Endoplasmic Reticulum Lumenal Indicators in <i>Drosophila</i> Reveal Effects of HSP-Related Mutations on Endoplasmic Reticulum Calcium Dynamics.
Oliva, Megan K
Perez Moreno, Juan
Wardill, Trevor J
Frontiers in neuroscience
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Oliva, M. K., Perez Moreno, J., O'Shaughnessy, J., Wardill, T. J., & O'Kane, C. (2020). Endoplasmic Reticulum Lumenal Indicators in <i>Drosophila</i> Reveal Effects of HSP-Related Mutations on Endoplasmic Reticulum Calcium Dynamics.. Frontiers in neuroscience, 14 816. https://doi.org/10.3389/fnins.2020.00816
Genes for ER-shaping proteins are among the most commonly mutated in Hereditary Spastic Paraplegia (HSP). Mutation of these genes in model organisms can lead to disruption of the ER network. To investigate how the physiological roles of the ER might be affected by such disruption, we developed tools to interrogate its Ca2+ signaling function. We generated GAL4-driven Ca2+ sensors targeted to the ER lumen, to record ER Ca2+ fluxes in identified Drosophila neurons. Using GAL4 lines specific for Type Ib or Type Is larval motor neurons, we compared the responses of different lumenal indicators to electrical stimulation, in axons and presynaptic terminals. The most effective sensor, ER-GCaMP6-210, had a Ca2+ affinity close to the expected ER lumenal concentration. Repetitive nerve stimulation generally showed a transient increase of lumenal Ca2+ in both the axon and presynaptic terminals. Mutants lacking neuronal reticulon and REEP proteins, homologs of human HSP proteins, showed a larger ER lumenal evoked response compared to wild type; we propose mechanisms by which this phenotype could lead to neuronal dysfunction or degeneration. Our lines are useful additions to a Drosophila Ca2+ imaging toolkit, to explore the physiological roles of ER, and its pathophysiological roles in HSP and in axon degeneration more broadly.
This work was supported by grants BB/L021706 from the UK Biotechnology and Biological Sciences Research Council and MR/S011226 from the UK Medical Research Council to CJO'K. MKO was supported by a Newton International Fellowship (NF150362) from The Royal Society and a Marie Skłodowska-Curie Fellowship (701397) from the European Commission, JJPM was supported by a Marie Skłodowska-Curie fellowship (745007) from the European Commission.
Royal Society (NF150362)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (701397)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (745007)
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External DOI: https://doi.org/10.3389/fnins.2020.00816
This record's URL: https://www.repository.cam.ac.uk/handle/1810/307905
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