The ER membrane protein complex (EMC) is a widely conserved and abundant complex found in the endoplasmic reticulum of eukaryotic cells. The mammalian EMC comprises ~10 subunits, in which EMC8 and EMC9 are ~40% identical and appear to be the result of a recent gene duplication. In D. melanogaster, there is a single gene encoding EMC8/9, whereas the EMC2 gene is duplicated (resulting in EMC2A and EMC2B). EMC can directly mediate the insertion of transmembrane domains (TMDs) into the lipid bilayer and may participate in the folding/assembly of other types of membrane proteins transiting through the ER by serving as a chaperone. EMC disruption has pleiotropic phenotypes, often impacting the abundance or localization of membrane proteins and affecting protein trafficking, organelle communication, ER stress, viral maturation and lipid homeostasis. (Adapted from PMID:30826214.)