Building ubiquitin chains: E2 enzymes at work

Abstract

The modification of proteins with ubiquitin chains can change their localization, activity and/or stability. Although ubiquitylation requires the concerted action of ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s), it is the E2s that have recently emerged as key mediators of chain assembly. These enzymes are able to govern the switch from ubiquitin chain initiation to elongation, regulate the processivity of chain formation and establish the topology of assembled chains, thereby determining the consequences of ubiquitylation for the modified proteins.

E3 Ubiquitin ligase RNF126 regulates the progression of tongue cancer

“…Ubiqutination recruits a catalytic reaction to ubiquitinate the substrate 1. Three ubiquitin enzymes, E1 ubiquitin activating, E2 ubiquitin conjugating, and E3 ubiquitin ligase are sequentially recruited in this cascade reaction 2, 3, 4. Ubiquitin‐proteolytic enzyme system is one of the key regulators in protein degradation.…”

Protein monoubiquitylation: targets and diverse functions

“…Fifth, monoubiquitin on the substrate might be immediately recognized by UBD protein which prevents further ubiquitin from being attached to the monoubiquitin moiety. In some cases, the choice of E2s might also contribute to mono‐, but not poly‐, ubiquitylation (Ye & Rape 2009; Ramanathan & Ye 2012). …”

Rôle de l’ubiquitine ligase c-Cbl dans l’ostéogenèse normale et cancéreuse

“…La première, E1, recrute l'ubiquitine sur un de ses résidus cystéine grâce à une liaison thioester [2]. L'ubiquitine est ensuite transférée de l'enzyme E1 sur un résidu cystéine de la seconde enzyme, E2 [3]. Enfin, la troisième enzyme, E3, est une ubiquitine ligase qui fait le lien entre la protéine cible à dégrader et l'enzyme E2 et, de ce fait, catalyse le transfert de l'ubiquitine sur la protéine cible.…”