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La fosforilación dependiente de voltaje puede reclutar la facilitación de corriente de Ca2+ en las células de
C R Artalejo1, S Rossie, R L Perlman
1Department of Pharmacological and Physiological Sciences, University of Chicago, Illinois 60637.
Nature
|July 2, 1992
Resumen
Las células de cromafina bovina exhiben dos corrientes de Ca2+. La fosforilación dependiente de voltaje regula el reclutamiento de corrientes de Ca2+ de facilitación, un hallazgo clave para comprender la modulación de los canales iónicos.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Biología celular Biología celular.
- Fisiología del canal iónico Fisiología del canal iónico
Sus antecedentes:
- Las células de cromafina bovina poseen distintas corrientes de Ca2+ de células enteras: componentes estándar y de facilitación.
- Las corrientes de Ca2+ de facilitación son típicamente quiescentes, pero pueden ser activadas por patrones específicos de despolarización.
- La activación de la proteína quinasa A sugiere un papel para la fosforilación en la facilitación de corriente de Ca2+.
Objetivo del estudio:
- Investigar el papel de la fosforilación de proteínas en el reclutamiento de corrientes de Ca2+ de facilitación.
- Aclarar los mecanismos subyacentes al reclutamiento dependiente de la tensión de estas corrientes.
Principales métodos:
- Células de cromafina de bovino utilizadas.
- Aplicó pre-pulsos y despolarizaciones repetitivas para estudiar el reclutamiento de corriente de Ca2+.
- Investigó los efectos de los inhibidores de la fosforilación de proteínas y la inyección de fosfatasa 2A.
- Examinó la reversibilidad de la contratación bajo diferentes condiciones.
Principales resultados:
- El reclutamiento inducido por la despolarización de la corriente de facilitación Ca2+ es un proceso rápido de primer orden.
- Los inhibidores de la fosforilación de proteínas y el reclutamiento suprimido de la fosfatasa 2A.
- El reclutamiento dependiente de voltaje, normalmente reversible, se volvió irreversible con los inhibidores de la fosfatasa.
Conclusiones:
- La fosforilación dependiente de voltaje del canal Ca2+ o de las proteínas asociadas media el reclutamiento de corrientes de facilitación Ca2+.
- Este mecanismo de fosforilación permite que el potencial de la membrana module la actividad del canal iónico.
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