Both endoplasmic reticulum (ER) and mitochondria are fundamental organelles that coordinate high-order cell functions.ER is an extensive network of cisteae and microtubules,which stretches from the nuclear envelope to the cell surface in all eukaryotic cells.ER works as the site for protein synthesis and corrects post-translational ‘folding’ of proteins.ER also has the ability to transport proteins to their destination.Moreover,ER acts as a calcium ion (Ca2+) reservoir which can be activated by both electrical and chemical stimulation.