Navigation Links
Study finds new role for protein in hearing
Date:8/15/2011

University of Iowa scientists have discovered a new role for a protein that is mutated in Usher syndrome, one of the most common forms of deaf-blindness in humans. The findings, which were published Aug. 8 in Nature Neuroscience, may help explain why this mutation causes the most severe form of the condition.

The study suggests that the protein called harmonin, which is known to be involved in sound sensing in the inner ear, may also play a role in the transmission of sound information to the brain.

Hearing starts with the transmission of sound by inner hair cells in the ear. Sound waves cause movement of special structures called stereocilia on the tips of the hair cells. Harmonin is thought to mediate this movement, which then activates the cells and initiates transmission of sound information as electrical and chemical signals to the brain.

"Most of the research until now has concentrated on the input end of the inner hair cells where the sound waves produce motion of the stereocilia," said Amy Lee, Ph.D., senior study author and UI associate professor in the Departments of Molecular Physiology and Biophysics, Otolaryngology-Head and Neck Surgery, and Neurology. "Now we have found a new role for harmonin at the opposite end of these sound-sensing inner hair cells where it appears to control the signal output of the cell."

Lee and colleagues, including UI postdoctoral fellows Frederick Gregory, Ph.D., and Keith Bryan, Ph.D., found that harmonin is important for regulating the number of calcium channels present at the sound-transmitting synapse of inner hair cells.

Studies from other labs have shown that too few or too many calcium channels at the hair cell synapse cause deafness in mice. This means factors that control how many channels are available are likely to be important for normal hearing.

"Harmonin appears to precisely control how many channels are available," Lee said. "What we think is happening in Usher syndrome where the harmonin protein is mutated is that there are too many calcium channels available, which causes abnormal signaling at the synapses.

"We are most excited about the idea that this mutation could contribute to the disease process of Usher syndrome in a way that was not imagined before," Lee added. "It may eventually be possible to alter this interaction between harmonin and the calcium channels in a way that might be useful as a therapy for patients with this form of Usher syndrome."

Harmonin is also expressed in the retina -- the light-sensitive tissue in the eye -- which is affected in Usher syndrome, and there are calcium channels in the photoreceptor cells of the retina. It is not known how the harmonin mutation affects the retina and how it might contribute to blindness in Usher syndrome, but that is another area of research Lee's team hopes to investigate.


'/>"/>

Contact: Jennifer Brown
jennifer-l-brown@uiowa.edu
319-356-7124
University of Iowa Health Care
Source:Eurekalert

Related biology news :

1. Long-term study shows effect of climate change on animal diversity
2. £2 million study to reveal workings of dementia genes
3. New study looks to define evangelicals and how they affect polling
4. CU-Boulder study suggests air quality regulations miss key pollutants
5. Researchers study acoustic communication in deep-sea fish
6. Study reveals homeowner perceptions in fire-prone areas
7. Researchers study how pistachios may improve heart health
8. Study: urban black bears live fast, die young
9. New study indicates link between weight gains during pregnancy and dieting history
10. Study reveals specific gene in adolescent men with delinquent peers
11. Sweat it out: UH study examines ability of sweat patches to monitor bone loss
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/27/2017)... , March 27, 2017  Catholic Health Services ... Management Systems Society (HIMSS) Analytics for achieving Stage ... Model sm . In addition, CHS previously earned ... hospitals using an electronic medical record (EMR). ... high level of EMR usage in an outpatient ...
(Date:3/23/2017)... 23, 2017 The report "Gesture Recognition and Touchless Sensing ... Geography - Global Forecast to 2022", published by MarketsandMarkets, the market is expected ... 29.63% between 2017 and 2022. Continue Reading ... ... ...
(Date:3/22/2017)... NEW YORK , March 21, 2017 /PRNewswire/ ... Customer Marketing Cloud used by retailers such as ... in its platform — Product Recommendations and Replenishment. Using ... to give more personalized product and replenishment recommendations ... purchases, but also on predictions of customer intent ...
Breaking Biology News(10 mins):
(Date:8/18/2017)... ... August 18, 2017 , ... OAI, a leading ... and Microfluidics Industries, announces the new Model 800E front and backside, semi-automatic mask ... production mask aligners. OAI has already received and installed several orders for ...
(Date:8/16/2017)... , ... August 16, 2017 , ... Tunnell Consulting ... in sessions at the ISPE Annual Meeting and Expo , to be held ... Marina. The event’s theme is “Driving innovation to advance patient therapies.” , The ISPE ...
(Date:8/16/2017)... ... August 16, 2017 , ... While art and science are often thought ... than one might think. A Mesh Is Also a Snare, a group exhibition ... Science Center’s Esther Klein Gallery (EKG) on August 17 and run through September 30. ...
(Date:8/16/2017)... Aug. 16, 2017  This year,s edition of the Inc. 5000 features ... sciences workforce solutions, has made the list for the third year in ... nation,s fastest-growing private companies based on a set of quantitative metrics. In ... the fastest-growing companies in the Bay State . ... Inc. 5000 ...
Breaking Biology Technology: