Estructura y mecanismo de acción de SYT1 de Arabidopsis thaliana: Regulación de la homeostasis lipídica en sitios de contacto

• Autores: Juan Luís Benavente Fernández
• Directores de la Tesis: Armando Albert de la Cruz (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2022
• Idioma: español
• Número de páginas: 145
• Tribunal Calificador de la Tesis: María Fernández Lobato (presid.), M. José Barrena Barrena (secret.), Noemí Ruiz López (voc.)
• Programa de doctorado: Programa de Doctorado en Biociencias Moleculares por la Universidad Autónoma de Madrid
• Materias:
  • Ciencias de la vida
    • Biología molecular
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Non-vesicular lipid transfer at ER and plasma membrane (PM) contact sites (CS) is crucial for the maintenance of membrane lipid homeostasis. Extended synaptotagmins (E-Syts) play a central role in this process as they act as molecular tethers of ER and PM and as lipid transfer proteins between these organelles. E-Syts are proteins constitutively anchored to the ER through an N-terminal hydrophobic segment and bind the PM via a variable number of C-terminal C2 domains.

    Synaptotagmins (SYTs) are the plant orthologous of E-Syts and regulate the ER–PM communication in response to abiotic stress. Combining different structural and biochemical techniques, we demonstrate that the binding of SYT1 to lipids occurs through a Ca2+-dependent lipid-binding site and by a site for phosphorylated forms of phosphatidylinositol, thus integrating two different molecular signals in response to stress. In addition, we show that SYT1 displays three highly flexible hinge points that provide conformational freedom to facilitate lipid extraction, protein loading, and subsequent transfer between PM and ER