GO:0019948 SUMO activating enzyme activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0019948 (SUMO activating enzyme activity) is a molecular function that catalyzes the ATP-dependent activation of processed SUMO, forming a high-energy thiolester bond on the E1 enzyme.
• The heterodimeric SAE1/UBA2 (SUMO-activating enzyme subunit 1/2) complex is the canonical human E1 for SUMOylation, and its upregulation is linked to cancer, fibrosis, and inflammatory diseases.
• SUMO activation is the first and rate-limiting step of the SUMO conjugation cascade, transferring SUMO to the E2 enzyme UBC9 and then to substrates.
• Dysregulated SUMO activating enzyme activity promotes glycolysis, stem cell maintenance, and pathogenic phenotypes in diabetic nephropathy, rheumatoid arthritis, and hepatocellular carcinoma.
• Research tools include CRISPR knockout, point-mutation, knock-in, overexpression models, plus proteomics, transcriptomics, and SUMOylation assays to dissect E1 function.
• Targeting SUMO activating enzyme activity is an emerging therapeutic strategy, with small-molecule inhibitors and genetic models revealing its role in disease.
Description
SUMO activating enzyme activity (GO:0019948) is a molecular function that catalyzes the activation of the proteolytically processed small ubiquitin-related modifier (SUMO) through the formation of an ATP-dependent high-energy thiolester bond. This activity is the first and essential step in the SUMO conjugation pathway, a post-translational modification that regulates protein stability, localization, and interactions. The enzyme responsible, a heterodimer of SAE1 and UBA2 (also known as AOS1 and UBA2 in yeast), uses ATP to adenylate SUMO and then forms a thiolester bond between the C-terminal glycine of SUMO and a catalytic cysteine in UBA2. This activation enables the subsequent transfer of SUMO to the E2 conjugating enzyme UBC9 and ultimately to target lysine residues in substrate proteins. Researchers study GO:0019948 because it controls the entire SUMOylation cascade and is implicated in diverse human diseases, including cancer, fibrosis, and inflammatory disorders. For example, increased SAE1/UBA2 expression promotes glycolysis and pathogenic behavior in rheumatoid fibroblast-like synoviocytes and diabetic nephropathy. In hepatocellular carcinoma, SAE1 is a promising diagnostic biomarker linked to cancer metabolism. The SUMO activating enzyme is also critical for cancer stem cell maintenance and self-renewal, making it a potential therapeutic target. Understanding the molecular mechanism, regulation, and disease relevance of GO:0019948 is therefore essential for both basic biology and translational research. This article provides a comprehensive overview of GO:0019948, covering its definition, mechanism, key genes, regulatory features, disease associations, and experimental models. It is designed for researchers seeking to investigate SUMO activating enzyme activity using CRISPR-based gene editing, proteomics, and other functional genomics approaches.
SUMO activating enzyme activity At A Glance
| GO ID | GO:0019948 |
|---|---|
| GO term | SUMO activating enzyme activity |
| Ontology | molecular_function |
| Synonym | SMT3 activating enzyme, SUMO E1 activator enzyme |
| Major function | ATP-dependent activation of SUMO via thiolester bond formation |
| Catalytic mechanism | Adenylation of SUMO C-terminus followed by thiolester transfer to E1 cysteine |
| Key enzyme complex | SAE1/UBA2 heterodimer (human), AOS1/UBA2 (yeast) |
| Pathway context | First step of SUMO conjugation cascade, upstream of UBC9 and substrate modification |
| Disease relevance | Cancer, fibrosis, inflammatory diseases, diabetic nephropathy |
What Is GO:0019948?
SUMO activating enzyme activity (GO:0019948) is defined as the catalysis of the activation of proteolytically processed SUMO through the formation of an ATP-dependent high-energy thiolester bond. In this reaction, the E1 enzyme (SAE1/UBA2) first adenylates the C-terminus of SUMO using ATP, releasing pyrophosphate, and then transfers SUMO to a catalytic cysteine residue on UBA2, forming a thiolester linkage. This activated SUMO is subsequently transferred to the E2 enzyme UBC9, which conjugates SUMO to target proteins. The activity is essential for all downstream SUMOylation events and is highly conserved from yeast to plants and humans.
Why Is SUMO activating enzyme activity Important in Cell Biology?
