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La estructura cristalina del segmento extracelular de la integrina alfa Vbeta3 en complejo con un ligando Arg-Gly-Asp
Jian-Ping Xiong1, Thilo Stehle, Rongguang Zhang
1Renal Unit, Leukocyte Biology and Inflammation Program, Structural Biology Program, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA.
Science (New York, N.Y.)
|March 9, 2002
Resumen
La estructura cristalina revela cómo los cationes divalentes median la unión de la integrina alfaVbeta3 a los ligandos Arg-Gly-Asp. Esto revela reordenamientos estructurales críticos para la señalización celular.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Biología celular Biología celular.
Sus antecedentes:
- Las integrinas son receptores cruciales de la superficie celular que median la adhesión celular y la señalización.
- Los cationes divalentes son esenciales para las interacciones integrina-ligando, en particular con los motivos Arg-Gly-Asp (RGD).
- Los mecanismos estructurales que subyacen a la activación de la integrina y la unión de ligandos siguen siendo incompletamente entendidos.
Objetivo del estudio:
- Para dilucidar la base estructural de la unión divalente dependiente de cationes de las integrinas de alphabeta a los ligandos Arg-Gly-Asp.
- Caracterizar los reordenamientos estructurales en la integrina alfaVbeta3 tras la interacción del ligando.
Principales métodos:
- Se empleó cristalografía de rayos X para determinar la estructura del segmento extracelular de la integrina alfaVbeta3.3.
- La integrina fue cristalizada en complejo con un péptido cíclico que contiene la secuencia Arg-Gly-Asp.
Principales resultados:
- La estructura cristalina reveló la unión del ligando en la interfaz entre las subunidades alphaV y beta3.
- La unión de ligandos indujo reorganizaciones terciarias en el dominio betaA de beta3, acomodando dos cationes.
- Un catión entró directamente en contacto con el residuo Asp del ligando, mientras que el otro estabilizó la superficie de unión.
- Se observaron pequeños cambios en la orientación relativa de las subunidades alphaV y beta3 al momento de la unión al ligando.
Conclusiones:
- El estudio proporciona un mecanismo estructural detallado para el reconocimiento de ligando de integrina alfaVbeta3-RGD mediado por cationes divalentes.
- Estos hallazgos iluminan cómo la unión de ligandos desencadena cambios conformacionales esenciales para la función de la integrina y la señalización aguas abajo.
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