RET (rearranged during transfection) is a transmembrane receptor tyrosine kinase that plays crucial roles in cell growth, differentiation, and survival. It functions as a receptor for glial cell line-derived neurotrophic factor (GDNF) family ligands. RET is particularly significant because mutations in this proto-oncogene are associated with multiple endocrine neoplasia type 2 (MEN2B), medullary thyroid carcinoma (MTC1), and other cancers. The protein is approximately 124.3 kilodaltons in mass and can be found in several isoforms, including RET51 . In neurological research, RET is notable for its expression in motor neurons and its role in neuronal development and function, making it an important target for studies on neurodegenerative diseases .
Research-grade RET antibodies are available in several formats with distinct specificities:
Total RET antibodies - Recognize all forms of the RET protein regardless of phosphorylation status
Phospho-specific antibodies - Target specific phosphorylation sites (e.g., Tyr905) that indicate active signaling
Isoform-specific antibodies - Distinguish between RET9 and RET51 splice variants
Domain-specific antibodies - Target extracellular, transmembrane, or cytoplasmic regions
Available species reactivity includes human, mouse, rat, and some non-human primates, with human RET antibodies showing varying degrees of cross-reactivity with mouse RET . The antibodies are produced in various host species including goat and mouse, which should be considered when designing multi-color immunofluorescence experiments to avoid secondary antibody cross-reactivity .
Methodological validation of RET antibodies should follow these steps:
Positive and negative control tissues/cells: For RET, human spinal cord sections showing motor neuron staining serve as excellent positive controls . Conversely, tissues known not to express RET can serve as negative controls.
Western blot validation: Confirm the antibody detects a band of appropriate molecular weight (~124 kDa for full-length RET). Compare with lysates from cells with RET knockdown or knockout.
Phospho-antibody validation: When using phospho-specific RET antibodies (e.g., pTyr905), include samples treated with phosphatase or samples from cells treated with RET kinase inhibitors .
Cross-reactivity testing: If working with multiple species, test the antibody against recombinant proteins or cell lysates from each species. Some RET antibodies show 100% cross-reactivity between human and mouse RET in direct ELISAs and Western blots .
Immunoprecipitation followed by mass spectrometry: For ultimate validation, perform IP with the RET antibody followed by mass spectrometry identification of the precipitated proteins.
When incorporating RET antibody into a flow cytometry panel, follow these methodological principles:
Prioritize marker placement based on expression levels: Since RET may be expressed at varying levels depending on the cell type, match antibody brightness with expected expression. For low RET expression, use bright fluorophores (like PE or APC); for high expression, dimmer fluorophores may suffice .
Consider autofluorescence interference: Neuronal cells often have high autofluorescence. Choose fluorochromes with emission spectra distinct from cellular autofluorescence patterns. The Cytek Aurora system may be preferable for samples with high autofluorescence .
Avoid spectral overlap with co-expressed markers: If examining markers co-expressed with RET (e.g., GFRα co-receptors), ensure their fluorophores have minimal spectral overlap to prevent false positives due to compensation issues .
Implement proper gating strategy:
Include fluorescence minus one (FMO) controls: Essential for setting gates accurately, especially when RET expression might form a continuum rather than discrete positive/negative populations.
A staining index calculation can help objectively compare fluorophore brightness options:
Staining Index = (MFI positive - MFI negative) / (2 × SD of negative)
For optimal immunohistochemical detection of RET in tissues, follow this validated protocol:
Tissue preparation:
Fresh tissues should be immediately fixed in 10% neutral buffered formalin
Paraffin embedding should follow standard protocols with careful temperature control
Cut sections at 4-6 μm thickness
Antigen retrieval:
Heat-induced epitope retrieval using citrate buffer (pH 6.0) or EDTA buffer (pH 9.0)
20 minutes at 95-98°C has been validated for RET epitope exposure
Antibody incubation:
Detection system:
Controls:
When performing western blot analysis with RET antibodies, follow these methodological guidelines:
Sample preparation:
Use RIPA buffer supplemented with phosphatase inhibitors (especially critical for phospho-RET detection)
Include protease inhibitors to prevent degradation
Sonicate briefly to shear DNA and reduce sample viscosity
Gel selection:
Use 7.5% or 4-12% gradient gels due to RET's large size (~124 kDa)
Run at lower voltage (80-100V) to improve resolution of high molecular weight proteins
Transfer conditions:
Use wet transfer for large proteins like RET
Transfer at 30V overnight at 4°C or 100V for 2 hours with cooling
PVDF membrane is recommended over nitrocellulose for better protein retention
Blocking and antibody incubation:
Detection considerations:
Enhanced chemiluminescence (ECL) with film exposure or digital imaging
For weakly expressed RET, consider signal amplification systems
Positive controls:
Multiple bands in RET western blots can occur for several legitimate biological and technical reasons:
Alternative splicing: RET has multiple isoforms including RET9 (≈120 kDa) and RET51 (≈124 kDa) that differ in their C-terminal tails. Depending on the epitope recognized by the antibody, you may see one or both isoforms .
