E3 ubiquitin ligase catalyzing the covalent attachment of ubiquitin moieties onto substrate proteins. Involved in the TLR and IL-1 signaling pathways via interaction with the complex containing IRAK kinases and TRAF6. Mediates 'Lys-63'-linked polyubiquitination of IRAK1 allowing subsequent NF-kappa-B activation (PubMed:12496252, PubMed:17675297). Mediates 'Lys-48'-linked polyubiquitination of RIPK3 leading to its subsequent proteasome-dependent degradation; preferentially recognizes and mediates the degradation of the 'Thr-182' phosphorylated form of RIPK3 (PubMed:29883609). Negatively regulates necroptosis by reducing RIPK3 expression (PubMed:29883609). Mediates 'Lys-63'-linked ubiquitination of RIPK1 (PubMed:29883609). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Interacts with MAP3K7. Upon IL1B treatment, forms a complex with TRAF6, IRAK1, IRAK4 and MYD88; this complex recruits MAP3K7/TAK1, TAB1 and TAB2 to mediate NF-kappa-B activation. Direct binding of SMAD6 to PELI1 prevents the complex formation and hence negatively regulates IL1R-TLR signaling and eventually NF-kappa-B-mediated gene expression (PubMed:12496252, PubMed:12804775, PubMed:16951688). Interacts (via atypical FHA domain) with RIPK3; preferentially binds to the 'Thr-182' phosphorylated form of RIPK3 (PubMed:29883609). Interacts with RIPK1 and IRAK1 (PubMed:29883609). Expressed at high levels in normal skin but decreased in keratinocytes from toxic epidermal necrolysis (TEN) patients (at protein level). Phosphorylation by IRAK1 and IRAK4 enhances its E3 ligase activity. Sumoylated. Belongs to the pellino family. Truncated N-terminus. Truncated N-terminus.