Palmitoylation acts as a checkpoint for MAVS aggregation to promote antiviral innate immune responses
Liqiu Wang, … , Yaoxing Wu, Jun Cui
Liqiu Wang, … , Yaoxing Wu, Jun Cui
Published December 2, 2024
Citation Information: J Clin Invest. 2024;134(23):e177924. https://doi.org/10.1172/JCI177924.
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Research Article Cell biology Immunology

Palmitoylation acts as a checkpoint for MAVS aggregation to promote antiviral innate immune responses

Abstract

Upon RNA virus infection, the signaling adaptor MAVS forms functional prion-like aggregates on the mitochondrial outer membrane, which serve as a central hub that links virus recognition to downstream antiviral innate immune responses. Multiple mechanisms regulating MAVS activation have been revealed; however, the checkpoint governing MAVS aggregation remains elusive. Here, we demonstrated that the palmitoylation of MAVS at cysteine 79 (C79), which is catalyzed mainly by the palmitoyl S-acyltransferase ZDHHC12, was essential for MAVS aggregation and antiviral innate immunity upon viral infection in macrophages. Notably, the systemic lupus erythematosus–associated mutation MAVS C79F was associated with defective palmitoylation, resulting in low type I interferon (IFN) production. Accordingly, Zdhhc12 deficiency apparently impaired RNA virus–induced type I IFN responses, and Zdhhc12-deficient mice were highly susceptible to lethal viral infection. These findings reveal a previously unknown mechanism by which the palmitoylation of MAVS is a checkpoint for its aggregation during viral infection to ensure timely activation of antiviral defense.

Authors

Liqiu Wang, Mengqiu Li, Guangyu Lian, Shuai Yang, Jing Cai, Zhe Cai, Yaoxing Wu, Jun Cui

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Figure 1

Palmitoylation of MAVS at C79 is critical for RLR signaling activation.

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Palmitoylation of MAVS at C79 is critical for RLR signaling activation. ...
(A and B) HEK293T cells transfected with FLAG-MAVS were treated with DMSO or 2-bromopalmitate (2-BP; 50 μM/12 h) to assess MAVS palmitoylation via acyl-biotin exchange (ABE) and immunoblot analysis. WCL, whole-cell lysates. (C and D) THP-1–derived macrophages (C) or BMDMs (D) were treated with SeV (MOI = 1) or intracellular (IC) poly(I:C) (5 μg/mL) to measure MAVS palmitoylation levels. (E–H) Cells pretreated with DMSO or 2-BP followed by SeV or IC poly(I:C) treatment showed altered MAVS palmitoylation levels in THP-1–derived macrophages (E and F) or BMDMs (G and H). (I and J) HEK293T cells transfected with wild-type (WT) FLAG-MAVS or MAVS mutants were evaluated for their palmitoylation levels using ABE. (K) Alignment of MAVS sequences from various species highlighting the palmitoylation site. (L and M) MAVS-knockout (MAVS-KO) HEK293T cells were transfected with indicated plasmids, followed by SeV or IC poly(I:C) treatment. Cell lysates and supernatants were collected for immunoblot, real-time qPCR analysis, and ELISA. (N) Luciferase reporter assays in MAVS-KO HEK293T cells indicated functional differences between WT and C79F MAVS. (O and P) ABE assay and immunoblot analysis were performed in HEK293T cells transfected with WT or C79F MAVS. (Q) MAVS-KO HEK293T cells were transfected with indicated plasmids, followed by SeV or IC poly(I:C) treatment. Cell lysates and supernatants were collected for immunoblot analysis. In A, C–E, G, I, L, O, and Q, similar results were obtained for 3 independent experiments. In B, F, H, J, and P, data are presented as mean values ± SD. In M and N, data are presented as mean values ± SEM. Statistical analysis was performed using 2-tailed Student’s t test in B, F, H, M, and P or 1-way ANOVA multiple comparisons in J and N.