INVESTIGADORES
CALVO Daniel Juan
congresos y reuniones científicas
Título:
Potentiation of the homomeric rho1 GABAC receptor function by H2O2 is mediated by the intracellular cysteine residue Cys-364.
Autor/es:
BELTRÁN GONZALEZ A; GASULLA J; CALVO DJ
Lugar:
Huerta Grande Córdoba
Reunión:
Congreso; XXVI Reunión Nacional Sociedad Argentina de Investigación en Neurociencias (SAN); 2011
Institución organizadora:
Sociedad Argentina de Investigación en Neurociencias
Resumen:
Potentiation of the homomeric ρ1 GABAC receptor function by H2O2 is mediated by the intracellular cysteine residue
Cys-364.
Andrea
Beltrán González, Javier Gasulla and Daniel J. Calvo
INGEBI-CONICET. Buenos Aires, Argentina
Reactive oxygen species (ROS) are generated as by products of the
cellular oxidative metabolism and secondary to the activation of NMDA and AMPA
receptors. They are implicated in signalling pathways and oxidative stress,
particularly during normal aging and neurodegenerative disorders. Numerous
neurotransmitter receptors and ion channels are modulated by ROS. We reported previously
that H2O2 significantly potentiates GABAC
receptor function. In the present study we characterized the mechanism
underlying this modulation.
Homomeric GABAρ1 receptors were expressed in Xenopus laevis oocytes and GABA-evoked chloride
currents recorded by two-electrode voltage-clamp in the presence or absence of
H2O2. Potentiation of GABAρ1 receptors by H2O2
was dose-dependent, reversible, voltage independent and strongly depended on GABA
concentration. GABAρ1 receptors subunits contain three cysteine
residues: two extracellular at the cys-loop (C177 and C191) and one
intracellular (C364). Chemical protection of cysteine residues by the
membrane-permeable sulfhydryl alkylating reagent (N-ethyl maleimide) prevented ROS
potentiation. Furthermore, site directed mutagenesis of the intracellular cysteine
by alanine (C364A) rendered receptors insensitive to H2O2,
suggesting a single modulatory site.