 Ubiquitin-like 3, UBL3, is a conserved ubiquitin-like protein found in eukaryotic cells. It has recently been discovered to play a key role in the sorting of proteins into small extracellular vesicles, CEVS, which are implicated in many diseases. This review discusses the structural similarities between UBL3 and other ubiquitin-like proteins, as well as its potential use in developing drugs and therapeutics. This article was authored by Usuker Takanashi, Tomoki Kahio, SAE Kamamoto, and others.