SUMO activating enzyme activity (GO:0019948) is critically important because it initiates the entire SUMOylation pathway, a post-translational modification that regulates thousands of proteins involved in transcription, DNA repair, cell cycle, and stress responses. Dysregulation of this activity is directly linked to human diseases: increased SAE1/UBA2 expression promotes glycolysis and fibrotic phenotypes in diabetic nephropathy and rheumatoid arthritis, and SAE1 is a diagnostic biomarker for hepatocellular carcinoma. Moreover, the SUMO activating enzyme is required for cancer stem cell maintenance and self-renewal, highlighting its potential as a therapeutic target. Understanding GO:0019948 provides insights into fundamental cell biology and offers opportunities for drug discovery and precision medicine.
• Initiates the SUMO conjugation cascade, controlling protein stability, localization, and interactions.
• Upregulated in diabetic nephropathy, promoting glycolysis and fibrosis.
• Drives pathogenic behavior of rheumatoid fibroblast-like synoviocytes via increased SAE1/UBA2.
• Serves as a diagnostic cancer metabolism biomarker in hepatocellular carcinoma.
• Essential for cancer stem cell maintenance and self-renewal.
• Regulates β-catenin activation and kidney fibrosis through SUMOylation.
• Conserved across eukaryotes, with plant-specific diversification in Arabidopsis.
• Targeted by SUMO-targeted ubiquitin ligases (STUbLs) that recognize SUMO-modified proteins.
• Modulated by phosphorylation events, such as SENP1 Tyr270 phosphorylation by Lck.
• Potential therapeutic target for cancer, fibrosis, and inflammatory diseases.
What Happens During SUMO activating enzyme activity?
ATP-dependent adenylation of SUMO
In simple terms: The enzyme uses ATP to attach a chemical tag to SUMO, making it ready for the next step.
The first step of SUMO activating enzyme activity involves the ATP-dependent adenylation of the C-terminal glycine of proteolytically processed SUMO. The E1 enzyme SAE1/UBA2 binds SUMO and ATP, catalyzing the formation of a SUMO-adenylate intermediate and releasing pyrophosphate. This reaction is essential for subsequent thiolester bond formation and is conserved from yeast to humans.
Thiolester bond formation on UBA2
In simple terms: SUMO is transferred to a cysteine on the enzyme, forming a high-energy bond that stores energy for the next step.
Following adenylation, the activated SUMO is transferred to a catalytic cysteine residue in the UBA2 subunit of the E1 complex, forming a high-energy thiolester bond. This thiolester-linked SUMO is the active form that can be passed to the E2 enzyme UBC9. The formation of this bond is the defining catalytic event of GO:0019948.
Transfer of SUMO to E2 enzyme UBC9
In simple terms: The enzyme hands off SUMO to a second enzyme, which will attach it to target proteins.
The thiolester-linked SUMO on UBA2 is transferred to the active-site cysteine of the E2 conjugating enzyme UBC9 through a trans-thiolesterification reaction. This step is facilitated by the E1 enzyme and is required for subsequent conjugation of SUMO to substrate lysine residues. UBC9 then directly binds target proteins and catalyzes isopeptide bond formation.
Substrate modification and downstream effects
In simple terms: SUMO gets attached to other proteins, changing their behavior and affecting many cellular processes.
Once transferred to UBC9, SUMO is conjugated to target proteins, often at lysine residues within consensus motifs. This modification alters protein function, localization, and interactions, impacting processes such as transcription, DNA repair, and signal transduction. SUMO-targeted ubiquitin ligases (STUbLs) can further recognize SUMO-modified proteins and target them for ubiquitination, linking SUMOylation to protein degradation.
Key Genes Involved in GO:0019948 SUMO activating enzyme activity
The following genes and proteins are directly involved in or regulate SUMO activating enzyme activity (GO:0019948) and its downstream pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SAE1 | SUMO-activating enzyme subunit 1; forms heterodimer with UBA2 | Upregulated in diabetic nephropathy, rheumatoid arthritis, hepatocellular carcinoma |
| UBA2 | SUMO-activating enzyme subunit 2; contains catalytic cysteine for thiolester bond | Essential for SUMO activation; target for cancer stem cell studies |
| UBC9 | SUMO-conjugating enzyme E2; receives SUMO from E1 | Mediates β-catenin activation and kidney fibrosis |
| SUMO1 | Small ubiquitin-related modifier 1; substrate for E1 activation | Key modifier in stress responses and cancer |
| SUMO2 | Small ubiquitin-related modifier 2; substrate for E1 activation | Involved in SUMOylation cascade |
| SUMO3 | Small ubiquitin-related modifier 3; substrate for E1 activation | Similar to SUMO2, contributes to SUMOylation |
| SENP1 | SUMO protease; deconjugates SUMO from targets | Regulated by Lck phosphorylation at Tyr270 |
| STUbL (e.g., RNF4) | SUMO-targeted ubiquitin ligase; recognizes SUMO-modified proteins | Links SUMOylation to ubiquitination and degradation |
| AOS1 (yeast) | Yeast homolog of SAE1 | Model for SUMO activation studies |
| UBA2 (yeast) | Yeast homolog of UBA2 | Model for SUMO activation studies |
| SAE1 (Arabidopsis) | Plant homolog of SAE1 | Diversification of SUMO-activating enzyme in plants |
| SAE2 (Arabidopsis) | Plant homolog of UBA2 | Plant SUMO conjugation studies |
| β-catenin | Downstream target of SUMOylation | Activated by UBC9-associated SUMOylation in kidney fibrosis |
| Lck | Tyrosine kinase; phosphorylates SENP1 | Modulates SENP1 activity and specificity |
| RNF4 | SUMO-targeted ubiquitin ligase | Recognizes SUMO-modified proteins |
| SAE1/UBA2 complex | Heterodimeric E1 enzyme | Central to GO:0019948; target for inhibitors |
How Is SUMO activating enzyme activity Regulated?
SUMO activating enzyme activity is regulated at multiple levels. The expression of SAE1 and UBA2 subunits is often upregulated in disease states such as diabetic nephropathy and rheumatoid arthritis, leading to increased SUMOylation. Post-translational modifications also play a role: phosphorylation of SENP1 at Tyr270 by Lck modulates SENP1 enzyme activity and specificity, indirectly affecting the balance of SUMOylation. Additionally, SUMO-targeted ubiquitin ligases (STUbLs) regulate the turnover of SUMO-modified proteins, providing a feedback mechanism. The activity is also influenced by the availability of SUMO and ATP, and by interactions with E2 enzyme UBC9. In plants, the SUMO-activating enzyme has diversified, with different isoforms showing distinct roles in SUMO conjugation.
SUMO activating enzyme activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SAE1 | Diabetic nephropathy, fibrosis | Knockout or overexpression in kidney cells; diabetic mouse models |
| SAE1/UBA2 | Rheumatoid arthritis | Knockdown in fibroblast-like synoviocytes; arthritis mouse models |
| SAE1 | Hepatocellular carcinoma | Knockout in liver cancer cell lines; xenograft models |
| UBA2 | Cancer stem cell maintenance | Knockout in cancer stem cell lines; self-renewal assays |
| UBC9 | Kidney fibrosis | Knockout or knock-in in kidney fibroblasts; fibrosis models |
SUMO activating enzyme activity in cancer
Increased SUMO activating enzyme activity, driven by SAE1/UBA2 upregulation, promotes glycolysis and pathogenic behavior in cancer cells. In hepatocellular carcinoma, SAE1 is a promising diagnostic biomarker linked to cancer metabolism. The enzyme is also essential for cancer stem cell maintenance and self-renewal, suggesting that targeting GO:0019948 could impair tumor growth and recurrence. These findings highlight the potential of SUMO activating enzyme inhibitors as anticancer therapeutics.
SUMO activating enzyme activity in fibrosis and kidney disease
In diabetic nephropathy, increased SUMO-activating enzyme subunit 1 promotes glycolysis and fibrotic phenotype, contributing to disease progression. Similarly, UBC9-associated SUMOylation contributes to β-catenin activation and kidney fibrosis, linking SUMO activating enzyme activity to fibrotic signaling. These studies suggest that inhibiting SUMO activation may reduce fibrosis in chronic kidney disease.
SUMO activating enzyme activity in inflammatory and autoimmune diseases
In rheumatoid arthritis, increased SAE1/UBA2 promotes glycolysis and pathogenic behavior of rheumatoid fibroblast-like synoviocytes, indicating a role for SUMO activating enzyme activity in inflammation and joint destruction. Modulating this activity could provide a therapeutic strategy for inflammatory diseases.
