Featured Research

from universities, journals, and other organizations

New role for protein in hearing

Date:
August 16, 2011
Source:
University of Iowa Health Care
Summary:
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 may help explain why this mutation causes the most severe form of the condition.

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.

Related Articles


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.

In addition to Lee, Gregory and Bryan, the research team included Tina Pangrsic and Tobias Moser at the University of Goettingen, Germay, and Irina Calin-Jageman at Dominican University, River Forest, Ill.

The study was funded in part by grants from the National Institutes of Health and the Deafness Research Foundation.


Story Source:

The above story is based on materials provided by University of Iowa Health Care. Note: Materials may be edited for content and length.


Journal Reference:

  1. Frederick D Gregory, Keith E Bryan, Tina Pangršič, Irina E Calin-Jageman, Tobias Moser, Amy Lee. Harmonin inhibits presynaptic Cav1.3 Ca2 channels in mouse inner hair cells. Nature Neuroscience, 2011; DOI: 10.1038/nn.2895

Cite This Page:

University of Iowa Health Care. "New role for protein in hearing." ScienceDaily. ScienceDaily, 16 August 2011. <www.sciencedaily.com/releases/2011/08/110815143945.htm>.
University of Iowa Health Care. (2011, August 16). New role for protein in hearing. ScienceDaily. Retrieved March 5, 2015 from www.sciencedaily.com/releases/2011/08/110815143945.htm
University of Iowa Health Care. "New role for protein in hearing." ScienceDaily. www.sciencedaily.com/releases/2011/08/110815143945.htm (accessed March 5, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, March 5, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Adults Only Get The Flu Twice A Decade, Researchers Say

Adults Only Get The Flu Twice A Decade, Researchers Say

Newsy (Mar. 4, 2015) Researchers found adults only get the flu about once every five years. Scientists analyzed how a person&apos;s immunity builds up over time as well. Video provided by Newsy
Powered by NewsLook.com
New Hormone Could Protect Against Diabetes And Weight Gain

New Hormone Could Protect Against Diabetes And Weight Gain

Newsy (Mar. 4, 2015) A newly discovered hormone mimics the effects of exercise, protecting against diabetes and weight gain. Video provided by Newsy
Powered by NewsLook.com
Mount Everest Has a Poop Problem

Mount Everest Has a Poop Problem

Buzz60 (Mar. 4, 2015) With no bathrooms to use, climbers of Mount Everest have been leaving human waste on the mountain for years, and it&apos;s becoming a health issue. Mike Janela (@mikejanela) has more. Video provided by Buzz60
Powered by NewsLook.com
The Best Tips to 'Skinny' Your Home

The Best Tips to 'Skinny' Your Home

Buzz60 (Mar. 4, 2015) If you&apos;re looking to reach your health goals this season, there are a few simple tips to help you spring clean your space and improve your nutrition. Krystin Goodwin (@krystingoodwin) has the skinny on keeping a healthy home. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins