Aug 2026· Frontiers in Physiology· Vol 17· 0 citations· 58 references
Medicine
TL;DR
Emerging insights into PTM-mediated regulation of MAVS are summarized and broader implications for mitochondrial antiviral signaling are outlined, highlighting new avenues for therapeutic modulation of innate immunity and cell fate during viral infection.
Abstract
Mitochondria function not only as metabolic and bioenergetic centers but also as critical signaling hubs that integrate cellular context with innate immune response. The mitochondrial antiviral-signaling protein (MAVS), anchored to the outer mitochondrial membrane, is a central adaptor in the RIG-I-like receptor (RLR) pathway, orchestrating type I interferon (IFN) production and apoptosis. Although long regarded as a docking platform for RLR-derived signals, recent advances, particularly concerning its diverse post-translational modifications (PTMs), reveal MAVS as a dynamic integrator that decodes cellular stress and metabolic cues to fine-tune antiviral immunity. Canonical PTMs such as ubiquitination and phosphorylation highlight the importance of precisely controlling both the initiation and downregulation of MAVS signaling, but recent discoveries substantially broaden this regulatory landscape. Stress-responsive phosphorylation mediated via the ASK1–p38 MAPK pathway enhances MAVS signaling capacity under oxidative and ER stress, linking cellular damage to amplified interferon production. In parallel, a newly identified vitamin K–dependent carboxylation of MAVS reshapes downstream signaling by promoting interferon induction while restraining apoptosis, introducing a regulatory layer that may reflect the metabolic context surrounding GGCX activity, including vitamin K availability. Understanding this multilayered regulatory network not only redefines MAVS as a stress-sensitive mitochondrial signaling hub responsive to cellular context but also highlights new avenues for therapeutic modulation of innate immunity and cell fate during viral infection. This review summarizes emerging insights into PTM-mediated regulation of MAVS and outlines their broader implications for mitochondrial antiviral signaling.
SUMOylation is a reversible post-translational modification increasingly recognized for its role in coordinating cellular responses to metabolic stress during aging. Emerging evidence indicates that it functions beyond a conventional modification, representing an adaptive stress‑responsive regulatory network that integrates metabolic, oxidative, inflammatory, and proteotoxic signals. Rather than acting on isolated pathways, this network finely tunes mitochondrial function, proteostasis, genome maintenance, immune balance, and epigenetic regulation. Accumulating evidence indicates that SUMO-dependent regulation exhibits remarkable tissue specificity, supporting mitochondrial adaptation and contractile integrity in skeletal muscle, shaping lipid and glucose metabolism in the liver, modulating proteotoxic stress and neuronal resilience in the brain, and contributing to immune cell differentiation and chronic low-grade inflammation during aging. In this review, we summarize current mechanistic insights into SUMO signaling across aging-relevant tissues, with particular emphasis on its functional interplay with other post-translational modifications, including ubiquitination and acetylation. We discuss how SUMOylation operates as a shared regulatory layer while enabling context-dependent outcomes that underlie diverse aging phenotypes and age-related disorders. Finally, we evaluate emerging translational approaches-ranging from pharmacological modulation of SUMO enzymes to lifestyle interventions such as caloric restriction and exercise-that highlight both the opportunities and challenges of targeting SUMO-regulated stress responses in aging. Together, this synthesis provides a framework for understanding how SUMOylation links metabolic stress to tissue-specific aging trajectories and therapeutic potential.
Xin-Yue Liu, Shuang Chen, Dong-Can Liu et al.· Ageing Research Reviews· 0 citations
5′-Adenosine monophosphate-activated protein kinase (AMPK) is the principal cellular energy sensor that coordinates metabolic adaptation by balancing anabolic and catabolic pathways in response to energic stress. Beyond its canonical role in maintaining energy homeostasis, AMPK has emerged as a central regulator of host–pathogen interactions by integrating lipid metabolism, autophagy, mitochondrial dynamics, oxidative stress, and innate immune signaling. Flaviviruses, including dengue virus, Zika virus, West Nile virus, Japanese encephalitis virus, and yellow fever virus, extensively remodel host metabolism to establish productive infection. As a master regulator of cellular metabolism, AMPK can either restrict or facilitate flavivirus replication in a context-dependent manner by regulating lipid droplet biogenesis, fatty acid synthesis and beta-oxidation, autophagy, mitochondrial homeostasis, and interferon-mediated antiviral responses. Conversely, flaviviruses actively manipulate AMPK signaling and its downstream metabolic networks to promote endoplasmic reticulum remodeling, replication organelle biogenesis, energy production, and immune evasion. In this review, we summarize recent advances in understanding the multifaceted roles of AMPK during flavivirus infection, with an emphasis on its regulation of metabolic reprogramming, organelle remodeling, and antiviral immunity. We further discuss the therapeutic potential of pharmacologically targeting AMPK and its downstream pathways as a host-directed strategy for broad-spectrum antiviral intervention against flaviviruses.
ISGylation is an interferon-inducible ubiquitin-like post-translational modification mediated by the interferon-stimulated gene 15 conjugation system. Initially characterized as an antiviral effector pathway, ISGylation is now increasingly recognized as a regulator of organelle homeostasis and cellular stress responses. This review summarizes emerging evidence linking ISG15-related mechanisms and covalent ISGylation to major organelle systems, including mitochondria, the endoplasmic reticulum–Golgi axis, endolysosomal compartments, ribosome-associated translation, and lipid droplets. We distinguish covalent ISGylation from free ISG15 signaling and ubiquitin specific protease 18-mediated interferon regulation, and further classify existing findings into evidence-based levels ranging from substrate-validated modification to correlative interferon signatures. At the mitochondrial level, direct and pathway-level evidence implicates ISG15 biology in DRP1-mediated fission, MFN1/2-associated mitophagy, oxidative metabolism, and redox regulation; direct effects of MFN1/2 ISGylation on mitochondrial fusion remain unproven. Along the ER–Golgi axis, ISG15-related pathways intersect with unfolded protein response signaling, endoplasmic reticulum-associated degradation, and stimulator of interferon genes-mediated innate immune activation. In the endolysosomal system, ISGylation and ISG15-associated pathways modulate autophagic flux, multivesicular body fate, and exosome secretion in a context-dependent manner. Ribosome-associated co-translational ISGylation links nascent protein surveillance with antiviral defense, whereas lipid droplet-associated ISG15/ISGylation pathways are linked to lipid metabolism and immune signaling. Current evidence supports an organelle-centered view of ISG15 biology but indicates that validated covalent mechanisms remain confined to selected substrates and contexts. Clinical translation will require organelle-resolved ISGylome mapping, substrate-level validation, and standardized biomarker assays before context-selective targeting can be considered.
Zhuo-Er Li, Chunli Wang, Jin-Rong Zhang et al.· Frontiers in Immunology· 0 citations
During viral infection and tissue injury, efficient immune clearance of infected or damaged cells is crucial for host defense and homeostasis. Here, we identify mitochondrial RNA (mtRNA) as a broad-spectrum damage-associated molecular pattern (DAMP) that coordinates antiviral and damage-related immune clearance. Through an integrative approach combining in vitro cellular assays and multi-strain murine models, we demonstrate that viral infection and cellular stress promote POLRMT-dependent mtRNA synthesis and its release into the cytosol through BAX/mPTP-mediated mitochondrial pores. Once released, mtRNA activates the MAVS signaling pathway, triggering a robust type I interferon response that operates independently of the cGAS-STING axis. Notably, viruses exploit a negative feedback loop for immune evasion: type I interferon upregulates the exoribonuclease PNPT1, which degrades cytosolic mtRNA and thereby dampens the mtRNA-MAVS axis. Critically, pharmacological inhibition of PNPT1 with lanthanum chloride (LanC), combined with BH3 mimetics that relieve the BCL-2-mediated blockade of BAX/BAK pores, synergistically reactivates mtRNA release and restores antiviral immunity. This dual strategy demonstrates potent antiviral and anti-fibrotic efficacy in preclinical models without significant toxicity. Our findings establish the mtRNA-MAVS axis as a central, broadly applicable immune surveillance pathway and provide a mechanistic framework for developing therapies that overcome both viral immune evasion and the limitations of current STING-targeted agonists.
Mingfu Tian, Guangli Li, Zelin Chai et al.· Cell Death & Disease· 0 citations
Ten key PTMs, including lactylation, succinylation, succinylation, SUMOylation, and S-nitrosylation, acting on core regulators such as dynamin-related protein 1(DRP1), optic atrophy 1 (OPA1), Parkin, and mitochondrial Rho GTPase 1 (MIRO1) are summarized to provide a comprehensive resource for understanding mitochondrial plasticity in health and disease.
Haolin Ding, E. Taoxia, Jing-Cai He et al.· Element· 0 citations
Metabolic reprogramming is a central determinant of host defense and pathogen persistence during infection. Although the bacterial type VI secretion system (T6SS) is primarily recognized as a contact-dependent apparatus for interbacterial competition and effector delivery, emerging evidence indicates that T6SS activity can also influence host metabolism at cellular, nutritional, and microbial-community levels. Here, we organize current evidence into three mechanistic tiers: direct biochemical interference with lipids, metabolites, or metal ions; organelle- and signaling-mediated immunometabolic reprogramming; and indirect metabolic effects arising from T6SS-dependent remodeling of microbial communities. T6SS effectors can disrupt endoplasmic-reticulum lipid homeostasis, activate the unfolded protein response and autophagy, alter mitochondrial Ca2+ handling and dynamics, promote redox imbalance, and modulate metabolically sensitive immune pathways including phosphoinositide 3-kinase (PI3K)-Akt, inflammasome, and cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling. T6SS-associated proteins also mediate manganese and zinc acquisition or sequestration, linking microbial nutrient acquisition to host nutritional immunity. At the community level, T6SS-mediated competition may reshape resource allocation, horizontal gene transfer, and microbiome-derived metabolite production. However, while T6SS-induced organelle stress is well established, direct causal links to systemic metabolic diseases, including type 2 diabetes and dyslipidemia, remain unproven. We therefore distinguish direct metabolic measurements from inferences based on organelle damage or signaling changes and discuss strategies to define T6SS-driven metabolic fluxes and evaluate host-directed, anti-virulence, and microbiome-engineering approaches. Viewing the T6SS through an immunometabolic framework may reveal therapeutic vulnerabilities overlooked by conventional models of bacterial toxicity and competition.
Zhen-Zhen Zhang, Zhen Hou· Frontiers in Microbiology· 0 citations
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