FIM1 Antibody
Description
Target Antigen and Antibody Characteristics
FIM1 belongs to the fimbrin/plastin family of actin-bundling proteins, characterized by two conserved actin-binding domains (ABDs) and calcium-binding EF-hand motifs . The FIM1 antibody specifically targets the C-terminal region of lily (Lilium longiflorum) FIM1 (Ll-FIM1), corresponding to amino acids 620–690 .
| Property | Details |
|---|---|
| Host Species | Rabbit |
| Immunogen | Recombinant Ll-FIM1 C-terminal fragment (620–690 AA) |
| Specificity | Reacts with ~80 kDa Ll-FIM1; no cross-reactivity with Arabidopsis FIM5 |
| Applications | Immunofluorescence, immunoblotting, functional inhibition assays |
Localization and Actin Interaction
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Subcellular Distribution: In lily pollen tubes, FIM1 colocalizes with actin filaments in two regions:
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Latrunculin B Sensitivity: FIM1-labeled structures disassemble upon actin depolymerization, confirming direct actin association .
Functional Inhibition Studies
Microinjection of the FIM1 antibody into pollen tubes revealed dose-dependent effects:
| Antibody Concentration | Pollen Tube Growth Rate (µm/min) | Actin Fringe Integrity | Cytoplasmic Streaming Velocity |
|---|---|---|---|
| Control (buffer/BSA) | 10.96 ± 1.33 | Intact | Normal |
| 0.3 mg/mL | 6.37 ± 1.34 | Partially disrupted | Reduced |
| 0.5 mg/mL | 5.08 ± 1.28 | Severely disrupted | Significantly reduced |
| 1.0 mg/mL | 1.64 ± 0.59 | Fully disrupted | Nearly halted |
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Actin Skewness and Occupancy: Antibody injection reduced skewness (bundling) by 42% and actin density by 55% in the subapical region, indicating FIM1’s role in stabilizing actin networks .
Actin Stabilization
FIM1 competitively excludes actin-depolymerizing factor Adf1 from filaments, delaying depolymerization . Overexpression of FIM1:
Cytokinesis Coordination
Genetic interactions in fission yeast (Schizosaccharomyces pombe) show FIM1 synergizes with:
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Cdc15 (PSTPIP): Regulates actomyosin ring assembly.
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Rng2 (IQGAP): Coordinates septum formation .
Double mutants (fim1Δ cdc15Δ or fim1Δ rng2Δ) fail to divide at restrictive temperatures .
Applications in Cytoskeletal Research
The FIM1 antibody has been instrumental in:
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Mapping Actin Dynamics: Visualizing actin fringe remodeling during tip growth .
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Functional Knockdown: Acute inactivation of FIM1 without genetic manipulation .
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Cross-Species Studies: Complementation assays in Arabidopsis fim5 mutants confirmed functional conservation between Ll-FIM1 and At-FIM5 .
Technical Validation
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- FIM1 Antibody fused to GFP has been utilized to label actin networks in various cell types, including Nicotiana, Medicago, and Lycopersicon. PMID: 15557099
- To enhance fluorescence for improved in vivo F-actin imaging, transgenic Arabidopsis plants were generated expressing a construct with green fluorescent protein fused to both the C- and N-termini of the actin binding domain of FIM1 Antibody. PMID: 18028299
