Currents through Hv1 channels deplete protons in their vicinity
Por:
De-la-Rosa, Victor, Suarez-Delgado, Esteban, Rangel-Yescas, Gisela E., Islas, Leon D.
Publicada:
1 feb 2016
Categoría:
Physiology
Resumen:
Proton channels have evolved to provide a pH regulatory mechanism,
affording the extrusion of protons from the cytoplasm at all membrane
potentials. Previous evidence has suggested that channel-mediated acid
extrusion could significantly change the local concentration of protons
in the vicinity of the channel. In this work, we directly measure the
proton depletion caused by activation of Hv1 proton channels using
patch-clamp fluorometry recordings from channels labeled with the Venus
fluorescent protein at intracellular domains. The fluorescence of the
Venus protein is very sensitive to pH, thus behaving as a genetically
encoded sensor of local pH. Eliciting outward proton currents increases
the fluorescence intensity of Venus. This dequenching is related to the
magnitude of the current and not to channel gating and is dependent on
the pH gradient. Our results provide direct evidence of local proton
depletion caused by flux through the proton-selective channel.
Filiaciones:
De-la-Rosa, Victor:
Univ Nacl Autonoma Mexico, Fac Med, Dept Fisiol, Mexico City 04510, DF, Mexico
Suarez-Delgado, Esteban:
Univ Nacl Autonoma Mexico, Fac Med, Dept Fisiol, Mexico City 04510, DF, Mexico
Rangel-Yescas, Gisela E.:
Univ Nacl Autonoma Mexico, Fac Med, Dept Fisiol, Mexico City 04510, DF, Mexico
Islas, Leon D.:
Univ Nacl Autonoma Mexico, Fac Med, Dept Fisiol, Mexico City 04510, DF, Mexico
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