Calcium Dynamics Mediated by the Endoplasmic/Sarcoplasmic Reticulum and Related Diseases.

The flow of intracellular calcium (Ca) is critical for the activation and regulation of important biological events that are required in living organisms. As the major Ca repositories inside the cell, the endoplasmic reticulum (ER) and the sarcoplasmic reticulum (SR) of muscle cells are central in maintaining and amplifying the intracellular Ca signal. The morphology of these organelles, along with the distribution of key calcium-binding proteins (CaBPs), regulatory proteins, pumps, and receptors fundamentally impact the local and global differences in Ca release kinetics. In this review, we will discuss the structural and morphological differences between the ER and SR and how they influence localized Ca release, related diseases, and the need for targeted genetically encoded calcium indicators (GECIs) to study these events.