TRIM31 Antibody

What is the molecular structure of TRIM31 and how does this affect antibody selection?

TRIM31 is composed of an N-terminal RING-finger domain, a B-box, and a coiled-coil (C-C) motif . The RING domain is essential for its E3 ligase activity, while the B-box domain mediates protein interactions, such as with TIGAR . When selecting antibodies, consider which domain you need to target based on your research question. For interaction studies, antibodies targeting the B-box domain may be more relevant, while for functional studies of ubiquitination, antibodies recognizing the RING domain might be preferable .

Which applications are most commonly validated for TRIM31 antibodies?

According to published data, TRIM31 antibodies have been validated for multiple applications:

For Western blotting, a dilution of 1:500-1:1000 is typically recommended, while for IHC applications, 1:200-1:1000 is suitable .

What is the expected molecular weight of TRIM31 in Western blotting?

TRIM31 has a calculated molecular weight of 48 kDa (425 amino acids), which corresponds to the observed molecular weight in Western blot analyses . When performing Western blotting, ensure proper sample preparation and gel percentage selection to accurately resolve proteins in this molecular weight range.

How should I design controls for TRIM31 knockdown/knockout experiments?

When designing TRIM31 knockdown/knockout experiments, multiple approaches should be considered for validation. For TRIM31 knockdown, studies have used lentivirus-shRNA systems with multiple shRNA sequences (e.g., TRIM31-sh3) targeting different regions of the gene . Western blot analysis should be performed to confirm knockdown efficiency, with the most effective construct being selected for further experiments . In knockout studies, validation through genotyping and protein expression analysis is essential. Additionally, phenotypic rescue experiments by reintroducing wild-type TRIM31 or specific domain mutants (such as RING domain mutants C53A/C56A) can provide evidence for specificity .

What methodological considerations are important for co-immunoprecipitation (Co-IP) experiments with TRIM31?

For Co-IP experiments investigating TRIM31 interactions:

• Cell lysis conditions: Use NP-40 lysis buffer with protease inhibitor cocktail, followed by centrifugation at 12,000 rpm at 4°C for 10 minutes .

• Antibody incubation: Incubate supernatants with 1 μL specific antibody at 4°C for 6 hours, followed by protein A+G agarose addition and overnight incubation at 4°C under rotation .

• Washing and elution: Wash bead-linked immune complexes five times with IP buffer, then elute by boiling with 1% SDS sample buffer before Western blot analysis .

• Domain mapping: For domain-specific interactions, use truncated mutants of TRIM31 (ΔRING, ΔB-box, ΔCoiled-coil) in Co-IP experiments to determine which domains are necessary for protein-protein interactions .

How can I assess the E3 ubiquitin ligase activity of TRIM31 in experimental systems?

To evaluate TRIM31's E3 ubiquitin ligase activity:

• Ubiquitination assay: Co-transfect cells with tagged versions of TRIM31, the substrate protein (e.g., TIGAR, p53, or NLRP3), and HA-tagged ubiquitin .

• Mutant controls: Include RING domain mutants (C53A, C56A) that lack E3 ligase activity as negative controls .

• Linkage specificity: Use ubiquitin mutants (K48-only or K63-only) to determine the type of polyubiquitin chains mediated by TRIM31 .

• Proteasomal inhibition: Treat cells with MG132 to block proteasomal degradation and enhance detection of ubiquitinated proteins for K48-linked substrates .

• Analysis methods: Immunoprecipitate the substrate protein and blot for ubiquitin, or vice versa, to detect ubiquitination .

How does TRIM31 function differ between cancer types, and how should research approaches be adapted?

TRIM31 exhibits context-dependent functions across different cancer types:

• Oncogenic role: In colorectal cancer, hepatocellular carcinoma, pancreatic cancer, and high-grade glioma, TRIM31 is upregulated and promotes tumor progression .

• Tumor suppressor role: In breast cancer and non-small cell lung cancer, TRIM31 is downregulated and exhibits tumor-suppressive functions .

• Dual role: In gastric cancer, TRIM31 may act as a tumor suppressor in early stages but promotes progression in advanced stages .

When studying TRIM31 in cancer, consider:

• Tissue-specific regulation of TRIM31 expression

• Different downstream pathways (p53, mTORC1, PI3K-AKT, NF-κB, Wnt/β-catenin)

• Specific protein interactions unique to each cancer type

• Stage-specific functions that may change during cancer progression

What molecular mechanisms underlie TRIM31's role in cerebral ischemic injury, and how can these be investigated?

In cerebral ischemic injury, TRIM31 deficiency ameliorates damage through:

• Regulation of TIGAR: TRIM31 directly interacts with TIGAR through its B-box domain and mediates TIGAR's ubiquitous degradation. Knockdown of TIGAR in TRIM31-deficient mice reverses the protective effects .

• Mitochondrial homeostasis: TRIM31 deficiency maintains mitochondrial function during ischemia by regulating proteins like DRP1, MFN1, MFN2, and PGC-1α .

• Reactive oxygen species (ROS): TRIM31 deletion reduces ROS production during ischemia by enhancing the pentose phosphate pathway through G6PD regulation .

To investigate these mechanisms:

• Use AAV-mediated gene delivery for in vivo knockdown studies

• Perform mitochondrial function assays (JC-1 staining)

• Measure ROS levels during ischemic conditions

• Evaluate the expression of key metabolic enzymes (G6PD)

• Conduct IP and co-localization studies to confirm protein interactions

What is known about TRIM31's role in inflammatory processes, and how can antibodies help elucidate these mechanisms?

TRIM31 regulates inflammatory processes through several mechanisms:

• NLRP3 inflammasome regulation: TRIM31 directly binds to NLRP3 and promotes its K48-linked polyubiquitination and proteasomal degradation, acting as a feedback suppressor. TRIM31 deficiency enhances NLRP3 inflammasome activation and aggravates alum-induced peritonitis .

• NF-κB pathway modulation: TRIM31 regulates chronic inflammation via the NF-κB pathway, contributing to epithelial-mesenchymal transition (EMT) in colorectal cancer .

• Anti-viral signaling: TRIM31 interacts with MAVS and catalyzes its K63-linked polyubiquitination, promoting antiviral signaling .

To study these mechanisms using antibodies:

• Perform co-immunoprecipitation to identify TRIM31 interaction partners

• Use immunofluorescence to assess co-localization with inflammasome components

• Conduct chromatin immunoprecipitation to study TRIM31's role in transcriptional regulation

• Employ proximity ligation assays to confirm direct protein interactions in situ

• Monitor ubiquitination status of target proteins using specific antibodies against different ubiquitin linkages

How can I reconcile contradictory data regarding TRIM31's role across different experimental systems?

Researchers frequently encounter seemingly contradictory data regarding TRIM31 function. To reconcile these differences:

• Context-specific analysis: TRIM31 exhibits tissue-specific and disease-stage-specific functions. For example, it acts as an oncogene in colorectal cancer but as a tumor suppressor in breast cancer .

• Protein interaction networks: Map TRIM31's interactome in each specific context using techniques like BioID or proximity-dependent biotinylation to identify tissue-specific binding partners .

• Domain-specific functions: Use truncation or point mutants of TRIM31 to determine which domains are responsible for context-specific functions .

• Conditional knockout models: Employ tissue-specific or inducible knockout systems to study TRIM31 function in specific contexts without developmental compensation .

• Multi-omic approach: Combine transcriptomic, proteomic, and ubiquitinomic analyses to create a comprehensive picture of TRIM31 function in each experimental system .

What are the optimal conditions for detecting endogenous TRIM31 in different cell and tissue types?

Detection of endogenous TRIM31 requires optimization based on tissue type:

• Cell line selection: TRIM31 expression varies significantly between cell lines. High expression has been reported in COLO 320, AGS, HT-29 cells, while low expression is observed in SW480, SW1116, and GES-1 cells .

• Tissue-specific considerations:

  • For intestinal tissues: Antigen retrieval with TE buffer pH 9.0 is recommended for IHC

  • For cancer tissues: Expression levels vary by cancer type, with higher levels in colorectal, gastric, and hepatocellular cancers

• Subcellular localization: TRIM31 can localize to different cellular compartments depending on context, including mitochondria during viral infection .

• Antibody validation: Confirm specificity using TRIM31 knockout controls or multiple antibodies targeting different epitopes.

• Detection methods:

  • Western blot: 1:500-1:1000 dilution, with 48 kDa expected band

  • IHC: 1:200-1:1000 dilution with appropriate antigen retrieval

  • Immunoprecipitation: 0.5-4.0 μg antibody for 1.0-3.0 mg total protein lysate

What techniques should be employed to study TRIM31-mediated ubiquitination in complex biological systems?

