Cell swelling activates cloned Ca(2+)-activated K(+) channels: a role for the F-actin cytoskeleton.
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Cell swelling activates cloned Ca(2+)-activated K(+) channels: a role for the F-actin cytoskeleton. / Jorgensen, Nanna K; Pedersen, Stine F; Rasmussen, Hanne B; Grunnet, Morten; Klaerke, Dan A; Olesen, Søren-Peter.
In: BBA General Subjects, Vol. 1615, No. 1-2, 2003, p. 115-25.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Cell swelling activates cloned Ca(2+)-activated K(+) channels: a role for the F-actin cytoskeleton.
AU - Jorgensen, Nanna K
AU - Pedersen, Stine F
AU - Rasmussen, Hanne B
AU - Grunnet, Morten
AU - Klaerke, Dan A
AU - Olesen, Søren-Peter
N1 - Keywords: Actins; Calcium; Cell Size; Cloning, Molecular; Cytochalasin D; Cytoskeleton; Humans; Kidney; Nucleic Acid Synthesis Inhibitors; Potassium Channels, Calcium-Activated
PY - 2003
Y1 - 2003
N2 - Cloned Ca(2+)-activated K(+) channels of intermediate (hIK) or small (rSK3) conductance were expressed in HEK 293 cells, and channel activity was monitored using whole-cell patch clamp. hIK and rSK3 currents already activated by intracellular calcium were further increased by 95% and 125%, respectively, upon exposure of the cells to a 33% decrease in extracellular osmolarity. hIK and rSK3 currents were inhibited by 46% and 32%, respectively, by a 50% increase in extracellular osmolarity. Cell swelling and channel activation were not associated with detectable increases in [Ca(2+)](i), evidenced by population and single-cell measurements. In addition, inhibitors of IK and SK channels significantly reduced the rate of regulatory volume decrease (RVD) in cells expressing these channels. Cell swelling induced a decrease, and cell shrinkage an increase, in net cellular F-actin content. The swelling-induced activation of hIK channels was strongly inhibited by cytochalasin D (CD), in concentrations that caused depolymerization of F-actin filaments, indicating a role for the F-actin cytoskeleton in modulation of hIK by changes in cell volume. In conclusion, hIK and rSK3 channels are activated by cell swelling and inhibited by shrinkage. A role for the F-actin cytoskeleton in the swelling-induced activation of hIK channels is suggested.
AB - Cloned Ca(2+)-activated K(+) channels of intermediate (hIK) or small (rSK3) conductance were expressed in HEK 293 cells, and channel activity was monitored using whole-cell patch clamp. hIK and rSK3 currents already activated by intracellular calcium were further increased by 95% and 125%, respectively, upon exposure of the cells to a 33% decrease in extracellular osmolarity. hIK and rSK3 currents were inhibited by 46% and 32%, respectively, by a 50% increase in extracellular osmolarity. Cell swelling and channel activation were not associated with detectable increases in [Ca(2+)](i), evidenced by population and single-cell measurements. In addition, inhibitors of IK and SK channels significantly reduced the rate of regulatory volume decrease (RVD) in cells expressing these channels. Cell swelling induced a decrease, and cell shrinkage an increase, in net cellular F-actin content. The swelling-induced activation of hIK channels was strongly inhibited by cytochalasin D (CD), in concentrations that caused depolymerization of F-actin filaments, indicating a role for the F-actin cytoskeleton in modulation of hIK by changes in cell volume. In conclusion, hIK and rSK3 channels are activated by cell swelling and inhibited by shrinkage. A role for the F-actin cytoskeleton in the swelling-induced activation of hIK channels is suggested.
M3 - Journal article
C2 - 12948593
VL - 1615
SP - 115
EP - 125
JO - B B A - General Subjects
JF - B B A - General Subjects
SN - 0304-4165
IS - 1-2
ER -
ID: 8418923