WDL7 Antibody

What is WDL7 and what is its biological function?

WDL7 (WAVE-DAMPENED2-LIKE7) is a microtubule-stabilizing protein that plays a critical role in plant stress responses. It functions primarily by binding to and bundling microtubules, protecting them from depolymerization under stress conditions. In plant physiology, WDL7 has been identified as a key negative regulator of stomatal closure in response to drought stress and abscisic acid (ABA) treatment. Research has demonstrated that WDL7 protein degradation through the ubiquitin-26S proteasome pathway is necessary for ABA-induced microtubule disassembly and subsequent stomatal closure . This mechanism represents an important adaptation for plants under drought conditions, as the regulation of stomatal aperture helps control water loss through transpiration.

How do WDL7 antibodies differ from other antibodies against microtubule-associated proteins?

WDL7 antibodies specifically target epitopes unique to the WDL7 protein, distinguishing it from other members of the WVD2/WDL family and other microtubule-associated proteins (MAPs). Unlike antibodies against structural components like tubulin, WDL7 antibodies recognize a regulatory protein whose levels change dynamically during stress responses. Commercial anti-WDL7 antibodies, such as those from Atlas Antibodies, are polyclonal antibodies developed against human WDL7 and validated for multiple applications including immunohistochemistry (IHC), immunocytochemistry-immunofluorescence (ICC-IF), and Western blotting (WB) . For plant research, custom antibodies against plant WDL7 may be necessary, as the function and regulation of WDL7 have been extensively studied in plant models such as Arabidopsis thaliana.

What are the key differences between WDL7 and other members of the WVD2/WDL family?

The WVD2/WDL family includes several members with functional similarities in microtubule regulation but distinct physiological roles:

Research has demonstrated that WDL7 is unique among these family members in being specifically degraded through the 26S proteasome pathway during ABA-induced stomatal closure . This degradation is mediated by the E3 ligase MREL57, which interacts with, ubiquitinates, and degrades WDL7 in response to ABA. This regulatory mechanism is not shared by the closely related WDL3, despite its expression in guard cells.

How can WDL7 antibodies be used to study plant responses to environmental stress?

WDL7 antibodies serve as powerful tools for investigating plant stress response mechanisms, particularly drought stress adaptation. Methodological approaches include:

• Protein level analysis: Western blotting with WDL7 antibodies can track changes in WDL7 protein abundance during drought stress or ABA treatment. Research has shown that WDL7-GFP protein levels decrease significantly after ABA treatment, and this decrease is blocked by the proteasome inhibitor MG132 .

• Subcellular localization studies: Immunofluorescence with WDL7 antibodies can visualize the distribution of WDL7 on microtubules in guard cells. Studies have confirmed that WDL7-GFP colocalizes with microtubules in guard cells, and this localization pattern changes during ABA treatment .

• Protein interaction analysis: Co-immunoprecipitation using WDL7 antibodies can identify proteins that interact with WDL7 during stress responses. Research has demonstrated that the E3 ligase MREL57 interacts with WDL7, and this interaction is enhanced by ABA treatment .

• Kinetic studies: Time-course experiments using WDL7 antibodies can reveal the dynamics of WDL7 degradation in response to ABA. In vivo time-course analysis has shown that degradation of WDL7-GFP temporally precedes microtubule disassembly and stomatal closure .

These approaches have revealed that the degradation of WDL7 is a key early event in the stomatal closure response to drought stress.

What experimental techniques can benefit from using WDL7 antibodies?

WDL7 antibodies can enhance multiple experimental techniques in plant cell biology and stress physiology research:

Research has demonstrated that cell-free degradation assays with recombinant WDL7 protein can effectively monitor its ABA-induced degradation. When purified MBP-WDL7-FLAG protein was incubated with total protein extracted from ABA-treated plants, degradation was significantly increased compared to untreated controls, and this degradation was blocked by MG132 .

How can WDL7 antibodies contribute to understanding the MREL57-WDL7 regulatory module?

The MREL57-WDL7 module represents an important UPS-dependent pathway that regulates microtubule disassembly and stomatal closure. WDL7 antibodies can be instrumental in elucidating this regulatory mechanism:

• Verification of protein-protein interactions: Co-immunoprecipitation with WDL7 antibodies has confirmed the physical interaction between MREL57 and WDL7 in plant cells .

