pH-Sensitive KCNK (K2P) Channel Antibody Explorer Kit

Two-pore domain potassium (K_2P) channels have four transmembrane domains, two pore-forming loops between transmembrane domains 1 and 2 as well as 3 and 4, and a large extracellular linker region between transmembrane domain 1 and the first pore-forming loop, which forms the K⁺ selectivity filter.
The TASK subfamily of this group is highly sensitive to variations in extracellular pH. TASK-1, TASK-2 and TASK-3 homo- and heteromers are inhibited by extracellular acidification but are left unaffected by intracellular pH changes. Acid-induced inhibition of TASK channel activity enhances nerve excitability and thus indirectly indicates the presence of acid. The high proton sensitivity of the TASK channels suggests a role in surveillance of tissue acidification by ischemia, inflammation or back-diffusion of luminal acid.

TREK-1 and TREK-2 do not respond to changes in extracellular pH but are inhibited by intracellular alkalization and are activated by intracellular acidification such that they become constitutively active.

TRESK K_2P member is blocked by extra- and intracellular acidification and is activated by extra and intracellular alkalization.

Additional pH-sensitive K_2P channels include TWIK-1 and TWIK-2 which are inhibited by intracellular acidification, TRAAK channels that are activated by intracellular alkalization but not acidification and lastly, TALK-1 and TALK-2 are blocked by extracellular acidification but are gated open by extracellular alkalization¹.