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Interruptor molecular específico de proteoglicanos para el agrupamiento RPTPσ y la extensión neuronal

Charlotte H Coles¹, Yingjie Shen, Alan P Tenney

¹Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.

Science (New York, N.Y.)

|April 2, 2011

Resumen

Los proteoglicanos de heparan y sulfato de condroitina (HSPG y CSPG) tienen efectos opuestos en la extensión de la neurona sensorial a través de la proteína receptor tirosina fosfatasa sigma (RPTPσ). RPTPσ media la inhibición por parte de los CSPG y la promoción por parte de los HSPG, revelando un nuevo mecanismo de regulación.

Área de la Ciencia:

La neurociencia es la neurociencia.
Biología celular Biología celular.
La bioquímica es la bioquímica.

Sus antecedentes:

Los proteoglicanos de heparan y sulfato de condroitina (HSPG y CSPG) modulan la señalización de la superficie celular con efectos opuestos.
Los proteoglicanos de sulfato de condroitina (CSPG) son inhibidores conocidos de la regeneración nerviosa a través del receptor de la proteína tirosina fosfatasa sigma (RPTPσ).

Objetivo del estudio:

Para investigar el doble papel de RPTPσ en la extensión de las neuronas sensoriales.
Para aclarar el mecanismo por el cual RPTPσ media los efectos opuestos de HSPGs y CSPGs.

Principales métodos:

Análisis cristalográfico del sitio de unión RPTPσ.
Ensayos bioquímicos que miden la oligomerización del ectodominio RPTPσ.
Microscopía de inmunofluorescencia para determinar la localización celular de RPTPσ y proteoglicanos.

Principales resultados:

RPTPσ exhibe plasticidad conformacional, acomodando tanto HSPGs como CSPGs con afinidades similares.
El sulfato de heparán (HS) indujo la oligomerización del ectodominio RPTPσ, mientras que el sulfato de condroitina (CS) la inhibió.
Las RPTPσ y las HSPG se colocalizan en el punto neuronal sensorial, mientras que las CSPG están en la matriz extracelular.

Conclusiones:

RPTPσ actúa bimodalmente en la extensión de la neurona sensorial, mediando la inhibición inducida por CSPG y la promoción del crecimiento inducida por HSPG.
Los proteoglicanos compiten para controlar la oligomerización RPTPσ, ejerciendo así efectos opuestos en la extensión neuronal.

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