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La fosforilación de tirosilo y la activación de las cinasas MAP por p56lckckl
E Ettehadieh1, J S Sanghera, S L Pelech
1Biomedical Research Centre, University of British Columbia, Vancouver, Canada.
Science (New York, N.Y.)
|February 14, 1992
Resumen
La proteína quinasa p56lck activa la señalización de la proteína quinasa activada por mitógeno (MAP) en las células T. Esta activación depende del antígeno de superficie CD4, destacando su papel en las vías de señalización de los receptores de células T.
Área de la Ciencia:
- Inmunología Inmunología.
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La señalización del receptor de células T (TCR) es crucial para la inmunidad adaptativa.
- El antígeno de superficie CD4 juega un papel clave en la mediación de la activación de las células T.
- Se sabe que la tirosil proteína quinasa p56lck está involucrada en la señalización de TCR.
Objetivo del estudio:
- Para investigar el papel de p56lck en la activación de la proteína activada por mitógeno (MAP) quinasa.
- Para determinar si la señalización mediada por CD4 influye en la activación de la MAP quinasa.
- Para dilucidar la interacción bioquímica entre p56lck y MAP quinasa.
Principales métodos:
- Utilizaron líneas celulares de linfoma T murino (171CD4+ y 171 con deficiencia de CD4).
- Células estimuladas con anticuerpos anti-CD3 para iniciar la señalización de las células T.
- Se emplearon ensayos bioquímicos para evaluar la tirosil-fosforilación y la actividad de la quinasa de la MAP quinasa (p42mapk).
- P56lck y p44mpk purificados (una isoforma de la cinasa MAP) para estudios de fosforilación in vitro.
Principales resultados:
- El tratamiento con anticuerpos CD3 indujo la tirosil-fosforilación y la activación de p42mapk en las células T CD4+, pero no en las células deficientes en CD4.
- Purificado p56lck directamente fosforilado y activado p44mpk, una MAP quinasa.
- El análisis cinético mostró una fosforilación eficiente de un sitio de péptido p42mapk por p56lck.
Conclusiones:
- p56lck es un mediador clave de la activación de la cinasa MAP dependiente de CD4 en las células T.
- Las quinasas MAP son efectores aguas abajo en la cascada de señalización iniciada por las quinasas de la familia Src como p56lck.
- Esta vía enlaza las quinasas de la familia Src con las moléculas de señalización aguas abajo involucradas en la activación de las células T.
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