gpr173 Antibody

What is GPR173 and where is it primarily expressed in the body?

GPR173, also known as Super Conserved Receptor Expressed in Brain 3 (SREB3), is a G protein-coupled receptor belonging to the Class A GPCR superfamily. In humans, the canonical protein consists of 373 amino acid residues with a molecular mass of approximately 41.5 kDa . This receptor shows predominant localization to the cell membrane, with notable expression patterns in both neural and reproductive tissues.

GPR173 expression has been documented in:

• Brain regions: Particularly in hippocampal CA3 pyramidal neurons and parietal cortex

• Ovarian tissues: Specifically in granulosa cells of post-primary follicles and oocytes

• Neuroblastoma cell lines: Expression varies based on MYCN amplification status

When designing experiments to study GPR173, researchers should consider these tissue-specific expression patterns to appropriately contextualize their findings within physiological frameworks.

What methods are available for detecting GPR173 in experimental systems?

GPR173 can be detected using various immunological techniques, with Western blot, ELISA, and immunofluorescence being the most commonly employed approaches . For optimal experimental design, researchers should consider application-specific recommendations:

When conducting these experiments, it's crucial to include appropriate controls. For instance, blocking peptide experiments have demonstrated the specificity of anti-GPR173 antibodies in brain sections, where pre-incubation with GPR173 blocking peptide effectively suppresses immunoreactivity .

How should researchers select the most appropriate GPR173 antibody for their specific application?

Selection of an appropriate GPR173 antibody depends on several experimental factors:

• Target region: Antibodies targeting different epitopes of GPR173 may provide varying results. Some antibodies target the C-terminal region (e.g., peptide GMDEVKGEKQLGR, corresponding to amino acids 274-286 in mouse GPR173) . Consider whether your research question focuses on a specific domain.

• Species cross-reactivity: Many commercially available GPR173 antibodies demonstrate reactivity across species, with documented cross-reactivity in human, mouse, rat, bovine, rabbit, dog, and bat samples . If working with less common model organisms, evaluate sequence homology data:

  • 100% homology: Human, gorilla, gibbon, monkey, marmoset, mouse, rat, dog, bat, bovine, rabbit

  • 95% homology: Panda

  • 90% homology: Hamster, elephant

• Validation data: Prioritize antibodies with substantial validation data in your application of interest. For example, antibodies validated by blocking peptide experiments in immunohistochemistry may be preferrable for similar applications .

• Host species: Consider the host species in which the antibody was raised to avoid cross-reactivity issues in multi-labeling experiments. Rabbit polyclonal antibodies are common for GPR173 detection .

What are the optimal protocols for using GPR173 antibodies in Western blot analysis?

Western blot analysis of GPR173 requires careful optimization due to the protein's membrane localization and post-translational modifications. Based on published protocols:

• Sample preparation:

  • For brain tissues: Homogenize in RIPA buffer containing protease inhibitors

  • For cell lines: Consider specialized membrane protein extraction methods to maximize yield

• Protein loading:

  • Load 20-50 μg of total protein per lane

  • Include positive controls such as SHSY-5Y neuroblastoma, BV-2 microglia, or HMC3 microglial cell lysates, which have demonstrated GPR173 expression

• Separation and transfer:

  • Use 10-12% SDS-PAGE gels

  • Transfer to PVDF membranes (preferred over nitrocellulose for membrane proteins)

• Antibody incubation:

  • Primary antibody: 1:500 dilution has been effective in published studies

  • Secondary antibody: HRP-conjugated anti-rabbit (for rabbit primaries)

• Detection and interpretation:

  • GPR173 may appear at different molecular weights due to glycosylation

  • Always include blocking peptide controls for confirmation of specificity

What is known about GPR173's role in systemic lupus erythematosus (SLE) pathophysiology?

Recent genome-wide association studies have identified a significant connection between GPR173 and SLE. A meta-analysis combining data from both Chinese and European populations identified SNP rs13440883 in GPR173 as significantly associated with SLE (Pmeta = 7.53 × 10−9, ORmeta = 1.16) . This finding is particularly noteworthy considering:

• X-chromosome linkage: GPR173 is located on the X chromosome, providing a potential mechanism to explain sex differences in SLE prevalence, which disproportionately affects females of childbearing age.

• Functional implications: Epigenetic analysis revealed that rs13440883 is located within a region marked by H3K27ac and H3K4me1 histone modifications in CD19 primary cells, suggesting potential regulatory functions in B cells .

• Linkage patterns: Further analysis identified SNP rs11091720, which shows high linkage disequilibrium with rs13440883 (r²EUR = 0.9384; r²Asian = 0.9915), as a transcription factor binding hotspot in the coding region of GPR173 .

Researchers investigating SLE might consider the following approaches when using GPR173 antibodies:

• Comparing GPR173 protein expression between SLE patient samples and healthy controls

• Examining potential correlations between GPR173 expression and disease severity or autoantibody profiles

• Investigating cell-type specific expression of GPR173 in immune cells from SLE patients

How is GPR173 being investigated as a target for neuroblastoma immunotherapy?

