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Preparation of Synaptic Plasma Membrane and Postsynaptic Density Proteins Using a Discontinuous Sucrose Gradient
Published on: September 3, 2014
Adición preferente de proteína de membrana recién sintetizada en los conos de crecimiento axonal
A M Craig1, R J Wyborski, G Banker
1Department of Neuroscience, University of Virginia School of Medicine, Charlottesville 22908, USA.
Nature
|June 15, 1995
Resumen
Las proteínas de membrana plasmática recién sintetizadas se agregan preferentemente a la neurona.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
Sus antecedentes:
- El crecimiento del axón requiere la adición de proteínas de la membrana plasmática.
- El mecanismo de inserción de proteínas en la membrana del axón en crecimiento no se entiende completamente.
- Los mecanismos potenciales incluyen la inserción en el cono de crecimiento, la inserción uniforme o la inserción en el cuerpo celular con flujo masivo.
Objetivo del estudio:
- Para investigar el sitio de la adición de nuevas proteínas de la membrana plasmática durante el crecimiento del axón.
- Para diferenciar entre la inserción del cono de crecimiento preferencial, la inserción uniforme o la inserción del cuerpo celular con flujo a granel.
Principales métodos:
- Utilizó un vector de herpesvirus defectuoso para la expresión génica en neuronas hipocampales de ratas cultivadas.
- Expresó una proteína transmembrana exógena, CD8 alfa, para rastrear su localización.
- Distribución de proteínas observada usando microscopía a lo largo del tiempo.
Principales resultados:
- La proteína CD8 alfa recién sintetizada apareció inicialmente casi exclusivamente en la superficie axonal en el cono de crecimiento.
- La adición preferente en el cono de crecimiento también se observó en dendritas inmaduras, pero no en dendritas maduras.
- Durante varias horas, CD8 alfa logró una distribución uniforme en toda la superficie neuronal, lo que sugiere difusión y reciclaje endocítico.
Conclusiones:
- Las proteínas de la membrana plasmática se agregan selectivamente en el cono de crecimiento neuronal.
- Esta inserción preferencial en el cono de crecimiento contribuye a la distribución polarizada de las moléculas de la superficie axonal.
- Los hallazgos apoyan un modelo en el que la orientación del cono de crecimiento es un mecanismo clave para el desarrollo del axón y la composición de la membrana.
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