A putative ER-PM contact site complex relocalizes in response to Rare Earth Elements-induced endocytosis

Lee, E.; Vila Nova Santana, B.; Samuels, E.; Benitez Fuente, F.; Corsi, E.; Botella, M. A.; Perez Sancho, J.; Vanneste, S.; Friml, J.; Macho, A.; Alves Azevedo, A.; Rosado, A.

doi:10.1101/720466

bioRxiv · 10.1101/720466

A putative ER-PM contact site complex relocalizes in response to Rare Earth Elements-induced endocytosis

Lee, E.·Vila Nova Santana, B.·Samuels, E.·Benitez Fuente, F.·Corsi, E.·Botella, M. A.·Perez Sancho, J.·Vanneste, S.·Friml, J.·Macho, A.·Alves Azevedo, A.·Rosado, A.

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Abstract

In plant cells, environmental stressors induce changes in the cytosolic concentration of calcium ([Ca2+]cyt) that are transduced by Ca2+-sensing proteins. To confer specificity to the stress signaling response, [Ca2+]cyt sensing must be tightly regulated in space and time; the molecular mechanisms that restrict the localization and dynamics of Ca2+ sensors in plants, however, are largely unknown. In this report, we identify a putative Ca2+-sensitive complex containing the synaptotagmins 1 and 5 (SYT1 and SYT5) and the Ca2+-dependent lipid binding protein (CLB1), which is enriched at ER-PM contact sites (EPCS) and relocalizes in response to Rare Earth Elements (REEs)-induced endocytosis. Our results show that endocytosed REEs influence cytosolic Ca2+ signaling, as indicated by the activation of the Ca2+/Calmodulin-based ratiometric sensor GCaMP3, and promote the cytoskeleton-dependent accumulation of ER-PM contact sites at the cell cortex. Based on these results, we propose that the EPCS-localized SYT1/SYT5/CLB1 complex is part of an evolutionarily conserved and spatially regulated Ca2+-responsive mechanism that control cER-PM communication during stress episodes.

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Lee, E., Vila Nova Santana, B., Samuels, E., Benitez Fuente, F., Corsi, E., Botella, M. A., Perez Sancho, J., Vanneste, S., Friml, J., Macho, A., Alves Azevedo, A., Rosado, A.. 2019-07-31. A putative ER-PM contact site complex relocalizes in response to Rare Earth Elements-induced endocytosis. https://doi.org/10.1101/720466

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