UBE2V1 Antibody

What is UBE2V1 and what are its primary cellular functions?

UBE2V1 is a ubiquitin-conjugating enzyme E2 variant that lacks the conserved catalytic cysteine residue required for ubiquitin transfer. Despite having no ubiquitin ligase activity on its own, UBE2V1 forms a heterodimer with UBE2N (Ubc13) to catalyze the synthesis of non-canonical poly-ubiquitin chains linked through Lys-63 .

UBE2V1 plays significant roles in:

• NF-kappa-B activation mediated by IL1B, TNF, TRAF6, and TRAF2

• Cell cycle progression and cellular differentiation

• Error-free DNA repair pathway

• Protein quality control and aggregation prevention

• Transcriptional activation of target genes

• Epigenetic regulation via histone modification

The UBE2V1-UBE2N heterodimer acts in concert with proteins like TRIM5 to generate Lys-63-linked polyubiquitin chains that activate signaling pathways leading to inflammatory gene expression .

How is UBE2V1 expressed in different tissues and what are its isoforms?

UBE2V1 is ubiquitously expressed in human tissues, with highest expression levels detected in brain, skeletal muscle, and kidney . The protein has five isoforms produced by alternative splicing , which may contribute to tissue-specific functions. The basic UBE2V1 protein is a 147 amino acid protein with a predicted molecular mass of 16 kD, though the observed molecular weight is typically around 20 kDa in Western blot analyses .

In cellular distribution, UBE2V1 is found in both the cytosol and nucleus , allowing it to participate in diverse cellular processes including DNA repair and transcriptional regulation.

What are the optimal conditions for using UBE2V1 antibodies in Western blotting?

For Western blotting applications with UBE2V1 antibodies, researchers should consider the following protocol guidelines:

• Sample preparation: Cell or tissue lysates should be prepared using standard lysis buffers containing protease inhibitors to prevent protein degradation.

• Antibody dilutions:

  • For polyclonal antibodies: 1:200-1:1000 dilution is typically recommended

  • For monoclonal antibodies: 1.0-10 µg/mL has shown optimal results

• Detection: When probing for UBE2V1, expect to visualize a band at approximately 20 kDa .

• Verified reactivity: Most antibodies show confirmed reactivity with human samples, while some also detect mouse, rat, and other species' UBE2V1 .

• Controls: Include positive controls such as human spleen tissue or BxPC-3 cells, which have been validated to express detectable levels of UBE2V1 .

It is recommended to titrate the antibody concentration for each specific experimental system to achieve optimal signal-to-noise ratio .

How can UBE2V1 antibodies be effectively used in immunohistochemistry for tissue samples?

For immunohistochemistry applications with UBE2V1 antibodies:

• Tissue fixation: Formalin-fixed, paraffin-embedded (FFPE) tissue sections are typically used, with standard antigen retrieval methods applied.

• Localization pattern: UBE2V1 expression in tissue samples is predominantly cytoplasmic, as observed in colorectal cancer tissue studies .

• Scoring system: For semi-quantitative analysis, researchers commonly use scoring systems based on staining intensity and percentage of positive cells:

  • Negative: No staining or <5% positive cells

  • Low expression: Weak staining in 5-25% of cells

  • Moderate expression: Moderate staining in 25-50% of cells

  • High expression: Strong staining in >50% of cells

• Interpretation: When evaluating clinical samples, correlate UBE2V1 expression with clinicopathological features. For example, in colorectal cancer studies, UBE2V1 expression has been associated with lymph node metastasis (p<0.05) .

• Controls: Include both positive and negative controls to validate staining specificity. Adjacent normal tissue can serve as an internal control for comparison with diseased tissue.

How does UBE2V1 influence protein aggregation in cardiomyocytes and what experimental approaches can investigate this relationship?

UBE2V1 positively regulates protein aggregation in cardiomyocytes, particularly in the context of cardiac proteinopathies. Research has revealed several experimental approaches to investigate this relationship:

• siRNA knockdown experiments:

  • Transfection of cardiomyocytes with Ube2v1-specific siRNAs (siUbe2v1 #1 and #2) has been shown to significantly reduce Ube2v1 protein levels

  • This knockdown dramatically decreased protein aggregate loads caused by CryAB^R120G expression in neonatal rat ventricular myocytes (NRVMs)

• Adenoviral overexpression systems:

  • Adenoviruses containing Ube2v1-myc (with c-Myc tag) showed dose-dependent expression levels

  • Co-infection with GFP-CryAB^WT or GFP-CryAB^R120G demonstrated that Ube2v1 overexpression enhanced aggregate content in a dose-dependent manner

• Fractionation experiments:

  • Analysis of soluble and insoluble protein fractions showed that knockdown of Ube2v1 increased soluble CryAB levels (indicating non-aggregation) and decreased insoluble fractions (indicating aggregation)

  • Conversely, Ube2v1 overexpression increased levels of insoluble ubiquitinated proteins

• Proteasome activity assays:

  • 20S proteasomal activity can be assayed by determining chymotrypsin-like activity

  • GFPu degron reporter systems can be used to measure UPS performance, with increased GFPu indicating decreased UPS performance

These methodologies provide comprehensive approaches for researchers to investigate UBE2V1's role in protein aggregation, particularly in cardiac disease models.

What is the role of UBE2V1 in cancer progression and metastasis, and how can this be experimentally investigated?

UBE2V1 plays significant roles in cancer progression, particularly in colorectal cancer (CRC) metastasis, through several mechanisms:

Understanding these pathways provides potential therapeutic targets, as autophagy inducers like rapamycin and trehalose have been shown to attenuate UBE2V1-mediated lung metastasis in mouse models .

How can researchers address discrepancies between UBE2V1 antibody detection methods in experimental results?

When facing discrepancies in UBE2V1 detection across different experimental platforms, consider these troubleshooting approaches:

• Antibody specificity verification:

  • Validate antibody specificity using positive and negative controls

  • Consider using multiple antibodies targeting different epitopes of UBE2V1:

    • N-terminal antibodies (AA 1-103)

    • C-terminal antibodies (AA 113-145)

    • Full-length protein antibodies

• Isoform-specific detection:

  • UBE2V1 has five isoforms produced by alternative splicing

  • Determine which isoform(s) your antibody recognizes by comparing the immunogen sequence with known isoform sequences

  • Use isoform-specific primers for RT-PCR validation when antibody results are inconsistent

• Cross-reactivity assessment:

  • Check for potential cross-reactivity with similar proteins (e.g., UBE2V2)

  • Perform siRNA knockdown experiments to confirm antibody specificity

• Methodological considerations:

  Application	Potential Issue	Solution
  Western blot	Protein masking	Use different lysis buffers; include reducing agents
  IHC	Epitope masking	Try different antigen retrieval methods
  IF	High background	Optimize blocking conditions; use monoclonal antibodies

• Post-translational modifications: UBE2V1 functions in ubiquitination pathways and may itself undergo modifications that affect antibody recognition, especially in different disease states or cellular conditions.

How do UBE2V1 interaction networks influence experimental design and data interpretation?

UBE2V1 functions within complex protein interaction networks that researchers should consider when designing experiments:

• Key protein interaction partners:

  • UBE2N (Ubc13): Forms heterodimer essential for catalyzing Lys-63-linked polyubiquitination

  • TRAF6, TRAF2: Mediates NF-κB activation pathways

  • Sirt1: Target for UBE2V1-mediated ubiquitination affecting epigenetic regulation

  • TRIM5: Partner in generating ubiquitin chains activating inflammatory pathways

  • RNF135: Collaborates in viral RNA-dependent polyubiquitination

• Experimental design considerations:

  • Co-immunoprecipitation studies: Should consider known interacting partners as positive controls

  • Cellular localization: UBE2V1 distributes between cytosol and nucleus , requiring subcellular fractionation for complete analysis

  • Functional assays: Should account for heterodimer formation with UBE2N for accurate interpretation of ubiquitination activity

• Integrated analysis approaches:

  • Combine Y2H (yeast two-hybrid) screens with true homology modeling methods to map higher-confidence protein interactions

  • Free-energy predictions can help assess the likelihood of detected interactions being functionally relevant

  • The probability of detecting positive Y2H interactions increases with more favorable (lower) free-energy predictions

• Validation methods for interaction studies:

  • Structure-based validation comparing predicted free-energy values to known functional complexes:

    • Interactions with more favorable values than UBE2L3-CBL complex (-7.87 ΔG int kcal/mol) are likely functional

  • Functional validation through activity assays examining effects on known downstream pathways

Understanding these interaction networks is crucial for interpreting UBE2V1-related experimental results in the broader cellular context.

How does UBE2V1 function as a bridge between oxidative stress response and ubiquitination pathways?

UBE2V1 and its family member UBE2V2 serve as critical links between redox signaling and ubiquitination pathways:

• Redox sensitivity of ubiquitination machinery:

  • Ubiquitination is dominated by reactive thiol chemistry through enzyme-bound Ub-thioester intermediates

  • These conjugating enzymes are reactive oxygen species (ROS)-sensitive

  • Unlike UBE2V1, many deubiquitinating/deSUMOylating enzymes (DUBs/SENPs) contain active-site cysteines that are sensitive to oxidative modification

• UBE2V1/UBE2V2 differential responses:

  • UBE2V2 has been identified as having privileged electrophile responsivity that promotes genome protection

  • UBE2V1, working with UBE2N, can mediate K63-linked polyubiquitination in response to cellular stress conditions

• Experimental approaches:

  • G-REX and T-REX (genetic and targeted REX) strategies can identify electrophile-responsive proteins like UBE2V2

  • For UBE2V1 research, similar approaches could reveal how oxidative stress modulates its function in various cellular contexts

• Mechanistic considerations:

  • Modification of UBE2V1 or its partner proteins by ROS may alter their interactions and functions

  • These modifications could serve as regulatory mechanisms for ubiquitination activity under stress conditions

Understanding this intersection between redox and ubiquitin systems offers new perspectives for targeting UBE2V1 in diseases characterized by oxidative stress, such as cardiovascular disorders and cancer.

What role might UBE2V1 play in COVID-19 severity, and how can researchers investigate this connection?

Recent genetic association studies have suggested a potential link between UBE2V1 and COVID-19 severity:

• Genetic evidence:

  • The TMEM189-UBE2V1 gene locus has displayed suggestive association with COVID-19 severity in whole genome sequencing studies of COVID-19 patients

  • This finding suggests UBE2V1 could influence host response to SARS-CoV-2 infection

• Potential mechanistic links:

  • UBE2V1 plays roles in NF-κB activation and inflammatory signaling pathways

  • UBE2V1-UBE2N heterodimer catalyzes viral RNA-dependent polyubiquitination of RIG-I to activate interferon beta production

  • These immune regulatory functions could influence cytokine responses and inflammation in COVID-19

• Experimental approaches for investigation:

  • Genetic studies: Further genotyping of UBE2V1 variants in COVID-19 cohorts with severity stratification

  • Expression analysis: Compare UBE2V1 expression levels in peripheral blood mononuclear cells from mild versus severe COVID-19 patients

  • Functional assays: Examine how UBE2V1 modulation affects viral replication and inflammatory responses in relevant cell models

  • Animal models: Investigate how UBE2V1 knockout or overexpression influences disease progression in COVID-19 animal models

• Prospective implications:

  • If validated, UBE2V1 could potentially serve as a biomarker for COVID-19 severity prediction

  • Understanding the role of UBE2V1 in COVID-19 could reveal novel therapeutic targets for modulating excessive inflammation

This emerging research direction highlights how UBE2V1's functions in ubiquitination and inflammation regulation may extend to infectious disease contexts.

What are the optimal strategies for studying UBE2V1-mediated protein-protein interactions in different cellular contexts?

To effectively study UBE2V1-mediated protein-protein interactions across different cellular contexts:

• Proximity ligation assays (PLA):

  • Provides visualization of endogenous protein interactions in situ

  • Particularly useful for detecting UBE2V1-UBE2N heterodimer formation in different subcellular compartments

  • Requires carefully validated antibodies that can simultaneously bind both target proteins

• FRET/BRET approaches:

  • Fusion of fluorescent or bioluminescent proteins to UBE2V1 and potential interacting partners

  • Allows real-time monitoring of dynamic interactions in live cells

  • Consider C-terminal tagging of UBE2V1 as N-terminal modification may affect function

• Co-immunoprecipitation optimization:

  • For transient or weak interactions, consider crosslinking approaches

  • Use physiologically relevant buffers that preserve complex integrity

  • Sequential immunoprecipitation can help identify components of multi-protein complexes containing UBE2V1

• Protein complementation assays:

  • Split-YFP or NanoBiT systems can confirm direct interactions

  • Allow visualization of where in the cell UBE2V1 interactions occur

  • Can be adapted for high-throughput screening of potential interaction partners

• Structure-based interaction prediction:

  • True homology modeling methods can predict interaction likelihood based on free energy values

  • E2/E3-RING pairs with more favorable predicted free-energy values than the canonical UBE2L3-CBL complex (-7.87 ΔG int kcal/mol) have higher probability of being functionally relevant

  • These predictions can guide experimental validation efforts

Each method offers distinct advantages for specific research questions regarding UBE2V1 interactions.

How can researchers effectively incorporate UBE2V1 studies into multi-omics approaches for comprehensive pathway analysis?

Integrating UBE2V1 studies into multi-omics frameworks requires strategic approaches:

• Integrated proteomics strategies:

  • Proximity-dependent biotinylation (BioID or TurboID) with UBE2V1 as bait to identify the proximal proteome

  • Ubiquitinome analysis using diGly-remnant antibodies to capture UBE2V1-dependent ubiquitination events

  • Interaction proteomics using quantitative methods (SILAC, TMT) to distinguish specific from non-specific interactions

• Transcriptomic integration:

  • RNA-seq following UBE2V1 modulation to identify transcriptional networks affected

  • Single-cell approaches to reveal cell-type specific roles of UBE2V1

  • Integration with ChIP-seq data (particularly for histone H4K16ac) to understand epigenetic mechanisms

• Functional genomics coordination:

  • CRISPR screens to identify synthetic lethal interactions with UBE2V1

  • Genetic knockdown/overexpression coupled with phenotypic assays

  • Correlation of genetic variants with UBE2V1 function in disease contexts

• Data integration framework:

  Omics Layer	UBE2V1-Specific Approach	Integration Method
  Proteomics	UBE2V1 interactome mapping	Network analysis
  Ubiquitinomics	K63-linkage enrichment	Pathway enrichment
  Transcriptomics	Gene expression profiles after UBE2V1 modulation	GSEA analysis
  Epigenomics	H4K16ac ChIP-seq	Motif analysis
  Metabolomics	Changes after UBE2V1 perturbation	Metabolic pathway mapping

• Visualization and analysis tools:

  • Cytoscape for network visualization of UBE2V1-centered interaction networks

  • STRING database integration for functional protein association networks

  • R packages for multi-omics data integration (mixOmics, MOFA)

This multi-layered approach provides comprehensive understanding of UBE2V1's role within the broader cellular context.