Navigating the Endoplasmic Reticulum: New Insights and Emerging Concepts

Abstract

Endoplasmic reticulum (ER) is a membrane bound organelle adjacent to the nucleus in eukaryotic cells. It exists in the form of membranous sacs called “cisternae”. It was first discovered by Emilio Veratti in 1902 and later named as ‘Endoplasmic Reticulum’ in 1953 after visualization through electron microscopy. There are two types of endoplasmic reticulum based on the presence of ribosomes i.e., ‘rough’ ER and ‘smooth’ ER. Rough ER is the site for protein synthesis and modification by glycosylation. While the smooth ER is involved in the metabolism of lipids and carbohydrates. Recently, it has been classified on the basis of membrane structure rather than appearance. It physically interconnects with the mitochondria and these sites are named as mitochondria-associated membranes (MAMs) that are crucial for Ca+2 homeostasis. Various mechanisms of ER signaling play vital role in physiology and the onset of disease. A thorough understanding of these mechanisms and their role in physiology and pathophysiology can be applied to develop new ER-targeted therapies.