The ER and cell calcium

Abstract

Calcium is one of the most versatile messengers in biological systems, translating developmental and environmental cues into cellular responses. The endoplasmic reticulum (ER) constitutes one of the most important calcium holding organelles in higher eukaryotes. Upon stimulation, calcium is released from the ER into the cytosol where it may trigger downstream effectors. However, the release of calcium may also affect internal ER functions, such as protein folding and secretion. It is therefore important not only to view cytosolic calcium signals as isolated events, but also in context to the organellar calcium status. In animals, the calcium levels of the ER can be sensed by other calcium re..