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La estructura cristalina de ICAM-2 revela una superficie distintiva de reconocimiento de integrinas

J M Casasnovas1, T A Springer, J H Liu

  • 1The Center for Blood Research, Harvard Medical School, Department of Pathology, Boston, Massachusetts 02115, USA.

Nature
|May 15, 1997
PubMed

Insights

La estructura cristalina de la molécula de adhesión intercelular-2 (ICAM-2) revela diferencias clave en la forma en que las integrinas con y sin.

Área de la Ciencia:

  • La adhesión celular es la adhesión celular.
  • Biología estructural Biología estructural.
  • Inmunología Inmunología.

Sus antecedentes:

  • Las proteínas integrinas median las interacciones de la matriz célula-célula y célula-extracelular.
  • Las estructuras conocidas de ligandos de integrinas (fibronectina, VCAM-1) involucran integrinas que carecen de dominios "I".
  • Las moléculas de adhesión intercelular (ICAM) son reconocidas por integrinas que contienen el dominio "I" como el antígeno 1 asociado a la función linfocítica (LFA-1).

Objetivo del estudio:

  • Determinar la estructura cristalina de la región extracelular del ICAM-2.
  • Para aclarar la base estructural para el reconocimiento LFA-1 de ICAM-2.
  • Para comparar las arquitecturas de reconocimiento de sitios entre las interacciones integrina-ligando que contienen dominio "I" y las que carecen de dominio "I".

Principales métodos:

  • Cristalografía de rayos X para determinar la estructura tridimensional del ICAM-2.
  • Análisis estructural para identificar los principales residuos y características involucradas en la unión de LFA-1.
  • Modelado estructural comparativo del ICAM-1 basado en la estructura del ICAM-2.

Principales resultados:

  • Se determinó la estructura cristalina de la región extracelular de ICAM-2.
  • El ácido glutámico en la posición 37 (Glu 37) en ICAM-2 es crítico para la unión de LFA-1 y puede coordinar el ion Mg2+ en el dominio "I" de LFA-1.
  • ICAM-2 presenta una superficie de reconocimiento relativamente plana con Glu 37 en una hebra beta, en contraste con los bucles sobresalientes en la fibronectina y VCAM-1.

Conclusiones:

  • Existen diferencias estructurales en los sitios de reconocimiento entre integrinas con y sin dominios "I".
  • Una curva entre los dominios ICAM-2 y los glicanos ligados a N puede facilitar la unión de LFA-1.
  • La estructura de ICAM-2 proporciona un modelo para comprender el reconocimiento de ICAM-1 y las posibles interacciones de patógenos.
Abstracto

No abstract available in PubMed .

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