Post-translational modifications:
Glycosylation: RET undergoes extensive N-glycosylation, producing bands at ≈150-170 kDa (mature) and ≈120 kDa (immature)
Phosphorylation: Multiple phosphorylation states can cause slight mobility shifts
Ubiquitination: Higher molecular weight smears may indicate ubiquitinated RET
Proteolytic processing: RET can undergo proteolytic cleavage, generating fragments of various sizes. Calpain-mediated cleavage produces a ≈100 kDa fragment.
Technical issues:
Incomplete reduction: Ensure fresh DTT or β-mercaptoethanol in sample buffer
Sample degradation: Always use protease inhibitors during lysis
Non-specific binding: Try different blocking agents or increase washing stringency
| Band Size (kDa) | Likely Identity | Validation Approach |
|---|---|---|
| 170 | Mature glycosylated RET | Sensitive to Endoglycosidase H treatment |
| 150 | Partially glycosylated RET | Sensitive to PNGase F treatment |
| 120-124 | Core RET protein (RET9/RET51) | Resistant to glycosidase treatment |
| 100 | Proteolytic fragment | Increases with calpain activators |
| 80-90 | Intracellular domain fragment | Detected only with C-terminal antibodies |
| <70 | Likely degradation product | Minimized with fresh samples and protease inhibitors |
To confirm band identity, compare staining patterns with antibodies targeting different RET epitopes or use genetic approaches (siRNA knockdown, CRISPR knockout) .
Variation in RET immunostaining intensity is common and requires careful interpretation:
Biological variables affecting RET expression:
Developmental stage: RET expression changes dramatically during development
Cell activation state: RET may be upregulated upon specific signaling events
Microenvironment: GDNF family ligands can alter RET expression and localization
Disease state: Mutations or chromosomal rearrangements can alter expression levels
Technical variables affecting staining intensity:
Fixation time: Overfixation can mask epitopes
Antigen retrieval efficiency: Critical for consistent results
Antibody concentration: Titrate carefully for optimal signal-to-noise ratio
Detection system sensitivity: Enhanced detection systems may be needed for low expression
Quantification approaches:
H-score method: Combines intensity (0-3+) and percentage of positive cells
Digital image analysis: Software-based quantification of DAB intensity
Cell-by-cell analysis: Important when expression is heterogeneous
Validation strategies:
Multi-antibody confirmation: Use antibodies against different RET epitopes
Correlation with mRNA expression: In situ hybridization or RT-PCR from microdissected samples
Functional correlation: Phospho-RET staining should correlate with downstream pathway activation
When examining RET in human spinal cord, motor neurons typically show moderate to strong staining as demonstrated in published data . Variations from this pattern may indicate technical issues or biological alterations worthy of further investigation.
When studying phosphorylated RET (e.g., pTyr905), implement these essential controls:
Positive controls:
Cell lines treated with RET ligands (e.g., GDNF plus GFRα1)
Tissues known to contain activated RET (e.g., developing enteric nervous system)
Cells transfected with constitutively active RET mutants (e.g., RET-MEN2A)
Negative controls:
Samples treated with lambda phosphatase to remove phosphorylation
RET kinase inhibitor-treated samples (e.g., vandetanib or cabozantinib)
RET knockout or knockdown samples
Specificity controls:
Pre-absorption with phospho-peptide vs. non-phospho-peptide
Parallel blots with total RET antibody to normalize phospho-signal
Combined IP-Western approach: IP with total RET, then blot with phospho-specific
Technical considerations:
Always include phosphatase inhibitors (sodium orthovanadate, sodium fluoride)
Maintain cold conditions during sample preparation
Process all comparable samples simultaneously
Quantification approach:
Express results as phospho-RET/total RET ratio
Include time-course studies when examining dynamic phosphorylation events
For immunohistochemistry, use phospho-specific antibodies on serial sections
Phospho-RET (Tyr905) antibodies have been validated in multiple studies, showing 58 citations and 119 figures according to supplier data, demonstrating their reliability for studying RET activation .
