GO:0031417 NatC complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031417 (NatC complex) is a conserved heterotrimeric N-terminal acetyltransferase that acetylates proteins starting with Met-Ile, Met-Leu, Met-Trp, or Met-Phe.
• In Saccharomyces cerevisiae, the NatC complex consists of Mak3p (catalytic), Mak10p, and Mak31p; in humans, the orthologous subunits are NAA30 (catalytic), NAA35, and NAA38.
• NatC-mediated N-terminal acetylation can protect proteins from degradation and influence age-dependent motility and longevity.
• The in vivo substrate profile of yeast NatC has been expanded by proteomics, revealing many new targets beyond the initially known ones.
• NatC function is linked to stress resistance via DAF-16/FOXO signaling in Caenorhabditis elegans, connecting insulin/IGF-1 signaling to protein N-terminal acetylation.
• Autoantibodies against NatC subunits have been detected in rheumatoid arthritis, suggesting a role in autoimmunity.
Description
The NatC complex (GO:0031417) is a conserved cellular component that catalyzes the transfer of an acetyl group to the N-terminal residue of proteins bearing Met-Ile, Met-Leu, Met-Trp, or Met-Phe N-termini. This co-translational modification, known as N-terminal acetylation, is one of the most abundant protein modifications in eukaryotes and plays critical roles in protein stability, localization, and interactions. In Saccharomyces cerevisiae, the complex comprises Mak3p, Mak10p, and Mak31p, while in humans the orthologous subunits are NAA30, NAA35, and NAA38. Researchers study NatC because its substrates include key regulatory proteins, and its dysfunction has been linked to stress responses, aging, and autoimmune conditions. Understanding the structure, assembly, and substrate specificity of NatC provides insights into fundamental cellular processes and potential therapeutic targets.
NatC complex At A Glance
| GO ID | GO:0031417 |
|---|---|
| GO term | NatC complex |
| Ontology | cellular_component |
| Synonym | N-terminal acetyltransferase C complex |
| Major function | Catalyzes N-terminal acetylation of proteins with Met-Ile, Met-Leu, Met-Trp, or Met-Phe N-termini |
| Subunits (S. cerevisiae) | Mak3p (catalytic), Mak10p, Mak31p |
| Subunits (human) | NAA30 (catalytic), NAA35, NAA38 |
| Substrate specificity | N-terminal Met followed by Ile, Leu, Trp, or Phe |
| Conservation | Conserved from yeast to humans |
What Is GO:0031417?
The NatC complex is a conserved heterotrimeric enzyme complex that acetylates the N-terminal amino group of protein substrates that begin with methionine followed by isoleucine, leucine, tryptophan, or phenylalanine. This N-terminal acetylation (Nt-acetylation) is an irreversible modification that occurs co-translationally and can affect protein half-life, subcellular targeting, and complex formation. The complex is found across eukaryotes, with subunit names varying by species: in Saccharomyces cerevisiae, the subunits are Mak3p (catalytic), Mak10p, and Mak31p; in humans, they are NAA30 (catalytic), NAA35, and NAA38.
Why Is NatC complex Important in Cell Biology?
The NatC complex is essential for understanding how N-terminal acetylation regulates protein fate and cellular physiology. It modifies a specific subset of proteins, thereby influencing their stability, interactions, and functions. Dysregulation of NatC has been implicated in aging, stress resistance, and autoimmune diseases, making it a focal point for research on protein homeostasis and disease mechanisms. Moreover, the complex serves as a model for studying substrate recognition and catalysis in N-terminal acetyltransferases, with implications for drug discovery.
• NatC-mediated N-terminal acetylation protects proteins from degradation, affecting protein turnover.
• It promotes age-dependent motility and longevity in model organisms.
• NatC regulates stress resistance through DAF-16/FOXO signaling in C. elegans.
• Its substrates include proteins involved in diverse cellular processes, as revealed by expanded in vivo profiling.
• Autoantibodies against NatC subunits are found in rheumatoid arthritis, linking it to autoimmunity.
