Pellino proteins are E3 ubiquitin ligases that play important roles in immunity, being involved in Toll-like signalling pathways, and associate with the kinase domain of the Pelle Ser/Thr kinase [1,2,3,4]. Mammalian Pellinos have been shown to mediate polyubiquitination of interleukin-1 receptor-associated kinase (IRAK) [5,6]. They consist of a forkhead-associated (FHA) domain at the N-terminal and a RING domain at the C-terminal. This entry represents the FHA domain, which is sufficient to interact with the ubiquitination substrates, such as IRAK1. This domain contains an unusual 'wing-like'appendage [7].

1: How low can toll go? Rich T, Allen R, Trowsdale J; Trends Genet 2000;16:292-294. PMID:10858658

2: Pellino-related sequences from Caenorhabditis elegans and Homo sapiens. Rich T, Allen RL, Lucas AM, Stewart A, Trowsdale J; Immunogenetics 2000;52:145-149. PMID:11132151

3: Oligomerisation of Tube and Pelle leads to nuclear localisation of dorsal. Grosshans J, Schnorrer F, Nusslein-Volhard C; Mech Dev 1999;81:127-138. PMID:10330490

4: Molecular and physiological roles of Pellino E3 ubiquitin ligases in immunity. Humphries F, Moynagh PN; Immunol Rev. 2015;266:93-108. PMID:26085209

5: The roles of Pellino E3 ubiquitin ligases in immunity. Moynagh PN; Nat Rev Immunol. 2014;14:122-131. PMID:24445667

6: The Pellino family: IRAK E3 ligases with emerging roles in innate immune signalling. Moynagh PN; Trends Immunol. 2009;30:33-42. PMID:19022706

7: Pellino proteins contain a cryptic FHA domain that mediates interaction with phosphorylated IRAK1. Lin CC, Huoh YS, Schmitz KR, Jensen LE, Ferguson KM; Structure. 2008;16:1806-1816. PMID:19081057