TY - JOUR
T1 - TMEM16F (Anoctamin 6), an anion channel of delayed Ca2+ activation
AU - Grubb, Søren
AU - Poulsen, Kristian Arild
AU - Juul, Christian Ammitzbøll
AU - Kyed, Tania
AU - Klausen, Thomas Kjær
AU - Larsen, Erik Hviid
AU - Hoffmann, Else Kay
PY - 2013/5
Y1 - 2013/5
N2 - Members of the TMEM16 (Anoctamin) family of membrane proteins have been shown to be essential constituents of the Ca2+-activated Cl- channel (CaCC) in many cell types. In this study, we have investigated the electrophysiological properties of mouse TMEM16F. Heterologous expression of TMEM16F in HEK293 cells resulted in plasma membrane localization and an outwardly rectifying ICl,Ca that was activated with a delay of several minutes. Furthermore, a significant Na+ current was activated, and the two permeabilities were correlated according to PNa = 0.3 PCl. The current showed an EC50 of 100 μM intracellular free Ca2+ concentration and an Eisenman type 1 anion selectivity sequence of PSCN > PI > PBr > PCl > PAsp. The mTMEM16F-associated ICl,Ca was abolished in one mutant of the putative pore region (R592E) but retained in two other mutants (K616E and R636E). The mutant K616E had a lower relative permeability to iodide, and the mutant R636E had an altered anion selectivity sequence (PSCN = PI = PBr = PCl PAsp). Ourdata provide evidence that TMEM16F constitutesa Ca2+-activated anion channel or a pore-forming subunit of an anion channel with properties distinct from TMEM16A.
AB - Members of the TMEM16 (Anoctamin) family of membrane proteins have been shown to be essential constituents of the Ca2+-activated Cl- channel (CaCC) in many cell types. In this study, we have investigated the electrophysiological properties of mouse TMEM16F. Heterologous expression of TMEM16F in HEK293 cells resulted in plasma membrane localization and an outwardly rectifying ICl,Ca that was activated with a delay of several minutes. Furthermore, a significant Na+ current was activated, and the two permeabilities were correlated according to PNa = 0.3 PCl. The current showed an EC50 of 100 μM intracellular free Ca2+ concentration and an Eisenman type 1 anion selectivity sequence of PSCN > PI > PBr > PCl > PAsp. The mTMEM16F-associated ICl,Ca was abolished in one mutant of the putative pore region (R592E) but retained in two other mutants (K616E and R636E). The mutant K616E had a lower relative permeability to iodide, and the mutant R636E had an altered anion selectivity sequence (PSCN = PI = PBr = PCl PAsp). Ourdata provide evidence that TMEM16F constitutesa Ca2+-activated anion channel or a pore-forming subunit of an anion channel with properties distinct from TMEM16A.
U2 - 10.1085/jgp.201210861
DO - 10.1085/jgp.201210861
M3 - Journal article
C2 - 23630341
SN - 0022-1295
VL - 141
SP - 585
EP - 600
JO - Journal of General Physiology
JF - Journal of General Physiology
IS - 5
ER -