Ubiquitination involves the attachment of ubiquitin, a small regulatory protein, to a target protein. This process is mediated by three classes of enzymes: E1 ubiquitin-activating enzymes, E2 ubiquitin-conjugating enzymes, and E3 ubiquitin ligases. Ubiquitinated proteins are typically tagged for proteasomal degradation, although ubiquitination can also alter protein activity, localization, or interactions.
