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La otoferlina, defectuosa en una forma de sordera humana, es esencial para la exocitosis en la sinapsis de la cinta
Isabelle Roux1, Saaid Safieddine, Régis Nouvian
1Inserm UMRS587, Unité de Génétique des Déficits Sensoriels, Collège de France, Institut Pasteur, 25 rue du Dr Roux, 75015 Paris, France.
Cell
|October 24, 2006
Resumen
La otoferlina es crucial para la audición, actuando como un sensor de calcio que desencadena la liberación de neurotransmisores en las sinapsis de las células ciliadas auditivas. La deficiencia de otoferlina causa sordera profunda al abolir este proceso esencial de exocitosis.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Biología Molecular Biología Molecular
- Genética La genética.
Sus antecedentes:
- Las sinapsis de la cinta de las células ciliadas internas auditivas (IHC) requieren una liberación precisa de neurotransmisores para la audición.
- Los mecanismos moleculares de la exocitosis sináptica IHC no se comprenden completamente.
- La otoferlina, una proteína transmembrana, está implicada en una forma recesiva de sordera humana.
Objetivo del estudio:
- Investigar el papel de la otoferlina en la exocitosis sináptica IHC.
- Determinar la función de la otoferlina en la neurotransmisión auditiva y la audición.
Principales métodos:
- Estudió la expresión y localización de la otoferlina en las células ciliadas.
- Se examinó la unión al calcio (Ca2+) de la otoferlina y las interacciones con las proteínas SNARE.
- Se utilizaron ratones con deficiencia de otoferlina (Otof(-/-)) para evaluar la exocitosis.
- Se analizó la estructura de la sinapsis de la cinta y las corrientes de Ca2+ en Otof(-/-) IHCs.
Principales resultados:
- La expresión de otoferlina se correlaciona con la sinaptogénesis aferente y se localiza en las sinapsis de cinta.
- La otoferlina se une al Ca2+ e interactúa con la sintaxina1 y el SNAP25 de una manera dependiente del Ca2+.
- Los ratones otof ((-/-) muestran sordera profunda con exocitosis IHC abolida, a pesar del desarrollo normal de las sinapsis y la afluencia de Ca2+.
Conclusiones:
- La otoferlina es esencial para una etapa tardía de la exocitosis de las vesículas sinápticas en la sinapsis de la cinta IHC.
- La otoferlina probablemente funciona como el sensor primario de Ca2+ mediando la fusión de la membrana para la neurotransmisión auditiva.
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