• Monitoring ubiquitination: Western blotting with WDL7 antibodies following immunoprecipitation can detect ubiquitinated forms of WDL7. Research has shown that MREL57 ubiquitinates WDL7, and this effect is enhanced by ABA treatment .

• Comparative analysis in mutants: Western blot analysis using WDL7 antibodies has demonstrated that ABA-induced degradation of WDL7 is impaired in mrel57 mutants, confirming MREL57's role in this process .

• Functional reconstitution: In vitro ubiquitination assays incorporating purified MREL57 and WDL7, detected with WDL7 antibodies, have characterized the biochemical mechanism of WDL7 ubiquitination.

• Genetic interaction studies: Western blotting with WDL7 antibodies in various genetic backgrounds (wild-type, mrel57 mutants, WDL7 overexpression lines) has demonstrated that the insensitivity of mrel57 mutants to ABA can be restored when WDL7 expression is decreased, confirming that MREL57 acts through WDL7 .

These approaches collectively establish that MREL57 targets WDL7 for degradation to promote microtubule disassembly during ABA-induced stomatal closure.

What are the optimal protocols for using WDL7 antibodies in Western blotting?

For optimal Western blotting results with WDL7 antibodies, researchers should consider the following methodological approach:

• Sample preparation:

  • Homogenize plant tissue in extraction buffer containing protease inhibitors

  • For studying WDL7 degradation, prepare parallel samples with and without proteasome inhibitor MG132

  • For ABA treatment studies, collect samples at multiple time points (0, 15, 30, 60 minutes) after treatment

• Protein separation and transfer:

  • Use 10-12% SDS-PAGE gels for optimal resolution of WDL7

  • Include positive controls (recombinant WDL7) and negative controls (wdl7 mutant samples)

  • Transfer proteins to PVDF membrane at 100V for 1 hour or 30V overnight at 4°C

• Antibody incubation:

  • Block membranes with 5% non-fat dry milk or BSA in TBST

  • Incubate with primary WDL7 antibody at manufacturer's recommended dilution (typically 1:1000)

  • For plant samples, validate antibody specificity using wdl7 mutant tissue as negative control

• Detection and quantification:

  • Develop using ECL substrate or fluorescent secondary antibodies

  • For quantitative analysis, normalize WDL7 signals to loading controls

  • Compare WDL7 levels between different treatments and genotypes

Research has shown that WDL7-GFP protein levels decrease significantly after ABA treatment, and this decrease is blocked by MG132, confirming degradation through the 26S proteasome pathway . When analyzing such degradation patterns, ensure that equal amounts of total protein are loaded for each sample to accurately quantify relative changes in WDL7 abundance.

How should researchers optimize immunofluorescence protocols for WDL7 localization in plant cells?

Immunofluorescence detection of WDL7 in plant cells requires specific considerations due to the unique challenges of plant sample preparation:

• Sample preparation for guard cell imaging:

  • Prepare epidermal peels to access guard cells

  • Fix samples in 4% paraformaldehyde in PME buffer (50 mM PIPES, 5 mM MgSO4, 5 mM EGTA, pH 7.0)

  • For microtubule preservation, include taxol (10 μM) during fixation

• Cell wall digestion and permeabilization:

  • Treat with cell wall degrading enzymes (1% cellulase, 0.5% macerozyme)

  • Permeabilize with 0.5% Triton X-100

  • For comparative studies, prepare samples with different ABA treatment durations

• Antibody incubation and detection:

  • Block with 3% BSA to reduce non-specific binding

  • Incubate with WDL7 antibody at optimized dilution (typically 1:100 to 1:500)

  • For co-localization studies, include anti-tubulin antibody or use plants expressing fluorescent tubulin

• Controls and validation:

  • Include negative controls (secondary antibody only)

  • Use wdl7 mutant tissues as specificity controls

  • Compare with fluorescent protein-tagged WDL7 localization patterns

Research using WDL7-GFP transgenic plants has shown that WDL7 colocalizes with microtubules in guard cells . This colocalization can serve as a reference for validating immunofluorescence results with WDL7 antibodies. For studying ABA-induced changes, prepare separate samples treated with ABA for different durations (0, 10, 20, 30, 40 minutes) before fixation to capture the dynamic changes in WDL7 localization.

What considerations should be made when using WDL7 antibodies for co-immunoprecipitation studies?

When planning co-immunoprecipitation (co-IP) experiments with WDL7 antibodies to study protein-protein interactions, researchers should optimize several parameters:

• Lysate preparation for maintaining interactions:

  • Use non-denaturing lysis buffers to preserve protein-protein interactions

  • Include protease inhibitors to prevent degradation

  • For studying ABA-induced interactions, prepare lysates from both control and ABA-treated samples

  • Consider including phosphatase inhibitors to preserve phosphorylation states

• Immunoprecipitation conditions:

  • Pre-clear lysates with protein A/G beads to reduce non-specific binding

  • Incubate cleared lysates with WDL7 antibody overnight at 4°C

  • For plant samples, optimize antibody amounts (typically 2-5 μg per mg of total protein)

  • Perform thorough washes to remove non-specific interactions

• Essential controls:

  • Input control (5-10% of starting lysate)

  • IgG control (non-specific antibody of same isotype)

  • Lysate from wdl7 mutant plants as negative control

  • For ABA response studies, include samples treated with both ABA and MG132

• Detection strategies:

  • Western blotting with antibodies against potential interaction partners

  • For novel interactions, consider mass spectrometry analysis

Research has established that the E3 ligase MREL57 interacts with WDL7, and this interaction is enhanced by ABA treatment . When designing co-IP experiments to study such dynamic interactions, it's crucial to prepare samples under different conditions (±ABA, ±proteasome inhibitors) to capture the physiologically relevant interactions that may be transient due to protein degradation.

How can researchers troubleshoot non-specific binding or weak signals when using WDL7 antibodies?

Non-specific binding and weak signals are common challenges when working with antibodies in plant systems. For WDL7 antibodies, consider these methodological solutions:

When studying ABA-induced degradation of WDL7, it's important to note that research has demonstrated significant decreases in WDL7-GFP levels after ABA treatment . Therefore, weak signals in ABA-treated samples may reflect actual biological degradation rather than technical issues. Always include appropriate controls, such as samples treated with proteasome inhibitors (MG132) that should prevent ABA-induced degradation of WDL7.

What control experiments should be included when validating WDL7 antibody specificity?

Proper validation of WDL7 antibody specificity is crucial for generating reliable research data. The following methodological controls are recommended:

• Genetic controls:

  • Test the antibody in wdl7 knockout/knockdown mutants (should show reduced or no signal)

  • Compare signal in WDL7 overexpression lines (should show increased signal)

  • Examine cross-reactivity with other wdl family mutants

• Molecular controls:

  • Perform peptide competition assays by pre-incubating antibody with immunizing peptide

  • Test reactivity against recombinant WDL7 protein

  • Compare reactivity with closely related WDL3 and WDL4 proteins

• Technical controls:

  • Include secondary antibody-only controls

  • Use isotype control antibodies (same species and isotype but unrelated specificity)

  • Compare results from multiple antibodies against different regions of WDL7 if available

• Validation approaches:

  • Compare antibody staining patterns with fluorescent protein-tagged WDL7 localization

  • Verify detected protein size matches predicted molecular weight

  • Cross-validate with mRNA expression data or reporter gene constructs

Research with WDL7-GFP transgenic plants has established patterns of WDL7 expression and localization . These can serve as references for validating the specificity of WDL7 antibodies in different experimental contexts. For plant research specifically, it's important to consider potential cross-reactivity with other WVD2/WDL family members, as they share sequence similarity.

How should researchers address variability in WDL7 detection across different plant tissues or experimental conditions?

Variability in WDL7 detection can arise from biological differences in expression or technical factors. To address this methodological challenge:

• For biological variability:

  • Standardize plant growth conditions (light, temperature, humidity)

  • Use plants of consistent age and developmental stage

  • Consider tissue-specific expression patterns when comparing results

  • Note that GUS staining has shown WDL7 is widely expressed throughout plants

• For technical variability:

  • Develop tissue-specific extraction protocols optimized for different plant tissues

  • Include appropriate internal loading controls

  • Normalize WDL7 signals to total protein or housekeeping proteins

  • Perform sufficient biological and technical replicates (minimum n=3)

• For stress-induced changes:

  • Standardize stress application methods and timing

  • Include time-course studies to capture transient changes

  • Use appropriate statistical methods to analyze variability

  • Note that research has shown WDL7 protein levels, but not transcript levels, decrease after ABA treatment

• For comparing results across experiments:

  • Include common reference samples across experiments

  • Use quantitative methods with appropriate standard curves

  • Report relative changes rather than absolute values

Research has demonstrated that while WDL7 transcript levels remain largely similar after ABA treatment, protein levels decrease significantly . This highlights the importance of examining both transcriptional and post-translational regulation when studying WDL7 function, and explains why protein-level detection might show greater variability than transcript analysis.

How can researchers use WDL7 antibodies to investigate post-translational modifications of WDL7?

Post-translational modifications (PTMs) of WDL7, particularly ubiquitination, play crucial roles in regulating its function and stability. Advanced methodological approaches include:

• For ubiquitination studies:

  • Immunoprecipitate WDL7 using specific antibodies, then probe with anti-ubiquitin antibodies

  • Compare ubiquitination patterns between wild-type plants and mrel57 mutants

  • Use tandem ubiquitin binding entities (TUBEs) to enrich ubiquitinated proteins

  • Employ mass spectrometry to identify specific ubiquitination sites

  • Research has demonstrated that MREL57 ubiquitinates WDL7, and this effect is enhanced by ABA

• For studying phosphorylation:

  • Use phospho-specific antibodies if available

  • Employ Phos-tag gels to separate phosphorylated from non-phosphorylated forms

  • Use λ-phosphatase treatment as a control to confirm phosphorylation

  • The relationship between phosphorylation and ubiquitination of WDL7 remains to be investigated

• For temporal dynamics of modifications:

  • Perform time-course experiments after ABA treatment

  • Use cell-free degradation assays with recombinant components

  • Research has shown that degradation of WDL7-GFP temporally precedes microtubule disassembly and stomatal closure

• For functional significance:

  • Correlate modification patterns with microtubule binding activity

  • Test modified and unmodified forms for differential interaction with binding partners

  • Generate transgenic plants expressing modification-resistant forms of WDL7

Cell-free degradation assays have demonstrated that MBP-WDL7-FLAG protein degradation is significantly increased in extracts from ABA-treated plants compared to untreated controls, and this degradation is blocked by MG132 . This experimental approach provides a powerful tool for studying the biochemical mechanisms of WDL7 modification and degradation.

What approaches can be used to study the interplay between WDL7 and other microtubule-associated proteins in stress responses?

The interaction between WDL7 and other microtubule-associated proteins (MAPs) represents a complex regulatory network governing cytoskeletal dynamics during stress responses. Methodological approaches include:

• Protein-protein interaction studies:

  • Perform co-immunoprecipitation with WDL7 antibodies followed by mass spectrometry

  • Use yeast two-hybrid or split-GFP assays to screen for direct interactions

  • Employ bimolecular fluorescence complementation (BiFC) to confirm interactions in planta

  • Research has demonstrated that WDL7 colocalizes with microtubules in guard cells

• Functional relationship studies:

  • Generate double mutants between wdl7 and other MAP genes

  • Compare microtubule behaviors in single and double mutants

  • Perform epistasis analysis by examining phenotypes of overexpression lines

  • Research has shown that overexpression of WDL7 renders microtubules less sensitive to oryzalin-induced depolymerization

• Competitive binding studies:

  • Test whether WDL7 competes with or enhances binding of other MAPs to microtubules

  • Use in vitro reconstitution with purified components

  • Perform microtubule co-sedimentation assays with combinations of MAPs

  • Research has demonstrated that His-WDL7-GFP fusion protein directly binds to and bundles paclitaxel-stabilized microtubules

• Microtubule stability assays:

  • Compare microtubule stabilization by WDL7 in the presence/absence of other MAPs

  • Use cold or dilution treatments to induce microtubule depolymerization

  • Research has shown that WDL7 stabilizes microtubules against cold- and dilution-induced depolymerization

These approaches can help elucidate how WDL7 functions within the broader network of MAPs to regulate microtubule dynamics during stress responses, providing insights into cytoskeletal reorganization mechanisms.

How can researchers investigate the mechanisms by which ABA treatment leads to WDL7 degradation?

Understanding the signaling pathway from ABA perception to WDL7 degradation represents an important area of research. Methodological approaches include:

• Genetic analysis:

  • Screen ABA signaling mutants for altered WDL7 degradation

  • Test whether canonical ABA signaling components (PYR/PYL/RCAR receptors, PP2C phosphatases, SnRK2 kinases) affect WDL7 stability

  • Examine whether transcription factors involved in ABA responses regulate MREL57 expression

  • Research has established that the E3 ligase MREL57 mediates WDL7 degradation in response to ABA

• Biochemical analysis:

  • Investigate phosphorylation of WDL7 or MREL57 in response to ABA

  • Test whether ABA-activated kinases directly modify WDL7 or MREL57

  • Examine whether ABA affects the intrinsic ubiquitination activity of MREL57

  • Research has shown that ABA enhances the interaction between MREL57 and WDL7

• Temporal analysis:

  • Perform detailed time-course studies of WDL7 degradation after ABA treatment

  • Compare the kinetics of MREL57-WDL7 interaction with WDL7 degradation

  • Determine the time interval between ABA application and increased MREL57-WDL7 interaction

  • Research has demonstrated that degradation of WDL7-GFP temporally precedes microtubule disassembly and stomatal closure

• Spatial analysis:

  • Examine cell-type specificity of ABA-induced WDL7 degradation

  • Compare WDL7 degradation in guard cells versus other cell types

  • Research has shown that ABA-induced degradation of WDL7-GFP occurs in guard cells but not in pavement or root epidermal cells

These approaches can help elucidate the signaling pathway connecting ABA perception to WDL7 degradation, providing insights into the molecular mechanisms of stress-induced cytoskeletal reorganization in plants.

What are the remaining knowledge gaps in understanding WDL7 function and regulation?

Despite significant advances in understanding WDL7 function, several important questions remain unanswered:

• Structural basis of function:

  • The specific domains of WDL7 responsible for microtubule binding and bundling have not been fully characterized

  • The structural changes that occur upon post-translational modifications remain unclear

  • The precise ubiquitination sites on WDL7 targeted by MREL57 have not been mapped

• Signaling integration:

  • How ABA signaling components connect to MREL57 activation remains to be elucidated

  • The potential crosstalk between drought stress and other environmental signals in regulating WDL7 is not well understood

  • The role of phosphorylation in modulating WDL7 stability or activity requires investigation

• Evolutionary perspectives:

  • The conservation of the MREL57-WDL7 regulatory module across plant species has not been systematically examined

  • The specialization of WDL family members for different cellular functions throughout plant evolution requires further study

  • The presence of similar regulatory mechanisms in non-plant systems remains unexplored

• Methodological challenges:

  • Development of phospho-specific antibodies for WDL7 would enable better analysis of its regulation

  • Improved tools for studying protein degradation dynamics in living cells are needed

  • Methods for manipulating WDL7 stability with temporal and spatial precision could advance understanding of its function

Addressing these knowledge gaps will require interdisciplinary approaches combining structural biology, biochemistry, cell biology, genetics, and evolutionary analysis, supported by advanced imaging and analytical techniques.

How might emerging technologies enhance the utility of WDL7 antibodies in plant science research?

Emerging technologies promise to expand the capabilities of WDL7 antibody-based research:

• Advanced imaging technologies:

  • Super-resolution microscopy can visualize WDL7-microtubule interactions at nanoscale resolution

  • Lattice light-sheet microscopy enables long-term 3D imaging of WDL7 dynamics with minimal phototoxicity

  • Expansion microscopy physically enlarges specimens for improved resolution

  • These techniques could reveal previously undetectable aspects of WDL7 localization and dynamics

• Single-cell approaches:

  • Single-cell proteomics can quantify WDL7 levels in individual guard cells

  • Spatial transcriptomics can correlate WDL7 protein with local transcript abundance

  • Microfluidic devices enable high-throughput single-cell analysis

  • These methods could uncover cell-to-cell variation in WDL7 regulation within tissues

• Protein engineering and synthetic biology:

  • Nanobodies or single-chain antibodies against WDL7 could improve penetration and reduce interference

  • Optogenetic control of WDL7 degradation could precisely manipulate microtubule dynamics

  • Engineered WDL7 variants with modified regulatory properties could test mechanistic hypotheses

  • These approaches could enable precise manipulation of WDL7 function in specific cells or tissues

• Computational approaches:

  • Machine learning algorithms can automate analysis of WDL7 localization patterns

  • Molecular dynamics simulations can model WDL7-microtubule interactions

  • Network analysis tools can integrate WDL7 into broader signaling networks

  • These computational methods could help interpret complex datasets and generate testable hypotheses

By leveraging these technologies, researchers can address previously intractable questions about the spatiotemporal dynamics of WDL7 and its precise mechanisms of action in regulating microtubule stability during plant stress responses.