At the tip of the new regenerating axon in Drosophila neurons, there is an increase in ER concentration. A 96-hour axon regeneration assay was performed in Drosophila ddaE neurons and it showed that Ryanodine Receptor is necessary for axon regeneration. This suggests that the release of Ca2+ by the ER is critical for regeneration. Understanding the mechanism and the role of the ER proteins in the pathway is crucial to potentially design treatments for diseases.