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El ensamblaje de la bicapa fosfolípida del retículo endoplasmático: el transportador de fosfatidilcolina
Cell
|August 1, 1985
Resumen
Los investigadores investigaron el transporte de fosfatidilcolina en los microsomas del hígado de rata. Encontraron evidencia de un transportador de proteínas, o "flippase", que facilita el movimiento de los fosfolípidos a través de las membranas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología celular Biología celular.
- Transporte de la membrana Transporte de la membrana
Sus antecedentes:
- Los fosfolípidos se sintetizan en el lado citoplasmático del retículo endoplasmático.
- El ensamblaje de la bicapa fosfolípida requiere movimiento hacia el lado luminal.
- El movimiento espontáneo de fosfolípidos transmembrana es limitado.
Objetivo del estudio:
- Para probar la hipótesis de un transportador de proteínas (flippase) para la fosfatidilcolina en los microsomas del hígado de rata.
- Para investigar el mecanismo de la translocación de la fosfatidilcolina.
Principales métodos:
- Se usó sn-1,2,-dibutiroilfosfatidilcolina (diC4PC), un análogo soluble de la fosfatidilcolina.
- Se midió el transporte de diC4PC en el compartimento luminal de las vesículas microsomales.
- Se evaluó la cinética del transporte, la inhibición por análogos y los efectos de los tratamientos químicos.
Principales resultados:
- DiC4PC entró en el compartimiento luminal de las vesículas microsomales.
- El transporte era saturable y dependiente del tiempo, los microsomas y la integridad de la membrana.
- El transporte fue inhibido por análogos estructurales y tratamientos proteasa / químicos, lo que sugiere la mediación de proteínas.
- DiC4PC no transportó a través de las vesículas de control o las membranas de los glóbulos rojos.
Conclusiones:
- Los microsomas del hígado de la rata poseen un sistema mediado por proteínas para la translocación de fosfatidilcolina.
- Esta actividad de la flipasa es específica y esencial para la formación de la bicapa fosfolípida.
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