X-ray irradiation activates K+ channels via H2O2 signaling.
Ionizing radiation is a universal tool in tumor therapy but may also cause secondary cancers or cell invasiveness. These negative side effects could be causally related to the human-intermediate-conductance Ca2+-activated-K+-channel (hIK), which is activated by X-ray irradiation and affects cell proliferation and migration. To analyze the signaling cascade downstream of ionizing radiation we use genetically encoded reporters for H2O2 (HyPer) and for the dominant redox-buffer glutathione (Grx1-roGFP2) to monitor with high spatial and temporal resolution, radiation-triggered excursions of H2O2 in A549 and HEK293 cells. The data show that challenging cells with ≥1 Gy X-rays or with UV-A laser micro-irradiation causes a rapid rise of H2O2 in the nucleus and in the cytosol. This rise, which is determined by the rate of H2O2 production and glutathione-buffering, is sufficient for triggering a signaling cascade that involves an elevation of cytosolic Ca2+ and eventually an activation of hIK channels.
Department of Biology, Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
Christine S
CS
Gibhardt
Department of Biology, Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
Bastian
B
Roth
Department of Biology, Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
Indra
I
Schroeder
Department of Biology, Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
Sebastian
S
Fuck
Department of Biology, Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
Patrick
P
Becker
Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany.
Burkhard
B
Jakob
Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany.
Claudia
C
Fournier
Department of Biosciences and CNR IBF-Mi, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
Anna
A
Moroni
Department of Biology, Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
Gerhard
G
Thiel
D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D015221:Potassium Channels / Q000378:metabolism*; D015398:Signal Transduction / Q000528:radiation effects*; D014965:X-Rays
D015221:Potassium Channels; D006861:Hydrogen Peroxide; D005978:Glutathione; D002118:Calcium