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Estructuras y mecanismo del transportador de auxinas con forma de PIN
Kien Lam Ung1, Mikael Winkler1, Lukas Schulz2
1Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
Nature
|June 29, 2022
Resumen
Las hormonas vegetales llamadas auxinas son cruciales para el crecimiento. Las proteínas formadas por PIN facilitan el transporte de auxinas, y las nuevas estructuras revelan un mecanismo similar a un ascensor para este proceso esencial de la planta.
Área de la Ciencia:
- Biología vegetal
- Biología molecular
- La bioquímica
Sus antecedentes:
- Las auxinas son hormonas vegetales vitales que regulan el crecimiento y el desarrollo.
- Las proteínas formadas por PIN son portadores esenciales del eflujo de auxinas.
- El mecanismo molecular del transporte de auxinas mediado por PIN sigue siendo poco conocido.
Objetivo del estudio:
- Elucidar el mecanismo molecular del transporte de auxinas por las proteínas PIN.
- Presentar los datos estructurales y biofísicos de la especie Arabidopsis thaliana PIN8.
Principales métodos:
- Análisis biofísico
- Cristalografía de rayos X de la especie Arabidopsis thaliana PIN8
- Ensayos bioquímicos
Principales resultados:
- Se determinaron tres estructuras de PIN8: orientadas hacia el exterior (con/sin auxina) y orientadas hacia el interior (unidas al ácido naftilftálmico).
- PIN8 forma un homodímero con dominios de transporte y andamio distintos y un sitio de unión de auxina definido.
- Se reveló un mecanismo de transporte de tipo ascensor, independiente de los gradientes de protones y impulsado por la carga negativa de la auxina.
Conclusiones:
- Se estableció un modelo molecular completo para el reconocimiento y el transporte de auxinas por las proteínas PIN.
- Los hallazgos explican el mecanismo central del transporte de auxinas polares en las plantas.
- El estudio proporciona información sobre una característica central de la fisiología, el crecimiento y el desarrollo de las plantas.
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