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The role of the protein CLIC5 in hearing and deafness

This is a Discovery Research Grant awarded to Dr Bo Zhao at Indiana University, USA, in 2020. 


Hearing loss affects roughly 5% of the global population – in the UK, around 12 million people have some form of hearing loss.

Sensorineural hearing loss is the most common form and is often caused by defects or damage to hair cells in the cochlea of the inner ear. Hair cells are the sensory receptors of the hearing system – they detect sound in the form of vibrations and convert the information into electrical signals that the brain can interpret.  

Hearing aids and cochlear implants are currently the only treatments for hearing loss. While they bring benefit to many people, neither device is perfect, nor can either device restore hearing to its ‘natural’ state.

Therefore, we need new, more effective treatments for hearing loss, which target the actual cause of the hearing loss. But to be able to create these treatments, we need to understand, in detail, the biological processes that underlie hearing loss. 

The protein CLIC5 is important for hearing. It’s found in structures called stereocilia in hair cells (stereocilia are the ‘hairs’ in hair cells, and are responsible for detecting sound). When the gene which produces the protein is mutated, it leads to deafness in people.

We don’t yet understand exactly what CLIC5 does in hair cells or in the process of hearing. We do know that it interacts with another protein called taperin, which has also been linked to hearing loss in people. This relationship between CLIC5 and taperin proteins is critical to uncovering why mutations in CLIC5 cause hearing loss, but as yet, we don’t understand it in detail.  


In this project, the research team aim to: 

  • Better understand the role of CLIC5 in hair cells, with a particular focus on its involvement in how hair cells form and develop 
  • Reveal the relationship between CLIC5 and taperin in hair cells, and understand why this interaction is so important for hearing
  • Identify other proteins that interact with CLIC5, and investigate what they do in hair cells.  


Upon successful completion, the researchers will have a detailed understanding of the role(s) of CLIC5 in hearing. They may also identify new molecules and processes that could be targeted with drugs aiming to correct hearing loss caused by CLIC5 mutations. The proposed research will serve as a basis for the discovery of other genes which are linked to hearing loss, paving the way for the subsequent discovery of new treatments for hearing loss.

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