To study TRIM31-mediated ubiquitination in complex systems:

• Ubiquitin chain specificity analysis:

  • Use specific antibodies against K48 or K63 linkages to determine ubiquitination type

  • Employ ubiquitin mutants (K48R, K63R) to confirm linkage specificity

• In vivo ubiquitination:

  • Tandem Ubiquitin Binding Entities (TUBEs) to isolate ubiquitinated proteins

  • Treatment with deubiquitinase inhibitors to stabilize ubiquitination

  • Proteasome inhibitors (MG132) for K48-linked substrates

• Mass spectrometry approaches:

  • Di-Gly remnant profiling to identify ubiquitination sites

  • Quantitative proteomics to analyze changes in ubiquitination patterns

  • Proximity-dependent labeling to identify substrates in their native environment

• CRISPR-mediated gene editing:

  • Generate TRIM31 catalytic mutants (C53A/C56A) to distinguish E3 ligase-dependent and independent functions

  • Create substrate mutants lacking critical lysine residues to confirm direct ubiquitination

• In vitro reconstitution:

  • Purified components (E1, E2, TRIM31, substrate) to demonstrate direct ubiquitination

  • Domain mapping to identify which regions of TRIM31 are required for substrate recognition versus catalytic activity

How can TRIM31 expression patterns be utilized as diagnostic or prognostic markers in clinical samples?

TRIM31 expression has significant clinical implications:

• Cancer prognosis:

  • High TRIM31 expression correlates with poor prognosis in hepatocellular carcinoma, gallbladder cancer, colorectal cancer, and high-grade glioma

  • Low TRIM31 expression is associated with worse outcomes in breast cancer

  • In gastric cancer, multivariate analysis showed TRIM31 had a hazard ratio of 1.642 (95% CI: 1.003–2.689, p=0.049) in univariate but not multivariate analysis

• Histological characteristics:

  • In breast cancer, decreased TRIM31 expression correlates with larger tumor size, higher Ki67 expression, advanced TNM stage, advanced histological grade, and lymph node invasion

  • In gastric cancer, TRIM31 expression correlates with T stage progression

• Detection methods in clinical samples:

  • IHC: 1:200-1:1000 dilution with TE buffer pH 9.0 for antigen retrieval

  • RT-PCR: For quantitative assessment of mRNA levels

• Combined biomarker approach:

  • Integrate TRIM31 expression with other molecular markers for improved diagnostic accuracy

  • Consider tissue-specific expression patterns when developing diagnostic panels

What are the optimal experimental models for studying TRIM31 function in specific disease contexts?

For disease-specific TRIM31 research:

• Cancer models:

  • Cell lines: AGS cells for gastric cancer, MCF7 and ZR-75-30 for breast cancer, SW620 and HT-29 for colorectal cancer

  • Animal models: Xenograft tumor models using TRIM31-overexpressing or knockdown cells

  • Patient-derived organoids to maintain tissue architecture and heterogeneity

• Cerebral ischemia models:

  • MCAO (Middle Cerebral Artery Occlusion) model in TRIM31 knockout mice

  • OGD/R (Oxygen-Glucose Deprivation/Reoxygenation) in primary cultured neurons

  • PC12 cells as an in vitro model for neural ischemia studies

• Inflammation models:

  • DSS-induced colitis for inflammatory bowel disease studies

  • Alum-induced peritonitis for studying inflammasome activation

  • LPS-stimulated macrophages for studying innate immune responses

• Genetic models:

  • TRIM31 knockout mice for systemic loss-of-function studies

  • AAV-mediated knockdown for tissue-specific manipulation

  • CRISPR/Cas9-edited cell lines with domain-specific mutations

How can TRIM31's dual roles in different diseases be leveraged for therapeutic development?

TRIM31's context-dependent functions offer unique therapeutic opportunities:

• Cancer therapy approaches:

  • For cancers where TRIM31 is oncogenic (colorectal, gastric): Develop inhibitors targeting TRIM31's E3 ligase activity or disrupt specific protein interactions

  • For cancers where TRIM31 is tumor-suppressive (breast): Strategies to upregulate or reactivate TRIM31 function

• Anti-inflammatory applications:

  • Modulate TRIM31-NLRP3 interaction to control inflammasome activation

  • Target TRIM31 to enhance or suppress NF-κB signaling depending on disease context

• Neuroprotective strategies:

  • Inhibit TRIM31-TIGAR interaction to mimic the protective effects of TRIM31 deficiency in cerebral ischemia

  • Enhance pentose phosphate pathway activation to reduce oxidative stress in ischemic conditions

• Therapeutic monitoring:

  • Use antibodies against TRIM31 and its modified substrates to monitor treatment efficacy

  • Develop assays for specific TRIM31-mediated ubiquitination events as pharmacodynamic markers

• Precision medicine approach:

  • Stratify patients based on TRIM31 expression levels and mutation status

  • Design combination therapies targeting both TRIM31 and relevant downstream pathways