RNF166 Determines Recruitment of Adaptor Proteins during Antibacterial Autophagy

Abstract

Summary Xenophagy is a form of selective autophagy that involves the targeting and elimination of intracellular pathogens through several recognition, recruitment, and ubiquitination events. E3 ubiquitin ligases control substrate selectivity in the ubiquitination cascade; however, systematic approaches to map the role of E3 ligases in antibacterial autophagy have been lacking. Here we screened more than 600 putative human E3 ligases, identifying E3 ligases that are required for adaptor protein recruitment and LC3-bacteria colocalization, critical steps in antibacterial autophagy. An unbiased informatics approach pinpointed RNF166 as a key gene that interacts with the autophagy network and controls the recruitment of ubiquitin as well as the autophagy adaptors p62 and NDP52 to bacteria. Mechanistic studies demonstrated that RNF166 catalyzes K29- and K33-linked polyubiquitination of p62 at residues K91 and K189. Thus, our study expands the catalog of E3 ligases that mediate antibacterial autophagy and identifies a critical role for RNF166 in this process.

Keap1/Cullin3 Modulates p62/SQSTM1 Activity via UBA Domain Ubiquitination

“…Recently, studies identified ubiquitin ligases that depending upon their site of ubiquitination inhibited or facilitated p62’s function (Heath et al, 2016; Jongsma et al, 2016; Pan et al, 2016). The E3 ubiquitin ligase TRIM21 ubiquitylates p62 at lysine 7 within it PB1 domain.…”

“…This ubiquitination event was proposed to enhance p62’s interaction with other ubiquitin adaptors such as, TOLLIP, thus facilitating vesicular cargo sorting (Jongsma et al, 2016). In addition, RNF166 ubiquitinates p62 at residues K91 and K189 (Heath et al, 2016). Interestingly, these events involve atypical ubiquitin chains that are K29- and K33-linked.…”

“…Interestingly, these events involve atypical ubiquitin chains that are K29- and K33-linked. RNF166 mediated ubiquitin ligase activity facilitates p62’s role in the xenophagic degradation of intracellular bacteria (Heath et al, 2016). …”

Genetic control of autophagy underlies pathogenesis of inflammatory bowel disease

“…Several E3 ubiquitin ligases including LRSAM1, Parkin, Smurf1, RNF166, and some TRIM proteins have each been shown to ubiquitinate bacteria or bacteria-associated proteins to drive antibacterial autophagy 73–76 . Various TRIM proteins have also been implicated in antibacterial autophagy as well as other types of selective autophagy that have a direct effect on inflammation 74, 77, 78 .…”

“…Recent studies have identified a number of proteins that function in mitophagy, antibacterial autophagy, and/or virophagy (autophagic elimination of viruses), suggesting that these processes share signaling components. The E3 ubiquitin ligase Parkin is critical for mitophagy and has recently been shown to be recruited to intracellular M. tuberculosis and S. Typhimurium to promote autophagy 54, 74, 85 . The E3 ligase SMURF1 and the peroxisomal protein PEX13 are also critical for mitophagy, virophagy, and antibacterial autophagy 76, 86, 87 .…”