Structural basis for pH gating of the two-pore domain K+ channel TASK2
Baobin Li
Nature 586, 457–462 (2020). WEB
Structures of TASK2 in the non-conductive closed conformation at pH 6.5 (orange) and conductive open conformation at pH 8.5 (purple).
The lipid bilayer is colored as a pH strip and the closed and open channels are positioned at pH 6.5 and 8.5, respectively.
Baobin and Robert identified two pH sensing gates in TASK2 channels - one extracellular and one intracellular.
They used CryoEM and electrophysiology to learn pH 8.5 both gates are open, and they are mostly closed at pH 6.5. The cryoEM structures identified the amino acids involved in each gate, and they validated the gating model by mutating these residues and recording pH sensitive currents.
Explain the significance of this work to a…
Ion channel biophysicist
CryoEM structures of TASK2 at low and high pH reveal two novel conformational changes that couple a pH sensing protonatable amino acid to a conformational change that gates the channel.
Scientist
Cells use a diverse array of membrane proteins that sense physical and chemical stimuli, our structures of TASK2 at low and high pH show two new types of pH sensor on the extracellular and intracellular sides of the channel.
High schooler
Cells use nanoscopic sensors and gates to measure what’s going on around them and respond. We show how one of these sensors, a pH gated ion channel called TASK2, works!
Elementary schooler
Just like how you can taste sour things, cells need a way to “taste” their surroundings. We learned about how cells are able to “taste” sour things around them!
Robert Rietmeijer
Interested? Read more about it here!
Structural basis for pH-gating of the two-pore domain K+ channel TASK2.
Li, B*, Rietmeijer, RA* & Brohawn, SG.
Nature 586, 457–462 (2020). WEB