• The complex is conserved across eukaryotes, enabling comparative studies.
• Structural studies have elucidated its unique architecture and catalytic mechanism.
• NatC is a potential target for therapeutic intervention in diseases related to protein misfolding and aging.
NatC complex: Biological Process, Structure, and Molecular Mechanism
What Happens During NatC complex?
In simple terms: The NatC complex adds a small chemical tag (acetyl group) to the start of certain proteins, which can change how those proteins behave in the cell.
The primary biological process mediated by the NatC complex is N-terminal acetylation, a co-translational modification that occurs on nascent polypeptides as they emerge from the ribosome. NatC specifically recognizes proteins with N-terminal Met-Ile, Met-Leu, Met-Trp, or Met-Phe sequences and transfers an acetyl group from acetyl-CoA to the alpha-amino group of the N-terminal residue. This modification is irreversible and can alter protein stability, localization, and interactions. In yeast, loss of NatC function leads to reduced acetylation of specific substrates, affecting processes such as stress response and longevity.
Structure and Composition of NatC complex
In simple terms: The NatC complex is made of three different proteins that work together as a machine.
The NatC complex is a heterotrimer composed of a catalytic subunit and two auxiliary subunits. In Saccharomyces cerevisiae, the catalytic subunit is Mak3p, which contains the acetyltransferase domain, while Mak10p and Mak31p are essential for complex stability and substrate recognition. In humans, the orthologous subunits are NAA30 (catalytic), NAA35, and NAA38. Structural studies have revealed that the complex adopts a unique architecture, with the auxiliary subunits forming a platform that positions the catalytic subunit for optimal substrate engagement. NAA38, in particular, plays a role in thermostability and catalytic activity of the human NatC complex.
Molecular Mechanism of NatC complex
In simple terms: The complex grabs acetyl-CoA and attaches the acetyl group to the protein's start, using a precise lock-and-key fit.
The catalytic mechanism of NatC involves the binding of acetyl-CoA and the substrate's N-terminus in the active site of the catalytic subunit (Mak3p in yeast, NAA30 in humans). The auxiliary subunits (Mak10p/Mak31p or NAA35/NAA38) contribute to substrate specificity by recognizing the second amino acid of the substrate, thereby ensuring that only proteins with the appropriate N-terminal sequences are acetylated. Recent studies have shown that NAA38 is critical for the thermostability and catalytic efficiency of the human NatC complex. The reaction proceeds via a ternary complex mechanism, as elucidated by structural and biochemical analyses.
Substrate Recognition and Specificity
In simple terms: The complex chooses which proteins to modify based on the first two amino acids of the protein.
NatC exhibits strict substrate specificity, acetylating proteins that begin with methionine followed by isoleucine, leucine, tryptophan, or phenylalanine. This specificity is determined by interactions between the substrate's N-terminal residues and the auxiliary subunits of the complex. Expanded in vivo substrate profiling in yeast has identified numerous new substrates, revealing that NatC targets a broader set of proteins than previously known, including those involved in metabolism and stress responses. The recognition mechanism involves a binding pocket that accommodates the bulky hydrophobic second residue, explaining the preference for these amino acids.
Key Genes Involved in GO:0031417 NatC complex
The following genes and proteins are key components or regulators of the NatC complex and its functions.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MAK3 (yeast) | Catalytic subunit of NatC; acetylates N-termini | Essential for N-terminal acetylation; knockout affects stress response and longevity |
| MAK10 (yeast) | Auxiliary subunit; substrate recognition and complex stability | Required for NatC function; mutations affect substrate specificity |
| MAK31 (yeast) | Auxiliary subunit; enhances catalytic activity | Contributes to complex assembly and substrate binding |
| NAA30 (human) | Catalytic subunit of NatC; ortholog of Mak3p | Target for studying human N-terminal acetylation and disease |
| NAA35 (human) | Auxiliary subunit; ortholog of Mak10p | Involved in substrate recruitment and complex integrity |
| NAA38 (human) | Auxiliary subunit; ortholog of Mak31p | Critical for thermostability and catalytic activity of human NatC |
| natc-1 (C. elegans) | Regulated by DAF-16/FOXO; modulates stress resistance | Links insulin/IGF-1 signaling to N-terminal acetylation |
| DAF-16 (C. elegans) | FOXO transcription factor; regulates natc-1 expression | Modulates stress resistance via NatC |
| NAA30 (human) | Catalytic subunit; autoantigen in rheumatoid arthritis | Potential biomarker for autoimmune diseases |
| NAA35 (human) | Auxiliary subunit; autoantigen in rheumatoid arthritis | Potential biomarker for autoimmune diseases |
| NAA38 (human) | Auxiliary subunit; autoantigen in rheumatoid arthritis | Potential biomarker for autoimmune diseases |
| MAK3 (yeast) | Target of DAF-16 regulation in C. elegans | Model for aging and stress studies |
| MAK10 (yeast) | Required for NatC stability | Genetic interaction studies |
| MAK31 (yeast) | Required for NatC stability | Genetic interaction studies |
| NAA30 (human) | Substrate-specific acetylation | Cancer and neurodegeneration research |
| NAA35 (human) | Complex assembly | Structural and functional studies |
| NAA38 (human) | Thermostability of NatC | Biochemical and structural studies |
How Is NatC complex Regulated?
The NatC complex is regulated at multiple levels. In Caenorhabditis elegans, the expression of natc-1 (the ortholog of NAA35) is controlled by the DAF-16/FOXO transcription factor, linking insulin/IGF-1 signaling to N-terminal acetylation and stress resistance. This regulation suggests that NatC activity can be modulated in response to environmental and metabolic cues. Additionally, the stability and activity of the human NatC complex are influenced by its subunit composition, particularly NAA38, which enhances thermostability and catalytic efficiency. Post-translational modifications of NatC subunits may also play a role, though specific mechanisms remain to be fully elucidated.
NatC complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NAA30 | Rheumatoid arthritis (autoantigen) | Knockout or knockdown in immune cells; autoantibody detection |
| NAA35 | Rheumatoid arthritis (autoantigen) | Knockout or knockdown in immune cells; autoantibody detection |
| NAA38 | Rheumatoid arthritis (autoantigen) | Knockout or knockdown in immune cells; autoantibody detection |
| natc-1 (C. elegans) | Stress resistance and aging | C. elegans knockout; DAF-16 regulation studies |
| MAK3 (yeast) | Longevity and motility | Yeast knockout; lifespan assays |
NatC complex in Aging and Longevity
N-terminal acetylation by NatC has been shown to shield proteins from degradation and promote age-dependent motility and longevity in model organisms. In C. elegans, the NatC subunit natc-1 is regulated by DAF-16/FOXO and modulates stress resistance, linking insulin/IGF-1 signaling to protein N-terminal acetylation. These findings suggest that NatC dysfunction may contribute to age-related decline and that enhancing NatC activity could have pro-longevity effects.
NatC complex and Autoimmune Diseases
Autoantibodies against NatC subunits (NAA30, NAA35, NAA38) have been detected in patients with rheumatoid arthritis using immunoprecipitation-mass spectrometry. This suggests that NatC components may be targets of autoimmunity and could serve as biomarkers for rheumatoid arthritis. The presence of these autoantibodies indicates a potential role for NatC in the pathogenesis or diagnosis of autoimmune conditions.
NatC complex in Cancer and Neurodegeneration
While direct links between NatC and cancer or neurodegeneration are still emerging, N-terminal acetylation is known to affect protein stability and aggregation, processes implicated in these diseases. The expanded substrate profile of NatC includes proteins involved in metabolism and stress responses, which may contribute to disease when dysregulated. Further research is needed to establish causal relationships.
From NatC complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of NatC loss on protein stability? | Knockout of MAK3/NAA30 in yeast or human cells; proteomics |
| How does NatC recognize substrates? | Point mutations in substrate N-termini; in vitro acetylation assays |
| What is the role of NAA38 in NatC thermostability? | Knock-in of NAA38 mutants; thermal shift assays |
| How does NatC affect stress resistance? | Overexpression of natc-1 in C. elegans; stress assays |
| What are the in vivo substrates of NatC? | Tagged knock-in of MAK3; immunoprecipitation-mass spectrometry |
| Does NatC dysfunction contribute to autoimmunity? | Knockout of NAA30/35/38 in mouse models; autoantibody profiling |
How to Study the NatC complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Immunoprecipitation-mass spectrometry | Protein interactions and autoantibodies | Discovery of NatC autoantigens in rheumatoid arthritis |
| N-terminal proteomics | Substrate profile and acetylation status | Expanded in vivo substrate profiling of yeast NatC |
| X-ray crystallography | Three-dimensional structure | Molecular mechanism of NatC |
| Cryo-electron microscopy | Structure of large complexes | Architecture of NatC |
| In vitro acetylation assays | Enzymatic activity | Catalytic mechanism and substrate specificity |
| Knockout models | Loss-of-function phenotypes | Stress resistance and longevity studies |
| Thermal shift assays | Protein stability | Role of NAA38 in NatC thermostability |
| Immunofluorescence | Subcellular localization | Localization of NatC subunits (general method) |
Proteomics and Mass Spectrometry
Mass spectrometry-based proteomics is essential for identifying NatC substrates and quantifying N-terminal acetylation. Immunoprecipitation-mass spectrometry has been used to discover autoantibodies against NatC subunits in rheumatoid arthritis. Expanded in vivo substrate profiling of yeast NatC using mass spectrometry revealed numerous new substrates, providing insights into its biological roles.
Structural Biology
X-ray crystallography and cryo-electron microscopy have elucidated the molecular architecture of the NatC complex. The ternary complex structure of NatC has been determined, revealing the mechanism of N-terminal acetylation. Divergent architecture of the heterotrimeric NatC complex explains its substrate specificity. Structural studies of human NatC have highlighted the role of NAA38 in thermostability and catalytic activity.
Genetic and Biochemical Assays
Knockout and knockdown models in yeast, C. elegans, and human cells are used to study NatC function. In C. elegans, DAF-16/FOXO regulation of natc-1 modulates stress resistance, linking insulin/IGF-1 signaling to N-terminal acetylation. In vitro acetylation assays with recombinant subunits help dissect catalytic mechanisms.
Imaging and Cellular Localization
Fluorescence microscopy of tagged NatC subunits can reveal their subcellular localization and dynamics. Although specific imaging studies are not cited here, such approaches are standard for studying complex assembly and function.
How CRISPR Can Be Used to Study GO:0031417 NatC complex
Knockout
CRISPR-Cas9 knockout of NatC subunits (e.g., MAK3, NAA30) in cell lines or model organisms can reveal loss-of-function phenotypes, such as reduced N-terminal acetylation, impaired stress resistance, and decreased longevity. Knockout studies in yeast have shown that NatC is essential for acetylating specific substrates and maintaining protein homeostasis.
Point Mutation
Introducing point mutations in the catalytic domain of NAA30 or in substrate N-termini can dissect the molecular determinants of substrate recognition and catalysis. Such mutations can be used to test the specificity of NatC for Met-Ile, Met-Leu, Met-Trp, or Met-Phe N-termini.
Knock-in
Knock-in of tagged NatC subunits (e.g., GFP-NAA30) allows for affinity purification and localization studies. Knock-in of disease-associated mutations, such as those affecting NAA38 thermostability, can model human disorders.
Overexpression
Overexpression of NatC subunits or substrates can enhance N-terminal acetylation and study its effects on protein stability and function. In C. elegans, overexpression of natc-1 modulates stress resistance and longevity.
How EDITGENE Supports NatC complex Research
Researchers studying NatC complex-related genes often need to determine whether a candidate gene is causally involved in N-terminal acetylation, stress responses, or disease. EDITGENE provides comprehensive CRISPR-based services to generate precise cellular and animal models, enabling functional validation and mechanistic studies.
Contact EDITGENE today to design your custom CRISPR model for NatC complex research.
Frequently Asked Questions About NatC complex
What is the NatC complex?
The NatC complex (GO:0031417) is a conserved heterotrimeric enzyme that acetylates the N-termini of proteins starting with Met-Ile, Met-Leu, Met-Trp, or Met-Phe.
What genes are involved in the NatC complex?
In yeast, the genes are MAK3, MAK10, and MAK31; in humans, they are NAA30, NAA35, and NAA38.
What is the function of N-terminal acetylation by NatC?
It modifies proteins to influence their stability, localization, and interactions, and can protect them from degradation.
How is the NatC complex regulated?
In C. elegans, natc-1 is regulated by DAF-16/FOXO, linking insulin/IGF-1 signaling to N-terminal acetylation. NAA38 also regulates thermostability and activity.
What diseases are associated with NatC complex dysfunction?
Autoantibodies against NatC subunits are found in rheumatoid arthritis, and NatC affects aging and stress resistance.
What are the substrates of NatC?
NatC targets proteins with N-terminal Met-Ile, Met-Leu, Met-Trp, or Met-Phe; expanded profiling has identified many new substrates in yeast.
How can I study the NatC complex using CRISPR?
CRISPR knockout, point mutation, knock-in, and overexpression models can be used to dissect NatC function and substrate specificity.
What is the structure of the NatC complex?
It is a heterotrimer with a catalytic subunit (Mak3p/NAA30) and two auxiliary subunits (Mak10p/Mak31p or NAA35/NAA38).
Does NatC complex affect lifespan?
Yes, N-terminal acetylation by NatC promotes age-dependent motility and longevity in model organisms.
What methods are used to study NatC complex?
Common methods include mass spectrometry, X-ray crystallography, in vitro acetylation assays, and CRISPR-based genetic models.
Conclusion
The NatC complex (GO:0031417) is a conserved N-terminal acetyltransferase that modifies a specific subset of proteins, influencing their stability, interactions, and cellular functions. Its roles in stress resistance, aging, and autoimmunity highlight its importance in health and disease. Advances in structural biology and proteomics have expanded our understanding of its substrate specificity and mechanism. Continued research using CRISPR models and bioinformatics will further elucidate its biological significance and therapeutic potential.
References
- 1. Deng S et al.. 2021. Molecular mechanism of N-terminal acetylation by the ternary NatC complex.. Structure 29(10):1094-1104.e4 PMID: 34019809
- 2. Grunwald S et al.. 2020. Divergent architecture of the heterotrimeric NatC complex explains N-terminal acetylation of cognate substrates.. Nat Commun 11(1):5506 PMID: 33139728
- 3. Varland S et al.. 2023. N-terminal acetylation shields proteins from degradation and promotes age-dependent motility and longevity.. Nat Commun 14(1):6774 PMID: 37891180
- 4. Van Damme P et al.. 2023. Expanded in vivo substrate profile of the yeast N-terminal acetyltransferase NatC.. J Biol Chem 299(2):102824 PMID: 36567016
- 5. Deng S et al.. 2023. Molecular role of NAA38 in thermostability and catalytic activity of the human NatC N-terminal acetyltransferase.. Structure 31(2):166-173.e4 PMID: 36638802
- 7. Warnhoff K et al.. 2014. The DAF-16 FOXO transcription factor regulates natc-1 to modulate stress resistance in Caenorhabditis elegans, linking insulin/IGF-1 signaling to protein N-terminal acetylation.. PLoS Genet 10(10):e1004703 PMID: 25330323
- 8. De Leeuw J et al.. 2026. Immunoprecipitation-mass spectrometry reveals known and novel (NatC, BCS1L) antinuclear antibodies in rheumatoid arthritis.. RMD Open 12(2) PMID: 41963076
