ESPN Antibody
Description
Definition and Biological Context
ESPN (espin) is a multifunctional actin-binding protein encoded by the ESPN gene. It plays a key role in the formation and maintenance of stereocilia, mechanosensory structures in hair cells of the inner ear and microvilli in other tissues . ESPN antibodies are polyclonal or monoclonal reagents designed to detect and study ESPN’s expression, localization, and function in research models.
Key features of ESPN:
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Structure: Contains actin-binding domains (ABD1 and ABD2) and ankyrin repeats for protein interactions .
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Isoforms: Multiple isoforms (e.g., ESPN-1, ESPN-2B) with distinct tissue distributions .
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Function: Stabilizes actin cores in stereocilia and regulates cytoskeletal dynamics .
Applications of ESPN Antibodies
ESPN antibodies are widely used in molecular and cellular biology research:
Role in Hearing and Deafness
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Genetic mutations: Autosomal recessive mutations in ESPN cause deafness (DFNB36) and vestibular dysfunction .
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Stereocilia defects: ESPN overexpression disrupts stereocilia staircase architecture, while loss-of-function mutations lead to shortened stereocilia .
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Therapeutic potential: Gene therapy using ESPN cDNA shows promise in restoring stereocilia morphology post-aminoglycoside damage .
Interaction with Actin Regulators
ESPN collaborates with other actin-binding proteins:
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FSCN2 (fascin-2) and PLS1 (plastin-1): Compete with ESPN for actin binding; overexpression of FSCN2 reduces ESPN levels in stereocilia .
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Myosin III motors: ESPN-1 and ESPN-like (ESPNL) proteins regulate stereocilia growth and spacing .
Technical Considerations
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Sample preparation: Use fresh-frozen or formaldehyde-fixed tissues for optimal antigen preservation .
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Controls: Include knockout tissues or siRNA-treated cells to confirm antibody specificity .
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Cross-reactivity: Some antibodies (e.g., PB538) recognize both ESPN-1 and ESPNL .
Emerging Insights and Challenges
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Dynamic remodeling: ESPN cross-linking in stereocilia is reversible, suggesting regulatory post-translational modifications .
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Disease modeling: ESPN antibodies aid in studying Usher syndrome and age-related hearing loss .
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Limitations: Commercial antibodies may exhibit batch variability; orthogonal validation (e.g., mass spectrometry) is recommended .
Product Specs
Target Background
- A significant inverse correlation was observed between miR-612 and Espin protein expression in melanoma tissues. PMID: 29385671
- Utricles were treated with a gamma-secretase inhibitor, followed by espin or control transduction and histochemistry. While gamma-secretase inhibition increased the number of hair cells (HCs), few had stereociliary arrays. In contrast, 46 hours after espin1 transduction, a significant increase in hair-bundle-like structures was observed. PMID: 26886463
- The espin actin-filament-binding site has a major effect on the formation and dynamics of actin bundles. PMID: 24424026
- Human deafness and vestibular dysfunction co-segregated with either of two frameshift mutations in the ESPN gene. PMID: 15286153
- These findings further strengthen the causative role of the espin gene in non-syndromic hearing loss and provide new insights into espin structure and function. PMID: 15930085
- A new activity of the espins has been reported, one that depends on their enigmatic WH2 domain: the ability to assemble a large actin bundle when targeted to a specific subcellular location. PMID: 16569662
- A recessive ESPN mutation causing congenital hearing loss in a Moroccan family was reported. PMID: 18973245
- Flies with mutations affecting the diaphanous, forked, and CG12026/TMHS genes displayed significant reductions in the amplitude of sound-evoked potentials compared to wild-type flies. PMID: 19102128
