To respectively characterize direct and indirect lipid-mediated mechanisms for TREK-1 inhibition, researchers use biophysical and cellular techniques. The results show that despite disrupting lipids, local anesthetics directly bind to and inhibit TREK-1 conductance through the inhibition of PLD2 lipid catalysis. |
| Result |
This report shows local anesthetic exerts a polymodal effect on TREK-1 channels. mechanism of TREK-1 inhibition comprised of (1) primarily indirect PLD2-dependent inhibition of lipid catalysis and (2) limited direct inhibition for select local anesthetics through partial open pore block. This study provides new insights into the mechanism of local anesthetics that could facilitate the development of better therapeutic approaches in anesthesia and chronic pain based on lipid signaling.
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Fig. 1. Tetracaine dissociates phospholipase D2 (PLD2) from monosialotetrahexosylganglioside (GM1) domains. (Pavel, 2019)
References
- Lamas, J. A.; et al. Ion Channels and Thermosensitivity: TRP, TREK, or Both? Int J Mol Sci. 2019, 20(10).
- Pavel, M. A.; et al. Polymodal Mechanism for TWIK-Related K+ Channel Inhibition by Local Anesthetic. Anesth Analg. 2019, 129(4): 973-982.
