TY - JOUR
T1 - Anoctamin 6 differs from VRAC and VSOAC but is involved in apoptosis and supports volume regulation in the presence of Ca2+
AU - Juul, C.A.
AU - Grubb, S.
AU - Poulsen, K.A.
AU - Kyed, T.
AU - Hashem, Nadia
AU - Lambert, Ian Henry
AU - Larsen, Erik Hviid
AU - Hoffmann, Else Kay
PY - 2014/10
Y1 - 2014/10
N2 - Anoctamin 6 (ANO6), also known as TMEM16F, has been shown to be a calcium-activated anion channel with delayed calcium activation. The cellular function of ANO6 is under debate, and different groups have come to different conclusions about ANO6’s physiological role. Although it is now quite well established that ANO6 is distinct from the volume-regulated anion channel, it is still unclear whether ANO6 or other anoctamins can be activated by cell swelling. In this study, we suggest that ANO1, ANO6, and ANO10 do not contribute to the volume-activated current in ANO-overexpressing HEK293 cells. Furthermore, knock-down of ANO6 in Ehrlich ascites tumor cells (EATC) and Ehrlich–Lettre ascites (ELA) did not decrease but instead significantly increased swelling-activated membrane currents. Knock-down of ANO6 in EATC did not reduce regulatory volume decrease (RVD) in the absence of extracellular calcium, whereas it significantly reduced RVD in the presence of calcium. Interestingly, we found that knock-down of ANO6 in ELA cells resulted in a decrease in cisplatin-induced caspase-3 activity, confirming earlier findings that ANO6 is involved in apoptosis. Finally, knock-down of ANO1 and ANO6 did not affect the volume-sensitive release of taurine in ELA cells. Thus, our data provide evidence that ANO6 cannot be activated directly by cell swelling unless Ca2+ is present. We also conclude that ANO6 carries a current during RVD, provided extracellular calcium is present. Thus, swelling activation of ANO6 requires the presence of free calcium.
AB - Anoctamin 6 (ANO6), also known as TMEM16F, has been shown to be a calcium-activated anion channel with delayed calcium activation. The cellular function of ANO6 is under debate, and different groups have come to different conclusions about ANO6’s physiological role. Although it is now quite well established that ANO6 is distinct from the volume-regulated anion channel, it is still unclear whether ANO6 or other anoctamins can be activated by cell swelling. In this study, we suggest that ANO1, ANO6, and ANO10 do not contribute to the volume-activated current in ANO-overexpressing HEK293 cells. Furthermore, knock-down of ANO6 in Ehrlich ascites tumor cells (EATC) and Ehrlich–Lettre ascites (ELA) did not decrease but instead significantly increased swelling-activated membrane currents. Knock-down of ANO6 in EATC did not reduce regulatory volume decrease (RVD) in the absence of extracellular calcium, whereas it significantly reduced RVD in the presence of calcium. Interestingly, we found that knock-down of ANO6 in ELA cells resulted in a decrease in cisplatin-induced caspase-3 activity, confirming earlier findings that ANO6 is involved in apoptosis. Finally, knock-down of ANO1 and ANO6 did not affect the volume-sensitive release of taurine in ELA cells. Thus, our data provide evidence that ANO6 cannot be activated directly by cell swelling unless Ca2+ is present. We also conclude that ANO6 carries a current during RVD, provided extracellular calcium is present. Thus, swelling activation of ANO6 requires the presence of free calcium.
U2 - 10.1007/s00424-013-1428-4
DO - 10.1007/s00424-013-1428-4
M3 - Journal article
C2 - 24419539
SN - 0031-6768
VL - 466
SP - 1899
EP - 1910
JO - Pflügers Archiv - European Journal of Physiology
JF - Pflügers Archiv - European Journal of Physiology
IS - 10
ER -