Ubiquitins and ubiquitin-like proteins

 Ubiquitin-activating enzymes (E1)

 Ubiquitin-conjugating enzymes (E2)

 Ubiquitin ligases (E3)

   HECT type E3

   U-box type E3

   Single Ring-finger type E3

   Atypical E3

   UBL E3 ligases

   Multi subunit Ring-finger type E3

     SCF complex

     Cul2 complex

     Cul3 complex

       Ring finger protein

       Cullin

       Adoptor and target recognizing subunit (BTB)

     Cul4 complex

     Cul5 complex

     Cul7 complex

     Cul8 complex

     Cul9 complex

     APC/C

     BRCC complex

     KPC complex

     LUBAC complex

     CTLH complex

     ERAD complex

     LMBR1L-GP78-UBAC2 complex

     SLX5-SLX8 complex

     Multi subunit type E3 associated proteins

 Deubiquitinating enzyme (DUB)