fml2 Antibody

What is FMNL2 and why is it important to study?

FMNL2, also known as FRL3 or FHOD2, belongs to the diaphanous-related formin family and contains GTPase-binding and autoregulatory domains. It functions as a downstream effector of Rho family GTPases . FMNL2 is critical for actin cytoskeleton regulation and is expressed in many tissues. Its dysregulation has been implicated in colorectal cancer, melanoma, and other cancers, making it an important target for cancer research .

The protein plays essential roles in:

• Actin filament assembly and polymerization

• Spindle migration during meiosis

• Organelle distribution and function

• Cell invasion and migration

Which validated applications are available for FMNL2 antibody detection?

FMNL2 antibodies have been validated for several experimental applications:

When selecting an FMNL2 antibody, verify that it has been validated for your specific application and species of interest.

How does FMNL2 regulate actin cytoskeleton dynamics?

FMNL2 regulates actin through multiple mechanisms:

• Direct actin polymerization: As a formin family member, FMNL2 nucleates and elongates unbranched actin filaments

• Protein interactions: FMNL2 physically interacts with other actin regulators, including:

  • Arp2 (part of the Arp2/3 complex)

  • Formin2

  • INF2 (an ER-associated actin regulator)

• Subcellular localization: FMNL2 localizes to the oocyte cortex and spindle periphery, where it regulates specialized actin networks

Research shows that FMNL2 knockdown significantly decreases cytoplasmic actin signals in oocytes (58.25 ± 2.05 vs. 37.92 ± 2.02, p<0.0001) , demonstrating its essential role in actin maintenance.

How can I validate FMNL2 antibody specificity in my experimental model?

Rigorous validation is essential for reliable FMNL2 antibody results:

• siRNA knockdown control: Transfect cells with FMNL2-specific siRNA and confirm signal reduction by Western blot. FMNL2 knockdown should show significantly reduced protein levels (e.g., ~50% reduction as demonstrated in oocyte studies)

• Rescue experiments: Reintroduce FMNL2 expression (via Fmnl2 mRNA microinjection in oocytes or plasmid transfection in cultured cells) and confirm recovery of signal

• Multiple antibody comparison: Use antibodies from different sources or clones targeting different epitopes of FMNL2

• Immunoprecipitation-mass spectrometry: Confirm that the antibody pulls down FMNL2 and its known interaction partners

• Molecular weight verification: Confirm detection at the expected molecular weight (140-150 kDa)

What techniques can I use to study FMNL2's role in organelle dynamics?

Based on research findings, FMNL2 regulates both mitochondrial and ER distribution:

• Organelle tracking with fluorescent markers:

  • Use ER-Tracker Red to visualize ER distribution

  • Use Mito-Tracker Green for mitochondria visualization

  • Track real-time changes following FMNL2 perturbation

• Functional assessments:

  • JC-1 staining to assess mitochondrial membrane potential (MMP)

  • Measure ratio of red/green fluorescence intensity (control: 0.40 vs. FMNL2-KD: 0.21 ± 0.01, p<0.01)

• ER stress markers:

  • Monitor Grp78 and Chop expression by Western blot

  • FMNL2 knockdown increases these markers (Grp78: 1 vs. 1.42 ± 0.12, p<0.05; Chop: 1 vs. 1.53 ± 0.16, p<0.05)

• Organelle distribution quantification:

  • Score normal vs. abnormal ER distribution

  • Quantify mitochondrial clumping patterns

  • FMNL2 knockdown increased abnormal ER distribution (28.91 ± 5.62% vs. 59.64 ± 6.95%, p<0.05)

How do FMNL2 antibodies perform in co-immunoprecipitation experiments?

Co-immunoprecipitation (Co-IP) is valuable for identifying FMNL2's interacting partners:

• Validated interactions: FMNL2 antibodies have successfully co-precipitated:

  • Arp2 (component of actin-nucleating Arp2/3 complex)

  • Formin2 (another actin regulator)

  • INF2 (ER-associated formin that mediates actin polymerization)

• Negative controls: Some proteins do not co-precipitate with FMNL2 despite actin associations:

  • Profilin

  • Fascin

• Reciprocal Co-IP: Confirm interactions by reversing the antibody approach

  • Example: FMNL2 precipitates INF2 and INF2 also precipitates FMNL2

• Buffer considerations: Use buffers that preserve native protein interactions while minimizing non-specific binding

What are the best approaches to study FMNL2's function in meiotic spindle migration?

FMNL2 plays critical roles in oocyte spindle migration and asymmetric division:

• Live-cell imaging: Track spindle movement in real-time after FMNL2 depletion

  • Demonstrate failure of spindle migration to cortex

• Knockdown-rescue experiments:

  • Use Fmnl2 siRNA for protein knockdown

  • Rescue with microinjection of Fmnl2-EGFP mRNA

  • Assess polar body extrusion rates (control: 74.26 ± 1.44% vs. FMNL2-KD: 59.5 ± 2.82%, p<0.001)

• Phenotypic analysis:

  • Measure polar body size

  • FMNL2 depletion causes larger polar bodies

• Cytoskeletal co-staining:

  • Stain for FMNL2, tubulin (spindle), and actin filaments

  • Analyze spatial relationships during spindle migration phases

What are the optimal conditions for FMNL2 immunofluorescence staining?

For successful FMNL2 visualization by immunofluorescence:

• Fixation protocol:

  • 4% paraformaldehyde (PFA) for 30 minutes at room temperature

  • Permeabilize with 0.5% Triton X-100 for 20 minutes

• Blocking conditions:

  • 1% BSA in PBS for 1 hour at room temperature

  • Including 0.1% Tween-20 can reduce background

• Antibody selection and dilution:

  • Primary: Rabbit monoclonal anti-FMNL2 (1:100 to 1:200)

  • Secondary: FITC-conjugated goat anti-rabbit IgG (1:100)

• Co-staining recommendations:

  • Anti-α-tubulin-FITC for spindle visualization

  • Phalloidin for F-actin staining

  • ER-Tracker Red or Mito-Tracker Green for organelles

• Controls:

  • Include FMNL2 knockdown samples as negative controls

  • Use known positive samples (e.g., cell types with high FMNL2 expression)

How can I optimize FMNL2 detection in Western blots?

For reliable FMNL2 detection by Western blotting:

• Sample preparation:

  • Use RIPA buffer with protease inhibitors

  • Maintain samples at 4°C during processing

  • Include phosphatase inhibitors if studying phosphorylation state

• Gel and transfer parameters:

  • Use 8% SDS-PAGE (FMNL2 is a large protein, 140-150 kDa)

  • Longer transfer time (e.g., 90-120 minutes) may be necessary

  • Cool transfer buffer to prevent overheating

• Antibody recommendations:

  • Proteintech mouse monoclonal FMNL2 antibody (68551-1-PBS) works well in WB applications

  • Starting dilution: 1:1000 in 5% non-fat milk or BSA

• Expected molecular weight:

  • Look for bands at 140-150 kDa

  • Validate specificity with knockdown controls

• Storage conditions:

  • Store antibody at -80°C for optimal stability

  • Avoid repeated freeze-thaw cycles

What controls are essential when studying FMNL2 knockdown effects?

Proper controls are crucial for valid FMNL2 functional studies:

• Knockdown validation:

  • Western blot showing protein reduction (expect ~50% reduction with siRNA)

  • Include non-targeting siRNA/shRNA as negative control

• Rescue experiments:

  • Reintroduce FMNL2 expression to confirm phenotype reversal

  • Rescue experiments for cytoplasmic actin should restore levels (from 37.98 ± 1.98 to 54.72 ± 2.88, p<0.0001)

• Functional markers:

  • For ER function: monitor Grp78 and Chop markers

  • For mitochondria: assess mitochondrial membrane potential

  • Rescue should reverse these markers (e.g., Grp78: 1 vs. 0.78 ± 0.05, p<0.01)

• Dose-response relationships:

  • Test multiple concentrations of siRNA

  • Correlate knockdown efficiency with phenotype severity

How should I design experiments to study FMNL2's interactome?

To comprehensively map FMNL2's protein interactions:

• Mass spectrometry approaches:

  • Immunoprecipitate FMNL2 followed by MS analysis

  • Consider tissue-specific analysis (e.g., ovarian tissue showed ER and mitochondria-related interactions)

• Validation strategies:

  • Co-immunoprecipitation for specific interactions

  • Proximity ligation assay for in situ confirmation

  • FMNL2 has confirmed interactions with Arp2, Formin2, and INF2

• Domain mapping:

  • Create truncation mutants to identify interaction domains

  • Focus on GBD/FH3, FH2, and DAD domains

• Functional validation:

  • Disrupt specific interactions and assess phenotypic consequences

  • Example: INF2 interaction disruption may affect ER distribution

How can I investigate FMNL2's role in cancer cell migration and invasion?

FMNL2 is implicated in cancer progression through actin regulation:

• Expression analysis:

  • Compare FMNL2 levels between normal and cancer tissues

  • FMNL2 is dysregulated in colorectal cancer, melanoma, breast cancer, chondrosarcoma, and glioblastoma

• Invasion assays:

  • Transwell invasion assays with FMNL2 knockdown/overexpression

  • 3D matrix invasion models for more physiological context

• Live cell migration tracking:

  • Monitor single-cell migration paths after FMNL2 manipulation

  • Quantify speed, directionality, and persistence

• Actin dynamics assessment:

  • Use LifeAct or SiR-actin for live actin visualization

  • FRAP (Fluorescence Recovery After Photobleaching) to measure actin turnover rates

• Rho GTPase signaling:

  • Investigate FMNL2's relationship with Rho family GTPases

  • FMNL2 functions as a downstream effector of Rho GTPases

What statistical analyses are recommended for FMNL2 functional studies?

Appropriate statistical approaches enhance the rigor of FMNL2 research:

• For phenotypic comparisons:

  • Student's t-test for two-group comparisons

  • ANOVA with post-hoc tests for multiple group comparisons

  • Example: Polar body extrusion rates (74.26 ± 1.44% vs. 59.5 ± 2.82%, p<0.001)

• For fluorescence intensity measurements:

  • Report mean ± SEM with appropriate sample sizes

  • Example: Cytoplasmic actin signals (58.25 ± 2.05, n=26 vs. 37.92 ± 2.02, n=24, p<0.0001)

• For distribution analyses:

  • Chi-square tests for categorical outcomes

  • Example: Mitochondrial distribution patterns across multiple categories

• Sample size considerations:

  • Most oocyte studies use 20-30 cells per condition

  • Power analysis can determine optimal sample sizes

• Presentation standards:

  • Include exact p-values

  • Report both statistical significance and biological significance

  • Use consistent visualization methods across related experiments