GO:0106068 SUMO ligase complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0106068 (SUMO ligase complex) is a cellular_component defined as a protein ligase complex that enables protein sumoylation, consisting of a SUMO-protein transferase and other proteins that may confer substrate specificity.
• The best-characterized SUMO ligase complex is the Nse2/Mms21-containing Smc5/6 complex, which maintains genome stability and homologous recombination.
• SUMO ligase complexes often cooperate with SUMO-targeted ubiquitin ligases such as RNF4 and TOPORS to manage stress and cell proliferation.
• Dysregulation of SUMO ligase complex components is linked to cancer stemness, chemoresistance, and genome instability.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect SUMO ligase complex subunit function.
• EDITGENE provides end-to-end CRISPR cell model and library screening services to study SUMO ligase complex biology.
Description
The SUMO ligase complex (GO:0106068) is a cellular component that enables protein sumoylation, a post-translational modification where small ubiquitin-like modifier (SUMO) proteins are covalently attached to target lysines. This complex consists of a SUMO-protein transferase and additional proteins that may confer substrate specificity, distinguishing it from monomeric SUMO ligases. Understanding this complex is critical because sumoylation regulates genome stability, transcription, and stress responses. The Nse2/Mms21 SUMO ligase within the Smc5/6 complex is a paradigm for how SUMO ligase complexes maintain genome integrity and homologous recombination. Beyond genome maintenance, SUMO ligase complexes coordinate with ubiquitin ligases like RNF4 and TOPORS to manage proteotoxic stress and cell cycle progression. Dysregulation of these complexes has been implicated in cancer stemness and chemoresistance, making them attractive therapeutic targets. Researchers studying SUMO ligase complexes require robust CRISPR models to dissect subunit-specific functions and substrate specificity.
SUMO ligase complex At A Glance
| GO ID | GO:0106068 |
|---|---|
| GO term | SUMO ligase complex |
| Ontology | cellular_component |
| Synonym | SUMO-protein ligase complex; SUMO transferase complex; Sumoylation complex |
| Major function | Enables protein sumoylation by transferring SUMO to substrate lysines |
| Key example | Nse2/Mms21 within the Smc5/6 complex |
| Associated processes | Genome stability, homologous recombination, stress response |
| Disease relevance | Cancer, chemoresistance, genome instability |
What Is GO:0106068?
GO:0106068 (SUMO ligase complex) is a protein complex that catalyzes protein sumoylation. It contains a SUMO-protein transferase catalytic subunit and accessory proteins that may determine which substrates are modified. This complex is distinct from the SUMO-activating enzyme (E1) and SUMO-conjugating enzyme (E2), acting as an E3-like factor to facilitate SUMO transfer to targets.
Why Is SUMO ligase complex Important in Cell Biology?
The SUMO ligase complex is essential for maintaining genome stability and coordinating cellular stress responses. Its catalytic activity and substrate specificity influence homologous recombination, cell cycle progression, and survival under proteotoxic stress. Because SUMO ligase complexes often cooperate with ubiquitin ligases, they sit at the nexus of post-translational networks that determine cell fate. Dysregulation of these complexes contributes to cancer stemness and chemoresistance, highlighting their therapeutic potential.
• Maintains genome stability through SUMOylation of DNA repair factors.
• Regulates homologous recombination via the Smc5/6 complex.
• Coordinates stress management with SUMO-targeted ubiquitin ligases.
• Modulates cell proliferation and cell cycle checkpoints.
• Contributes to cancer stemness and chemoresistance.
• Provides substrate specificity through accessory subunits.
• Serves as a target for CRISPR-based functional genomics.
• Links sumoylation to ubiquitin signaling pathways.
• Implicated in proteotoxic stress responses.
• Potential biomarker for genome instability syndromes.
What Happens During SUMO ligase complex?
Substrate recognition and SUMO transfer
In simple terms: The complex recognizes a target protein and attaches SUMO to it.
The SUMO ligase complex binds substrate proteins and facilitates the transfer of SUMO from the E2 conjugating enzyme to specific lysine residues. The Nse2/Mms21 subunit within the Smc5/6 complex exemplifies this by sumoylating proteins involved in homologous recombination.
Coordination with SUMO-targeted ubiquitin ligases
In simple terms: After SUMO is attached, other enzymes can add ubiquitin to the same protein.
SUMO ligase complexes often work with SUMO-targeted ubiquitin ligases such as RNF4 and TOPORS. This concerted activity is essential for stress management and cell proliferation, as shown by combined loss of TOPORS and RNF4.
Genome stability maintenance
In simple terms: The complex helps repair DNA and keep chromosomes stable.
The Nse2/Mms21 SUMO ligase of the Smc5/6 complex is critical for maintaining genome stability. Its SUMOylation activity supports homologous recombination and prevents DNA damage accumulation.
Stress response and cell cycle regulation
In simple terms: The complex helps cells survive stress and divide properly.
SUMO ligase complexes participate in stress management and cell cycle progression. Their activity is required for proliferation under proteotoxic stress, and their dysfunction leads to cell cycle defects.
Key Genes Involved in GO:0106068 SUMO ligase complex
The following genes encode components or regulators of the SUMO ligase complex and related pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NSE2/MMS21 | SUMO ligase subunit of Smc5/6 complex | Genome stability and homologous recombination |
| SMC5 | Structural maintenance of chromosomes subunit | Smc5/6 complex assembly |
| SMC6 | Structural maintenance of chromosomes subunit | Smc5/6 complex assembly |
| RNF4 | SUMO-targeted ubiquitin ligase | Stress management and proliferation |
| TOPORS | SUMO-targeted ubiquitin ligase | Stress management and proliferation |
| USP51 | Deubiquitinase | Cancer stemness and chemoresistance |
| HIF1A | Transcription factor | Feed-forward loop with USP51 |
| SUMO1 | Small ubiquitin-like modifier | Substrate for sumoylation |
| SUMO2 | Small ubiquitin-like modifier | Substrate for sumoylation |
| SUMO3 | Small ubiquitin-like modifier | Substrate for sumoylation |
| UBC9 | SUMO-conjugating enzyme E2 | SUMO transfer |
| SAE1 | SUMO-activating enzyme E1 subunit | SUMO activation |
| SAE2 | SUMO-activating enzyme E1 subunit | SUMO activation |
| PRKN | Parkin E3 ubiquitin ligase | Mitophagy regulation |
| APC/C | Anaphase promoting complex | Cell cycle regulation |
| NSE2 | SUMO ligase | Genome stability |
| MMS21 | SUMO ligase | Homologous recombination |
How Is SUMO ligase complex Regulated?
SUMO ligase complex activity is regulated by subunit availability, post-translational modifications, and interaction with SUMO-targeted ubiquitin ligases. The concerted action of TOPORS and RNF4 is essential for stress management and cell proliferation, indicating that ubiquitin ligases modulate SUMO ligase complex function. Additionally, lactate can remodel the anaphase promoting complex, indirectly influencing cell cycle regulation that intersects with SUMO pathways.
SUMO ligase complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| USP51 | Colorectal cancer stemness and chemoresistance | Knockout in HCT116 cells |
| NSE2/MMS21 | Genome instability | Knockout in U2OS cells |
| RNF4 | Stress management defects | Knockout in HeLa cells |
| TOPORS | Cell proliferation defects | Knockout in HEK293T cells |
| HIF1A | Cancer stemness | Overexpression in colorectal cancer cells |
Cancer and chemoresistance
USP51 facilitates colorectal cancer stemness and chemoresistance by forming a positive feed-forward loop with HIF1A, linking deubiquitinase activity to SUMO-related pathways. Dysregulation of SUMO ligase complex components may contribute to genome instability in cancer.
Genome instability syndromes
The Nse2/Mms21 SUMO ligase of the Smc5/6 complex is critical for homologous recombination and genome stability. Defects in this complex can lead to DNA damage accumulation and chromosomal instability.
Stress-related disorders
Concerted SUMO-targeted ubiquitin ligase activities of TOPORS and RNF4 are essential for stress management. Their dysfunction may impair cellular responses to proteotoxic stress.
From SUMO ligase complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does NSE2 loss affect homologous recombination? | NSE2 knockout in U2OS cells |
| Does RNF4 cooperate with TOPORS in stress? | Double knockout in HeLa cells |
| Does USP51 promote chemoresistance? | USP51 knockout in HCT116 cells |
| Does SUMOylation of a specific substrate require MMS21? | Point mutation in MMS21 |
| Does overexpression of SUMO1 increase sumoylation? | SUMO1 overexpression in HEK293T cells |
| Does HIF1A regulate USP51? | HIF1A knockout in colorectal cancer cells |
How to Study the SUMO ligase complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout | Gene function loss | Identify essential SUMO ligase subunits |
| Proteomics | Protein interactions and modifications | Map SUMOylation substrates |
| RNA-seq | Transcriptional changes | Assess downstream effects |
| Imaging | Protein localization | Visualize Smc5/6 foci |
| Co-IP | Protein-protein interactions | Detect complex assembly |
| Western blot | Protein expression and SUMOylation | Validate knockout efficiency |
| Cell viability assay | Proliferation and survival | Test chemoresistance |
CRISPR knockout screens
Genome-wide CRISPR knockout screens can identify genes required for SUMO ligase complex function and stress responses.
Proteomics and SUMOylome analysis
Mass spectrometry-based proteomics can map SUMOylation sites and identify substrates of specific SUMO ligase complexes.
Imaging and cell-based assays
Fluorescence microscopy can visualize Smc5/6 complex localization and DNA damage foci in cells with SUMO ligase mutations.
Transcriptomics and RNA-seq
RNA-seq can reveal transcriptional changes upon SUMO ligase complex disruption, linking sumoylation to gene expression programs.
How CRISPR Can Be Used to Study GO:0106068 SUMO ligase complex
Knockout
CRISPR knockout of SUMO ligase complex subunits such as NSE2 or MMS21 can reveal their roles in genome stability and homologous recombination.
Point Mutation
Point mutations in catalytic residues of SUMO ligases can dissect enzymatic activity from scaffolding functions.
Knock-in
Knock-in of tagged SUMO ligase subunits enables affinity purification and live-cell imaging of the complex.
Overexpression
Overexpression of SUMO ligase components or substrates can enhance sumoylation and probe pathway activation.
How EDITGENE Supports SUMO ligase complex Research
Researchers studying SUMO ligase complex-related genes often need to determine whether a candidate gene is causally involved in genome stability, stress responses, or cancer phenotypes. EDITGENE provides validated CRISPR cell models to accelerate this discovery.
Contact EDITGENE today to design your custom CRISPR model for SUMO ligase complex research.
Frequently Asked Questions About SUMO ligase complex
What is the SUMO ligase complex?
GO:0106068 is a protein complex that enables protein sumoylation, consisting of a SUMO-protein transferase and accessory proteins.
What genes are involved in the SUMO ligase complex?
Key genes include NSE2/MMS21, SMC5, SMC6, RNF4, TOPORS, and USP51.
What is the function of the SUMO ligase complex?
It transfers SUMO to substrate proteins, regulating genome stability, stress responses, and cell proliferation.
How is the SUMO ligase complex regulated?
It is regulated by subunit availability and cooperation with SUMO-targeted ubiquitin ligases like RNF4 and TOPORS.
What diseases are linked to SUMO ligase complex dysfunction?
Cancer, chemoresistance, and genome instability syndromes.
What is the Nse2/Mms21 SUMO ligase?
It is a SUMO ligase subunit of the Smc5/6 complex critical for homologous recombination and genome stability.
How can CRISPR be used to study the SUMO ligase complex?
CRISPR knockout, point mutation, knock-in, and overexpression models can dissect subunit functions.
What methods study SUMO ligase complex activity?
Proteomics, imaging, RNA-seq, and cell viability assays.
What is the role of RNF4 in SUMO ligase complex biology?
RNF4 is a SUMO-targeted ubiquitin ligase that cooperates with TOPORS in stress management.
How does USP51 relate to SUMO ligase complexes?
USP51 facilitates colorectal cancer stemness and chemoresistance via a feed-forward loop with HIF1A.
Conclusion
The SUMO ligase complex (GO:0106068) is a central regulator of protein sumoylation, genome stability, and stress responses. Its components, including Nse2/Mms21 and associated ubiquitin ligases, are critical for homologous recombination and cell proliferation. Dysregulation contributes to cancer and chemoresistance, making it a promising target for therapeutic intervention. CRISPR-based models are indispensable for dissecting the molecular mechanisms of this complex and translating findings into clinical applications.
References
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- 4. Stephan AK et al.. 2011. The Nse2/Mms21 SUMO ligase of the Smc5/6 complex in the maintenance of genome stability.. FEBS Lett 585(18):2907-13 PMID: 21550342
- 5. Liu W et al.. 2023. Lactate regulates cell cycle by remodelling the anaphase promoting complex.. Nature 616(7958):790-797 PMID: 36921622
- 6. Potts PR. 2009. The Yin and Yang of the MMS21-SMC5/6 SUMO ligase complex in homologous recombination.. DNA Repair (Amst) 8(4):499-506 PMID: 19217832
- 7. Liu JCY et al.. 2024. Concerted SUMO-targeted ubiquitin ligase activities of TOPORS and RNF4 are essential for stress management and cell proliferation.. Nat Struct Mol Biol 31(9):1355-1367 PMID: 38649616
- 8. Mu M et al.. 2023. USP51 facilitates colorectal cancer stemness and chemoresistance by forming a positive feed-forward loop with HIF1A.. Cell Death Differ 30(11):2393-2407 PMID: 37816999
