Lysine lactylation (Kla), a newly identified PTM (Zhang et al., 2019), involves the formation of a stable amide bond between lactic acid’s carboxyl group and the ε-amino group of lysine residues (Xu K. et al., 2024). Through analytical chemistry and mass spectrometry, researchers have distinguished the following three stereochemically distinct isomers: L-lactyl-lysine (KL-la), D-lactyl-lysine (KD-la), and N-ε(carboxyethyl)-lysine (Kce) (Zhang et al., 2025). Current research revealed two distinct pathways of lactylation: non-enzymatic and enzyme-dependent mechanisms (Figure 1). A detailed description of each mechanism is provided below.

Lactylation and acetylation share significant similarities: both derive primarily from pyruvate, possess similar molecular structures, and target lysine residues (Liu et al., 2023; Sabari et al., 2017; Stacpoole and Dirain, 2024). Owing to these structural and functional parallels, early lactylation research recommended lactyl-CoA as the substrate for this modification (Zhang et al., 2019). Initial investigations identified several acetyltransferases that function dually as lactyl transferases, including p300, CREB-binding protein (CBP), KAT2A, KAT5/TIP60, HBO1 (KAT7), KAT8, NAA10, ATAT1, and GCN5 (Wang X. et al., 2023; Chen Y. et al., 2024; Chen H. et al., 2024; Huang Y. et al., 2024; Fan M. et al., 2023; Hu et al., 2024; Huang H. et al., 2024; Liu et al., 2025; Moreno-Yruela et al., 2022; Wang et al., 2024; Yang et al., 2022; Yang et al., 2024; Zhang N. et al., 2023; Chen J. et al., 2024; Zhu et al., 2025; Chen et al., 2025b; Niu et al., 2024; Xie et al., 2024; Yuan et al., 2025; Niu et al., 2025; Yan et al., 2024; Cai et al., 2011; Wang N. et al., 2022; Tong et al., 2024). These writers demonstrated selectivity during lactylation catalysis, suggesting that different proteins’ lactylation may involve distinct catalytic enzymes, with lactyl-CoA majorly serving as the lactyl group donor (Gao et al., 2024). However, the field of lactyl-CoA synthetase research remained relatively underexplored.

A breakthrough occurred in November 2024 when (Zhu et al., 2025) identified acyl-CoA synthetase short-chain family member 2 (ACSS2) as the first mammalian lactyl-CoA synthetase (Zhu et al., 2025). When phosphorylated at S267, ACSS2 translocates to the nucleus where it converts lactate dehydrogenase (LDH) A -produced lactate into lactyl-CoA. ACSS2 then complexes with KAT2A, which then uses this lactyl-CoA as a substrate to complete histone lactylation (Zhu et al., 2025). Subsequently, Liu et al. discovered that GTP-specific succinate-CoA synthetase (GTPSCS) can relocate from the mitochondria to the nucleus, where it interacts with p300. Within this complex, GTPSCS generates lactyl-CoA in situ from lactate, while p300 mediates KL-la (Figure 1), thereby ultimately promoting glioblastoma progression through the GTPSCS/p300/H3K18la/GDF15 signaling axis (Liu et al., 2025). Despite these discoveries, lactyl-CoA concentration in cancer cells remains approximately 1000-fold lower than acetyl-CoA (Ju et al., 2024), which potentially limits the activity of lactyl transferases that utilize lactyl-CoA as a substrate. This significant disparity highlights the importance of further research to identify additional lactyl transferases and elucidate their catalytic mechanisms.

In 2023, Sun’s research on gastric cancer revealed that elevated copper levels enhanced interaction between alanine-tRNA synthetase (AARS) 1/2 and methyltransferase-like protein (METTL)16. Silencing AARS1/2 effectively suppressed copper-induced lactylation at K229 of METTL16. In vitro lactylation assay demonstrated that lactylation at METTL16 K229 was mediated by AARS1/2, same effect absented in METTL16 K229R mutant, suggesting AARS1/2 might mediate METTL16 K229 lactylation (Sun L. et al., 2023). By January 2024, Mao et al. observed structural similarities between lactate and alanine, which led them to hypothesize that alanyl-tRNA synthetases may recognize lactate. Their experiments confirmed AARS2’s ability to catalyze lactylation of mitochondrial proteins pyruvate dehydrogenase E1 alpha 1 (PDHA1) at K336 and carnitine palmitoyltransferase 2 (CPT2) at K457/458 (Mao et al., 2024). In March 2024, Ju et al. identified AARS1 as a bona fide lactyl transferase with multiple functions. Under ATP-dependent conditions, AARS1 senses lactate levels, translocate to the nucleus and directly uses lactate as a lactyl group donor to catalyze Yes-associated protein (YAP) and transcriptional enhanced associate domain (TEAD) lactylation in the Hippo pathway, which activates downstream gene transcription (Ju et al., 2024). Simultaneously, Zong demonstrated that AARS1 directly binds lactate and promotes p53 lactylation (K120/K139). The mechanism involves ATP activating lactate within AARS1 to form lactate-adenosine monophosphate, which then covalently attaches to lysine residues while releasing AMP. Among the AARS family, only AARS1-depleted cell lysates failed to lactylate p53, thereby establishing AARS1 as the primary p53 lactyl transferase (Zong et al., 2024). Further lactylation proteomics analysis confirmed AARS1/AARS2 as lactate-sensing proteins with lactyl transferase activity and identified that AARS2 catalyzed cyclic GMP-AMP synthase (cGAS) lactylation, which decreased cGAMP and interferon-β levels and suppressed innate immune responses (Li H. et al., 2024). The balance between AARS1/AARS2’s lactylation and alanine transfer functions involves competitive inhibition: alanine inhibits AARS’s lactylation activity, with β-alanine pretreatment dramatically reducing the lactylation levels in gastric cancer cells. Conversely, increased lactate competitively inhibits alanine function, while AARS1-mediated YAP lactylation enhances the AARS expression through positive feedback, thereby improving both lactate modification and alanine transport functions (Zong et al., 2024; Ju et al., 2024).

The first evidence of lactylation readers was reported by a study on induced pluripotent stem cell (iPSC) reprogramming, which revealed Brahma-related gene 1’s binding to H3K18 lactylation, thereby confirming its role as a lactylation reader (Hu et al., 2024). Subsequent research in cervical cancer, using multivalent photoaffinity probes with quantitative proteomics, identified Double PHD Fingers 2 as a specific reader of H3K14 lactylation (Zhai et al., 2024). In addition, AlphaScreen technology screening of 28 human bromodomain proteins discovered that tripartite motif (TRIM) 33 could specifically recognize multiple lactylation sites (Nuñez et al., 2024).

Previous studies have identified several erasers for lactylation modification, primarily histone deacetylase (HDAC) one to three and sirtuin (SIRT) 1–3 (Chen Y. et al., 2024; Moreno-Yruela et al., 2022; Jin et al., 2023). Zessin et al. discovered that HDAC6 and HDAC8 also exhibit potential delactylase activity, although their enzymatic activity is lower than that of HDAC3 (Zessin et al., 2022). All these enzymes have been primarily known for their deacetylase activities, although now they are recognized to possess dual functionality in removing both acetyl and lactyl groups from proteins. This functional duality raises questions regarding their enzymatic properties and biological roles in lactylation dynamics.

Lactylation, as a reversible PTM, provides cells with a dynamic and precise mechanism for regulating protein function. However, the full landscape of lactylation-modifying enzymes—writers, readers, erasers, and lactyl-CoA synthetases—remains unclear. Due to the unclear specific conditions through which lactylation-modification enzymes exert lactylation-related functions, future research may focus on comprehensively elucidating the functional specificity, substrate specificity, regulatory mechanisms of lactylation-modification enzymes, and their roles in tumorigenesis.

Lactylation modifies to specify protein-RNA interactions by altering protein conformation and surface charge. In N6-methyladenosine (m6A) RNA modification, K281la and K345la within the zinc finger domain of METTL3 considerably augment its binding affinity for m6A-modified RNA (Xiong et al., 2022). Similarly, insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) K76la strengthens its binding to m6A-modified phosphoenolpyruvate carboxykinase 2 (PCK2) and nuclear factor erythroid 2-related factor 2 mRNAs, triggering serine metabolism reprogramming (Lu et al., 2024). Furthermore, in intrahepatic cholangiocarcinoma, nucleolin K477la promotes target RNA binding via conformational changes, subsequently regulating downstream gene expression (Yang et al., 2024).

In addition, lactylation influences protein–DNA interactions. ATP-binding cassette transporter F1 (ABCF1) K430la mediates its nuclear translocation and enhances its binding to the lysine demethylase 3A (KDM3A) promoter, upregulating its expression (Hong et al., 2025). Meiotic recombination 11 (MRE11) K678la improves DNA binding and stimulates DNA end resection and homologous recombination repair efficiency without affecting the formation of the MRE11-RAD50-NBS complex (Chen Y. et al., 2024). Yin Yang-1 (YY1) K138la increases the binding to fibroblast growth factor 2 promoter, upregulating the transcription of fibroblast growth factor 2 (Wang X. et al., 2023). Similarly, YY1 K138la accentuates its binding to the FBXO33 promoter, substantially upregulating FBXO33 mRNA and protein expression (Wu et al., 2025).

In addition, protein–protein interactions are impacted by lactylation. Membrane-organizing extension spike protein (MOESIN) K72la forms hydrogen bonds with the transforming growth factor-β (TGF-β) type I receptor, strengthening their interaction (Gu et al., 2022) (Figure 2). In gastric cancer research, Nijmegen breakage syndrome 1 (NBS1) K388la promotes binding to MRE11, enabling MRE11-RAD50-NBS1 complex formation and DNA damage repair (Chen H. et al., 2024). α-MHC K1897la enhances its interaction with titin; in contrast, the K1897R mutation, which prevents lactylation, considerably reduces this interaction (Zhang N. et al., 2023). X-ray repair cross-complementing protein 1 (XRCC1) K247la increases the interaction with importin α in glioblastoma stem cells (GSCs) (Li G. et al., 2024). Vps34 lactylation at K356/K781 reinforces its interactions with Beclin 1, autophagy-related protein 14-like protein, and UV radiation resistance-associated gene, promoting lipid kinase activity (Sun W. et al., 2023; Jia et al., 2023).

Moreover, lactation can inhibit protein interactions. For instance, transcription factor EB (TFEB) K91la inhibits the interaction with WW domain containing E3 ubiquitin protein ligase 2 (WWP2) in pancreatic cancer cells (Huang Y. et al., 2024) (Figure 2). Compared with nonlactylated p53, 100-fold, 10-fold, and 1,000-fold reductions in the binding affinities of p53 K120la, p53 K139la, and p53 K120/K139la were observed (Zong et al., 2024). Aldolase A (ALDOA) K230/K322la weakens the binding to DEAD-box helicase 17 in liver cancer stem cells (Feng et al., 2024), and Ikzf1 K164la significantly decreases the binding to TH17 differentiation-related gene promoters (Fan W. et al., 2023).

Polypyrimidine tract-binding protein 1 (PTBP1) K436la displays bidirectional regulatory effects, disrupting hydrogen bond formation with TRIM21 while augmenting its binding to the 3′UTR of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase four mRNA (Figure 2). The effect of lactylation on all molecular interactions of a protein is not likely to be uniform owing to the selective modulation. This process specifically alters binding interfaces via conformational changes (Zhou et al., 2025).

The bidirectional regulatory effects of lactylation on nonhistone molecular interactions imply that its influence on protein function may be highly specific. Its underlying mechanisms and pathological significance warrant further exploration.

Lactylation considerably affects nonhistone protein stability. Several studies have reported that the stability of proteins such as lymphocyte cytosolic protein 1, hypoxia-inducible factor-1α (HIF-1α), carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), β-catenin, nucleolar and spindle associated protein 1 (NUSAP1), and phosphofructokinase P (PFKP) is enhanced after lactylation (Zhang W. et al., 2023; Luo et al., 2022; Chu et al., 2023; Miao et al., 2023; Chen et al., 2023; Mi, 2024) and is therefore positively regulated. When glycolysis is inhibited, the lactylation levels of these proteins are reduced, which decreases their stability, revealing a direct link between lactylation and cellular metabolic status.

One of the primary mechanisms by which lactylation influences nonhistone stability is by antagonizing the ubiquitination pathway. Fan identified K70 as the sole lactylation site of apolipoprotein C2 (APOC2). Together with K52, K61, and K96 residues, it serves as the target for ubiquitination (Chen J. et al., 2024). Lactate treatment substantially reduced the ubiquitination of wild-type APOC2 but did not affect the lactylation-deficient APOC2-K70R mutant. These findings confirmed that K70 lactylation maintains APOC2 stability by inhibiting ubiquitination (Chen J. et al., 2024) (Figure 2). Similar mechanisms operate in other proteins too. For instance, TFEB K91la disrupts its interaction with E3 ubiquitin ligase WWP2, lowering TFEB ubiquitination and proteasomal degradation in pancreatic cancer (Huang Y. et al., 2024). In glioma stem cells, PTBP1 K436la disrupts the formation of hydrogen bonds with the E3 ubiquitin ligase TRIM21, preventing proteasomal degradation and improving stability (Zhou et al., 2025) (Figure 2). In cervical cancer, discoidin, CUB and LCCL domain-containing 1 (DCBLD1) K172la inhibits ubiquitination, enhancing the stability and extending the protein half-life (Meng et al., 2024).

Besides regulating the ubiquitin–proteasome degradation pathway, lactylation controls protein stability via other mechanisms. In colorectal cancer (CRC), Tong et al. found that programmed death-ligand 1 (PD-L1) lactylation inhibits its degradation via the lysosomal pathway. Consequently, PD-L1 protein expression is increased, and PD-L1 mRNA is maintained at a constant level, revealing a novel lactylation mechanism that regulates the lysosomal degradation pathway (Tong et al., 2024). Furthermore, K147-lactylated ALDOA shows better thermal stability than the wild-type enzyme, signifying that lactylation directly affects the physicochemical properties of proteins (Shao et al., 2025).

In conclusion, lactylation regulates nonhistone protein stability by antagonizing ubiquitination, enhancing thermal stability, and inhibiting lysosomal degradation. These processes involve complex molecular interactions and crosstalk among various PTMs, constituting a complex regulatory network that modulates protein stability and influences cellular functions in physiological and pathological contexts.

Lactylation of nonhistone proteins exerts bidirectional regulatory effects on enzymatic activity.

Many studies have asserted the ability of lactylation to enhance the catalytic activity of enzymes. Nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) K128la is essential for maintaining enzymatic activity and nuclear NAD⁺ levels. The K128R delactylation mutant exhibits significantly reduced activity than the wild-type enzyme (Huang H. et al., 2024). In CRC, eukaryotic translation elongation factor 1 alpha 2 (eEF1A2) K408la improves GTPase activity in response to aa-tRNA stimulation, accelerating ribosomal translation elongation and promoting cancer cell proliferation (Xie et al., 2024). NOP2/Sun RNA methyltransferase 2 (NSUN2) K508la augments its RNA methyltransferase catalytic activity (Niu et al., 2025). In gastric cancer, METTL16 K229la status is directly correlated with its enzymatic activity. The K229R delactylation mutant shows decreased methyltransferase activity, whereas the K229E lactylation-mimicking mutant exhibits substantially improved activity (Sun L. et al., 2023). Moreover, pyruvate kinase M2 (PKM2) K62la contracts the amino acid binding pocket via conformational changes, stabilizing the tetrameric conformation and promoting the catalytic activity (Wang J. et al., 2022) (Figure 2).

Conversely, lactylation inhibits the catalytic activity of some enzymes. For instance, ALDOA K147la considerably reduces the enzymatic activity compared with the wild-type (Wan et al., 2022) (Figure 2). In 2025, researchers successfully introduced a precise K147la modification into ALDOA in HEK293T cells using the genetic code expansion technology. Functional analyses verified that lactylation significantly inhibited the enzymatic activity in vivo (Shao et al., 2025). Hypoxic conditions induced the accumulation of AARS2, which catalyzed PDHA1 K336la and CPT2 K457/K458la. Lactylation inactivated both enzymes and inhibited mitochondrial oxidative phosphorylation (Mao et al., 2024). Adenylate kinase 2 K28la substantially decreases the enzymatic activity and is correlated with hepatocellular carcinoma progression (Yang Z. et al., 2023).

Advanced LC–MS/MS technologies have aided in systematically identifying and analyzing nonhistone lactylation sites and their subcellular distribution. In gastrointestinal tumors, lactylation sites are distributed across the cytoplasm (39.58%), nucleus (35.41%), mitochondria (7.64%), extracellular regions, cell membrane, and endoplasmic reticulum (Chen J. et al., 2024). However, related research reported slightly different findings, with the highest proportion in the nucleus, followed by the cytoplasm, mitochondria, extracellular regions, and cytoplasmic membrane (Duan et al., 2024). The extensive distribution of lactylation implies that it may regulate protein function via subcellular localization, providing essential insights into cellular physiological and pathological processes.

Several studies have confirmed the role of lactylation in promoting the nuclear localization of proteins. ABCF1 K430la, which is upregulated in hepatocellular carcinoma, alters the protein conformation and exposes the nuclear localization sequence (NLS), guiding ABCF1 into the nucleus (Figure 2) and activating the HIF1 signaling pathway (Hong et al., 2025). In addition, lactate treatment augments Snail1 lactylation, increasing its nuclear translocation and TGF-β gene binding (Fan M. et al., 2023). NMNAT1 K128la, present within the NLS (K123-K129), considerably improves its nuclear localization (Huang H. et al., 2024). In GSCs, XRCC1-K247 lactylation aids its nuclear translocation and enhances DNA damage repair (Li G. et al., 2024). ALDOA K147la stimulates cytoplasm-to-nucleus translocation (Shao et al., 2025). Moreover, the oncogene c-Myc exhibits elevated nuclear localization and heightened protein levels under high lactate conditions, an effect eliminated by the P300 inhibitor C464 (Li Y. et al., 2024). Under high lactate conditions, increased lactylated and total c-Myc protein levels are seen in the nucleus. Upon inhibiting lactylation with the P300 inhibitor C464, the previously noted increase in nuclear c-Myc was eliminated (Li Y. et al., 2024). Transcription factor Twist1-K150 lactylation (rather than K73/K76) stimulates its nuclear translocation (Xu Y. et al., 2024).

Nonetheless, the effects of lactylation on nonhistone localization are not unidirectional. Wang observed that p300-mediated PKM2 lactylation can suppress its nuclear translocation (Wang et al., 2024). Similarly, another research uncovered that the PKM2-K62R mutant shows approximately 1.41-fold higher nuclear levels than the wild-type, which confirms that K62 lactylation inhibits nuclear localization when exogenous lactate is added (Wang J. et al., 2022). Lactylation in proximity to the NLS of high-mobility group box 1 (HMGB1) augments its cytoplasmic translocation (Yang et al., 2022) (Figure 2). In addition, mitochondrial elongation factor Tu (TUFM) K286la prevents its mitochondrial translocation by suppressing its interaction with the translocase of the outer mitochondrial membrane 40 (Weng et al., 2025) (Figure 2).

As proteins perform specific roles in various cellular compartments, regulating subcellular localization is a key mechanism by which lactylation affects protein function. This regulatory mechanism offers a new perspective on the functional significance of lactylation.

A comprehensive review of studies reveals that lactylation regulates nonhistone functions via multiple coordinated mechanisms rather than a single mechanism. ALDOA exemplifies this comprehensive regulation, with lactylation simultaneously altering its molecular interaction network, protein stability, enzymatic activity, and subcellular localization, resulting in functional reshaping (Shao et al., 2025).

Enrichment analyses have demonstrated that differentially expressed proteins with lactylation modifications are significantly enriched in metabolic pathways such as glycolysis, fatty acid metabolism, and amino acid metabolism, strongly influencing tumor initiation and progression (Gaffney et al., 2020; Yang Z. et al., 2023; Duan et al., 2024; Wang J. et al., 2022). Cancer cells undergo metabolic reprogramming to obtain the substantial amount of energy required for their rapid proliferation. This reprogramming upregulates glycolysis, increases lactate production and accumulation, and further promotes lactylation modification (He et al., 2024). Metabolism-linked nonhistone lactylation regulates glycolysis by altering protein function, creating glycolysis–lactylation–a glycolysis feedback loop. The following examples further illustrate how nonhistone lactylation contributes to metabolism-driven feedback loops in various cancer types.

In hepatocellular carcinoma cell line (HepG2), ABCF1 K430la facilitates tumor progression by stimulating the expression of HIF1A and its downstream molecules, enhancing lactate production. Increased lactate levels further promote ABCF1-K430 lactylation, establishing a positive feedback loop of lactate–ABCF1-HIF1A–lactate (Hong et al., 2025). In CRC cell lines (SW620 and RRKO), lactate produced via glycolysis promotes β-catenin lactylation, augmenting its stability. β-catenin knockdown inhibits glycolysis indicators such as lactate production and extracellular acidification rate, confirming the glycolysis–β-catenin-Kla–glycolysis positive feedback loop (Miao et al., 2023). In pancreatic cancer, NUSAP1 lactylation increases its stability and forms a complex with c-Myc and HIF-1α, binding to the LDHA promoter region. This binding promotes LDHA expression and glycolysis, establishing lactate–NUSAP1-Kla-LDHA–lactate positive feedback pathway (Chen et al., 2023) (Figure 3). In ovarian cancer, lactate accumulation stimulates phosphofructokinase P (PFKP) K392la, suppressing PTEN expression and enhancing glycolysis (Mi, 2024). Nevertheless, in HEK293T cells, ALDOA K147la abrogates enzymatic activity and inhibits glycolytic flux, creating a negative feedback regulation (Shao et al., 2025). Thus, the feedback loop mechanism between nonhistone lactylation and glycolysis must be investigated further to decipher its regulatory roles across different cell types and pathological conditions.

Nonhistone lactylation also regulates metabolic pathways other than glycolysis. Oxidative phosphorylation is negatively regulated by mitochondrial protein lactylation. Under hypoxic conditions, AARS2 accumulation promotes PDHA and CPT2 lactylation, preventing their enzymatic activities and curbing acetyl-CoA production, which shifts the metabolism toward glycolysis (Mao et al., 2024). Lactylome analysis of non-small cell lung cancer revealed that APOC2 is the only upregulated lactylated protein involved in lipid transport and metabolism. APOC2 K70la improves extracellular lipolysis and promotes free fatty acid release (Chen J. et al., 2024) (Figure 3). PCK2 K100la enhances enzymatic activity and competitively inhibits ubiquitin-mediated degradation of mitochondrial 3-oxoacyl-ACP synthase (OXSM), enabling the metabolic remodeling of mitochondrial fatty acid synthesis (Yuan et al., 2025).

IGF2BP3 K76la upregulates PCK2 expression in lenvatinib-resistant hepatocellular carcinoma cells, triggering serine metabolism reprogramming and conferring drug resistance (Lu et al., 2024). DCBLD1 K172la suppresses its ubiquitination, stabilizes the protein, and extends its half-life. By inhibiting the autophagic degradation of glucose-6-phosphate dehydrogenase, DCBLD1 K172la activates the pentose phosphate pathway, providing crucial precursors for nucleotide biosynthesis in cancer cells (Meng et al., 2024) (Figure 3).

The MRE11-RAD50-NBS1 complex is critical for sensing and repairing DNA double-strand breaks (DSBs). Chen et al. identified that MRE11 K673la increases its DNA-binding affinity, promoting homologous recombination repair and leading to chemotherapeutic resistance in basal-like breast cancer (Chen Y. et al., 2024). Similarly, NBS1 lactylation at K388 considerably improves MRE11-RAD50-NBS1 complex stability at DSB sites, enhancing homologous recombination repair efficiency (Chen H. et al., 2024). In GSCs, lactylation of XRCC1 at K247 promotes its nuclear translocation, mediating DNA damage repair and conferring resistance to radiotherapy and chemotherapy (Li G. et al., 2024) (Figure 3).

Nonhistone lactylation impacts epigenetic processes via multiple pathways, creating a complex regulatory network.

NSUN2 K508la boosts its RNA methyltransferase activity, stimulating 5-methylcytosine modification of the glutamate–cysteine ligase catalytic subunit (GCLC) mRNA and affecting the cellular redox balance (Niu et al., 2025). In lenvatinib-resistant hepatocellular carcinoma, lactylation of IGF2BP3 at K76 promotes the generation of S-adenosylmethionine and induces RNA m⁶A modification, leading to drug resistance (Lu et al., 2024). In gastric cancer, METTL16 K229la increases m⁶A modification of ferredoxin 1 mRNA, which triggers cuproptosis (Sun L. et al., 2023). Furthermore, nonhistone lactylation regulates histone PTMs. ABCF1 K430la mediates its nuclear translocation, upregulates KDM3A expression, and enhances H3K9me2 demethylation (Figure 3), activating the HIF1A pathway to promote hepatocellular carcinoma progression (Hong et al., 2025). In addition, histone lactylation itself is a unique epigenetic modification (Zhang et al., 2019). Lactylation of nonhistones is predominantly enriched in metabolic enzyme pathways (Yang Z. et al., 2023), signifying that any enzyme affecting glycolysis could theoretically influence lactylation modifications, including histone lactylation.

These mechanisms indicate complex interactions between nonhistone lactylation and epigenetic modifications, providing key information on metabolic–epigenetic crosstalk and potential cancer therapeutic targets.

Nonhistone lactylation regulates numerous cell death pathways such as ferroptosis, cuproptosis, apoptosis, and autophagy (Zhao et al., 2020).

Nonhistone lactylation exerts bidirectional effects on ferroptosis regulation. NSUN2 K508la augments glutathione synthesis, suppressing ferroptosis in gastric cancer cells (Niu et al., 2025). This cascade reaction increases GSH synthesis, maintains redox homeostasis, effectively suppresses lipid peroxidation, and ultimately suppresses ferroptosis (Figure 3). Conversely, Yuan et al. reported that PCK2 K100la stabilizes OXSM, promotes mitochondrial fatty acid synthesis, and activates hepatocyte ferroptosis (Yuan et al., 2025). METTL16 K229 upregulates ferredoxin 1 in gastric cancer, disrupting copper metabolism and inducing cuproptosis (Sun L. et al., 2023) (Figure 3).

In addition, nonhistone lactylation affects apoptosis and autophagy. SIRT3, a lactylation eraser, induces apoptosis in hepatocellular carcinoma by inhibiting cyclin E2 lactylation (Jin et al., 2023). Adenylate kinase 2 K28la prevents its kinase activity, downregulating apoptotic pathways (Yang Z. et al., 2023). Weng et al. showed that TUFM K286la inhibits its interaction with the outer mitochondrial membrane complex, impairing mitophagy and driving cells toward apoptosis (Weng et al., 2025) (Figure 3). Lactylation of HMGB1 near its NLS facilitates cytoplasmic translocation, improving macrophage secretion of HMGB1 (Yang et al., 2022) and activating autophagy via the advanced glycosylation end-product-specific receptor or toll-like receptor (Chen R. et al., 2024; Kim et al., 2021). Moreover, PFKP lactylation inhibits PTEN activity (Mi, 2024) and indirectly suppresses autophagy (Zhang K. K. et al., 2023).

The regulation of programmed cell death by nonhistone lactylation is complex and context-dependent, differing based on the tumor type, metabolic status, microenvironment, and signaling pathways. Hence, further studies should focus on mechanistic investigations and functional validations across various cancer types and experimental models.

Nonhistone lactylation critically shapes the tumor microenvironment by modulating key immune-related proteins.

In innate immunity, AARS2-mediated lactylation of cGAS results in its inactivation, decreasing cGAMP and interferon-β levels and weakening immune responses (Li H. et al., 2024). MOESIN lactylation activates SMAD3 signaling, upregulates forkhead box P3 (FOXP3), and stimulates the differentiation of regulatory T cell, leading to immunosuppression (Gu et al., 2022). Ikzf1 K164la promotes TH17 cell differentiation by increasing the binding to Runx1, Tlr4, IL2, and IL4 promoters (Fan W. et al., 2023).

Macrophage polarization plays a crucial role in the tumor microenvironment. Proinflammatory macrophages activate T cells and natural killer cells, disrupting tissue integrity and impeding tumor progression. Conversely, reparative macrophages are involved in anti-inflammatory responses and tissue remodeling, fostering tumor growth, invasion, and immune suppression (Locati et al., 2020). PKM2 K62la triggers macrophage transition from the proinflammatory to the reparative phenotype, facilitating tumor immune evasion (Wang J. et al., 2022). Innon-small cell lung cancer, APOC2 K70la augments its stability, increasing free fatty acid release and Treg accumulation (Chen J. et al., 2024). In CRC, lactate induces H3K18 lactylation in tumor-infiltrating macrophages, leading to the upregulation of METTL3. Moreover, it directly induces METTL3 K281/K345 lactylation within the target recognition domain. This lactylation activates the METTL3-m6A-JAK1-STAT3 axis, leading to myeloid cell immunosuppression (Xiong et al., 2022). PD-L1 K810–813 lactylations retard its degradation, maintaining its high expression and inhibiting T-cell activation, proliferation, and cytotoxicity (Tong et al., 2024). HMGB1 lactylation near its NLS stimulates cytoplasmic translocation and exosomal secretion, with extracellular HMGB1 activating HIF1A via advanced glycosylation end-product-specific receptor, upregulating PD-L1, and triggering immunosuppression (Yang et al., 2022) (Figure 3). Furthermore, FOXP3⁺ natural killer T-like cells sustain the immunosuppressive function in malignant pleural effusion by ensuring high lactylation levels (Wang Z.-H. et al., 2023).

Nonhistone lactylation exerts multifaceted effects on the tumor immunosuppressive microenvironment by regulating immune cell differentiation, function, and phenotype. Previous studies noted that lactate inhibits several immune cells, including dendritic cells, T cells, and natural killer cells. However, whether these effects occur via nonhistone lactylation requires further investigation (Fischer et al., 2007; Certo et al., 2021). In addition, future research should focus on the specific roles of lactylation across different immune cells, providing a robust theoretical foundation for developing more effective antitumor immunotherapies.

CEACAM6 is highly expressed in malignant tumors and results in resistance to multiple chemotherapeutic agents (Duxbury et al., 2004; Rizeq et al., 2018). Recent findings suggest that CEACAM6 lactylation improves its stability, modulates cancer cell sensitivity to 5-fluorouracil, and induces chemotherapeutic resistance in CRC cell lines (HT29 and WiDr) (Chu et al., 2023). However, this conclusion is based on a single study with limited sample size and lacks validation in primary tumor samples or clinical cohorts. AARS1-catalyzed p53 lactylation facilitates doxorubicin resistance, which can be reversed by β-alanine via competitive inhibition of lactate binding (Zong et al., 2024). In basal-like breast cancer, MRE11 K673la improves DNA end resection and homologous recombination repair, conferring resistance to poly ADP-ribose polymerase inhibitors, olaparib, and cisplatin (Chen Y. et al., 2024). In patient-derived organoid models, effectively inhibiting CBP and LDH reverses this resistance. Researchers have designed K673-pe, a peptide inhibitor that specifically blocks MRE11 lactylation, augmenting the antitumor therapeutic response (Chen Y. et al., 2024). NSUN2 K508la upregulates glutathione levels in gastric cancer, enhancing the resistance to ferroptosis-inducing agents such as doxorubicin and RSL3. NSUN2 knockout downregulates GCLC expression and GSH synthesis, thereby increasing chemotherapeutic sensitivity (Niu et al., 2025).

Exogenous lactate treatment alleviates p53-mediated cell death in irradiated mice, with p53 lactylation at K120/K139 impairing its DNA-binding ability and mediating radiotherapeutic resistance (Zong et al., 2024). Li et al. found that aldehyde dehydrogenase 1 A3 (ALDH1A3) overexpression in glioblastoma promotes tetrameric PKM2 formation, increasing XRCC1 K247 lactylation. This process enhances DNA damage repair and protein stability, leading to radiotherapeutic and temozolomide resistance (Li G. et al., 2024). The compound D34-919 disrupts ALDH1A3-PKM2 interaction and decreases lactylation, restoring glioblastoma sensitivity to radiotherapy (Li G. et al., 2024). Developing small molecules targeting XRCC1 K247 lactylation may similarly augment the efficacy of radiotherapy and chemotherapy. Moreover, HMGB1 lactylation stimulates its extracellular release (Yang et al., 2022), and earlier studies have asserted that the release of HMGB1 could attenuate radiotherapeutic efficacy (Shinde-Jadhav et al., 2021).

Nonhistone lactylation shapes the tumor immune microenvironment, influencing immunotherapeutic sensitivity. In non-small cell lung cancer, APOC2 K70 lactylation is substantially upregulated in patients resistant to immunotherapy and is negatively linked to overall survival in both non-small cell lung cancer and gastric cancer (Chen J. et al., 2024). APOC2 K70 lactylation enhances Treg metabolism and reduces CD8⁺ T cell frequency (Kumagai et al., 2020). Anti-APOC2-K70lac antibody or LDH inhibitor FX11, combined with anti-PD-1 therapy, substantially decreases Treg frequency and the proportions of TNF-α⁺ IFN-γ⁺ and CD69⁺ CD8⁺ T cells in the tumor microenvironment, conferring immunotherapeutic resistance (Chen J. et al., 2024). In hepatocellular carcinoma, lower MOESIN lactylation is associated with improved response to camrelizumab, implying that patients with lower lactylation levels benefit more from anti-PD-1 therapy (Gu et al., 2022). Lactylation scoring models in gastric cancer and hepatocellular carcinoma indicate that patients with high lactylation scores display stronger immune evasion and lower immunotherapeutic response rates (Yang H. et al., 2023; Cheng et al., 2023).

In lenvatinib-resistant hepatocellular carcinoma, proteomic analysis showed elevated lactylation modifications, especially IGF2BP3 K76la, which enhances serine metabolism reprogramming and m6A modification, improving antioxidant ability and lenvatinib resistance (Lu et al., 2024). Not all studies indicate a direct correlation between reduced lactylation and increased targeted therapy sensitivity. For instance, a bioinformatics-based lactylation scoring model revealed that while most drugs exhibited higher sensitivity in the low-lactylation score group, gefitinib and metoprolol were more effective in the high-lactylation score group (Yang H. et al., 2023). Similarly, another investigation identified that patients with high lactylation scores were more sensitive to sorafenib than those with low scores (Cheng et al., 2023). These diverse findings suggest that the effect of lactylation on drug sensitivity may vary considerably depending on the tumor type, therapeutic modality, and molecular background. Hence, specific lactylation sites and their functional mechanisms should be examined to develop precise therapeutic strategies.

It is important to note that current lactylation research faces several methodological limitations. Most studies rely on cell line models rather than primary tissues, and sample sizes are limited. Future studies should prioritize validation in clinical samples and larger cohorts.