The endoplasmic reticulum (ER) is a network of membranes found in eukaryotic cells that plays a crucial role in protein synthesis, folding, and transport. It can be divided into two regions: the rough ER, which is studded with ribosomes and is involved in protein synthesis, and the smooth ER, which is responsible for lipid synthesis and detoxification of drugs and other harmful substances. The ER is also involved in calcium storage and signaling, as well as the processing of membrane proteins. Research in this area focuses on understanding the functions and mechanisms of the ER, as well as its role in various diseases such as cancer, neurodegenerative disorders, and metabolic diseases. Additionally, researchers are studying how ER stress and dysfunction contribute to the pathogenesis of these diseases and exploring potential therapeutic targets to alleviate ER-related disorders.