UBXN11 Antibody

What is UBXN11 and what are its known cellular functions?

UBXN11 (UBX domain protein 11) is a member of the UBXD family (UBXDF), a group of proteins containing ubiquitin regulatory X (UBX) domains. Also known as SOC, SOCI, UBXD5, and COA-1, UBXN11 plays crucial roles in cellular function, particularly in protein quality control mechanisms .

Research indicates that UBXN11 may be involved in the reorganization of actin cytoskeleton mediated by RND1, RND2, and RND3 . Like other UBXD family members, UBXN11 likely interacts with p97/VCP, an AAA ATPase involved in various cellular processes including protein degradation, membrane fusion, and cell cycle regulation .

The broader UBXD family has been implicated in maintaining the balance between proliferation and apoptosis in cancer cells, suggesting potential roles for UBXN11 in cancer biology . The protein contains an approximately 80-residue UBX domain, which is evolutionarily conserved across eukaryotic species .

What are the optimal applications and conditions for using UBXN11 antibodies?

UBXN11 antibodies have been validated for multiple research applications with specific recommended protocols:

Western Blot (WB):

• Recommended dilutions: 1:500-1:2000

• Expected molecular weight: ~57 kDa

• Sample preparation: Cell lysates (e.g., HepG2 cells)

• Detection method: Enhanced chemiluminescence (ECL) system

Immunohistochemistry (IHC):

• Recommended dilutions: 1:50-1:300

• Sample types: Formalin/PFA-fixed paraffin-embedded sections

• Antigen retrieval: May be required depending on fixation method

• Visualization: DAB (3,3'-diaminobenzidine) chromogen detection system

Immunofluorescence (IF):

• Recommended dilutions: 1:200-1:1000

• Sample preparation: Fixed cells or tissue sections

• Mounting medium: Anti-fade with DAPI for nuclear counterstaining

Other applications:

• ELISA: 1:20000 dilution

• Immunoprecipitation (IP): 1:200-1:2000 dilution

How can researchers validate the specificity of UBXN11 antibodies?

Rigorous validation of UBXN11 antibodies is essential for reliable research outcomes. Multiple complementary approaches should be employed:

Peptide blocking experiments:

• Pre-incubate antibody with immunizing peptide prior to application

• Run parallel Western blots or IHC with blocked and unblocked antibody

• Specific signal should be absent or significantly reduced in blocked samples

• Example: In Western blot analysis of HepG2 cell extracts, UBXN11 signal was eliminated after peptide blocking

Genetic validation:

• Use CRISPR-Cas9 knockout or siRNA knockdown models

• Compare antibody signal between wild-type and knockout/knockdown samples

• A specific antibody will show significantly reduced signal in knockout/knockdown samples

Multi-application concordance:

• Test antibody across multiple applications (WB, IHC, IF)

• Consistent patterns (molecular weight, localization) across applications increases confidence

• Compare results across different cell/tissue types to verify expected expression patterns

Cross-antibody validation:

• Use multiple antibodies targeting different epitopes of UBXN11

• Concordant results with different antibodies enhances confidence in specificity

• Consider both monoclonal and polyclonal antibodies for comprehensive validation

What expression patterns of UBXN11 have been observed across cancer types?

Analysis of UBXN11 expression in cancer tissues reveals distinct patterns that may have clinical significance:

• Cancer cells generally show weak or negative UBXN11 staining in most cancer types

• Moderate staining has been observed in subsets of breast, prostate, and pancreatic cancer cases

• Breast cancer specifically shows strong immunoreactivity in a subpopulation of cells

Unlike some UBXD family members (such as FAF1), UBXN11 has not been extensively characterized across all cancer types. The Human Protein Atlas data shows that UBXN11 protein expression is generally lower compared to other UBXD family members like UBXN4, which shows moderate to strong cytoplasmic immunoreactivity in most cancer cells .

Further research is needed to determine whether UBXN11 expression correlates with cancer progression, patient survival, or treatment response. The observed heterogeneity of expression within the same cancer type (particularly in breast cancer) suggests potential functional significance in cancer biology .

What is known about UBXN11's subcellular localization and how can researchers investigate it?

UBXN11 shows distinct subcellular localization patterns that may reflect its functional roles:

• In cancer cells, UBXN11 can demonstrate both cytoplasmic and nuclear localization

• Most UBXD family members are predominantly found in the nucleoplasm in U-2-OS cells

• The variable localization patterns may indicate context-dependent functions

Methodological approaches to investigate localization:

• Immunofluorescence co-localization studies:

  • Co-stain with organelle markers (e.g., DAPI for nucleus, MitoTracker for mitochondria)

  • Use confocal microscopy for high-resolution imaging

  • Analyze Pearson's correlation coefficient for quantitative assessment

• Subcellular fractionation:

  • Separate nuclear, cytoplasmic, membrane, and other cellular fractions

  • Perform Western blot with UBXN11 antibody on each fraction

  • Include fraction-specific markers as controls (e.g., histone H3 for nuclear, GAPDH for cytoplasmic)

• Live-cell imaging:

  • Create fluorescent protein-tagged UBXN11 constructs

  • Monitor localization under different conditions or stimuli

  • Validate observations with antibody-based detection methods

• Super-resolution microscopy:

  • Employ techniques like STORM or PALM for nanoscale resolution

  • Determine precise subcellular compartment association

How does UBXN11 interact with the p97/VCP system and other UBXD family proteins?

UBXN11, like other UBXD family members, interacts with the AAA ATPase p97/VCP, which is central to many cellular protein quality control mechanisms:

• The UBX domain of UBXN11 mediates binding to the N-terminal domain of p97/VCP

• This interaction occurs at the hydrophobic sac between the two subdomains of the p97 N-terminal domain

• UBXN11 likely serves as a cofactor for the endoplasmic reticulum-associated degradation (ERAD) pathway through its association with p97/VCP

Protein-protein interaction network:

• Significant co-expression exists among most UBXD family members

• p97/VCP shows significant co-expression with most UBXD family members

• Studies of other UBXD family proteins reveal connections to various cellular processes including autophagy, lipid metabolism, and NF-κB signaling

Methodological approaches to study these interactions:

• Co-immunoprecipitation (Co-IP):

  • Use UBXN11 antibody to pull down associated proteins

  • Analyze by Western blot or mass spectrometry

  • Confirm interactions with reciprocal Co-IP experiments

• Proximity Ligation Assay (PLA):

  • Detect protein-protein interactions in situ with single-molecule sensitivity

  • Visualize interactions in their native cellular environment

• FRET or BRET analysis:

  • Create fluorescent or bioluminescent fusion proteins

  • Measure energy transfer as indicator of physical proximity

• Yeast two-hybrid screening:

  • Identify novel interaction partners

  • Validate using biochemical methods

What are the potential implications of UBXN11 in cancer biology and drug response?

While research specifically on UBXN11 in cancer is limited, studies on the broader UBXD family suggest several important implications:

• UBXDF members influence tumor microenvironment (TME) and drug therapy responses

• UBXD family proteins play crucial roles in balancing proliferation and apoptotic pathways in cancer

• Expression of UBXD family proteins correlates with cancer stem cell properties (stemness) in various cancer types

Drug sensitivity correlations:

• Expression of some UBXD family members correlates with sensitivity to specific cancer drugs

• Half of UBXD family member expressions were inversely linked with IC50 values in cancer cell lines in the CTRP database

• This suggests potential value as predictive biomarkers for pharmacological therapy

Immune system interactions:

• UBXD family expression level correlates with immune cell infiltration patterns in tumors

• This includes negative correlations with infiltration of several immune cell types (CD4 T cells, Tregs, macrophages)

• UBXD proteins may influence responses to immunotherapy through effects on the tumor microenvironment

Research directions:

• Analyze UBXN11 expression across clinical samples correlated with treatment outcomes

• Investigate the impact of UBXN11 modulation on cancer cell sensitivity to chemotherapeutics

• Explore connections between UBXN11 and cancer-related signaling pathways

What are common pitfalls in UBXN11 antibody experiments and how can they be addressed?

Researchers working with UBXN11 antibodies may encounter several challenges. Here are methodological solutions:

Western Blot troubleshooting:

Immunohistochemistry troubleshooting:

General considerations:

• Always include positive and negative controls

• Validate antibody specificity using methods described in Question 3

• Consider cell/tissue-specific expression levels of UBXN11

• Store antibodies according to manufacturer recommendations (-20°C, avoid freeze-thaw cycles)

How does UBXN11 structurally and functionally compare to other UBXD family members?

UBXN11 shares structural characteristics with other UBXD family members but also has distinct features:

Structural comparison:

• UBXN11 belongs to the UBX group (8 members) rather than the UBA-UBX group (5 members)

• In the UBX group, the UBX domain is the only ubiquitin-related domain

• The UBX domain (~80 residues) is typically located at the C-terminal region

• Unlike UBXD9, which has two UBX domains, UBXN11 has a single UBX domain

Functional comparison:

• Many UBXD proteins serve as adaptors for p97/VCP, targeting it to specific cellular compartments or substrates

• UBXD proteins with UBA domains (unlike UBXN11) can directly bind ubiquitinated substrates

• Different UBXD members show specialized functions in processes like ERAD, autophagy, and DNA damage responses

• Expression patterns vary across tissues and cancer types, suggesting context-specific functions

Evolutionary conservation:

• The UBXD family is evolutionarily conserved across eukaryotic species

• The UBX domain's structure is conserved, allowing common interaction mechanisms with p97/VCP

• Differences in additional domains contribute to functional specialization

What research models and methodologies are most suitable for studying UBXN11 function?

Several experimental systems and approaches are appropriate for investigating UBXN11:

Cellular models:

• Cancer cell lines with varying UBXN11 expression (e.g., HepG2, as mentioned in antibody validation studies)

• Primary cells to study physiological functions

• CRISPR-Cas9 engineered knockout/knockin cell lines

• Inducible expression systems to control UBXN11 levels

Methodological approaches:

• Loss-of-function studies:

  • siRNA or shRNA-mediated knockdown

  • CRISPR-Cas9 knockout

  • Dominant-negative mutant expression

• Gain-of-function studies:

  • Overexpression of wild-type UBXN11

  • Expression of tagged UBXN11 for purification/visualization

  • Point mutants to investigate specific domains/functions

• Interaction studies:

  • Co-immunoprecipitation with p97/VCP and other potential partners

  • Proximity labeling (BioID, APEX) to identify local interaction networks

  • In vitro binding assays with purified components

• Functional assays:

  • Ubiquitination assays

  • Protein degradation tracking

  • Cell cycle analysis

  • Cytoskeletal dynamics assessment (based on potential role in actin reorganization)

• Advanced imaging:

  • Live-cell imaging to track dynamics

  • FRAP (Fluorescence Recovery After Photobleaching) for mobility studies

  • Super-resolution microscopy for precise localization

How might UBXN11's function in normal physiology inform its role in disease states?

Understanding UBXN11's normal physiological functions provides context for its potential roles in disease:

Normal physiological functions:

• Based on limited data, UBXN11 may be involved in actin cytoskeleton reorganization

• As a UBX domain protein, it likely participates in protein quality control via interaction with p97/VCP

• Expression varies across normal tissues, suggesting tissue-specific functions

Disease implications:

• Cancer:

  • Altered expression in some cancer types, particularly breast, prostate, and pancreatic cancers

  • May influence cancer cell properties through effects on protein homeostasis

  • Potential contribution to tumor microenvironment and immune cell infiltration

• Protein misfolding disorders:

  • As part of the protein quality control system, dysfunction could contribute to accumulation of misfolded proteins

  • Potential implications for neurodegenerative diseases characterized by protein aggregation

• Cell cycle dysregulation:

  • UBX domain proteins are involved in cell cycle regulation

  • Aberrant function could affect proliferation in both cancer and developmental disorders

Research directions:

• Comparative analysis of UBXN11 function in normal vs. diseased tissues

• Investigation of post-translational modifications affecting UBXN11 function

• Studies correlating UBXN11 genetic variants with disease susceptibility

What techniques can researchers use to study the interaction between UBXN11 and the ubiquitin-proteasome system?

The connection between UBXN11 and the ubiquitin-proteasome system (UPS) can be investigated using several methodological approaches:

Biochemical techniques:

• Ubiquitination assays:

  • In vitro ubiquitination with purified components

  • Cell-based ubiquitination analysis following UBXN11 manipulation

  • Analysis of ubiquitin chain types (K48, K63, etc.) associated with UBXN11 complexes

• Proteasome activity assays:

  • Fluorogenic substrate assays in cells with modulated UBXN11 expression

  • Measurement of proteasome subunit composition and assembly

  • Analysis of substrate degradation rates

• p97/VCP functional studies:

  • ATPase activity assays in the presence/absence of UBXN11

  • Analysis of substrate extraction from membranes or complexes

  • Investigation of p97/VCP cofactor interactions influenced by UBXN11

Imaging approaches:

• Live-cell imaging of degradation:

  • Fluorescent reporters for proteasome activity

  • Pulse-chase analysis of substrate degradation

  • Visualization of ubiquitinated protein aggregates

• Colocalization studies:

  • UBXN11 localization relative to proteasomes, p97/VCP, and ubiquitinated substrates

  • Analysis of dynamics during cellular stress or specific stimuli

  • Super-resolution microscopy for nanoscale interactions

Systems biology approaches:

• Proteomics:

  • Identification of UBXN11-associated ubiquitinated proteins

  • Quantitative analysis of proteome changes following UBXN11 manipulation

  • Phospho-proteomics to identify regulatory mechanisms

• Network analysis:

  • Integration of interaction, expression, and functional data

  • Identification of UPS-related pathways affected by UBXN11

  • Comparison with other UBXD family members