GO:0061657 UFM1 conjugating enzyme activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0061657 describes the enzymatic activity that transfers UFM1 from a thioester-linked E2~UFM1 intermediate to a target protein, forming a new thioester bond.
• The reaction is isoenergetic and requires a catalytic cysteine in the E2 enzyme, typically UBE2M or UBE2F in the UFM1 pathway.
• UBA5 acts as the E1 activating enzyme for UFM1, and UFL1 functions as the E3 ligase that determines substrate specificity.
• UFM1 conjugating enzyme activity is essential for ER stress responses, ribosome quality control, and maintenance of proteostasis.
• Dysregulation of UFM1 conjugation is linked to tumorigenesis, neurodegenerative conditions, and developmental disorders.
• CRISPR knockout, point-mutation, and knock-in models enable precise dissection of E2 enzyme function in UFM1 conjugation.
Description
UFM1 conjugating enzyme activity (GO:0061657) is a molecular function that catalyzes the transfer of the ubiquitin-like protein UFM1 from a thioester-linked E2~UFM1 intermediate to a substrate protein, forming a new thioester bond between the C-terminal glycine of UFM1 and a cysteine residue on the target. This activity is a central step in the UFM1 conjugation cascade, which mirrors ubiquitination but uses dedicated E1, E2, and E3 enzymes. The reaction is isoenergetic, meaning the thioester bond energy is conserved during transfer, and it requires a catalytic cysteine in the E2 enzyme. In humans, the principal E2 enzymes for UFM1 are UBE2M and UBE2F, although their specific roles in UFM1 conjugation are still being defined. Understanding this activity is critical because UFM1 conjugation regulates diverse cellular processes, including ER stress responses, ribosome quality control, and DNA damage repair. Dysregulation of UFM1 conjugating enzyme activity has been implicated in cancer, neurodegeneration, and developmental disorders, making it a potential therapeutic target. Researchers studying this activity need robust tools to identify substrates, measure conjugation rates, and manipulate E2 enzyme levels in cells.
UFM1 conjugating enzyme activity At A Glance
| GO ID | GO:0061657 |
|---|---|
| GO term | UFM1 conjugating enzyme activity |
| Ontology | molecular_function |
| Synonym | E2 |
| Major function | Transfer of UFM1 from E2~UFM1 thioester to substrate, forming a new thioester bond |
| Catalytic residue | Cysteine (sulfhydryl group) in the E2 active site |
| Representative E2 enzymes | UBE2M, UBE2F |
| Upstream activator | UBA5 (E1) |
| Downstream ligase | UFL1 (E3) |
What Is GO:0061657?
UFM1 conjugating enzyme activity (GO:0061657) is defined as the isoenergetic transfer of UFM1 from one protein to another via the reaction X-UFM1 + Y = Y-UFM1 + X, where both the X-UFM1 and Y-UFM1 linkages are thioester bonds between the C-terminal amino acid of UFM1 and a sulfhydryl side group of a cysteine residue. In simpler terms, it is the E2 enzyme step in the UFM1 conjugation pathway, where the E2 receives UFM1 from the E1 and passes it to a substrate or E3 ligase.
Why Is UFM1 conjugating enzyme activity Important in Cell Biology?
UFM1 conjugating enzyme activity is a critical node in the UFM1 conjugation cascade, which regulates protein homeostasis, ER stress responses, and ribosome quality control. Because this activity determines the efficiency and specificity of UFM1 transfer, its dysregulation can lead to accumulation of misfolded proteins, impaired stress responses, and disease. Targeting this activity may offer therapeutic opportunities in cancer and neurodegenerative disorders.
• Central step in UFM1 conjugation, a ubiquitin-like modification pathway.
• Required for ER stress response and unfolded protein response.
• Modulates ribosome quality control and translational stress responses.
• Implicated in tumorigenesis and cancer progression.
• Linked to neurodegenerative diseases and developmental disorders.
• Potential target for small-molecule inhibitors or activators.
• Enables substrate identification via thioester profiling.
• Essential for studying crosstalk with ubiquitin and other UBLs.
• Provides mechanistic insights into E2 enzyme specificity.
• Facilitates development of CRISPR models for functional validation.
What Happens During UFM1 conjugating enzyme activity?
Activation and Transfer of UFM1 to E2
In simple terms: UFM1 is first activated by the E1 enzyme UBA5 and then handed to the E2 enzyme.
