Introduction: Decoding How Lactate Regulates Innate Immune Surveillance
The cyclic GMP–AMP synthase (cGAS) pathway is one of the central pillars of mammalian innate immunity. By sensing cytosolic DNA, cGAS activates the STING signaling cascade, triggering antiviral defense, inflammatory responses, and antitumor immunity. The importance of this pathway was further underscored by its recognition through the prestigious Lasker Award, highlighting its transformative impact on immunology.
The activity of cGAS is tightly controlled by post-translational modifications, including acetylation and phosphorylation, which fine-tune its ability to distinguish self from foreign DNA. More recently, lysine lactylation has emerged as another important regulatory mechanism linking cellular metabolism with immune signaling.
However, one fundamental question has remained unresolved: How do mammalian cells sense intracellular L-lactate and translate this metabolic signal into cGAS lactylation that regulates innate immunity?
Addressing this challenge requires technologies capable of precisely detecting lactylation events and validating modification-specific mechanisms at both the global and site-specific levels.
Research Discovery: AARS1/2 Identified as Global L-Lactate Sensors and Lactyltransferases
A groundbreaking study published in Nature, titled “AARS1 and AARS2 sense L-lactate to regulate cGAS as global lysine lactyltransferases,” led by Prof. Long Zhang from Zhejiang University, uncovered a previously unknown mechanism connecting lactate metabolism with innate immune regulation.
The researchers discovered that AARS1 and AARS2 function as intracellular L-lactate sensors and ATP-dependent lactyltransferases, revealing an unexpected non-canonical role for these aminoacyl-tRNA synthetases beyond protein translation.
Unlike conventional acylation pathways that depend on lactyl-CoA, AARS1/2 directly utilize L-lactate and ATP to generate a reactive lactyl-AMP intermediate, enabling transfer of lactyl groups onto lysine residues across numerous proteins.
Most notably, the study demonstrated that AARS2 specifically mediates lactylation of cGAS, leading to its inactivation. This modification suppresses cGAMP production, weakens innate immune responses, and ultimately influences antiviral defense and immune escape.
Furthermore, blocking MCT1-mediated lactate transport prevented cGAS lactylation and restored immune signaling, highlighting a promising strategy for therapeutic intervention.
Core Breakthrough: PTM BIO’s L-Lactylation Tools Enable High-Confidence Mechanistic Validation
Deciphering this previously unknown regulatory pathway required highly specific tools capable of distinguishing L-lactylation events from other closely related protein modifications.
To systematically investigate lactate-dependent regulation, the research team combined genome-wide CRISPR screening with lactylation proteomics, while utilizing PTM BIO’s L-lactylation antibodies and L-lactylation pan-antibody enrichment resin to validate modification events throughout the study.
The integrated workflow demonstrated that depletion of either AARS1 or AARS2 markedly reduced global L-lactylation levels, while overexpression produced the opposite effect, establishing both enzymes as key regulators of cellular lactylation.
Mechanistic experiments further revealed that AARS2, rather than AARS1, serves as the principal enzyme responsible for cGAS lactylation. Site-specific analyses showed that lactylation of human cGAS Lys131 (corresponding to mouse Lys156) impaired the protein’s ability to undergo liquid-liquid phase separation (LLPS), reducing its enzymatic activity and preventing efficient recognition of mitochondrial DNA.
Rather than relying solely on candidate-based validation, the combination of modification-specific reagents and functional assays enabled researchers to connect global lactylation remodeling with precise molecular mechanisms governing innate immunity.
PTM BIO: Supporting Discovery from Modification Detection to Functional Validation
In this landmark Nature study, PTM BIO provided critical research tools that helped transform modification-specific observations into mechanistic understanding.
Precise Detection of L-Lactylation
Discriminating L-lactylation from closely related acyl modifications requires highly specific reagents. PTM BIO’s L-lactylation antibodies enabled reliable detection of endogenous modification events throughout multiple stages of the research workflow.
Enrichment for Comprehensive Analysis
The L-lactylation pan-antibody enrichment resin supported sensitive isolation of modified peptides, facilitating systematic investigation of lactylation dynamics across biological samples.
Strengthening Mechanistic Research
By integrating modification-specific reagents with functional validation experiments, PTM BIO’s research tools helped establish a robust experimental framework linking metabolic signaling with immune regulation.
Scientific Impact: Expanding the Landscape of Lactylation Biology
This study significantly advances our understanding of how metabolic signals regulate innate immunity.
By identifying AARS1 and AARS2 as evolutionarily conserved L-lactate sensors and ATP-dependent lactyltransferases, the research establishes a new paradigm in which lactate itself—rather than lactyl-CoA—serves as the direct donor for protein lactylation.
The work also broadens the growing landscape of lactylation biology by demonstrating that AARS2-mediated cGAS lactylation suppresses innate immune surveillance, affecting antiviral responses and potentially contributing to immune evasion.
Beyond infectious disease, the findings extend into neuroimmunology. The study showed that elevated L-lactate levels associated with anxiety reduce immune surveillance through cGAS lactylation, while inhibition of MCT1 restores DNA sensing and innate immune function.
More broadly, this work establishes new opportunities for targeting lactate-dependent signaling pathways in immunotherapy, antiviral intervention, and metabolic disease research.
PTM BIO: Empowering Next-Generation PTMomics Research
As a leader in proteomics-driven life science research, PTM BIO is committed to helping researchers decode complex biological regulation through advanced PTMomics technologies and high-performance modification-specific research tools.
Our integrated solutions—including L-lactylation antibodies, D-lactylation antibodies, lactylation enrichment platforms, comprehensive PTMomics workflows, and targeted validation technologies—enable researchers worldwide to uncover previously hidden layers of protein regulation.
From global modification profiling to mechanistic validation, PTM BIO continues to support cutting-edge discoveries across immunology, cancer biology, metabolism, neuroscience, and beyond.
