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Las proteínas farnesiltransferasa y geranilgeraniltransferasa comparten una subunidad alfa común
M C Seabra1, Y Reiss, P J Casey
1Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235.
Cell
|May 3, 1991
Resumen
Las preniltransferasas, farnesiltransferasas y geranilgeraniltransferasas de los mamíferos comparten una subunidad alfa común. Diferentes subunidades beta dictan distintas especificidades proteicas para estas enzimas esenciales.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Enzimología Enzimología.
- La prenilación de las proteínas.
Sus antecedentes:
- La farnesiltransferasa de los mamíferos es crucial para modificar las proteínas p21ras con un grupo farnesilo.
- Este complejo enzimático consta de subunidades alfa y beta, con la subunidad beta conocida por unirse a p21ras.
- La composición precisa de las subunidades y los componentes compartidos de las preniltransferasas siguen siendo un área de investigación.
Objetivo del estudio:
- Para investigar la composición de las subunidades de la farnesiltransferasa de mamíferos y las preniltransferasas relacionadas.
- Para determinar si la subunidad alfa de la farnesiltransferasa se comparte con otras enzimas prenilantes.
- Para aclarar las especificidades del sustrato y las relaciones estructurales entre las diferentes preniltransferasas.
Principales métodos:
- Purificación y caracterización de enzimas mediante filtración en gel y cromatografía de intercambio iónico.
- Inmunoprecipitación e inmunoblotación utilizando anticuerpos contra la subunidad alfa de la farnesiltransferasa.
- Análisis de las especificidades del receptor de proteínas para la farnesiltransferasa y la geranilgeraniltransferasa.
Principales resultados:
- La subunidad alfa de la farnesiltransferasa se comparte con otra preniltransferasa que geranila las proteínas relacionadas con Ras.
- Si bien exhiben pesos moleculares similares, estas dos enzimas se pueden separar cromatográficamente.
- Los anticuerpos contra la subunidad alfa reconocieron ambas enzimas, confirmando la homología de la subunidad.
- Se observaron distintas preferencias de aminoácidos terminales COOH (metionina/serina frente a leucina) para la farnesiltransferasa y la geranilgeraniltransferasa, respectivamente.
Conclusiones:
- La farnesiltransferasa y la geranilgeraniltransferasa de los mamíferos son enzimas heterodiméricas distintas.
- Ambas enzimas comparten una subunidad alfa común, pero poseen diferentes subunidades beta.
- Esta arquitectura compartida de subunidades permite diversas vías de prenilación de proteínas.
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