The UFM1 conjugation cascade begins with the ATP-dependent activation of UFM1 by UBA5 (E1), forming a UBA5~UFM1 thioester intermediate. UFM1 is then transferred to the active-site cysteine of an E2 enzyme, such as UBE2M or UBE2F, generating an E2~UFM1 thioester. This step is isoenergetic and requires the UFM1-interacting sequence (UIS) in UBA5 for efficient binding to UFM1.
Substrate Recognition and E3-Mediated Transfer
In simple terms: The E2~UFM1 complex interacts with an E3 ligase that helps select the target protein.
The E2~UFM1 thioester is directed to a substrate protein by the E3 ligase UFL1, which recognizes specific target lysines. UFL1 forms a complex with DDRGK1 and possibly other factors to facilitate UFM1 transfer. The E2 enzyme itself may also contribute to substrate specificity through its surface interactions.
Formation of UFM1-Substrate Thioester or Isopeptide Bond
In simple terms: UFM1 is attached to the target protein, often via a thioester bond to cysteine or an isopeptide bond to lysine.
The catalytic cysteine of the E2 transfers UFM1 to a cysteine residue on the substrate, forming a new thioester bond, as defined by GO:0061657. In some cases, UFM1 may be transferred to a lysine residue, forming an isopeptide bond, but the GO term specifically describes thioester linkages. This reaction is reversible and can be reversed by UFM1-specific proteases.
Deconjugation and Recycling
In simple terms: UFM1 can be removed from substrates by specific proteases, allowing recycling.
UFM1-specific proteases (e.g., UFSP1, UFSP2) cleave UFM1 from substrates, reversing the conjugation. This deconjugation is important for maintaining free UFM1 pools and regulating pathway activity. Herpesvirus-encoded deconjugases can also target UFM1 conjugates, highlighting the pathway's role in immune evasion.
Key Genes Involved in GO:0061657 UFM1 conjugating enzyme activity
The following genes encode proteins directly involved in UFM1 conjugating enzyme activity or its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| UFM1 | Ubiquitin-like modifier transferred by E2 enzymes | Core substrate for conjugation assays |
| UBA5 | E1 activating enzyme for UFM1 | Required for E2~UFM1 thioester formation |
| UBE2M | E2 conjugating enzyme (candidate) | Potential UFM1 E2, studied via profiling |
| UBE2F | E2 conjugating enzyme (candidate) | Potential UFM1 E2, studied via profiling |
| UFL1 | E3 ligase for UFM1 | Determines substrate specificity |
| DDRGK1 | UFL1 adaptor protein | Stabilizes UFL1 and promotes UFMylation |
| UFSP1 | UFM1-specific protease | Reverses conjugation, regulates free UFM1 |
| UFSP2 | UFM1-specific protease | Reverses conjugation, linked to disease |
| CDK5RAP3 | UFL1-associated protein | Modulates UFMylation in ER stress |
| PDCD4 | Substrate of UFMylation | Implicated in tumorigenesis |
| p62/SQSTM1 | Substrate/regulator of UFM1 pathway | Links UFMylation to autophagy |
| RPL26 | Ribosomal protein substrate | UFMylation affects ribosome quality control |
| HSPA5/BiP | ER chaperone, UFMylation target | Connects UFMylation to ER stress |
| TP53 | Tumor suppressor, UFMylation target | UFMylation modulates p53 stability |
| KEAP1 | Oxidative stress regulator | UFMylation affects NRF2 pathway |
| NFE2L2/NRF2 | Transcription factor | UFMylation influences antioxidant response |
| ATG7 | Autophagy-related protein | UFMylation crosstalk with autophagy |
How Is UFM1 conjugating enzyme activity Regulated?
UFM1 conjugating enzyme activity is regulated at multiple levels. The E1 enzyme UBA5 controls the supply of UFM1~E1 thioester, and its UFM1-interacting sequence (UIS) is essential for efficient UFM1 binding and transfer to E2. E3 ligase UFL1 and its adaptor DDRGK1 determine substrate selection and spatial organization of the conjugation machinery. UFM1-specific proteases (UFSP1, UFSP2) remove UFM1 from substrates, balancing conjugation and deconjugation. Additionally, cellular stress conditions such as ER stress and translational stress can modulate UFM1 conjugation activity. Herpesvirus deconjugases can also perturb the pathway by removing UFM1 from host proteins.
UFM1 conjugating enzyme activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| UFM1 | Cancer, neurodegeneration | KO and point-mutation cell lines |
| UBA5 | Developmental disorders | Knock-in of patient mutations |
| UFL1 | ER stress-related diseases | KO and tagged knock-in |
| UFSP2 | Skeletal dysplasia | Point mutation and KO |
| p62/SQSTM1 | Neurodegeneration, cancer | Overexpression and KO |
UFM1 Conjugation in Cancer
Dysregulation of UFM1 conjugating enzyme activity has been observed in various cancers, where altered UFMylation affects tumor suppressor stability, DNA damage responses, and cell survival. For example, UFMylation of PDCD4 and p53 modulates their function, influencing tumorigenesis. Targeting the E2 step may provide a therapeutic strategy, but further studies are needed to identify specific inhibitors.
UFM1 Conjugation in Neurodegeneration
Impaired UFM1 conjugation is linked to neurodegenerative conditions, possibly due to defective ER stress responses and accumulation of misfolded proteins. Mutations in UFM1 pathway components have been associated with developmental and neurological disorders, although the exact mechanisms remain under investigation.
UFM1 Conjugation in ER Stress and Ribosomopathies
UFM1 conjugating enzyme activity is essential for ER stress responses, and its disruption leads to ER stress sensitivity. UFMylation also plays a role in ribosome quality control, and defects may contribute to ribosomopathies. Herpesvirus deconjugases target UFM1 conjugates, suggesting a role in viral pathogenesis.
From UFM1 conjugating enzyme activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of E2 enzyme affect UFM1 conjugation? | CRISPR KO of UBE2M/UBE2F |
| Which cysteine is catalytic in E2? | Point mutation (Cys-to-Ala) |
| How does E2 interact with E3? | Knock-in of tagged E2 |
| Does overexpression of E2 enhance UFMylation? | Overexpression cell line |
| Can patient mutations in UBA5 alter E2 activity? | Knock-in of patient variants |
| Does E2 inhibition affect ER stress response? | KO + ER stress induction |
How to Study the UFM1 conjugating enzyme activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro thioester assay | E2~UFM1 intermediate formation | Mechanistic studies |
| Activity-based probes | Active UFM1 proteases and ligases | Profiling in cell lysates |
| Mass spectrometry | UFM1 substrate identification | Proteome-wide mapping |
| CRISPR KO screen | Genes affecting UFM1 conjugation | Pathway discovery |
| Fluorescence microscopy | Subcellular localization of UFM1 | ER stress and ribosome studies |
| Western blot | UFM1 conjugate levels | Validation of KO/overexpression |
| Ribo-seq | Translational changes upon UFM1 loss | Ribosome quality control |
| Proximity proteomics | Protein interactions with UFM1 machinery | Noncanonical functions |
Biochemical Assays for UFM1 Conjugation
In vitro thioester formation assays using recombinant UBA5, E2, and UFM1 can measure E2~UFM1 intermediate formation. These assays typically use fluorescently labeled UFM1 and SDS-PAGE to detect thioester-linked species. Mutational analysis of the catalytic cysteine confirms the specific activity.
Proteomic Profiling of UFM1 Substrates
Activity-based probes and UFM1-specific proteases can be used to profile UFM1 conjugates in cells. Mass spectrometry-based proteomics identifies substrate proteins and conjugation sites, revealing the landscape of UFM1 conjugation. Proximity proteomics can uncover noncanonical functions of UFM1 pathway components.
CRISPR Screening for UFM1 Pathway Regulators
Genome-wide CRISPR knockout screens can identify genes that modulate UFM1 conjugating enzyme activity or its downstream effects. Such screens have revealed connections to ER stress, DNA damage, and cancer pathways. Validation of hits using targeted KO or point mutations is essential.
Imaging and Cellular Localization
Fluorescently tagged UFM1 or E2 enzymes can be used to visualize conjugation dynamics in live cells. Co-localization with ER markers or ribosomes provides spatial context. These methods help link UFM1 conjugation to specific cellular compartments.
How CRISPR Can Be Used to Study GO:0061657 UFM1 conjugating enzyme activity
Knockout
CRISPR knockout of E2 enzymes (UBE2M, UBE2F) or other UFM1 pathway genes can abolish UFM1 conjugating enzyme activity, leading to accumulation of unmodified substrates. These models are useful for studying the consequences of pathway loss on ER stress, ribosome quality control, and cell viability.
Point Mutation
Point mutations of the catalytic cysteine in E2 enzymes (e.g., Cys-to-Ala) can be introduced to specifically inactivate UFM1 conjugating enzyme activity without affecting protein stability. Such models help distinguish catalytic activity from scaffolding functions.
Knock-in
Knock-in of tagged E2 enzymes (e.g., HA or FLAG) allows for affinity purification and identification of interacting proteins and substrates. Knock-in of patient-derived mutations in UBA5 or UFL1 can model disease-associated variants.
Overexpression
Overexpression of wild-type or mutant E2 enzymes can enhance or disrupt UFM1 conjugation, respectively. These models are useful for gain-of-function studies and for testing the effects of increased UFMylation on cellular processes.
How EDITGENE Supports UFM1 conjugating enzyme activity Research
Researchers studying UFM1 conjugating enzyme activity-related genes often need to determine whether a candidate gene is causally involved in the pathway, which requires precise genetic models. EDITGENE provides a comprehensive suite of CRISPR services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for UFM1 conjugating enzyme activity research.
Frequently Asked Questions About UFM1 conjugating enzyme activity
What is UFM1 conjugating enzyme activity?
It is the enzymatic activity (GO:0061657) that transfers UFM1 from an E2~UFM1 thioester to a substrate, forming a new thioester bond.
What genes are involved in UFM1 conjugating enzyme activity?
Key genes include UFM1, UBA5, UBE2M, UBE2F, UFL1, DDRGK1, UFSP1, and UFSP2.
Which enzymes catalyze UFM1 conjugation?
UBA5 (E1), UBE2M/UBE2F (E2), and UFL1 (E3) catalyze the cascade.
How is UFM1 conjugating enzyme activity regulated?
It is regulated by E1 and E3 enzymes, proteases, and cellular stress conditions.
What diseases are linked to UFM1 conjugation?
Cancer, neurodegeneration, ER stress-related disorders, and developmental diseases.
How can I study UFM1 conjugating enzyme activity?
Use in vitro thioester assays, proteomics, CRISPR KO, and point mutations.
What is the role of UBA5 in UFM1 conjugation?
UBA5 activates UFM1 and transfers it to E2 enzymes.
What is the role of UFL1 in UFM1 conjugation?
UFL1 is the E3 ligase that facilitates UFM1 transfer to substrates.
Can CRISPR be used to study UFM1 conjugation?
Yes, CRISPR KO, point mutation, knock-in, and overexpression models are powerful tools.
What are the research methods for UFM1 conjugating enzyme activity?
Biochemical assays, mass spectrometry, CRISPR screens, and imaging.
Conclusion
UFM1 conjugating enzyme activity (GO:0061657) is a fundamental molecular function in the UFM1 conjugation pathway, with critical roles in ER stress, ribosome quality control, and disease. Understanding its mechanism and regulation requires precise genetic and biochemical tools. EDITGENE offers comprehensive CRISPR services to support mechanistic studies and therapeutic development.
References
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- 3. Xie Z et al.. 2019. Ufl1/RCAD, a Ufm1 E3 ligase, has an intricate connection with ER stress.. Int J Biol Macromol 135:760-767 PMID: 31129212
- 4. Padala P et al.. 2017. Novel insights into the interaction of UBA5 with UFM1 via a UFM1-interacting sequence.. Sci Rep 7(1):508 PMID: 28360427
- 5. Witting KF et al.. 2018. Generation of the UFM1 Toolkit for Profiling UFM1-Specific Proteases and Ligases.. Angew Chem Int Ed Engl 57(43):14164-14168 PMID: 30188611
- 6. Liu J et al.. 2026. Differential regulation of translational stress responses by herpesvirus ubiquitin deconjugases.. FEBS J 293(4):1024-1044 PMID: 41076568
- 7. Habisov S et al.. 2016. Structural and Functional Analysis of a Novel Interaction Motif within UFM1-activating Enzyme 5 (UBA5) Required for Binding to Ubiquitin-like Proteins and Ufmylation.. J Biol Chem 291(17):9025-41 PMID: 26929408
- 8. Wang X et al.. 2023. Proximity Proteomics and Biochemical Analysis Reveal a Noncanonical Function for UFM1-Specific Protease 1 in the p62 Body Formation.. J Proteome Res 22(7):2352-2363 PMID: 37285312
