Luminal transport rates through intact endoplasmic reticulum limit the magnitude of localized Ca2+ signals

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.06.23.546357v1?rss=1 Authors: Crapart, C., Scott, Z. C., Konno, T., Sharma, A., Bailey, D. M., Avezov, E., Koslover, E. F. Abstract: The endoplasmic reticulum (ER) forms an interconnected network of tubules stretching throughout the cell. Understanding how ER functionality relies on its structural organization is crucial for elucidating cellular vulnerability to ER perturbations, which have been implicated in several neuronal pathologies. One of the key functions of the ER is enabling Ca2+ signalling by storing large quantities of this ion and releasing it into the cytoplasm in a spatiotemporally controlled manner. Through a combination of physical modeling and live-cell imaging, we demonstrate that alterations in ER shape significantly impact its ability to support efficient local Ca2+ releases, due to hindered transport of luminal content within the ER. Our model reveals that rapid Ca2+ release necessitates mobile luminal buffer proteins with moderate binding strength, moving through a well-connected network of ER tubules. These findings provide insight into the functional advantages of normal ER architecture, emphasizing its importance as a kinetically efficient intracellular Ca2+ delivery system. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC