The roles of Pellino E3 ubiquitin ligases in immunity

Key Points

  • Toll-like receptors (TLRs) and NOD-like receptors (NLRs) sense pathogen-associated molecules and trigger effector pathways to facilitate the destruction and removal of the pathogen. Post-translational modifications, such as ubiquitylation, have important roles in regulating the activities and the levels of signalling molecules in these pathways.

  • The Pellino family (Pellino 1, Pellino 2 and Pellino 3) were initially identified as interleukin-1 receptor-associated kinase (IRAK)-interacting proteins with E3 ubiquitin ligase activity. They are activated by kinases such as IRAKs and TANK-binding kinase 1 (TBK1) and can promote ubiquitylation of their upstream kinases.

  • Pellino 1 regulates TIR domain-containing adaptor protein inducing IFNβ (TRIF)-dependent signalling in the TLR3 and TLR4 pathways by promoting the ubiquitylation of the kinase receptor-interacting protein 1 (RIP1) and the downstream activation of nuclear factor-κB (NF-κB), and by mediating the TRIF-dependent induction of type I interferons (IFNs). In addition, in microglial cells, Pellino 1 can mediate the myeloid differentiation primary-response protein 88 (MYD88)-dependent activation of mitogen-activated protein kinase (MAPK) pathways to trigger neuroinflammation.

  • Pellino 1 also functions as a negative regulator of T cell activation to ensure self tolerance is maintained and to avoid the development of autoimmunity.

  • Pellino 3 negatively regulates the TLR3-induced expression of type I IFNs by ubiquitylating TNF receptor-associated factor 6 (TRAF6) to inhibit the downstream activation of IFN-regulatory factor 7 (IRF7). In addition, Pellino 3 mediates nucleotide-binding oligomerization domain-containing protein 2 (NOD2) signalling and regulates intestinal inflammation by functioning as the E3 ubiquitin ligase for the RIP2 kinase.

  • Pellino 3 is cytoprotective in response to tumour necrosis factor (TNF) challenge, as it targets RIP1 and impairs the formation of the death-inducing signalling complex (DISC).

  • Further investigation of the role of Pellino proteins in immunity will provide a molecular and a functional understanding of their contribution to physiological and pathological conditions.

Abstract

Pellino proteins were initially characterized as a family of E3 ubiquitin ligases that can catalyse the ubiquitylation of interleukin-1 receptor-associated kinase 1 (IRAK1) and regulate innate immune signalling pathways. More recently, physiological and molecular roles for members of the Pellino family have been described in the regulation of innate and adaptive immune responses by ubiquitylation. This Review describes the emerging roles of Pellino proteins in innate and adaptive immunity and discusses the mechanistic basis of these functions.

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Figure 1: Molecular features of Pellino proteins.
Figure 2: Pellino 1 regulates TLR signalling.
Figure 3: Pellino 1 negatively regulates T cell activation.
Figure 4: Roles of Pellino 3 in innate immune signalling.

References

  1. 1

    O'Neill, L. A., Golenbock, D. & Bowie, A. G. The history of Toll-like receptors — redefining innate immunity. Nature Rev. Immunol. 13, 453–460 (2013).

    CAS  Article  Google Scholar 

  2. 2

    Chen, G., Shaw, M. H., Kim, Y. G. & Nunez, G. NOD-like receptors: role in innate immunity and inflammatory disease. Annu. Rev. Pathol. 4, 365–398 (2009).

    CAS  Article  Google Scholar 

  3. 3

    Loo, Y. M. & Gale, M. Jr. Immune signaling by RIG-I-like receptors. Immunity 34, 680–692 (2011).

    CAS  Article  Google Scholar 

  4. 4

    Paludan, S. R. & Bowie, A. G. Immune sensing of DNA. Immunity 38, 870–880 (2013).

    CAS  Article  Google Scholar 

  5. 5

    Jiang, X. & Chen, Z. J. The role of ubiquitylation in immune defence and pathogen evasion. Nature Rev. Immunol. 12, 35–48 (2012).

    CAS  Article  Google Scholar 

  6. 6

    Grosshans, J., Schnorrer, F. & Nüsslein-Volhard, C. Oligomerisation of Tube and Pelle leads to nuclear localisation of dorsal. Mech. Dev. 81, 127–138 (1999). This study describes the discovery of Pellino as a Pelle-interacting protein in Drosophila melanogaster.

    CAS  Article  Google Scholar 

  7. 7

    Haghayeghi, A., Sarac, A., Czerniecki, S., Grosshans, J. & Schock, F. Pellino enhances innate immunity in Drosophila. Mech. Dev. 127, 301–307 (2010).

    CAS  Article  Google Scholar 

  8. 8

    Yu, K. Y. et al. Cutting edge: mouse Pellino-2 modulates IL-1 and lipopolysaccharide signaling. J. Immunol. 169, 4075–4078 (2002).

    CAS  Article  Google Scholar 

  9. 9

    Jiang, Z. et al. Pellino 1 is required for interleukin-1 (IL-1)-mediated signaling through its interaction with the IL-1 receptor-associated kinase 4 (IRAK4)-IRAK-tumor necrosis factor receptor-associated factor 6 (TRAF6) complex. J. Biol. Chem. 278, 10952–10956 (2003).

    CAS  Article  Google Scholar 

  10. 10

    Jensen, L. E. & Whitehead, A. S. Pellino3, a novel member of the Pellino protein family, promotes activation of c-Jun and Elk-1 and may act as a scaffolding protein. J. Immunol. 171, 1500–1506 (2003).

    CAS  Article  Google Scholar 

  11. 11

    Rich, T., Allen, R. L., Lucas, A. M., Stewart, A. & Trowsdale, J. Pellino-related sequences from Caenorhabditis elegans and Homo sapiens. Immunogenetics 52, 145–149 (2000).

    CAS  Article  Google Scholar 

  12. 12

    Resch, K., Jockusch, H. & Schmitt-John, T. Assignment of homologous genes, Peli1/PELI1 and Peli2/PELI2, for the Pelle adaptor protein Pellino to mouse chromosomes 11 and 14 and human chromosomes 2p13.3 and 14q21, respectively, by physical and radiation hybrid mapping. Cytogenet. Cell Genet. 92, 172–174 (2001).

    CAS  Article  Google Scholar 

  13. 13

    Schauvliege, R., Janssens, S. & Beyaert, R. Pellino proteins are more than scaffold proteins in TLR/IL-1R signalling: a role as novel RING E3-ubiquitin-ligases. FEBS Lett. 580, 4697–4702 (2006). This work provides the first indication that Pellino proteins may be E3 ubiquitin ligases.

    CAS  Article  Google Scholar 

  14. 14

    Strelow, A., Kollewe, C. & Wesche, H. Characterization of Pellino2, a substrate of IRAK1 and IRAK4. FEBS Lett. 547, 157–161 (2003). This study provides the first indication that Pellino proteins may be substrates for IRAKs.

    CAS  Article  Google Scholar 

  15. 15

    Jensen, L. E. & Whitehead, A. S. Pellino2 activates the mitogen activated protein kinase pathway. FEBS Lett. 545, 199–202 (2003).

    CAS  Article  Google Scholar 

  16. 16

    Butler, M. P., Hanly, J. A. & Moynagh, P. N. Pellino3 is a novel upstream regulator of p38 MAPK and activates CREB in a p38-dependent manner. J. Biol. Chem. 280, 27759–27768 (2005).

    CAS  Article  Google Scholar 

  17. 17

    Butler, M. P., Hanly, J. A. & Moynagh, P. N. Kinase-active interleukin-1 receptor-associated kinases promote polyubiquitination and degradation of the Pellino family: direct evidence for PELLINO proteins being ubiquitin-protein isopeptide ligases. J. Biol. Chem. 282, 29729–29737 (2007). This study provides the first direct evidence that Pellino proteins have E3 ubiquitin ligase activity.

    CAS  Article  Google Scholar 

  18. 18

    Ordureau, A. et al. The IRAK-catalysed activation of the E3 ligase function of Pellino isoforms induces the Lys63-linked polyubiquitination of IRAK1. Biochem. J. 409, 43–52 (2008).

    CAS  Article  Google Scholar 

  19. 19

    Lin, C. C., Huoh, Y. S., Schmitz, K. R., Jensen, L. E. & Ferguson, K. M. Pellino proteins contain a cryptic FHA domain that mediates interaction with phosphorylated IRAK1. Structure 16, 1806–1816 (2008). This study describes the only X-ray crystal structure of Pellino proteins that has so far been identified and reveals a cryptic FHA domain that was not apparent from primary sequences.

    CAS  Article  Google Scholar 

  20. 20

    Smith, H. et al. Identification of the phosphorylation sites on the E3 ubiquitin ligase Pellino that are critical for activation by IRAK1 and IRAK4. Proc. Natl Acad. Sci. USA 106, 4584–4590 (2009). This study identifies the IRAK phosphorylation sites in Pellino 1 and highlights key sites that are sufficient to mediate full E3 ubiquitin ligase activity in Pellino 1.

    CAS  Article  Google Scholar 

  21. 21

    Smith, H. et al. The role of TBK1 and IKKε in the expression and activation of Pellino 1. Biochem. J. 434, 537–548 (2011).

    CAS  Article  Google Scholar 

  22. 22

    Goh, E. T. et al. Identification of the protein kinases that activate the E3 ubiquitin ligase Pellino 1 in the innate immune system. Biochem. J. 441, 339–346 (2012). This study delineates the relative importance of IRAKs and TBK1–IKKε in regulating Pellino proteins in different signalling pathways.

    CAS  Article  Google Scholar 

  23. 23

    Baines, K. J. et al. Novel immune genes associated with excessive inflammatory and antiviral responses to rhinovirus in COPD. Respir. Res. 14, 15 (2013).

    CAS  Article  Google Scholar 

  24. 24

    Bennett, J. A. et al. Pellino-1 selectively regulates epithelial cell responses to rhinovirus. J. Virol. 86, 6595–6604 (2012).

    CAS  Article  Google Scholar 

  25. 25

    Baines, K. J., Simpson, J. L., Wood, L. G., Scott, R. J. & Gibson, P. G. Transcriptional phenotypes of asthma defined by gene expression profiling of induced sputum samples. J. Allergy Clin. Immunol. 127, 153–160 (2011).

    CAS  Article  Google Scholar 

  26. 26

    Kim, J. H. et al. Pellino-1, an adaptor protein of interleukin-1 receptor/toll-like receptor signaling, is sumoylated by Ubc9. Mol. Cells 31, 85–89 (2011).

    CAS  Article  Google Scholar 

  27. 27

    Choi, K. C. et al. Smad6 negatively regulates interleukin 1-receptor-Toll-like receptor signaling through direct interaction with the adaptor Pellino-1. Nature Immunol. 7, 1057–1065 (2006). This study highlights Pellino 1 as a target for the TGFβ signalling pathway and describes the disruption of Pellino 1–IRAK complexes as underlying the inhibitory effects of TGFβ on IL-1 signalling.

    CAS  Article  Google Scholar 

  28. 28

    Lee, Y. S. et al. Smad7 and Smad6 bind to discrete regions of Pellino-1 via their MH2 domains to mediate TGF-β1-induced negative regulation of IL-1R/TLR signaling. Biochem. Biophys. Res. Commun. 393, 836–843 (2010).

    CAS  Article  Google Scholar 

  29. 29

    Kim, T. W. et al. Pellino 2 is critical for Toll-like receptor/interleukin-1 receptor (TLR/IL-1R)-mediated post-transcriptional control. J. Biol. Chem. 287, 25686–25695 (2012). This study indicates an important role for Pellino 2 in mediating ubiquitylation of IRAK1 and in triggering the downstream activation of MAPKs that stabilize transcripts encoding pro-inflammatory genes.

    CAS  Article  Google Scholar 

  30. 30

    Chang, M., Jin, W. & Sun, S. C. Peli1 facilitates TRIF-dependent Toll-like receptor signaling and proinflammatory cytokine production. Nature Immunol. 10, 1089–1095 (2009). This study describes the first physiological role for Pellino 1 with a focus on its role as an E3 ubiquitin ligase for RIP1 and in mediating the TRIF-dependent activation of NF-κB.

    CAS  Article  Google Scholar 

  31. 31

    Cusson-Hermance, N., Khurana, S., Lee, T. H., Fitzgerald, K. A. & Kelliher, M. A. Rip1 mediates the Trif-dependent toll-like receptor 3- and 4-induced NF-κB activation but does not contribute to interferon regulatory factor 3 activation. J. Biol. Chem. 280, 36560–36566 (2005).

    CAS  Article  Google Scholar 

  32. 32

    Yamamoto, M. et al. Cutting edge: a novel Toll/IL-1 receptor domain-containing adapter that preferentially activates the IFNβ promoter in the Toll-like receptor signaling. J. Immunol. 169, 6668–6672 (2002).

    CAS  Article  Google Scholar 

  33. 33

    Oshiumi, H., Matsumoto, M., Funami, K., Akazawa, T. & Seya, T. TICAM-1, an adaptor molecule that participates in Toll-like receptor 3-mediated interferon-β induction. Nature Immunol. 4, 161–167 (2003).

    CAS  Article  Google Scholar 

  34. 34

    Yamamoto, M. et al. Role of adaptor TRIF in the MyD88-independent toll-like receptor signaling pathway. Science 301, 640–643 (2003).

    CAS  Article  Google Scholar 

  35. 35

    Fitzgerald, K. A. et al. IKKε and TBK1 are essential components of the IRF3 signaling pathway. Nature Immunol. 4, 491–496 (2003).

    CAS  Article  Google Scholar 

  36. 36

    Sharma, S. et al. Triggering the interferon antiviral response through an IKK-related pathway. Science 300, 1148–1151 (2003).

    CAS  Article  Google Scholar 

  37. 37

    Enesa, K. et al. Pellino1 is required for interferon production by viral double-stranded RNA. J. Biol. Chem. 287, 34825–34835 (2012). This study describes the generation of knock-in mice expressing a mutant form of Pellino 1 that is devoid of E3 ligase activity and suggests that Pellino 1 promotes increased binding of IRF3 to the Ifnb promoter.

    CAS  Article  Google Scholar 

  38. 38

    Ordureau, A. et al. DEAF1 is a Pellino1-interacting protein required for interferon production by Sendai virus and double-stranded RNA. J. Biol. Chem. 288, 24569–24580 (2013).

    CAS  Article  Google Scholar 

  39. 39

    Xiao, Y. et al. Peli1 promotes microglia-mediated CNS inflammation by regulating Traf3 degradation. Nature Med. 19, 595–602 (2013). This study shows a microglial cell-specific role for Pellino 1 in mediating the MYD88-dependent activation of MAPK pathways that result in neuroinflammation.

    CAS  Article  Google Scholar 

  40. 40

    Tseng, P. H. et al. Different modes of ubiquitination of the adaptor TRAF3 selectively activate the expression of type I interferons and proinflammatory cytokines. Nature Immunol. 11, 70–75 (2010).

    CAS  Article  Google Scholar 

  41. 41

    Chang, M. et al. The ubiquitin ligase Peli1 negatively regulates T cell activation and prevents autoimmunity. Nature Immunol. 12, 1002–1009 (2011). This study indicates that the function of Pellino 1 extends to adaptive immunity as this protein functions as a negative regulator of T cell activation.

    CAS  Article  Google Scholar 

  42. 42

    Moynagh, P. N. Peli1 (rel)ieves autoimmunity. Nature Immunol. 12, 927–929 (2011).

    CAS  Article  Google Scholar 

  43. 43

    Liu, Y. et al. BCL10 mediates lipopolysaccharide/toll-like receptor-4 signaling through interaction with Pellino2. J. Biol. Chem. 279, 37436–37444 (2004).

    CAS  Article  Google Scholar 

  44. 44

    Xiao, H. et al. Pellino 3b negatively regulates interleukin-1-induced TAK1-dependent NF-κB activation. J. Biol. Chem. 283, 14654–14664 (2008).

    CAS  Article  Google Scholar 

  45. 45

    Mellett, M., Atzei, P., Jackson, R., O'Neill, L. A. & Moynagh, P. N. Mal mediates TLR-induced activation of CREB and expression of IL-10. J. Immunol. 186, 4925–4935 (2011).

    CAS  Article  Google Scholar 

  46. 46

    Siednienko, J. et al. Pellino3 targets the IRF7 pathway and facilitates autoregulation of TLR3- and viral-induced expression of type I interferons. Nature Immunol. 13, 1055–1062 (2012). This study is the first description of a physiological role for Pellino 3 and indicates that it targets the IRF7 pathway to negatively regulate the TLR3-induced expression of IFNβ.

    CAS  Article  Google Scholar 

  47. 47

    Ning, S., Campos, A. D., Darnay, B. G., Bentz, G. L. & Pagano, J. S. TRAF6 and the three C-terminal lysine sites on IRF7 are required for its ubiquitination-mediated activation by the tumor necrosis factor receptor family member latent membrane protein 1. Mol. Cell. Biol. 28, 6536–6546 (2008).

    CAS  Article  Google Scholar 

  48. 48

    Tzieply, N. et al. OxLDL inhibits LPS-induced IFNβ expression by Pellino3- and IRAK1/4-dependent modification of TANK. Cell Signal. 24, 1141–1149 (2012).

    CAS  Article  Google Scholar 

  49. 49

    Conway, J. P. & Kinter, M. Proteomic and transcriptomic analyses of macrophages with an increased resistance to oxidized low density lipoprotein (oxLDL)-induced cytotoxicity generated by chronic exposure to oxLDL. Mol. Cell Proteom. 4, 1522–1540 (2005).

    CAS  Article  Google Scholar 

  50. 50

    Yang, S. et al. Pellino3 ubiquitinates RIP2 and mediates Nod2-induced signaling and protective effects in colitis. Nature Immunol. 14, 927–936 (2013). This study shows that Pellino 3 has a mediatory role in NOD2 signalling and in regulating intestinal inflammation by functioning as an E3 ubiquitin ligase for RIP2.

    CAS  Article  Google Scholar 

  51. 51

    Rubino, S. J., Selvanantham, T., Girardin, S. E. & Philpott, D. J. Nod-like receptors in the control of intestinal inflammation. Curr. Opin. Immunol. 24, 398–404 (2012).

    CAS  Article  Google Scholar 

  52. 52

    Damgaard, R. B. et al. The ubiquitin ligase XIAP recruits LUBAC for NOD2 signaling in inflammation and innate immunity. Mol. Cell 46, 746–758 (2012).

    CAS  Article  Google Scholar 

  53. 53

    Emmerich, C. H. et al. Activation of the canonical IKK complex by K63/M1-linked hybrid ubiquitin chains. Proc. Natl Acad. Sci. USA 110, 15247–15252 (2013).

    CAS  Article  Google Scholar 

  54. 54

    Yang, S. et al. Pellino3 targets RIP1 and regulates the pro-apoptotic effects of TNFα. Nature Commun. 4, 2583 (2013). This study suggests that Pellino 3 has a cytoprotective role in TNF signalling, as it targets RIP1 and blocks the formation of DISC as well as blocking downstream caspase-mediated apoptosis.

    Article  Google Scholar 

  55. 55

    Aggarwal, B. B. Signalling pathways of the TNF superfamily: a double-edged sword. Nature Rev. Immunol. 3, 745–756 (2003).

    CAS  Article  Google Scholar 

  56. 56

    Wong, W. W. et al. RIPK1 is not essential for TNFR1-induced activation of NF-κB. Cell Death Differ. 17, 482–487 (2010).

    CAS  Article  Google Scholar 

  57. 57

    Griffin, B. D. et al. A poxviral homolog of the Pellino protein inhibits Toll and Toll-like receptor signalling. Eur. J. Immunol. 41, 798–812 (2011).

    CAS  Article  Google Scholar 

  58. 58

    Nogueira, E. et al. Toll-like receptors-related genes in kidney transplant patients with chronic allograft nephropathy and acute rejection. Int. Immunopharmacol. 9, 673–676 (2009).

    CAS  Article  Google Scholar 

  59. 59

    Kim, J. J. et al. Assessment of risk factors for Korean children with Kawasaki disease. Pediatr. Cardiol. 33, 513–520 (2012).

    Article  Google Scholar 

  60. 60

    Kim, J. J. et al. A genome-wide association analysis reveals 1p31 and 2p13.3 as susceptibility loci for Kawasaki disease. Hum. Genet. 129, 487–495 (2011).

    Article  Google Scholar 

  61. 61

    Malynn, B. A. & Ma, A. Ubiquitin makes its mark on immune regulation. Immunity 33, 843–852 (2010).

    CAS  Article  Google Scholar 

  62. 62

    Kirisako, T. et al. A ubiquitin ligase complex assembles linear polyubiquitin chains. EMBO J. 25, 4877–4887 (2006).

    CAS  Article  Google Scholar 

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Acknowledgements

The work carried out in the author's laboratory related to this Review is supported by grants from Science Foundation Ireland (07/IN.1/B972 and 12/IA/1736) and the Health Research Board of Ireland (Grant No. PhD/2007/09).

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Correspondence to Paul N. Moynagh.

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Glossary

Pattern recognition receptors

(PRRs). Host receptors (such as Toll-like receptors (TLRs) and NOD-like receptors (NLRs)) that can sense pathogen-associated molecular patterns and initiate signalling cascades that lead to an innate immune response. These can be membrane bound (for example, TLRs) or soluble cytoplasmic receptors (such as retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated protein 5 (MDA5) and NLRs).

Pathogen-associated molecular patterns

(PAMPs). Molecular motifs that are characteristic of bacteria and archaea and are recognized by the mammalian innate immune system.

Lys63-linked polyubiquitin chains

Polyubiquitin chains that are formed on a target protein linked through the lysine residue at position 63 (Lys63) in ubiquitin. In contrast to Lys48-linked polyubiquitin chains, which are the principal signal for targeting substrates for proteasomal degradation, Lys63-linked polyubiquitin modifications regulate protein function, target certain proteins for endocytosis, and/or facilitate the interaction of these proteins with other proteins that have specific ubiquitin-binding domains.

Chronic obstructive pulmonary disease

A group of diseases characterized by the pathological limitation of airflow in the airways, including chronic obstructive bronchitis and emphysema. These diseases are most often caused by tobacco smoking, but can also be caused by other airborne irritants, such as coal dust, and occasionally by genetic abnormalities, such as α1-antitrypsin deficiency.

Sumoylation

The post-translational modification of proteins that involves the covalent attachment of a small ubiquitin-related modifier (SUMO) and that regulates the interactions of those proteins with other macromolecules.

Septic shock

A systemic response to severe bacterial infections, which are generally caused by Gram-negative bacterial endotoxins, that leads to a hyperactive and out-of-balance network of inflammatory cytokines, affecting vascular permeability, cardiac function and metabolic balance, and leading to tissue necrosis, multiple organ failure and death.

Polyinosinic–polycytidylic acid

(PolyI:C). A substance that is used as a mimic of viral double-stranded RNA, which is sensed by Toll-like receptor 3.

Self tolerance

Tolerance to an individual's own antigens that is achieved through both central and peripheral tolerance mechanisms, including T cell deletion, anergy and immune regulation.

Foam cells

Macrophages that localize to sites of early stage inflammation in the vessel wall and that subsequently ingest oxidized low-density lipoprotein and slowly become overloaded with lipids. They are called foam cells because of their appearance, including numerous cytoplasmic vesicles that contain cholesterol and other lipids. Foam cells eventually die and attract more macrophages, and further propagate the inflammation in the vessel wall.

Crohn's disease

One of two idiopathic inflammatory bowel diseases that are characterized by chronic intestinal inflammation. The inflammatory lesions of Crohn's disease can occur in any part of the gastrointestinal tract. By contrast, ulcerative colitis is typically confined to the colon and to the distal small bowel.

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Moynagh, P. The roles of Pellino E3 ubiquitin ligases in immunity. Nat Rev Immunol 14, 122–131 (2014). https://doi.org/10.1038/nri3599

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