Figure 7. Model of RING dimerization in different TRIM ligases.

TRIM25 and TRIM32 use different mechanisms to allow their respective RING domains to dimerize: in TRIM25, the propensity to dimerize is low and happens in an intramolecular fashion possibly aided by E2~Ub and substrate binding. It is possible that the B‐box domains may contact the CC region to support dimerization. The RINGs of TRIM32 are constitutive dimers even in the absence of the rest of the remainder of the protein or additional binding partners. Tetramerization of TRIM32 may be important for the recognition of low‐affinity substrates or may allow co‐localization of different binding partners.