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Identification of Kinase-substrate Pairs Using High Throughput Screening

Identification of Kinase-substrate Pairs Using High Throughput Screening

Published on: August 29, 2015

La fosforilación específica del sitio de IkappaBalpha por una nueva actividad de la proteína quinasa dependiente de

Z J Chen¹, L Parent, T Maniatis

¹ProScript Incorporated, Cambridge, Massachusetts, 02139, USA.

|March 22, 1996

Resumen

Una nueva quinasa fosforila el IkappaBalpha, activando la señalización NF-kappaB. Este proceso requiere ubiquitinación, revelando una nueva función reguladora para la ubiquitina más allá de la proteólisis.

Área de la Ciencia:

Biología Molecular Biología Molecular
La señalización celular de las células.
Biología de la ubiquitina.

Sus antecedentes:

La activación de la vía NF-kappaB es crucial para las respuestas celulares.
La inhibición y degradación de IkappaBalpha son pasos reguladores clave.
La fosforilación de IkappaBalpha en S32 y S36 se dirige a su degradación.

Objetivo del estudio:

Identificar la quinasa responsable de la fosforilación de IkappaBalpha en las regiones S32 y S36.
Elucidar los mecanismos reguladores que rigen este evento de fosforilación.
Investigar el papel de la ubiquitinación en la regulación de IkappaBalpha.

Principales métodos:

Purificación bioquímica de un complejo de quinasa grande y con múltiples subunidades.
Ensayos in vitro de la quinasa utilizando componentes purificados.
Ensayos de ubiquitinación y análisis de eventos de ubiquitinación dentro del complejo de la quinasa.

Principales resultados:

Se identificó una quinasa multisubunitaria de ~700 kDa que fosforila IkappaBalpha en S32 y S36.
La actividad de la quinasa dependía de la enzima activadora de Ub (E1), las enzimas Ubc4/Ubc5 E2 y la ubiquitina.
Un evento de ubiquitinación dentro del complejo de la quinasa precedió a la fosforilación de IkappaBalpha.

Conclusiones:

La ubiquitinación juega un nuevo papel regulador en la activación de la quinasa, independiente de la proteólisis.
Este hallazgo amplía las funciones conocidas del sistema de ubiquitina en la transducción de señales.
El complejo de quinasa identificado representa un nuevo objetivo para la modulación de la señalización NF-kappaB.

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