Designing experiments to distinguish between RET9 and RET51 isoform signaling requires a strategic approach:
Isoform-specific antibody selection:
Choose antibodies targeting the unique C-terminal sequences of RET9 (9 residues) or RET51 (51 residues)
Validate specificity using cells expressing only one isoform through genetic engineering
Consider using epitope-tagged RET constructs (HA-RET9, FLAG-RET51) with well-characterized tag antibodies
Combinatorial immunoprecipitation approach:
Immunoprecipitate with isoform-specific antibodies
Blot for co-precipitating proteins to identify isoform-specific binding partners
Alternatively, IP with antibodies against suspected binding partners and blot for RET isoforms
Phosphorylation analysis workflow:
IP with isoform-specific antibodies
Blot with phospho-specific antibodies to compare activation patterns
Examine downstream pathway activation (ERK, AKT, STAT3) following isoform-specific IP
Proximity ligation assay (PLA) strategy:
Use isoform-specific antibodies paired with antibodies against putative interactors
This allows visualization of protein-protein interactions in situ with isoform specificity
Quantify PLA signals to measure relative interaction strengths
Functional readouts:
Couple antibody-based detection with functional assays
Measure neurite outgrowth, cell survival, or proliferation after isoform-specific perturbation
Correlate antibody-detected expression patterns with functional outcomes
This methodological approach has been validated in studies examining the differential roles of RET isoforms in development and disease, revealing isoform-specific signaling complexes and biological outcomes .
When studying RET expression in rare cell populations by flow cytometry, implement these advanced methodological approaches:
Sample enrichment strategies:
Magnetic bead pre-enrichment using markers co-expressed with RET
Density gradient separation to remove unwanted cell populations
Depletion of abundant negative populations prior to staining
High-dimensional panel design:
Acquisition parameters optimization:
Collect more events (minimum 1-5 million) to capture sufficient rare cells
Reduce flow rate to improve signal resolution
Use threshold triggering on parameters relevant to your population
Analysis considerations:
Apply sequential gating strategy beginning with viability and singlets
Consider using probability contour plots rather than dot plots for rare events
Implement dimensionality reduction algorithms (tSNE, UMAP) to identify populations
Use SH-SY5Y cells as a positive control for setting up RET detection parameters
Validation approach:
Back-sorting of putative RET+ populations for functional or molecular validation
Correlation of flow cytometry results with immunohistochemistry of the same tissue
Single-cell RNA-seq of sorted populations to confirm RET mRNA expression
This approach has been validated for detecting RET in neuroblastoma cell lines, where intracellular staining following fixation and permeabilization with saponin proved effective .
To investigate RET splicing variants (particularly RET9 vs. RET51) in disease models, employ this comprehensive methodology:
Antibody-based splicing variant detection:
Western blot analysis using antibodies that either:
a) Recognize both variants but resolve them by size difference
b) Specifically target unique C-terminal sequences
Quantify the ratio of variants using densitometry with normalization to loading controls
Immunohistochemical localization:
Use isoform-specific antibodies on serial sections
Implement multiplexed immunofluorescence to co-localize with disease markers
Quantify relative expression in different cell types within diseased tissue
Co-immunoprecipitation for variant-specific interactomes:
IP with isoform-specific antibodies
Identify differential binding partners using mass spectrometry
Validate key interactions with reverse co-IP and proximity ligation assays
Correlation with disease parameters:
Create a scoring system for variant expression levels
Correlate with clinical data (survival, treatment response)
Track changes in variant ratios during disease progression
Functional validation approach:
Combine antibody detection with genetic manipulation
Create cells expressing only one variant through CRISPR-mediated editing
Use antibodies to confirm expression and track signaling differences
This approach has been successfully applied in cancer research, particularly in thyroid carcinomas where RET splicing variants show differential oncogenic potential .
To study RET trafficking and membrane localization, implement these advanced antibody-based approaches:
Surface biotinylation coupled with immunoprecipitation:
Biotinylate surface proteins on live cells
Immunoprecipitate with RET antibodies
Blot with streptavidin-HRP to detect surface fraction
Blot separate aliquot with RET antibody to determine total RET
Calculate surface/total ratio to quantify membrane localization
Antibody internalization assay workflow:
Incubate live cells with RET antibodies that recognize extracellular domain
Allow internalization at 37°C for various time points
Strip remaining surface antibodies with acid wash
Detect internalized antibody-RET complexes by microscopy or flow cytometry
Immunofluorescence co-localization analysis:
Co-stain RET with markers of specific cellular compartments:
Na+/K+ ATPase (plasma membrane)
EEA1 (early endosomes)
Rab11 (recycling endosomes)
LAMP1 (lysosomes)
GM130 (Golgi)
Calculate Pearson's correlation coefficients to quantify co-localization
Track changes following ligand stimulation or inhibitor treatment
TIRF microscopy approach:
Use RET antibodies or fluorescent protein-tagged RET
Visualize only molecules within ~100 nm of the plasma membrane
Quantify dwelling time at the membrane under different conditions
Antibody-based RUSH system implementation:
Combine retention using selective hooks (RUSH) with antibody detection
Track synchronized protein trafficking from ER to plasma membrane
Use pulse-chase approach with antibody detection at fixed timepoints
This multi-faceted approach has been validated in neuronal cell models, where RET trafficking dynamics are critical for proper signaling in response to neurotrophic factors .
To integrate RET antibody detection with functional signaling assays, implement this comprehensive workflow:
Split-sample approach:
Divide each sample for parallel antibody-based and functional analyses
Use antibodies to quantify RET expression/phosphorylation levels
Simultaneously measure functional outcomes in the matched sample
Correlate expression/activation with function on a sample-by-sample basis
Sequential analysis workflow:
Perform functional assays on live cells (e.g., calcium flux, neurite outgrowth)
Fix and immunostain the same cells for RET expression/activation
Use image registration to correlate functional readouts with antibody staining at single-cell level
Reporter system integration:
Generate cell lines with RET-dependent transcriptional reporters
Validate reporter activity correlates with antibody-detected RET activation
Use reporter for live monitoring and antibodies for endpoint validation
Multiplexed signaling analysis:
Perform phospho-flow cytometry with antibodies against:
a) Phospho-RET (e.g., pTyr905)
b) Downstream effectors (pERK, pAKT, pSTAT3)
Analyze correlation between receptor activation and pathway activation
Gate on different expression levels to determine signaling thresholds
In vivo correlation approach:
Use functional imaging (PET, SPECT) to assess activity in animal models
Perform post-mortem antibody-based analysis on the same tissues
Map functional data to molecular expression patterns
This integrated approach has been validated in studies examining RET signaling in neuronal populations, demonstrating clear correlation between antibody-detected activation states and functional outcomes in neural development and maintenance .
To effectively combine RET antibody detection with genetic manipulation, implement this methodological framework:
CRISPR/Cas9 modification validation:
Design genetic modifications (knockout, point mutations, tagged insertions)
Use RET antibodies to confirm successful editing:
a) Total RET antibodies to confirm knockout
b) Phospho-specific antibodies to validate functional impact of point mutations
c) Epitope tag antibodies to detect inserted tags
Compare antibody signals between wild-type and edited cells
Overexpression system analysis:
Transfect cells with RET variant constructs
Use antibodies to:
a) Quantify expression levels for normalization
b) Detect subcellular localization changes
c) Measure phosphorylation status as readout of activity
Compare antibody staining patterns between endogenous and overexpressed RET
RNA interference correlation:
Implement siRNA or shRNA against RET
Use antibodies to verify knockdown efficiency at protein level
Quantify relationship between mRNA reduction and protein reduction
Establish time course of protein depletion following RNA interference
Rescue experiment design:
Knockout endogenous RET
Re-express specific variants or mutants
Use antibodies to:
a) Confirm absence of endogenous protein
b) Verify expression of the rescue construct
c) Measure restoration of downstream signaling
Domain-swapping analysis:
Create chimeric receptors with domains from other RTKs
Use domain-specific antibodies to verify chimera expression
Examine altered signaling using phospho-specific antibodies
This approach has been validated in multiple studies examining the functional consequences of RET mutations found in cancer and developmental disorders .
For integrating RET antibodies into single-cell analysis workflows, implement these cutting-edge approaches:
Single-cell Western blotting protocol:
Separate single cells in microwell arrays
Lyse in situ and separate proteins by size
Probe with RET antibodies and normalization controls
Quantify expression level heterogeneity across individual cells
Compare with bulk population averages to identify rare subpopulations
Mass cytometry (CyTOF) integration:
Conjugate RET antibodies to rare earth metals
Combine with 30-40 other antibodies for comprehensive phenotyping
Analyze RET expression in relation to cell lineage and activation markers
Implement unsupervised clustering to identify novel RET-expressing populations
Single-cell immunofluorescence quantification:
Immunostain for RET and co-markers
Image using high-content microscopy
Extract quantitative features:
a) Expression level (intensity)
b) Subcellular localization (spatial distribution)
c) Morphological parameters (cell shape, neurite length)
Correlate RET expression patterns with morphological phenotypes
Imaging mass cytometry approach:
Use metal-tagged RET antibodies on tissue sections
Ablate tissue with laser and analyze released metals
Generate high-dimensional spatial maps of RET expression
Preserve tissue architecture context while obtaining single-cell resolution
CODEX multiplexed imaging integration:
Incorporate RET antibodies into DNA-barcoded antibody panels
Perform iterative imaging cycles with fluorescent reporters
Achieve 40+ marker detection on the same tissue section
Map RET expression to complex cellular neighborhoods
These approaches enable unprecedented resolution of RET biology at the single-cell level, revealing heterogeneity masked by bulk analyses and providing insight into rare cell populations with unique RET expression or activation patterns .
To comprehensively map the RET interactome using antibody-based methods, implement this advanced methodological framework:
Co-immunoprecipitation with mass spectrometry:
Immunoprecipitate RET using validated antibodies under different conditions
Perform LC-MS/MS analysis of co-precipitated proteins
Implement SILAC or TMT labeling for quantitative comparison
Filter against control IPs to remove non-specific interactions
Validate key interactions by reverse IP and western blotting
BioID proximity labeling approach:
Generate RET-BioID fusion proteins
Use antibodies to confirm expression and proper localization
Purify biotinylated proteins and identify by mass spectrometry
Compare interactome of wild-type RET versus mutant forms
Validate spatial proximity of identified partners using antibodies
APEX2 proximity labeling strategy:
Create RET-APEX2 fusions
Validate using antibodies against RET and the APEX2 tag
Perform rapid biotin labeling of proximal proteins
Compare interaction landscapes across different cellular compartments
Confirm key interactions with conventional antibody-based methods
Multiplex co-immunoprecipitation array:
IP RET under various conditions
Probe co-precipitates with antibody arrays targeting RTK signaling proteins
Quantify relative binding across different experimental conditions
Create dynamic interactome maps in response to ligands or inhibitors
Proximity ligation assay (PLA) screening:
Perform systematic PLA between RET and candidate interactors
Quantify interaction signals at subcellular resolution
Map interaction networks to specific cellular compartments
Track dynamic changes in interactions following stimulation
This integrated approach reveals context-dependent interactions that may be missed by single methods and has been validated in studies of RET signaling complexes in both physiological signaling and pathological contexts .
For integrating phospho-RET antibody data with other -omics datasets, implement this comprehensive analytical framework:
Multi-omics data normalization strategy:
Convert phospho-RET antibody signals to standardized scores
Apply batch correction when combining datasets from different experiments
Normalize against total RET levels to focus on activation rather than expression
Create integrated data matrices suitable for multi-omics analysis
Correlation analysis approach:
Calculate Spearman or Pearson correlations between:
a) Phospho-RET levels and transcriptomic signatures
b) Phospho-RET and other phospho-proteins (phospho-proteomics)
c) Phospho-RET and metabolomic profiles
Visualize correlation networks using force-directed layouts
Identify modules of co-regulated biomolecules
Pathway enrichment integration:
Map phospho-RET levels to known signaling pathways
Perform gene set enrichment analysis (GSEA) on genes correlating with phospho-RET
Integrate with pathway databases (KEGG, Reactome, WikiPathways)
Identify pathway-level consequences of RET activation
Causal network inference:
Apply Bayesian network algorithms to infer directionality
Test causal relationships with intervention data (RET inhibitors, knockdown)
Build predictive models of downstream effects of RET activation
Validate key network connections experimentally
Visualization and representation:
Create multi-level network visualizations
Develop interactive dashboards for exploring relationships
Implement dimensionality reduction (PCA, t-SNE) for sample clustering
Generate publication-quality figures showing key associations
This analytical framework has been applied to understand RET signaling in the context of neural development and cancer biology, revealing novel connections between RET activation and broader cellular processes .
For rigorous quantification and statistical analysis of RET antibody signals in tissue microarrays (TMAs), implement this methodological framework: