MAPRE2 Antibody

What is MAPRE2 and what are its key cellular functions?

MAPRE2, also known as EB2, belongs to the end-binding (EB) protein family that includes EB1, EB2, and EB3. These proteins share high homology with a notable exception of a 43 amino acid segment at the N-terminus of EB2 not present in other family members . MAPRE2 binds to the growing plus-ends of microtubules via its N-terminal domain and interacts with other proteins through its C-terminus .

MAPRE2 plays critical roles in:

• Regulating microtubule dynamics and stability

• Maintaining spindle symmetry during mitosis

• Contributing to cell polarity and adherens junction formation

• Potentially influencing sodium channel localization in cardiomyocytes

• Controlling microtubule growth velocity and distance

Recent research has demonstrated that MAPRE2 loss-of-function leads to altered microtubule dynamics, with knockdown experiments showing 1.11-1.26 fold increases in microtubule growth velocity and 1.22-1.34 fold increases in growth distance in human iPSC-derived cardiomyocytes .

What are the optimal dilutions for MAPRE2 antibody in different applications?

The optimal dilution of MAPRE2 antibody varies depending on the specific application and the antibody source. Based on current commercial antibodies, the following dilutions are recommended:

It is important to note that these are general guidelines, and optimal dilutions should be determined empirically for each specific experimental system . For Western blotting applications, validation has been confirmed in various cell lines including K-562 and Jurkat cells . For IHC applications, positive detection has been reported in human stomach tissue, with suggested antigen retrieval using TE buffer pH 9.0 or alternatively with citrate buffer pH 6.0 .

How should MAPRE2 antibody be stored to maintain its activity?

To maintain optimal activity of MAPRE2 antibody, the following storage conditions are recommended:

• Store at -20°C for long-term preservation

• Avoid repeated freeze-thaw cycles that can degrade antibody quality

• For commercial preparations in glycerol buffer (e.g., PBS with 0.02% sodium azide and 50% glycerol, pH 7.4), aliquoting is generally unnecessary for -20°C storage

• The antibody remains stable for approximately 12 months after shipment when stored properly

For short-term usage, refrigeration (4°C) is acceptable, but returning to -20°C is recommended for periods longer than a week to prevent degradation of the antibody's binding capacity.

How can I validate the specificity of a MAPRE2 antibody for my research?

Validating antibody specificity is crucial for ensuring reliable research results. For MAPRE2 antibody, consider implementing the following validation approaches:

• Positive and negative controls:

  • Use cell lines with known MAPRE2 expression (e.g., K-562, Jurkat cells) as positive controls

  • Implement MAPRE2 knockdown or knockout models as negative controls, similar to those described in recent publications

• Western blot analysis:

  • The expected molecular weight of MAPRE2 is approximately 29-37 kDa (calculated), but the observed molecular weight is typically around 32-42 kDa

  • Verify a single band at the appropriate molecular weight

  • Be aware that post-translational modifications may result in slight variations from the expected size

• Cross-reactivity testing:

  • Test antibody on tissues/cells from different species if working across species boundaries

  • Verify reactivity with human and mouse samples as documented in product information

• Immunoprecipitation followed by mass spectrometry:

  • For the most rigorous validation, perform IP-MS to confirm specific binding to MAPRE2

Researchers should be aware that the observed molecular weight of MAPRE2 in Western blotting may not always match the calculated weight due to various factors that affect protein mobility during electrophoresis, including post-translational modifications .

What are the recommended protocols for detecting MAPRE2 in different cellular compartments?

MAPRE2 primarily localizes to microtubule plus-ends but can also be found in other cellular compartments depending on the cell cycle stage and cellular context. Here are optimized protocols for different cellular compartment analyses:

• Microtubule plus-ends (primary localization):

  • Fix cells with 4% paraformaldehyde (10 minutes at room temperature)

  • Permeabilize with 0.1% Triton X-100 (5 minutes)

  • Block with 5% BSA in PBS (1 hour)

  • Incubate with MAPRE2 antibody (1:50-1:500 dilution, overnight at 4°C)

  • Co-stain with α-tubulin antibody to visualize microtubules

  • Use high-resolution confocal microscopy for visualization

• Whole-cell distribution analysis:

  • For live-cell imaging, use EB3-GFP to track microtubule plus-ends as performed in recent studies

  • Employ microtubule plus-end tracking to analyze MAPRE2 dynamics, measuring:

    • Microtubule growth velocity (normal range: ~8.05 μm/min)

    • Microtubule growth distance (normal range: ~5.76 μm)

• Subcellular fractionation approach:

  • Separate cytoskeletal, cytoplasmic, and nuclear fractions

  • Run Western blot on each fraction

  • MAPRE2 should be primarily detected in the cytoskeletal fraction

  • Include appropriate compartment-specific markers as controls

For all protocols, it's essential to include proper controls and consider using the recommended antigen retrieval methods (TE buffer pH 9.0 or citrate buffer pH 6.0) for fixed tissue samples .

How does MAPRE2 antibody performance compare across different experimental models?

MAPRE2 antibody performance can vary across experimental models due to factors such as protein expression levels, accessibility of epitopes, and species-specific differences. Based on available data:

When transitioning between model systems, it is advisable to:

• Perform pilot experiments to determine optimal conditions

• Consider using multiple antibodies targeting different epitopes of MAPRE2

• Include appropriate positive and negative controls specific to each model system

• Be aware that some experimental models may require specialized fixation or antigen retrieval methods

What approaches can resolve discrepancies in MAPRE2 antibody staining patterns?

Researchers occasionally encounter discrepancies in MAPRE2 staining patterns. Here are methodological approaches to resolve such issues:

• Epitope masking issues:

  • Test different fixation protocols (4% PFA, methanol, or acetone)

  • Optimize antigen retrieval methods (try both TE buffer pH 9.0 and citrate buffer pH 6.0)

  • Extend permeabilization time for dense tissues or adjust detergent concentration

• Signal specificity concerns:

  • Implement blocking with 5% BSA or normal serum from the same species as the secondary antibody

  • Include a peptide competition assay using the immunogen peptide

  • Validate with genetic knockdown/knockout controls as demonstrated in recent studies

• Inconsistent results between techniques:

  • For discrepancies between IF and WB results, consider native vs. denatured protein conformations

  • If subcellular localization differs from expectations, co-stain with organelle markers

  • Consider post-translational modifications that might affect epitope recognition

• Cross-validation strategy:

  • Use multiple antibodies targeting different regions of MAPRE2

  • Complement antibody-based detection with mRNA analysis (qPCR or RNA-seq)

  • Consider tagged MAPRE2 expression systems for validation

Recent research highlights that alterations in microtubule dynamics can affect MAPRE2 localization, with knockdown experiments showing microtubules become straighter and sometimes bundled, potentially affecting staining patterns .

How can MAPRE2 antibodies be used to study its role in cardiac conduction disorders?

Recent research has implicated MAPRE2 in cardiac conduction disorders, particularly Brugada syndrome (BrS). Here's a methodological approach to investigate this connection:

• Cardiac tissue immunostaining protocol:

  • Fix cardiac tissue sections with 4% paraformaldehyde

  • Perform antigen retrieval with TE buffer pH 9.0

  • Block with 5% normal goat serum

  • Incubate with MAPRE2 antibody (1:50-1:200) overnight at 4°C

  • Co-stain with markers for:

    • Sodium channels (Nav1.5)

    • Adherens junctions (N-cadherin)

    • Microtubules (α-tubulin and detyrosinated tubulin)

• Functional studies in cardiac models:

  • Create MAPRE2 knockdown or knockout models in cardiac cell lines or animal models

  • Assess:

    • Sodium current density using patch-clamp techniques

    • Action potential upstroke velocity (Vmax)

    • Conduction velocity via voltage mapping

    • ECG parameters, particularly QRS duration

• Mechanistic investigation workflow:

  • Examine microtubule dynamics using plus-end tracking

  • Quantify the ratio of detyrosinated tubulin to total α-tubulin

  • Assess adherens junction organization and N-cadherin localization

  • Correlate these findings with sodium channel function

Recent work has shown that MAPRE2 loss-of-function in zebrafish models led to a 25% decrease in the fraction of detyrosinated tubulin in ventricular cells, associated with decreased sodium current density, prolonged QRS interval, and arrhythmias . These findings suggest MAPRE2 antibodies can be valuable tools for investigating the microtubule-dependent regulation of cardiac conduction.

How should researchers address multiple bands in Western blots using MAPRE2 antibodies?

Multiple bands in Western blots can complicate data interpretation. Here's a systematic approach to address this issue with MAPRE2 antibodies:

• Common causes of multiple bands:

  • Post-translational modifications of MAPRE2

  • Alternative splicing (MAPRE2 is known to have multiple transcript variants)

  • Cross-reactivity with other EB family members (EB1, EB3)

  • Non-specific binding or sample degradation

• Validation approaches:

  • Run MAPRE2 knockout/knockdown samples alongside wild-type to identify specific bands

  • Use phosphatase treatment to remove phosphorylation if multiple bands are due to phosphorylated forms

  • Perform immunoprecipitation followed by mass spectrometry to identify proteins in each band

  • Test multiple antibodies targeting different epitopes of MAPRE2

• Technical optimization:

  • Adjust antibody concentration (try a range from 1:500 to 1:2000)

  • Optimize blocking conditions (5% non-fat milk vs. 5% BSA)

  • Increase wash duration and volume

  • For suspected cross-reactivity, pre-absorb antibody with recombinant related proteins

Product information indicates that the calculated molecular weight of MAPRE2 is 29-37 kDa, but the observed molecular weight is typically 32-42 kDa . Researchers should be aware that "different modified forms at the same time may result in multiple bands being detected on the membrane" .

What controls are essential when using MAPRE2 antibodies in studies of microtubule dynamics?

When studying microtubule dynamics with MAPRE2 antibodies, implementing proper controls is critical for data validity:

• Essential experimental controls:

  • Positive control: Include cells with known high MAPRE2 expression (e.g., rapidly dividing cells)

  • Negative control:

    • MAPRE2 knockdown/knockout cells (validated by Western blot)

    • Primary antibody omission control

  • Treatment controls: Include known microtubule-altering agents:

    • Nocodazole (depolymerizes microtubules)

    • Taxol (stabilizes microtubules)

    • Compare these to MAPRE2 manipulation effects

• Co-localization controls:

  • Co-stain with established microtubule markers (α-tubulin)

  • Include markers for stable microtubules (detyrosinated/Glu-tubulin)

  • Use plus-end tracking proteins (EB1 or EB3-GFP) for dynamic studies

• Quantification standards:

  • For microtubule growth velocity measurements, calibrate using standard cell lines

  • Normal growth velocity in control cells: ~8.05 μm/min

  • Normal growth distance in control cells: ~5.76 μm

• Technical validation:

  • For live imaging, include photobleaching controls

  • For fixed specimens, include autofluorescence controls

  • When measuring dynamics, establish baseline parameters in standard conditions

Recent research demonstrated that MAPRE2 knockdown resulted in measurable changes to microtubule dynamics, with growth velocity increasing to 8.91-10.17 μm/min and growth distance increasing to 7.03-7.69 μm compared to controls . These parameters provide excellent reference points for validation studies.

How can researchers distinguish between specific MAPRE2 effects and general microtubule perturbations?

Distinguishing specific MAPRE2-mediated effects from general microtubule alterations requires careful experimental design:

• Comparative analysis strategy:

  • Compare MAPRE2 knockdown/knockout with:

    • Other EB protein family knockdowns (EB1, EB3)

    • General microtubule-targeting drugs (nocodazole, taxol)

    • Other microtubule plus-end tracking protein manipulations

  • Analyze for unique phenotypic signatures specific to MAPRE2 loss

• Rescue experiments:

  • Perform rescue experiments with:

    • Wild-type MAPRE2

    • MAPRE2 with mutated domains (N-terminal vs. C-terminal)

    • Other EB family members

  • A successful rescue only with wild-type MAPRE2 confirms specificity

• Domain-specific approach:

  • Target specific functional domains of MAPRE2 (e.g., the unique 43 amino acid segment)

  • Use domain-specific antibodies or constructs

  • Assess whether phenotypes match global MAPRE2 loss

• Downstream pathway analysis:

  • Examine known MAPRE2-specific binding partners

  • Assess post-translational modifications specific to MAPRE2 function

  • Investigate cellular processes particularly sensitive to MAPRE2 (e.g., adherens junctions)

Recent research demonstrated that MAPRE2 loss-of-function specifically affected detyrosinated tubulin levels and N-cadherin localization at adherens junctions . Furthermore, knockdown of TTL (tubulin tyrosine ligase) rescued both the detyrosination defect and functional consequences in ventricular cells, providing strong evidence for a MAPRE2-specific mechanism rather than general microtubule disruption .

How can MAPRE2 antibodies help elucidate differences between EB family proteins?

MAPRE2 (EB2) belongs to a family of three end-binding proteins, including EB1 and EB3, which share significant homology but appear to have distinct functions. MAPRE2 antibodies can be instrumental in distinguishing these roles:

• Comparative localization studies:

  • Use specific antibodies against each EB protein in co-localization studies

  • Quantify relative distribution patterns at microtubule plus-ends

  • Compare subcellular distribution across cell cycle phases

  • Pay particular attention to the unique 43 amino acid segment in MAPRE2's N-terminus not present in other EB proteins

• Interactome mapping approach:

  • Perform immunoprecipitation with specific antibodies against each EB protein

  • Couple with mass spectrometry to identify unique binding partners

  • Create comparative interactome maps to highlight MAPRE2-specific interactions

  • Validate key interactions with co-immunoprecipitation and proximity ligation assays

• Functional replacement experiments:

  • Knockdown MAPRE2 and attempt rescue with EB1 or EB3

  • Identify functions that can or cannot be rescued by other family members

  • Use domain-swap experiments to identify critical regions for specific functions

• Tissue-specific expression analysis:

  • Use antibodies to map expression patterns of all three EB proteins across tissues

  • Identify tissues with differential expression patterns

  • Correlate with tissue-specific functions (e.g., cardiac conduction for MAPRE2)

Research has shown that while EB1 regulates sodium channel density in cardiomyocytes and targeted delivery of connexin-43 to intercellular junctions, MAPRE2 appears to have distinct functions, particularly in adherens junction formation and stability .

What methodological approaches can detect MAPRE2 post-translational modifications and their functional consequences?

Post-translational modifications (PTMs) of MAPRE2 may significantly affect its function. Here are methodological approaches to study these modifications:

• PTM-specific detection strategy:

  • Use phospho-specific antibodies for known or predicted phosphorylation sites

  • Employ treatment with phosphatases, deubiquitinases, or other PTM-removing enzymes before Western blotting

  • Compare migration patterns before and after treatment

  • Combine with mass spectrometry to identify specific modification sites

• Functional correlation experiments:

  • Create point mutations at potential PTM sites

  • Assess functional consequences on:

    • Microtubule binding and dynamics

    • Protein-protein interactions

    • Subcellular localization

    • Physiological functions (e.g., cardiac conduction)

• Cell cycle and stimulation-dependent analysis:

  • Examine changes in MAPRE2 PTMs across cell cycle phases

  • Assess modifications after cellular stimulation (e.g., growth factors, stress)

  • Correlate with changes in microtubule dynamics

• PTM crosstalks investigation:

  • Study how MAPRE2 modifications affect tubulin post-translational modifications

  • Particularly focus on detyrosination, which was shown to be decreased by 25% in MAPRE2 knockout models

  • Investigate whether rescue of tubulin detyrosination (e.g., through TTL knockdown) affects MAPRE2 modifications

Recent research has demonstrated that MAPRE2 loss-of-function affects the post-translational modification of tubulin, specifically decreasing the fraction of detyrosinated tubulin, which has downstream effects on adherens junctions and cardiac conduction . This suggests a complex interplay between MAPRE2 and the post-translational modification machinery of the cell.

How can super-resolution microscopy enhance MAPRE2 localization studies beyond conventional techniques?

Super-resolution microscopy offers significant advantages for studying MAPRE2 localization and dynamics compared to conventional microscopy techniques:

• Methodological optimization for super-resolution techniques:

  • STORM/PALM approach:

    • Use photoconvertible fluorophore-conjugated secondary antibodies

    • Optimize buffer conditions (oxygen scavenging system with glucose oxidase)

    • Adjust laser power and acquisition parameters for optimal blinking behavior

    • Achieve 20-30 nm resolution compared to ~250 nm in conventional microscopy

  • STED microscopy protocol:

    • Select appropriate fluorophores with good depletion properties (e.g., ATTO647N)

    • Optimize depletion laser power and timing

    • Use appropriate mounting media to reduce photobleaching

    • Achieve 30-80 nm resolution for detailed microtubule plus-end structure

  • SIM methodology:

    • Optimize sample preparation to minimize background

    • Adjust acquisition parameters for each fluorophore

    • Apply appropriate reconstruction algorithms

    • Achieve 100-120 nm resolution with minimal processing artifacts

• Advanced co-localization analysis:

  • Perform precise distance measurements between MAPRE2 and:

    • Other plus-end tracking proteins

    • Adherens junction components (N-cadherin)

    • Sodium channels in cardiomyocytes

  • Use coordinate-based co-localization analysis rather than pixel-based methods

  • Implement cluster analysis to identify functional domains at microtubule plus-ends

• Dynamic structural analysis:

  • Combine super-resolution with live-cell imaging techniques

  • Track individual MAPRE2 molecules at microtubule plus-ends

  • Measure recruitment and dissociation rates with single-molecule precision

  • Correlate with microtubule growth parameters measured in recent studies

Super-resolution approaches would be particularly valuable for clarifying the relationship between MAPRE2, adherens junctions, and sodium channels in cardiomyocytes, which was inferred but not directly visualized in recent zebrafish studies due to antibody limitations .