Evolution-inspired dissection of caspase activities enables the redesign of caspase-4 into an LPS sensing interleukin-1 converting enzyme

AbstractInnate immune signaling pathways comprise multiple proteins that promote inflammation. This multistep means of information transfer suggests that complexity is a prerequisite for pathway design. Herein, we examined this possibility by studying caspases that regulate inflammasome-dependent inflammation. Several caspases differ in their ability to recognize bacterial LPS and cleave interleukin-1β (IL-1β). No caspase is known to contain both activities, yet distinct caspases with complementary activities bookend an LPS-induced pathway to IL-1β cleavage. Using unique caspases present in carnivorans as a guide, we identified molecular determinants of IL-1β cleavage specificity within caspase-1. This knowledge enabled the redesign of human caspase-4 to operate as a one-protein signaling pathway, which intrinsically links LPS detection to IL-1β cleavage and release, independent of inflammasomes. Strikingly, cat caspase-4 displays the activities of redesigned human caspase-4. These findings illustrate natural signaling pathway diversity and highlight how multistep innate immune pathways can be condensed into a single protein.

Download Full-text

Evolution-inspired redesign of the LPS receptor caspase-4 into an interleukin-1β–converting enzyme

Science Immunology ◽

10.1126/sciimmunol.abh3567 ◽

2021 ◽

Vol 6 (62) ◽

pp. eabh3567

Author(s):

Pascal Devant ◽

Anh Cao ◽

Jonathan C. Kagan

Keyword(s):

Signaling Pathway ◽

Information Transfer ◽

Innate Immune ◽

Interleukin 1Β ◽

Protein Signaling ◽

Caspase 1 ◽

Hybrid Proteins ◽

Innate Immune Signaling ◽

Molecular Determinants ◽

Human Caspase

Innate immune signaling pathways comprise multiple proteins that promote inflammation. This multistep means of information transfer suggests that complexity is a prerequisite for pathway design. Here, we test this hypothesis by studying caspases that regulate inflammasome-dependent inflammation. Several caspases differ in their ability to recognize bacterial lipopolysaccharide (LPS) and cleave interleukin-1β (IL-1β). No caspase is known to contain both activities, yet distinct caspases with complementary activities bookend an LPS-induced pathway to IL-1β cleavage. Using caspase-1/4 hybrid proteins present in canines as a guide, we identified molecular determinants of IL-1β cleavage specificity within human and murine caspase-1. This knowledge enabled the redesign of human caspase-4 to operate as a one-protein signaling pathway, which intrinsically links LPS detection to IL-1β cleavage and release, independent of inflammasomes. We identified caspase-4 homologs in multiple carnivorans that display the activities of redesigned human caspase-4. These findings illustrate natural signaling pathway diversity and highlight how multistep innate immune pathways can be condensed into a single protein.

Download Full-text

Hepatitis C Virus Infection Is Inhibited by a Noncanonical Antiviral Signaling Pathway Targeted by NS3-NS4A

Journal of Virology ◽

10.1128/jvi.00725-19 ◽

2019 ◽

Vol 93 (23) ◽

Cited By ~ 9

Author(s):

Christine Vazquez ◽

Chin Yee Tan ◽

Stacy M. Horner

Keyword(s):

Hepatitis C ◽

Viral Replication ◽

Signaling Pathway ◽

Transmembrane Domain ◽

Innate Immune ◽

Hcv Infection ◽

Interferon Induction ◽

Innate Immune Signaling ◽

Huh7 Cells ◽

Irf3 Activation

ABSTRACT The hepatitis C virus (HCV) NS3-NS4A protease complex is required for viral replication and is the major viral innate immune evasion factor. NS3-NS4A evades antiviral innate immunity by inactivating several proteins, including MAVS, the signaling adaptor for RIG-I and MDA5, and Riplet, an E3 ubiquitin ligase that activates RIG-I. Here, we identified a Tyr-16-Phe (Y16F) change in the NS4A transmembrane domain that prevents NS3-NS4A targeting of Riplet but not MAVS. This Y16F substitution reduces HCV replication in Huh7 cells, but not in Huh-7.5 cells, known to lack RIG-I signaling. Surprisingly, deletion of RIG-I in Huh7 cells did not restore Y16F viral replication. Rather, we found that Huh-7.5 cells lack Riplet expression and that the addition of Riplet to these cells reduced HCV Y16F replication, whereas the addition of Riplet lacking the RING domain restored HCV Y16F replication. In addition, TBK1 inhibition or IRF3 deletion in Huh7 cells was sufficient to restore HCV Y16F replication, and the Y16F protease lacked the ability to prevent IRF3 activation or interferon induction. Taken together, these data reveal that the NS4A Y16 residue regulates a noncanonical Riplet-TBK1-IRF3-dependent, but RIG-I-MAVS-independent, signaling pathway that limits HCV infection. IMPORTANCE The HCV NS3-NS4A protease complex facilitates viral replication by cleaving and inactivating the antiviral innate immune signaling proteins MAVS and Riplet, which are essential for RIG-I activation. NS3-NS4A therefore prevents IRF3 activation and interferon induction during HCV infection. Here, we uncover an amino acid residue within the NS4A transmembrane domain that is essential for inactivation of Riplet but does not affect MAVS cleavage by NS3-NS4A. Our study reveals that Riplet is involved in a RIG-I- and MAVS-independent signaling pathway that activates IRF3 and that this pathway is normally inactivated by NS3-NS4A during HCV infection. Our study selectively uncouples these distinct regulatory mechanisms within NS3-NS4A and defines a new role for Riplet in the antiviral response to HCV. Since Riplet is known to be inhibited by other RNA viruses, such as such influenza A virus, this innate immune signaling pathway may also be important in controlling other RNA virus infections.

Download Full-text

Stimulator of Interferon Genes Signaling Pathway and its Role in Anti-tumor Immune Therapy

Current Pharmaceutical Design ◽

10.2174/1381612826666200610183048 ◽

2020 ◽

Vol 26 (26) ◽

pp. 3085-3095 ◽

Cited By ~ 1

Author(s):

Yuanjin Gong ◽

Chang Chang ◽

Xi Liu ◽

Yan He ◽

Yiqi Wu ◽

...

Keyword(s):

Signaling Pathway ◽

Immune Therapy ◽

Signal Transduction Pathway ◽

The Body ◽

Innate Immune ◽

Type I ◽

Innate Immune Signaling ◽

Critical Problems ◽

Molecular Patterns ◽

Damage Associated Molecular Patterns

Stimulator of interferon genes is an important innate immune signaling molecule in the body and is involved in the innate immune signal transduction pathway induced by pathogen-associated molecular patterns or damage-associated molecular patterns. Stimulator of interferon genes promotes the production of type I interferon and thus plays an important role in the innate immune response to infection. In addition, according to a recent study, the stimulator of interferon genes pathway also contributes to anti-inflammatory and anti-tumor reactions. In this paper, current researches on the Stimulator of interferon genes signaling pathway and its relationship with tumor immunity are reviewed. Meanwhile, a series of critical problems to be addressed in subsequent studies are discussed as well.

Download Full-text

CS17-5. Arteri- and nairovirus OTU domain-containing proteases target ubiquitin-regulated factors in the RLR-mediated innate immune signaling pathway

Cytokine ◽

10.1016/j.cyto.2011.07.419 ◽

2011 ◽

Vol 56 (1) ◽

pp. 108

Author(s):

Marjolein Kikkert ◽

Puck B. van Kasteren ◽

Corrine Beugeling ◽

Dennis Ninaber ◽

Sander van Boheemen ◽

...

Keyword(s):

Signaling Pathway ◽

Innate Immune ◽

Immune Signaling ◽

Innate Immune Signaling ◽

Immune Signaling Pathway ◽

Innate Immune Signaling Pathway

Download Full-text

Hepatitis C virus infection is inhibited by a non-canonical antiviral signaling pathway targeted by NS3-NS4A

10.1101/625640 ◽

2019 ◽

Cited By ~ 1

Author(s):

Christine Vazquez ◽

Chin Yee Tan ◽

Stacy M. Horner

Keyword(s):

Hepatitis C ◽

Viral Replication ◽

Signaling Pathway ◽

Transmembrane Domain ◽

Innate Immune ◽

Hcv Infection ◽

Interferon Induction ◽

Innate Immune Signaling ◽

Huh7 Cells ◽

Irf3 Activation

AbstractThe hepatitis C virus (HCV) NS3-NS4A protease complex is required for viral replication and is the major viral innate immune evasion factor. NS3-NS4A evades antiviral innate immunity by inactivating several proteins, including MAVS, the signaling adaptor for RIG-I and MDA5, and Riplet, an E3 ubiquitin ligase that activates RIG-I. Here, we identified a Tyr-16-Phe (Y16F) change in the NS4A transmembrane domain that prevents NS3-NS4A targeting of Riplet but not MAVS. This Y16F substitution reduces HCV replication in Huh7 cells, but not in Huh-7.5 cells, known to lack RIG-I signaling. Surprisingly, deletion of RIG-I in Huh7 cells did not restore Y16F viral replication. Rather, we found that Huh-7.5 cells lack Riplet expression and that addition of Riplet to these cells reduced HCV Y16F replication. In addition, IRF3 deletion in Huh7 cells was sufficient to restore HCV Y16F replication, and the Y16F protease lacked the ability to prevent IRF3 activation or interferon induction. Taken together, these data reveal that the NS4A Y16 residue regulates a non-canonical Riplet-IRF3-dependent, but RIG-I-MAVS-independent, signaling pathway that limits HCV infection.ImportanceThe HCV NS3-NS4A protease complex facilitates viral replication by cleaving and inactivating the antiviral innate immune signaling proteins MAVS and Riplet, which are essential for RIG-I activation. NS3-NS4A therefore prevents IRF3 activation and interferon induction during HCV infection. Here, we uncover an amino acid residue within the NS4A transmembrane domain that is essential for inactivation of Riplet, but does not affect MAVS cleavage by NS3-NS4A. Our study reveals that Riplet is involved in a RIG-I- and MAVS-independent signaling pathway that activates IRF3 and that this pathway is normally inactivated by NS3-NS4A during HCV infection. Our study selectively uncouples these distinct regulatory mechanisms within NS3-NS4A and defines a new role for Riplet in the antiviral response to HCV. As Riplet is known to be inhibited by other RNA viruses, such as such influenza A virus, this innate immune signaling pathway may also be important in controlling other RNA virus infections.

Download Full-text

Abstract PS17-18: Eribulin-mediated release of mitochondrial DNA activates the cGAS-STING innate immune signaling pathway

10.1158/1538-7445.sabcs20-ps17-18 ◽

2021 ◽

Author(s):

Charles Steven Fermaintt ◽

Leila Takahashi-Ruiz ◽

Susan L Mooberry ◽

April L Risinger

Keyword(s):

Mitochondrial Dna ◽

Signaling Pathway ◽

Innate Immune ◽

Immune Signaling ◽

Innate Immune Signaling ◽

Immune Signaling Pathway ◽

Innate Immune Signaling Pathway

Download Full-text

A one-protein signaling pathway in the innate immune system

Science Immunology ◽

10.1126/sciimmunol.aah6184 ◽

2016 ◽

Vol 1 (2) ◽

pp. eaah6184-eaah6184

Author(s):

Megan H. Orzalli ◽

Jonathan C. Kagan

Keyword(s):

Immune System ◽

Signaling Pathway ◽

Innate Immune System ◽

Innate Immune ◽

Protein Signaling

Download Full-text

Interactions between Viperin, IRAK1 andTRAF6 couple innate immune signaling to antiviral ribonucleotide synthesis

10.1101/318840 ◽

2018 ◽

Cited By ~ 2

Author(s):

Arti B. Dumbrepatil ◽

Soumi Ghosh ◽

Ayesha M. Patel ◽

Kelcie A. Zegalia ◽

Paige A. Malec ◽

...

Keyword(s):

Structural Changes ◽

Interleukin 1 ◽

Innate Immune ◽

Tnf Receptor ◽

Toll Like Receptor ◽

Immune Signaling ◽

Innate Immune Signaling ◽

Synergistic Activation ◽

Catalytically Active ◽

Cellular Antiviral Response

SummaryViperin is a radical S-adenosylmethionine (SAM) enzyme that plays a multifaceted role in the cellular antiviral response. Viperin was recently shown to catalyze the SAM-dependent formation of 3′-deoxy-3′,4′-didehydro-CTP (ddhCTP), which inhibits some viral RNA polymerases. Viperin is also implicated in regulating K63-linked poly-ubiquitination of interleukin-1 receptor-associated kinase-1 (IRAK1) by the E3 ubiquitin ligase TNF Receptor-Associated Factor 6 (TRAF6) as part of the Toll-like receptor-7 and 9 (TLR7/9) innate immune signaling pathways. We show that IRAK1 and TRAF6 activate viperin to efficiently catalyze the radical-mediated dehydration of CTP to ddhCTP. Furthermore, poly-ubiquitination of IRAK1 requires the association of viperin with IRAK1 and TRAF6. Poly-ubiquitination appears dependent on structural changes induced by SAM binding to viperin but does not require catalytically active viperin. The synergistic activation of viperin and IRAK1 provides a mechanism that couples innate immune signaling with the production of the antiviral nucleotide ddhCTP.

Download Full-text