GO:0140794 histone arginine deiminase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140794 (histone arginine deiminase activity) is a biological_process term describing the enzymatic conversion of histone arginine residues to citrulline, a reaction catalyzed by peptidyl-arginine deiminase (PAD) enzymes, most notably PAD4.
• Histone citrullination by PAD4 neutralizes positive charge on histone tails, driving chromatin decondensation and facilitating neutrophil extracellular trap (NET) formation.
• PAD4 is essential for antibacterial innate immunity mediated by NETs, as PAD4-deficient neutrophils fail to form NETs and are impaired in bacterial killing.
• Dysregulated histone arginine deiminase activity contributes to immune-mediated diseases, sterile inflammatory liver injury, impaired diabetic wound healing, and anti-Pseudomonal host defense.
• Key genes and proteins include PADI4 (PAD4), PADI1, PADI2, PADI3, PADI6, and histone substrates H3 and H4; PAD4 is the best-characterized nuclear isoform.
• CRISPR-based knockout, point-mutation, knock-in, and overexpression models enable causal interrogation of PADI4 and related genes in NET formation, inflammation, and infection.
Description
Histone arginine deiminase activity (GO:0140794) is a biological process in which arginine residues on histone proteins are enzymatically converted to citrulline, a post-translational modification termed citrullination. This activity is catalyzed by the peptidyl-arginine deiminase (PAD) family, with PAD4 (encoded by PADI4) being the principal nuclear isoform responsible for histone citrullination in humans. The reaction is calcium-dependent and results in the loss of a positive charge on the histone tail, which weakens electrostatic interactions with DNA and promotes chromatin decondensation. Researchers study GO:0140794 because it sits at the intersection of epigenetic regulation, innate immunity, and inflammatory disease. Histone citrullination by PAD4 is a hallmark of neutrophil extracellular trap (NET) formation, a process in which neutrophils release decondensed chromatin to trap and kill pathogens. Beyond infection, dysregulated histone arginine deiminase activity has been implicated in immune-mediated diseases, sterile inflammatory liver injury, and impaired wound healing in diabetes. Understanding the molecular players, regulatory inputs, and disease contexts of GO:0140794 is therefore critical for both basic chromatin biology and translational research.
histone arginine deiminase activity At A Glance
| GO ID | GO:0140794 |
|---|---|
| GO term | histone arginine deiminase activity |
| Ontology | biological_process |
| Synonym | None listed in QuickGO |
| Major function | Enzymatic conversion of histone arginine to citrulline, leading to chromatin decondensation and NET formation |
| Enzyme family | Peptidyl-arginine deiminases (PADs), especially PAD4/PADI4 |
| Substrates | Histone H3 and H4 arginine residues |
| Cofactor | Calcium-dependent |
| Cellular context | Neutrophils, innate immune cells, and other PAD4-expressing cells |
What Is GO:0140794?
GO:0140794, histone arginine deiminase activity, is defined as the catalysis of the deimination of arginine residues on histone proteins, converting them to citrulline. This process is a type of post-translational modification that alters the charge and function of histone tails, thereby influencing chromatin structure and gene expression. The activity is mediated by PAD enzymes, particularly PAD4, which translocates to the nucleus and citrullinates histones H3 and H4.
Why Is histone arginine deiminase activity Important in Cell Biology?
Histone arginine deiminase activity is important because it provides a direct enzymatic link between chromatin modification and innate immune function. PAD4-mediated histone citrullination is required for NET formation, a key antimicrobial strategy, and its dysregulation is associated with autoimmune and inflammatory pathologies. Studying this process helps researchers understand how epigenetic changes drive immune responses and how to target them therapeutically.
• Essential for antibacterial innate immunity through NET formation.
• Drives chromatin decondensation by neutralizing histone charge.
• Implicated in immune-mediated diseases such as rheumatoid arthritis and vasculitis.
• Contributes to sterile inflammatory liver injury via DAMP-activated NETs.
• Delays diabetic wound healing by inducing endothelial-to-mesenchymal transition.
• Plays a role in anti-Pseudomonal defense through neutrophil granule PAD enzymes.
• Provides a target for anti-inflammatory drug discovery.
• Serves as a model for studying calcium-dependent post-translational modifications.
• Links neutrophil biology to epigenetic regulation.
• Enables research on NET-associated pathologies in infection and autoimmunity.
What Happens During histone arginine deiminase activity?
Calcium-dependent activation of PAD4
In simple terms: PAD4 needs calcium to become active and modify histones.
PAD4 (PADI4) is a calcium-dependent enzyme that undergoes conformational changes upon calcium binding, enabling its catalytic activity. In resting neutrophils, PAD4 is largely inactive, but upon cell activation, calcium influx triggers its activation and nuclear translocation.
Nuclear translocation and histone binding
In simple terms: PAD4 moves into the nucleus and attaches to histones.
Activated PAD4 translocates from the cytoplasm to the nucleus, where it binds to histone tails, particularly histone H3 and H4. This binding is a prerequisite for the subsequent deimination reaction.
Deimination of histone arginine to citrulline
In simple terms: PAD4 chemically converts arginine on histones into citrulline.
PAD4 catalyzes the hydrolysis of the guanidinium group of arginine residues on histones, converting them to citrulline and releasing ammonia. This reaction neutralizes the positive charge of the histone tail, reducing its affinity for negatively charged DNA.
Chromatin decondensation and NET formation
In simple terms: The modified histones loosen DNA, allowing NETs to form.
Histone citrullination leads to chromatin decondensation, a critical step in the formation of neutrophil extracellular traps (NETs). PAD4-deficient neutrophils fail to form NETs and show impaired antibacterial activity, demonstrating the essential role of this process in innate immunity.
Downstream inflammatory signaling
In simple terms: NETs can trigger inflammation and tissue damage.
Once released, NETs can activate damage-associated molecular patterns (DAMPs) and exacerbate sterile inflammatory liver injury. In diabetic wounds, NETs delay healing by inducing endothelial-to-mesenchymal transition via the Hippo pathway.
Key Genes Involved in GO:0140794 histone arginine deiminase activity
The following genes and proteins are central to histone arginine deiminase activity and its biological consequences.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PADI4 | Encodes PAD4, the main nuclear histone arginine deiminase | Key enzyme for histone citrullination and NET formation |
| PADI1 | Encodes PAD1, expressed in epidermis and other tissues | Potential role in skin and inflammatory processes |
| PADI2 | Encodes PAD2, found in various tissues including brain | May contribute to citrullination in non-neutrophil contexts |
| PADI3 | Encodes PAD3, involved in hair follicle development | Less studied in NETs but part of PAD family |
| PADI6 | Encodes PAD6, important for oocyte and embryo development | Not directly linked to NETs but shares deiminase activity |
| H3 | Histone H3, substrate for PAD4 | Citrullination of H3 drives chromatin decondensation |
| H4 | Histone H4, substrate for PAD4 | Citrullination of H4 contributes to NET formation |
| ELANE | Neutrophil elastase, cooperates with PAD4 in NET formation | Modulates chromatin decondensation |
| MPO | Myeloperoxidase, involved in NET formation | Interacts with PAD4 pathway |
| TLR4 | Toll-like receptor 4, senses DAMPs | Activates NET formation in sterile inflammation |
| Hippo pathway components | Regulate endothelial-to-mesenchymal transition | Mediate NET-induced diabetic wound healing delay |
| NADPH oxidase | Produces reactive oxygen species for NET formation | Required for PAD4 activation in some contexts |
| CXCR2 | Chemokine receptor on neutrophils | Promotes neutrophil recruitment and NET formation |
| IL-8 | Cytokine that recruits neutrophils | Indirectly promotes histone citrullination |
| TNF-alpha | Pro-inflammatory cytokine | Can induce NET formation and PAD4 activation |
| PAD4 inhibitors | Small molecules targeting PAD4 | Therapeutic candidates for inflammatory diseases |
How Is histone arginine deiminase activity Regulated?
Histone arginine deiminase activity is tightly regulated at multiple levels. PAD4 activity requires calcium binding, and its nuclear translocation is triggered by neutrophil activation signals. Inflammatory cytokines such as TNF-alpha and IL-8 can promote NET formation and PAD4 activation. Additionally, reactive oxygen species produced by NADPH oxidase are required for PAD4 activation in some contexts. The Hippo pathway has been implicated downstream of NETs in diabetic wound healing, linking histone citrullination to endothelial-to-mesenchymal transition.
histone arginine deiminase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PADI4 | Rheumatoid arthritis, vasculitis | Padi4 knockout mouse, neutrophil-specific KO |
| PADI4 | Sterile inflammatory liver injury | Liver ischemia-reperfusion model in Padi4-/- mice |
| PADI4 | Diabetic wound healing | Diabetic mouse model with Padi4 KO |
| PADI4 | Bacterial infection | Padi4-/- mice challenged with bacteria |
| PADI4 | Anti-Pseudomonal defense | Neutrophil granule PAD inhibition assays |
Immune-mediated and autoimmune diseases
PAD4-mediated histone citrullination and NET formation are implicated in immune-mediated diseases such as rheumatoid arthritis and vasculitis. The generation of citrullinated histones can break tolerance and drive autoantibody production.
Sterile inflammatory liver injury
DAMP-activated NETs exacerbate sterile inflammatory liver injury, and histone citrullination is a key step in this process. Targeting PAD4 may reduce liver damage in ischemia-reperfusion and other sterile inflammatory conditions.
Diabetic wound healing
NETs delay diabetic wound healing by inducing endothelial-to-mesenchymal transition via the Hippo pathway. Histone arginine deiminase activity is therefore a potential therapeutic target to improve wound repair in diabetes.
Bacterial infections
PAD4 is essential for antibacterial innate immunity mediated by NETs, and PAD4-deficient mice are more susceptible to bacterial infections. Neutrophil granule PAD enzymes also exhibit anti-Pseudomonal activity.
From histone arginine deiminase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is PADI4 required for NET formation? | Padi4 knockout mouse or human neutrophil KO |
| Does a specific point mutation in PADI4 affect catalytic activity? | Point-mutation knock-in of PADI4 in cell lines |
| What is the effect of PAD4 overexpression on chromatin structure? | Overexpression of PADI4 in HEK293 or neutrophil-like cells |
| Can a tagged PAD4 be used to track nuclear translocation? | Tagged knock-in of PADI4 with fluorescent protein |
| Which genes are downstream of histone citrullination? | Transcriptomic analysis of Padi4 KO vs WT neutrophils |
| Does PAD4 inhibition reduce liver injury? | Padi4 KO mice in sterile inflammatory liver injury model |
How to Study the histone arginine deiminase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Western blot | Citrullinated histone levels | Detection of PAD4 activity in cell lysates |
| Immunofluorescence | NET formation and chromatin decondensation | Visualization of NETs in neutrophils |
| Mass spectrometry | Site-specific citrullination | Mapping modified arginine residues |
| Bacterial killing assay | Antimicrobial function of NETs | Assessing PAD4-dependent immunity |
| ELISA | Citrullinated histone H3 in serum | Biomarker for NET-associated diseases |
| Flow cytometry | Neutrophil activation and NET markers | Quantifying NET-forming cells |
| CRISPR screening | Genes required for histone citrullination | Identifying novel regulators of PAD4 pathway |
Detection of histone citrullination by Western blot
Western blotting with anti-citrulline antibodies can detect citrullinated histones in cell lysates, providing a direct readout of PAD4 activity.
Immunofluorescence imaging of NETs
Immunofluorescence microscopy using antibodies against citrullinated histones and DNA dyes visualizes NET formation and chromatin decondensation.
Mass spectrometry for citrulline mapping
Mass spectrometry can identify specific arginine residues converted to citrulline on histones, offering site-specific information.
Functional assays for NET-mediated killing
Bacterial killing assays using PAD4-deficient neutrophils assess the functional impact of histone citrullination on innate immunity.
How CRISPR Can Be Used to Study GO:0140794 histone arginine deiminase activity
Knockout
CRISPR knockout of PADI4 in neutrophil-like cell lines or primary neutrophils abolishes histone citrullination and NET formation, providing a clean loss-of-function model.
Point Mutation
Point mutations in the catalytic domain of PADI4 can be introduced to dissect the requirement for specific residues in calcium binding or catalysis.
Knock-in
Knock-in of a fluorescent tag or epitope tag into the endogenous PADI4 locus allows real-time tracking of PAD4 nuclear translocation and histone binding.
Overexpression
Overexpression of PADI4 in non-immune cells induces histone citrullination and chromatin decondensation, enabling study of downstream effects.
How EDITGENE Supports histone arginine deiminase activity Research
Researchers studying histone arginine deiminase activity-related genes often need to determine whether a candidate gene is causally involved in NET formation, inflammation, or infection. EDITGENE provides a comprehensive suite of CRISPR services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for histone arginine deiminase activity research.
Frequently Asked Questions About histone arginine deiminase activity
What is histone arginine deiminase activity?
It is the enzymatic conversion of arginine residues on histones to citrulline, a post-translational modification that alters chromatin structure and is mediated by PAD enzymes such as PAD4.
What genes are involved in histone arginine deiminase activity?
The main gene is PADI4, which encodes PAD4; other PAD family members include PADI1, PADI2, PADI3, and PADI6.
What is the role of PAD4 in NET formation?
PAD4 citrullinates histones, leading to chromatin decondensation and the release of neutrophil extracellular traps (NETs).
Which diseases are associated with histone citrullination?
It is linked to immune-mediated diseases, sterile inflammatory liver injury, diabetic wound healing impairment, and bacterial infections.
How can I study histone arginine deiminase activity in the lab?
Common methods include Western blot with anti-citrulline antibodies, immunofluorescence for NETs, mass spectrometry, and bacterial killing assays.
What is the GO ID for histone arginine deiminase activity?
The GO ID is GO:0140794.
Is PAD4 the only enzyme with histone arginine deiminase activity?
PAD4 is the best-characterized, but other PAD family members may also citrullinate histones in specific contexts.
Can CRISPR be used to study histone arginine deiminase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect PADI4 function.
What are neutrophil extracellular traps (NETs)?
NETs are web-like structures of decondensed chromatin and antimicrobial proteins released by neutrophils to trap pathogens.
How does histone citrullination affect chromatin?
Citrullination neutralizes the positive charge of histone tails, weakening DNA binding and promoting chromatin decondensation.
Conclusion
Histone arginine deiminase activity (GO:0140794) is a critical biological process that links epigenetic modification to innate immunity. PAD4-mediated histone citrullination drives NET formation and is implicated in a range of inflammatory and infectious diseases. Understanding its regulation and downstream effects offers opportunities for therapeutic intervention. EDITGENE provides advanced CRISPR tools to study this process and accelerate discovery.
References
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- 4. Wang Y et al.. 2009. Histone hypercitrullination mediates chromatin decondensation and neutrophil extracellular trap formation.. J Cell Biol 184(2):205-13 PMID: 19153223
- 5. Li P et al.. 2010. PAD4 is essential for antibacterial innate immunity mediated by neutrophil extracellular traps.. J Exp Med 207(9):1853-62 PMID: 20733033
- 6. Yang S et al.. 2023. Neutrophil Extracellular Traps Delay Diabetic Wound Healing by Inducing Endothelial-to-Mesenchymal Transition via the Hippo pathway.. Int J Biol Sci 19(1):347-361 PMID: 36594092
- 7. Baird R et al.. 2024. The vacuolar anti-Pseudomonal activity of neutrophil primary granule peptidyl-arginine deiminase enzymes.. Front Immunol 15:1452393 PMID: 39493757
- 8. Huang H et al.. 2015. Damage-associated molecular pattern-activated neutrophil extracellular trap exacerbates sterile inflammatory liver injury.. Hepatology 62(2):600-14 PMID: 25855125
