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La protección del centrómero requiere una estricta inactivación mitótica del complejo de helicasa del síndrome de
María Fernández-Casañas1,2, Eleftheria Karanika1, Umit Aliyaskarova1
1Chromosome Dynamics and Stability Group, Genome Damage and Stability Centre, University of Sussex, Brighton, UK.
Nature communications
|August 22, 2025
Resumen
El complejo BTRR y PICH resuelven los puentes de ADN durante la mitosis. CDK1 y PLK1 controlan la actividad de BTRR en los centrómeros, asegurando la estabilidad del genoma y la segregación cromosómica adecuada.
Área de la Ciencia:
- Biología molecular
- Biología celular
- La genética
Sus antecedentes:
- El complejo BLM/TOP3A/RMI1/RMI2 (BTRR) y el PICH resuelven los intermediarios de replicación y recombinación del ADN, cruciales para la estabilidad del genoma.
- Estos factores se dirigen a los puentes de ADN ultrafinos (UFB) durante la mitosis para facilitar la segregación cromosómica.
- No se comprende bien la importancia biológica de la hiperfosforilación mitótica transitoria de BLM y PICH.
Objetivo del estudio:
- Investigar el papel de las quinasas del ciclo celular CDK1 y PLK1 en la regulación del complejo BTRR en los centrómeros durante la mitosis.
- Elucidar el impacto de la fosforilación del complejo BTRR en su interacción con el PICH y su función en la resolución de los UFB.
- Descubrir los mecanismos que controlan la actividad del complejo BTRR para la función adecuada del centrómero y la segregación cromosómica.
Principales métodos:
- Investigó la regulación espacio-temporal del complejo BTRR por CDK1 y PLK1 durante la mitosis temprana.
- Se analizaron los efectos de la inactivación de la interacción BLM-TOP3A en la resolución UFB y la integridad del centrómero.
- Se estudió el impacto de la fosforilación BLM, particularmente en los sitios de Ser144 y PLK1, en las interacciones del subcomplejo BTRR y la actividad mitótica.
Principales resultados:
- Se encontró que CDK1 y PLK1 restringen la actividad del complejo BTRR en los centrómeros desestabilizando el complejo y limitando la unión a PICH.
- La inactivación de la interacción BLM-TOP3A interrumpió las funciones complejas de unión de UFB y evitó la destrucción del centrómero.
- La fosforilación específica de BLM, incluso en los sitios de Ser144 y PLK1, suprimió el desenrollo del ADN en los centrómeros, mientras que su liberación facilitó la separación cromosómica.
Conclusiones:
- Una nueva vía de protección del centrómero en las células mitóticas humanas se basa en el control espacio-temporal del complejo BTRR.
- CDK1 y PLK1 juegan un papel crítico en la regulación de la actividad del complejo BTRR en los centrómeros durante la mitosis.
- Las dinámicas de fosforilación de BLM son esenciales para modular la función del complejo BTRR y garantizar una segregación cromosómica precisa.
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