DELTEX2 C-terminal domain recognizes and recruits ADP-ribosylated proteins for ubiquitination.
Ahmed, S.F., Buetow, L., Gabrielsen, M., Lilla, S., Chatrin, C., Sibbet, G.J., Zanivan, S., Huang, D.T.(2020) Sci Adv 6
- PubMed: 32937373 
- DOI: https://doi.org/10.1126/sciadv.abc0629
- Primary Citation of Related Structures:  
6Y22, 6Y2X, 6Y3J - PubMed Abstract: 
Cross-talk between ubiquitination and ADP-ribosylation regulates spatiotemporal recruitment of key players in many signaling pathways. The DELTEX family ubiquitin ligases (DTX1 to DTX4 and DTX3L) are characterized by a RING domain followed by a C-terminal domain (DTC) of hitherto unknown function. Here, we use two label-free mass spectrometry techniques to investigate the interactome and ubiquitinated substrates of human DTX2 and identify a large proportion of proteins associated with the DNA damage repair pathway. We show that DTX2-catalyzed ubiquitination of these interacting proteins requires PARP1/2-mediated ADP-ribosylation and depends on the DTC domain. Using a combination of structural, biochemical, and cell-based techniques, we show that the DTX2 DTC domain harbors an ADP-ribose-binding pocket and recruits poly-ADP-ribose (PAR)-modified proteins for ubiquitination. This PAR-binding property of DTC domain is conserved across the DELTEX family E3s. These findings uncover a new ADP-ribose-binding domain that facilitates PAR-dependent ubiquitination.
Organizational Affiliation: 
Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK.