Unveiling the Mechanisms of Protein Lactylation: From Metabolic Origin to Functional Implications
In recent years, lysine lactylation (Kla) has emerged as a novel post-translational modification (PTM) with increasing relevance in epigenetic regulation and cellular metabolism, gaining attention as a promising frontier in the post-genomic era. The identification of protein lactylation has significantly broadened our understanding of the interplay between metabolic flux and transcriptional regulation, offering new perspectives for investigating cancer, immune responses, and metabolic disorders. This review aims to dissect the biochemical and metabolic basis underlying protein lactylation, focusing on lactate origin, enzymatic pathways, and substrate specificity, and to explore its potential research directions and applications.
Definition of Protein Lactylation
Protein lactylation is a recently identified post-translational modification occurring at the ε-amino group of lysine residues. In mouse macrophages, lactate can modify histone lysine residues via both enzymatic and non-enzymatic routes, thereby modulating gene expression.
Key characteristics include:
1. Utilization of lactate as the acyl group donor.
2. Modification sites located on lysine (Lys) residues of proteins.
3. Functional impact on chromatin structure, gene transcription, and signaling activity.
Origin of Lactylation: Lactate as a Critical Precursor
1. Lactate Production through Glycolysis and Metabolic Reprogramming
Lactate is the terminal product of glycolysis and is especially enriched under hypoxic conditions or in cells with elevated metabolic rates, such as cancer cells and activated immune cells. This conversion is catalyzed by lactate dehydrogenase (LDH):
Pyruvate + NADH ⇌ Lactate + NAD⁺
Beyond being a metabolic byproduct, lactate is increasingly recognized as a signaling metabolite involved in diverse processes such as transcriptional control and immunosuppression.
2. L-lactyl-CoA: A Potential Reactive Intermediate
It is hypothesized that L-lactyl-CoA functions as an active donor for lactylation, cooperating with lysine acyltransferases to transfer lactyl groups to target lysines. However, direct detection of L-lactyl-CoA in mammalian systems remains technically challenging, and current evidence supporting its existence is largely indirect.
Mechanistic Pathways of Protein Lactylation: Enzymatic and Non-enzymatic Modes
Research on specific lactylation sites, including H2A.Z and H3K18la, has revealed two principal mechanisms of lactylation:
1. Non-Enzymatic Lactylation
Under conditions of elevated lactate concentration, lactate or its derivatives can undergo spontaneous chemical reactions with lysine residues, leading to lactylation. This process is influenced by factors such as local acidity and protein surface accessibility.
Notable Features: low reaction rate, limited site selectivity, but potentially pronounced under pathological conditions characterized by lactate accumulation (e.g., tumor microenvironments).
2. Enzyme-Catalyzed Lactylation
Recent findings indicate that certain histone acetyltransferases (e.g., p300/CBP) are capable of catalyzing lysine lactylation in the presence of lactyl-CoA, thereby transferring the lactyl group to defined lysine residues.
Notable Features: high substrate specificity, dynamic regulation, and strong association with epigenetic modulation.
Protein Targets of Lactylation: Beyond Histones
Although initially identified on histones (e.g., H3K18la, H4K8la), accumulating evidence supports the lactylation of non-histone proteins, including metabolic enzymes and transcriptional regulators. Noteworthy examples include:
1. Lactylation of pyruvate kinase M2 (PKM2) modulates its catalytic activity.
2. Lactylation of the NF-κB p65 subunit affects its nuclear localization and immunological functions.
3. Lactylation of HIF-1α may play a role in the cellular hypoxia response pathway.
These observations suggest that lactylation extends beyond epigenetic regulation and may function as a widespread mechanism of metabolic signaling.
MtoZ Biolabs' Perspective: Advantages of Mass Spectrometry in Lactylation Research
Advanced mass spectrometry (MS) platforms are indispensable for investigating protein lactylation, offering high sensitivity and quantitative accuracy. MtoZ Biolabs has established an integrated analytical pipeline encompassing histone-specific profiling, global lactylation mapping, site-specific quantification, and validation.
Our workflow includes:
1. High-sensitivity LC-MS/MS systems (e.g., Orbitrap Exploris 480).
2. Optimized peptide enrichment strategies to enhance lactyl-peptide identification.
3. Customizable data processing pipelines supporting co-detection of various PTMs, including lactylation, acetylation, and ubiquitination.
Protein lactylation represents a novel post-translational regulatory layer that bridges cellular metabolic status and transcriptional control. From lactate biosynthesis to L-lactyl-CoA formation and site-specific lysine modification, the process underscores a dynamic adaptive mechanism to environmental stimuli. Leveraging state-of-the-art mass spectrometry and PTM-focused proteomics, MtoZ Biolabs has developed a robust platform for comprehensive lactylation analysis.
MtoZ Biolabs, an integrated chromatography and mass spectrometry (MS) services provider.
Related Services
How to order?
