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TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila

In Drosophila photoreceptors Ca(2+)-permeable channels TRP and TRPL are the targets of phototransduction, occurring in photosensitive microvilli and mediated by a phospholipase C (PLC) pathway. Using a novel Drosophila brain slice preparation, we studied the distribution and physiological properties...

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Autores principales: Astorga, Guadalupe, Härtel, Steffen, Sanhueza, Magdalena, Bacigalupo, Juan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432082/
https://www.ncbi.nlm.nih.gov/pubmed/22952921
http://dx.doi.org/10.1371/journal.pone.0044182
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author Astorga, Guadalupe
Härtel, Steffen
Sanhueza, Magdalena
Bacigalupo, Juan
author_facet Astorga, Guadalupe
Härtel, Steffen
Sanhueza, Magdalena
Bacigalupo, Juan
author_sort Astorga, Guadalupe
collection PubMed
description In Drosophila photoreceptors Ca(2+)-permeable channels TRP and TRPL are the targets of phototransduction, occurring in photosensitive microvilli and mediated by a phospholipase C (PLC) pathway. Using a novel Drosophila brain slice preparation, we studied the distribution and physiological properties of TRP and TRPL in the lamina of the visual system. Immunohistochemical images revealed considerable expression in photoreceptors axons at the lamina. Other phototransduction proteins are also present, mainly PLC and protein kinase C, while rhodopsin is absent. The voltage-dependent Ca(2+) channel cacophony is also present there. Measurements in the lamina with the Ca(2+) fluorescent protein G-CaMP ectopically expressed in photoreceptors, revealed depolarization-induced Ca(2+) increments mediated by cacophony. Additional Ca(2+) influx depends on TRP and TRPL, apparently functioning as store-operated channels. Single synaptic boutons resolved in the lamina by FM4-64 fluorescence revealed that vesicle exocytosis depends on cacophony, TRP and TRPL. In the PLC mutant norpA bouton labeling was also impaired, implicating an additional modulation by this enzyme. Internal Ca(2+) also contributes to exocytosis, since this process was reduced after Ca(2+)-store depletion. Therefore, several Ca(2+) pathways participate in photoreceptor neurotransmitter release: one is activated by depolarization and involves cacophony; this is complemented by internal Ca(2+) release and the activation of TRP and TRPL coupled to Ca(2+) depletion of internal reservoirs. PLC may regulate the last two processes. TRP and TRPL would participate in two different functions in distant cellular regions, where they are opened by different mechanisms. This work sheds new light on the mechanism of neurotransmitter release in tonic synapses of non-spiking neurons.
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spelling pubmed-34320822012-09-05 TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila Astorga, Guadalupe Härtel, Steffen Sanhueza, Magdalena Bacigalupo, Juan PLoS One Research Article In Drosophila photoreceptors Ca(2+)-permeable channels TRP and TRPL are the targets of phototransduction, occurring in photosensitive microvilli and mediated by a phospholipase C (PLC) pathway. Using a novel Drosophila brain slice preparation, we studied the distribution and physiological properties of TRP and TRPL in the lamina of the visual system. Immunohistochemical images revealed considerable expression in photoreceptors axons at the lamina. Other phototransduction proteins are also present, mainly PLC and protein kinase C, while rhodopsin is absent. The voltage-dependent Ca(2+) channel cacophony is also present there. Measurements in the lamina with the Ca(2+) fluorescent protein G-CaMP ectopically expressed in photoreceptors, revealed depolarization-induced Ca(2+) increments mediated by cacophony. Additional Ca(2+) influx depends on TRP and TRPL, apparently functioning as store-operated channels. Single synaptic boutons resolved in the lamina by FM4-64 fluorescence revealed that vesicle exocytosis depends on cacophony, TRP and TRPL. In the PLC mutant norpA bouton labeling was also impaired, implicating an additional modulation by this enzyme. Internal Ca(2+) also contributes to exocytosis, since this process was reduced after Ca(2+)-store depletion. Therefore, several Ca(2+) pathways participate in photoreceptor neurotransmitter release: one is activated by depolarization and involves cacophony; this is complemented by internal Ca(2+) release and the activation of TRP and TRPL coupled to Ca(2+) depletion of internal reservoirs. PLC may regulate the last two processes. TRP and TRPL would participate in two different functions in distant cellular regions, where they are opened by different mechanisms. This work sheds new light on the mechanism of neurotransmitter release in tonic synapses of non-spiking neurons. Public Library of Science 2012-08-31 /pmc/articles/PMC3432082/ /pubmed/22952921 http://dx.doi.org/10.1371/journal.pone.0044182 Text en © 2012 Astorga et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Astorga, Guadalupe
Härtel, Steffen
Sanhueza, Magdalena
Bacigalupo, Juan
TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila
title TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila
title_full TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila
title_fullStr TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila
title_full_unstemmed TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila
title_short TRP, TRPL and Cacophony Channels Mediate Ca(2+) Influx and Exocytosis in Photoreceptors Axons in Drosophila
title_sort trp, trpl and cacophony channels mediate ca(2+) influx and exocytosis in photoreceptors axons in drosophila
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432082/
https://www.ncbi.nlm.nih.gov/pubmed/22952921
http://dx.doi.org/10.1371/journal.pone.0044182
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