Mark Kin-Fai Ma, Irene Oi-Lin NG and Terence Kin-Wah Lee
The endoplasmic reticulum (ER) is a very important organelle in the eukaryotic cells. It has two types: rough endoplasmic reticulum (rough ER, RER) and smooth endoplasmic reticulum (smooth ER, SER). ER plays a vital role in many cellular processes such as secretory and membrane protein synthesis, folding, assembly, trafficking and post-modulation.