Functional interactions between Ubiquitin E2 enzymes and TRIM proteins
Résumé
The TRIM family of proteins is characterized by the presence of the tripartite motif module, composed of a RING domain, one or two B-box domains and a Coiled-coil region. TRIM proteins are involved in many cellular processes and represent the largest subfamily of RING-containing putative ubiquitin E3 ligases. While their role as E3 ubiquitin ligases has been presumed, and in several cases established, little is known about their specific interactions with the ubiquitin conjugating enzymes or UBE2s. Here, we report a thorough screening of interactions between the TRIM and UBE2 families. We found a general preference of the TRIM proteins for the D and E classes of UBE2 enzymes but we also revealed very specific interactions between TRIM9-UBE2G2 and TRIM32-UBE2V1/2. Furthermore, we demonstrated that the TRIM E3 activity is only manifest with the UBE2 they interact with. For most specific interactions we could also observe subcellular co-localisation of the TRIM involved and its cognate UBE2 enzyme suggesting that the specific selection of TRIM-UBE2 pairs has physiological relevance. Our findings represent the basis for future studies on the specific reactions catalyzed by the TRIM E3 ligases to determine the fate of their targets.
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