From SUMO activating enzyme activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of SAE1 affect SUMOylation and glycolysis? | CRISPR knockout of SAE1 in disease-relevant cell lines |
| Does a point mutation in UBA2 catalytic cysteine abolish E1 activity? | CRISPR point mutation (C173A) in UBA2 |
| Does tagging SAE1 with a fluorescent protein affect its localization? | Knock-in of GFP or HA tag at endogenous SAE1 locus |
| Does overexpression of SAE1/UBA2 drive pathogenic phenotypes? | Overexpression of SAE1 and UBA2 in cell lines or mouse models |
| What is the role of SENP1 phosphorylation in SUMOylation balance? | Point mutation of SENP1 Tyr270 (Y270F) via CRISPR |
| Can SUMO activating enzyme inhibitors reduce tumor growth? | Xenograft models with SAE1/UBA2 knockout or inhibitor treatment |
How to Study the SUMO activating enzyme activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro SUMOylation assay | E1-mediated thiolester bond formation | Measuring SAE1/UBA2 activity with recombinant proteins |
| Mass spectrometry | Global SUMO-modified proteome | Identifying substrates affected by E1 inhibition |
| RNA-seq | Transcriptional changes | Assessing downstream effects of SAE1/UBA2 modulation |
| Metabolic assays | Glycolysis and metabolic flux | Linking SUMO activation to cancer metabolism |
| CRISPR knockout | Loss-of-function phenotypes | Determining essentiality of SAE1/UBA2 in disease models |
| CRISPR point mutation | Specific catalytic residue function | Dissecting UBA2 catalytic cysteine |
| Knock-in tagging | Protein localization and interactions | Tracking endogenous SAE1/UBA2 |
| Overexpression | Gain-of-function phenotypes | Modeling disease-associated upregulation |
Proteomics and SUMOylation assays
Proteomic approaches such as mass spectrometry can identify SUMO-modified proteins and quantify global SUMOylation changes upon modulation of SUMO activating enzyme activity. In vitro SUMOylation assays using recombinant SAE1/UBA2, UBC9, and SUMO can directly measure E1 activity and thiolester bond formation.
Transcriptomics and metabolic profiling
RNA sequencing and metabolic assays reveal how changes in SUMO activating enzyme activity affect gene expression and cellular metabolism, such as glycolysis. These methods are useful for studying the downstream consequences of SAE1/UBA2 dysregulation in disease models.
CRISPR-based functional genomics
CRISPR knockout, point mutation, and knock-in models enable precise dissection of GO:0019948. For example, knockout of SAE1 or UBA2 can abolish SUMOylation, while point mutations in the catalytic cysteine can separate activation from downstream conjugation. Overexpression models can mimic disease-associated upregulation.
Imaging and cellular localization
Fluorescence microscopy with tagged SAE1 or UBA2 can visualize the subcellular localization of the SUMO activating enzyme complex and its dynamics during stress or disease. Co-localization with SUMO substrates or UBC9 can provide insights into the spatial regulation of SUMOylation.
How CRISPR Can Be Used to Study GO:0019948 SUMO activating enzyme activity
Knockout
CRISPR knockout of SAE1 or UBA2 completely abolishes SUMO activating enzyme activity, providing a powerful tool to study the loss-of-function phenotypes in cancer, fibrosis, and inflammatory diseases. Knockout cell lines can be used to confirm the requirement of GO:0019948 for cell proliferation, glycolysis, and stem cell maintenance.
Point Mutation
CRISPR point mutation can be used to substitute the catalytic cysteine in UBA2 (e.g., C173A) to specifically inactivate the thiolester bond formation without affecting protein stability. This allows researchers to separate the activation step from downstream SUMO conjugation and to study the precise contribution of GO:0019948 to cellular processes.
Knock-in
Knock-in of epitope tags (e.g., HA, GFP) or fluorescent proteins at the endogenous SAE1 or UBA2 loci enables real-time tracking of the SUMO activating enzyme complex and its interactions with SUMO and UBC9. Tagged knock-in models are valuable for imaging and proteomic studies.
Overexpression
CRISPR-mediated overexpression or lentiviral overexpression of SAE1 and UBA2 can mimic the upregulation observed in diabetic nephropathy, rheumatoid arthritis, and hepatocellular carcinoma, allowing researchers to study the pathogenic consequences of increased SUMO activating enzyme activity.
How EDITGENE Supports SUMO activating enzyme activity Research
Researchers studying SUMO activating enzyme activity-related genes often need to determine whether a candidate gene is causally involved in disease phenotypes or whether its modulation can alter SUMOylation and downstream cellular processes. EDITGENE provides a comprehensive suite of CRISPR-based services to enable precise genetic manipulation of SAE1, UBA2, UBC9, and other components of the SUMO pathway, from knockout to point mutation, knock-in, and overexpression, as well as library screening and bioinformatics support.
Contact EDITGENE today to design your custom CRISPR model for SUMO activating enzyme activity research.
Related Products
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Frequently Asked Questions About SUMO activating enzyme activity
What is SUMO activating enzyme activity?
SUMO activating enzyme activity (GO:0019948) is the ATP-dependent activation of processed SUMO through formation of a high-energy thiolester bond, catalyzed by the SAE1/UBA2 heterodimer.
What genes are involved in SUMO activating enzyme activity?
The core genes are SAE1 and UBA2, which form the E1 enzyme, along with SUMO isoforms and the E2 enzyme UBC9.
What is the role of SAE1 in disease?
SAE1 upregulation promotes glycolysis and fibrotic phenotypes in diabetic nephropathy and rheumatoid arthritis, and is a diagnostic biomarker in hepatocellular carcinoma.
How is SUMO activating enzyme activity regulated?
It is regulated by expression levels of SAE1/UBA2, post-translational modifications such as SENP1 phosphorylation, and interactions with STUbLs and UBC9.
What diseases are associated with SUMO activating enzyme activity?
Cancer, diabetic nephropathy, rheumatoid arthritis, and kidney fibrosis are linked to dysregulated SUMO activating enzyme activity.
How can I study SUMO activating enzyme activity in the lab?
Common methods include in vitro SUMOylation assays, mass spectrometry, RNA-seq, and CRISPR knockout or point mutation models.
What is the difference between SUMO activating enzyme and UBC9?
The SUMO activating enzyme (E1) activates SUMO and transfers it to UBC9 (E2), which then conjugates SUMO to target proteins.
Can CRISPR be used to study SUMO activating enzyme activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect the function of SAE1/UBA2 and GO:0019948.
What are the synonyms for SUMO activating enzyme activity?
Synonyms include SMT3 activating enzyme and SUMO E1 activator enzyme.
Why is SUMO activating enzyme activity important for cancer?
It supports cancer stem cell maintenance, promotes glycolysis, and is upregulated in several cancers, making it a potential therapeutic target.
Conclusion
SUMO activating enzyme activity (GO:0019948) is a fundamental molecular function that initiates the SUMOylation cascade, with critical roles in cellular stress responses, metabolism, and disease. The SAE1/UBA2 heterodimer catalyzes the ATP-dependent activation of SUMO, and its dysregulation is implicated in cancer, fibrosis, and inflammatory diseases. Understanding the mechanism, regulation, and disease relevance of this activity provides a foundation for developing targeted therapies and diagnostic biomarkers. EDITGENE offers a comprehensive suite of CRISPR services, including knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics, to support researchers in dissecting the function of SUMO activating enzyme activity and its associated genes. By leveraging these tools, the scientific community can accelerate discoveries in SUMO biology and translate them into clinical applications.
References
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- 2. Wang C et al.. 2020. Increased SUMO-activating enzyme SAE1/UBA2 promotes glycolysis and pathogenic behavior of rheumatoid fibroblast-like synoviocytes.. JCI Insight 5(18) PMID: 32938830
- 3. Ong JR et al.. 2021. SUMO-Activating Enzyme Subunit 1 (SAE1) Is a Promising Diagnostic Cancer Metabolism Biomarker of Hepatocellular Carcinoma.. Cells 10(1) PMID: 33477333
- 4. Castaño-Miquel L et al.. 2013. Diversification of SUMO-activating enzyme in Arabidopsis: implications in SUMO conjugation.. Mol Plant 6(5):1646-60 PMID: 23482370
- 5. Sriramachandran AM et al.. 2014. SUMO-targeted ubiquitin ligases.. Biochim Biophys Acta 1843(1):75-85 PMID: 24018209
- 6. Cai J et al.. 2025. UBC9-associated SUMOylation contributes to β-catenin activation and kidney fibrosis.. Kidney Int 108(4):642-657 PMID: 40712886
- 7. Du L et al.. 2016. Role of SUMO activating enzyme in cancer stem cell maintenance and self-renewal.. Nat Commun 7:12326 PMID: 27465491
- 8. Li YY et al.. 2021. TCR-Induced Tyrosine Phosphorylation at Tyr270 of SUMO Protease SENP1 by Lck Modulates SENP1 Enzyme Activity and Specificity.. Front Cell Dev Biol 9:789348 PMID: 35186948
