MAP65-4 Antibody
Description
Target Protein: MAP65-4 Functional Overview
MAP65-4 belongs to the evolutionarily conserved MAP65 family and specifically regulates microtubule dynamics during cell division. Key properties include:
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Microtubule bundling: Forms 15-nm cross-bridges between adjacent microtubules, stabilizing parallel and antipolar arrays .
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Dynamic modulation: Reduces catastrophe events (44.8% at plus ends; 52.7% at minus ends) and increases rescue events (51% at plus ends) .
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Localization: Associates with kinetochore fibers from prometaphase to anaphase and persists in the phragmoplast midzone during cytokinesis .
Antibody Applications in Research
MAP65-4 antibodies enable precise localization and functional studies through:
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Immunofluorescence: Visualizes MAP65-4 on spindle MTs, cortical division sites, and phragmoplasts .
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Immunoblotting: Detects MAP65-4 in protein extracts, typically used at 1:100 dilution .
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Genetic interaction studies: Reveals synthetic lethality with MAP65-3 mutations and functional redundancy in phragmoplast MT engagement .
Microtubule Dynamics Modulation
MAP65-4 alters microtubule instability parameters in vitro:
| Parameter | Plus End Change | Minus End Change | Source |
|---|---|---|---|
| Catastrophe frequency | ↓ 44.8% | ↓ 52.7% | |
| Rescue frequency | ↑ 51% | ↑ 23.9% | |
| Elongation phase duration | ↑ 100% | ↑ 148% |
This stabilization promotes progressive MT bundle lengthening, critical for spindle and phragmoplast formation .
Subcellular Localization Patterns
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Mitotic spindle: Enriched at kinetochore fibers from prometaphase .
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Phragmoplast: Shows dispersed distribution along MTs but enhances midzone localization in MAP65-3 mutants .
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Cortical division site: Persists post-preprophase band dissolution, suggesting a role in cytokinesis positioning .
Functional Redundancy and Genetic Interactions
MAP65-4 exhibits partial functional overlap with MAP65-3:
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Synthetic lethality: map65-4 mutations exacerbate cytokinesis defects in map65-3 mutants .
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Compensatory localization: MAP65-4 accumulation increases in phragmoplast midzones of map65-3 mutants, restoring MT engagement .
Comparative Analysis With Other MAP65 Isoforms
| Feature | MAP65-4 | MAP65-1 | MAP65-6 |
|---|---|---|---|
| MT bundling | 15-nm cross-bridges | Dense bundles | Mesh-like networks |
| Polymerization promotion | No | Yes | No |
| Subcellular target | Kinetochore fibers | Phragmoplast midzone | Mitochondria |
| Salt resistance | Moderate | Low | High |
Technical Considerations for Antibody Use
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Specificity: MAP65-4 antibodies show no cross-reactivity with MAP65-1 or MAP65-6 due to sequence divergence in variable regions .
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Buffer conditions: Optimal activity requires low salt concentrations (≤100 mM NaCl) to maintain MT-binding affinity .
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Phosphorylation effects: Localization patterns may vary depending on cell cycle-dependent phosphorylation states .
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- MAP65-4 is involved in engaging and bundling anti-parallel microtubules (MTs) within the phragmoplast. PMID: 28370001
- Studies have shown that the flexibility of MT bundles is regulated differently depending on the specific MAP65 cross-linker. PMID: 23615441
- Research indicates that MAP65-4 specifically associates with the forming mitotic spindle during prophase and with the kinetochore fibers from prometaphase to the end of anaphase in Arabidopsis thaliana. PMID: 21119057
- Analysis of microtubule organization in a MAP65-3 mutant demonstrated that MAP65-3 plays a critical role in organizing the mitotic microtubule array during both early and late mitosis in all plant organs. PMID: 18263774
