Dynamic change of electrostatic field in TMEM16F permeation pathway shifts its ion selectivity.

ABSTRACT: TMEM16F is activated by elevated intracellular Ca²⁺, and functions as a small-conductance ion channel and as a phospholipid scramblase. In contrast to its paralogs, the TMEM16A/B calcium-activated chloride channels, mouse TMEM16F has been reported as a cation-, anion-, or non-selective ion channel, without a definite conclusion. Starting with the Q559K mutant that shows no current rundown and less outward rectification in excised patch, we found that the channel shifted its ion selectivity in response to the change of intracellular Ca²⁺ concentration, with an increased permeability ratio of Cl^- to Na⁺ (P_Cl-/P_Na+) at a higher Ca²⁺ level. The gradual shift of relative ion permeability did not correlate with the chan

SUBMITTER: Ye W 

PROVIDER: S-EPMC6690719 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature