dlg2 Antibody

What is DLG2 and what cellular functions does it perform?

DLG2, also known as postsynaptic density protein 93 (PSD-93) or channel-associated protein of synapse-110 (chapsyn-110), belongs to the membrane-associated guanylate kinase (MAGUK) family. It functions as a postsynaptic scaffold protein that links cell adhesion molecules like CADM1 to core components of the postsynaptic density . In CA1 pyramidal neurons, DLG2 is required for synaptic KCNN2-containing channel function and long-term potentiation expression . The protein typically forms heterodimers with related family members to create multimeric scaffolds for the clustering of receptors, ion channels, and associated signaling proteins . Recent research has also revealed that DLG2 negatively regulates SRC function in epithelial cells and participates in NMDA receptor signaling pathways .

What are the expected molecular weights for DLG2 protein detection?

While the calculated molecular weight of human DLG2 is approximately 98 kDa, researchers typically observe bands at around 110 kDa in Western blot applications . This discrepancy between calculated and observed molecular weights may be attributed to post-translational modifications or the specific isoform being detected. When designing experiments, researchers should consider that:

The canonical human DLG2 protein has a reported length of 870 amino acid residues and a mass of 97.6 kDa . Multiple isoforms of varying sizes have been identified, which may complicate band pattern interpretation.

What is the tissue expression profile of DLG2?

DLG2 is primarily expressed in neural tissues but has recently been identified in other cell types. Researchers should be aware of the following expression patterns when designing experiments:

This expression profile supports DLG2's utility as a neuronal cell marker, particularly in studies of neuronal differentiation and function . Recent studies have expanded our understanding of DLG2 expression to include certain immune cells and gut tissue, suggesting broader biological roles than previously recognized .

What are the optimal sample preparation techniques for DLG2 detection in Western blot?

For successful Western blot detection of DLG2, researchers should follow these methodological guidelines:

• Use fresh tissue or properly stored frozen samples (-80°C) to preserve protein integrity.

• For brain tissue, which contains high endogenous DLG2 levels, consider using mouse or rat brain as positive controls .

• Employ SDS-PAGE gels with lower percentage (7.5%) to adequately resolve the high molecular weight DLG2 protein .

• When extracting DLG2 from cellular membranes, include detergents like RIPA buffer supplemented with protease inhibitors.

• Load sufficient protein (≥30 μg of whole cell lysate) to ensure detection of lower-expressing samples .

• Use recommended antibody dilutions, typically in the range of 1:1000-1:6000 for most commercial anti-DLG2 antibodies .

Data from validation studies indicates that non-neural samples may require optimization of protein loading and detection methods due to lower expression levels compared to brain tissue.

How can researchers validate DLG2 antibody specificity?

To ensure experimental rigor, validation of DLG2 antibody specificity is crucial using the following approaches:

• Genetic knockout controls: Compare antibody reactivity between wild-type and DLG2 knockout samples. Research demonstrates that CRISPR/Cas9-generated DLG2-/- human embryonic stem cell lines show absence of DLG2 in proteomic pulldowns compared to wild-type lines .

• Peptide competition assays: Pre-incubate the antibody with the immunizing peptide to confirm specific binding.

• Multi-antibody validation: Use antibodies targeting different epitopes of DLG2 to confirm consistent detection patterns.

• Recombinant protein controls: Include purified DLG2 protein as a positive control in Western blots.

• Cross-species validation: Test antibody across species with known DLG2 homology (human, mouse, rat) to verify conservation of binding .

Validation studies should include appropriate negative controls, especially when working with new antibodies or tissues with previously uncharacterized DLG2 expression.

What are the recommended protocols for immunohistochemical detection of DLG2?

For successful immunohistochemical (IHC) detection of DLG2 in tissue sections, researchers should consider:

• Fixation method: Formalin fixation has been validated for DLG2 detection in multiple tissues including brain, kidney, and esophagus .

• Antigen retrieval: Optimize temperature and pH conditions based on the specific antibody recommendations.

• Antibody concentration: Titrate antibody concentration; published protocols utilize 10-20 μg/ml for IHC-P applications .

• Detection system: DAB staining has been successfully employed for DLG2 visualization in paraffin-embedded tissues .

• Controls: Include tissue types with known high expression (brain) and low/no expression as positive and negative controls, respectively.

For immunocytochemistry applications, researchers have successfully detected DLG2 in cell lines such as A549 using similar protocols, though concentration optimization may be necessary for different cell types .

How can DLG2 antibodies be utilized to study neurodevelopmental disorders?

DLG2 has been implicated in multiple neurodevelopmental disorders, particularly schizophrenia. Researchers investigating these connections can employ the following methodological approaches:

• Knockout model phenotyping: DLG2-/- human embryonic stem cells show altered neuronal morphology with reduced secondary neurite branching and impaired migration . Antibodies against neuronal markers (NEUN, TUJ1, MAP2) can be used alongside DLG2 antibodies to characterize these phenotypes.

• Transcriptional profiling: Studies indicate DLG2 knockout alters expression of 40-60% of protein-coding genes during neuronal differentiation . Researchers can correlate protein-level changes (detected via antibodies) with transcriptional changes.

• Protein-protein interaction networks: Co-immunoprecipitation using DLG2 antibodies can identify disrupted protein interactions in disease models.

• NMDA receptor complex analysis: Given DLG2's role in NMDA receptor signaling, antibodies can be used to investigate alterations in receptor complexes in disease states .

Recent research demonstrated that genes down-regulated in DLG2 knockout cells at day 30 of differentiation are significantly enriched for schizophrenia-associated common variants, providing a specific developmental timepoint for investigating disease mechanisms .

What methodological approaches can reveal DLG2's role in inflammasome formation?

Recent studies have uncovered DLG2's involvement in inflammatory processes and inflammasome formation. Researchers can investigate this role using the following approaches:

• Expression modulation: Overexpression or silencing of DLG2 in colon cancer or immune cells has revealed significant effects on inflammasome components. DLG2 overexpression leads to increased expression of IL1B, IκBζ, and BAX - critical components for inflammasome formation .

• Cytokine analysis: DLG2 silencing in THP1 cells results in increased IL-6 release, which can be measured in cell culture supernatants .

• Signaling pathway investigation: DLG2 manipulation affects key signaling pathways including STAT3 phosphorylation and AKT/S6 signaling. Researchers can use phospho-specific antibodies alongside DLG2 antibodies to track these changes .

• Disease model correlation: DLG2 expression is repressed in inflammatory bowel diseases and colorectal cancer tissues compared to healthy controls, suggesting utility as a disease marker .

These findings indicate that DLG2 antibodies can serve as valuable tools in investigating the connection between inflammation and cancer progression.

How can researchers study DLG2 isoform diversity?

DLG2 exists in multiple isoforms with potentially distinct functions. To effectively study these variants:

• Isoform-specific antibody selection: Choose antibodies raised against regions that can distinguish between isoforms. The first PDZ domain has been targeted in knockout studies, suggesting its importance for function .

• Transcriptional analysis: A novel splice variant of mouse Dlg2 termed Dlg2η has been identified in IFNβ-producing plasmacytoid dendritic cells. Researchers can use RT-PCR with isoform-specific primers to identify expression patterns .

• Recombinant expression systems: Studies have successfully created expression constructs for different DLG2 isoforms (DLG2α, DLG2γ, and DLG2η) fused to tags like EGFP for visualization and functional analysis .

• Domain-specific interaction studies: Different domains (PDZ, SH3, GK) mediate distinct protein interactions. Antibodies targeting specific domains can help elucidate isoform-specific binding partners.

Understanding isoform diversity is particularly relevant when investigating tissue-specific functions, as expression patterns may vary significantly between tissues and developmental stages.

What are common challenges in DLG2 antibody applications and how can they be addressed?

Researchers may encounter several technical challenges when working with DLG2 antibodies:

• Background signal: When performing immunohistochemistry or immunofluorescence, non-specific binding can occur. Address this by:

  • Optimizing blocking conditions (5% BSA or normal serum)

  • Increasing wash duration and frequency

  • Using antigen-specific pre-absorption controls

• Inconsistent detection: DLG2 expression varies significantly across tissues. Ensure:

  • Adequate positive controls (brain tissue for high expression)

  • Appropriate exposure times for low-expressing tissues

  • Consistent sample preparation procedures

• Multiple bands in Western blot: This may reflect isoform diversity or proteolytic processing. Improve specificity by:

  • Using gradient gels for better separation

  • Including protease inhibitors during sample preparation

  • Comparing band patterns with known isoform molecular weights

• Cross-reactivity with other MAGUK family proteins: Verify antibody specificity against other family members (DLG1, DLG3, DLG4) which share structural similarities.

How can researchers optimize co-immunoprecipitation experiments with DLG2 antibodies?

Co-immunoprecipitation (Co-IP) is valuable for studying DLG2's protein interactions, particularly at the synapse. For successful Co-IP experiments:

• Antibody selection: Choose antibodies validated for immunoprecipitation applications. Many commercially available antibodies are only validated for Western blot and immunohistochemistry.

• Lysis conditions: Use mild lysis buffers that preserve protein-protein interactions (e.g., NP-40 or Triton X-100 based buffers rather than stronger RIPA buffers).

• Crosslinking consideration: For transient interactions, consider using chemical crosslinkers before lysis.

• Control for specificity: Include IgG controls and, when possible, tissue/cells lacking DLG2 expression.

• Bait verification: Always confirm successful DLG2 pulldown before assessing co-immunoprecipitated proteins.

Research has successfully used quantitative mass spectrometry-based proteomic analysis of peptide-affinity pulldowns with NMDA receptor NR2 subunit PDZ peptide ligand to identify DLG2 interactions , demonstrating the feasibility of this approach.

How are DLG2 antibodies being used to investigate pubertal development disorders?

Recent research has implicated DLG2 in pubertal development and reproductive function. When investigating these connections:

• Genetic correlation: DLG2 variants have been identified in families with delayed puberty and in patients with idiopathic hypogonadotropic hypogonadism (IHH) .

• Functional analysis: DLG2 variants impair GnRH expression in vitro, suggesting a mechanistic link to pubertal timing .

• Protein interaction studies: The variant identified in delayed puberty patients interferes with binding of PSD-93 (the protein encoded by DLG2) to Fyn, a non-receptor type protein kinase that phosphorylates NMDA receptors .

• NMDA receptor signaling: Since NMDA signaling regulates puberty in animal models, researchers can use DLG2 antibodies to investigate this pathway in human samples.

This emerging area offers opportunities for using DLG2 antibodies in reproductive neuroendocrinology research, potentially revealing new therapeutic targets for pubertal disorders.

What are the latest applications of DLG2 antibodies in cancer research?

DLG2 has recently emerged as a potential tumor suppressor in various cancers. Researchers investigating this connection should consider:

• Expression profiling: DLG2 expression is repressed in colorectal cancer tissues compared to healthy controls, suggesting utility as a prognostic marker .

• Inflammatory microenvironment: DLG2 silencing in THP1 cells alters the inflammatory microenvironment, potentially promoting tumor cell proliferation through increased IL-6 release and STAT3 phosphorylation .

• Cell cycle analysis: Cells exposed to conditioned media from DLG2-silenced cells show an increase in G2/M phase populations, indicating effects on cell cycle progression .

• Signaling pathway investigation: DLG2 restoration reduces AKT and S6 signaling, key pathways in cancer progression .

These findings highlight the potential of DLG2 antibodies as tools for cancer research, particularly in understanding the connection between inflammation, cell cycle regulation, and tumor development.