Emerging research has identified GPR173 as a promising target for neuroblastoma immunotherapy, particularly in paired-antigen targeting approaches. In MYCN non-amplified stage 4 neuroblastoma, GPR173 paired with neurotrophic tyrosine kinase 1 (NTRK1), anaplastic lymphoma kinase (ALK), or other surface markers has been proposed as a strategy to increase the specificity and safety of chimeric antigen receptor (CAR) T-cell therapy .

The paired-antigen approach represents an innovative strategy to overcome limitations of single-antigen targeting, potentially allowing:

Researchers investigating GPR173 in neuroblastoma contexts should consider:

• Validating antibody specificity in neuroblastoma cell lines and patient-derived xenografts

• Quantifying GPR173 expression levels across neuroblastoma subtypes and normal tissues

• Developing dual-recognition immunotherapeutic constructs that target GPR173 in combination with other markers

How can researchers effectively study GPR173 signaling pathways and downstream effects?

Investigating GPR173 signaling pathways presents unique challenges due to incomplete characterization of its endogenous ligands and signaling partners. Researchers approaching this question should consider:

• Functional assays:

  • G-protein activation assays (e.g., GTPγS binding)

  • Second messenger quantification (cAMP, Ca²⁺, etc.)

  • Receptor internalization and trafficking experiments

• Interaction studies:

  • Co-immunoprecipitation with anti-GPR173 antibodies

  • Proximity ligation assays to detect protein-protein interactions

  • BRET/FRET experiments for real-time interaction analysis

• Genetic manipulation approaches:

  • CRISPR/Cas9-mediated knockout or knockin studies

  • Conditional expression systems to control GPR173 levels

  • Domain-specific mutations to identify critical signaling regions

When selecting antibodies for signaling studies, researchers should prioritize those with demonstrated specificity in immunoprecipitation applications and minimal interference with protein-protein interactions.

What approaches can be used to study post-translational modifications of GPR173?

GPR173 undergoes various post-translational modifications, including glycosylation , which may affect both protein function and antibody recognition. To effectively study these modifications:

• Glycosylation analysis:

  • Compare migration patterns before and after glycosidase treatment

  • Use lectins in conjunction with GPR173 antibodies for co-localization studies

  • Consider glycoprotein-specific enrichment methods prior to antibody-based detection

• Phosphorylation studies:

  • Use phospho-specific antibodies (if available)

  • Employ phosphatase treatments as controls

  • Consider mass spectrometry approaches for comprehensive phosphosite mapping

• Other modifications:

  • Investigate ubiquitination and SUMOylation patterns

  • Examine potential palmitoylation sites that may affect membrane localization

When interpreting antibody-based detection results, researchers should be aware that post-translational modifications may mask epitopes or alter apparent molecular weights on Western blots.

How are GPR173 antibodies being used to investigate neurodevelopmental processes?

GPR173's prominent expression in the brain, particularly in hippocampal and cortical neurons , suggests important roles in neurodevelopment and neuronal function. Researchers exploring these connections have employed GPR173 antibodies to:

• Map developmental expression patterns:

  • Tracking GPR173 expression through developmental stages

  • Correlating expression with key neurodevelopmental milestones

  • Comparing expression across brain regions using immunohistochemistry

• Examine co-localization with neuronal markers:

  • Double-labeling with neuron-specific markers (e.g., NeuN, MAP2)

  • Investigating potential expression in glial cells

  • Examining synaptic localization patterns

• Study activity-dependent regulation:

  • Comparing GPR173 expression between normal and seizure models

  • Investigating changes following learning paradigms

  • Examining alterations in neurodevelopmental disorder models

When designing such experiments, researchers should carefully select antibodies validated in neural tissues and consider fixation and permeabilization protocols optimized for preserving GPR173 epitopes in complex brain tissues.

What strategies can improve reproducibility when working with GPR173 antibodies?

Ensuring reproducibility in GPR173 antibody-based research requires addressing several technical considerations:

• Antibody validation strategies:

  • Always include knockdown/knockout controls where possible

  • Use blocking peptide competition assays

  • Compare results across multiple antibodies targeting different epitopes

  • Correlate protein detection with mRNA expression data

• Standardized protocols:

  • Document complete antibody information (supplier, catalog number, lot, dilution)

  • Maintain consistent sample preparation techniques

  • Standardize image acquisition settings for immunofluorescence

  • Establish quantification methods for signal intensities

• Positive and negative controls:

  • Include tissues/cells with known GPR173 expression patterns

  • Use samples from related species to evaluate cross-reactivity claims

  • Consider synthetic peptide standards for quantitative applications

• Batch effects management:

  • Process experimental and control samples simultaneously

  • Maintain consistent antibody lots for long-term studies

  • Include internal reference standards for quantitative comparisons

By implementing these strategies, researchers can enhance the reliability and reproducibility of their GPR173 antibody-based research, contributing to the growing body of knowledge about this important receptor.