Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


Home > Press > Scientists identify molecular cause for one form of deafness

Scientists exploring the physics of hearing have found an underlying molecular cause for one form of deafness, and a conceptual connection between deafness and the organization of liquid crystals, which are used in flat-panel displays.

Scientists identify molecular cause for one form of deafness

Champaign, IL | Posted on February 5th, 2007

Within the cochlea of the inner ear, sound waves cause the basilar
membrane to vibrate. These vibrations stimulate hair cells, which
then trigger nerve impulses that are transmitted to the brain.

Researchers have now learned that mutations in a protein called espin
can cause floppiness in tiny bundles of protein filaments within the
hair cells, impairing the passage of vibrations and resulting in

Filamentous actin (F-actin) is a rod-like protein that provides
structural framework in living cells. F-actin is organized into
bundles by espin, a linker protein found in sensory cells, including
cochlear hair cells. Genetic mutations in espin's F-actin binding
sites are linked to deafness in mice and humans.

"We found the structure of the bundles changes dramatically when
normal espin is replaced with espin mutants that cause deafness,"
said Gerard Wong, a professor of materials science and engineering,
of physics, and of bioengineering at the University of Illinois at

"The interior structure of the bundles changes from a rigid,
hexagonal array of uniformly twisted filaments, to a liquid
crystalline arrangement of filaments," Wong said. "Because the new
organization causes the bundles to be more than a thousand times
floppier, they cannot respond to sound in the same way. The rigidity
of these bundles is essential for hearing."

Wong and his co-authors - Illinois postdoctoral research associate
Kirstin Purdy and Northwestern University professor of cell and
molecular biology James R. Bartles - report their findings in a paper
accepted for publication in the journal Physical Review Letters, and
posted on its Web site.

High-resolution X-ray diffraction experiments, performed by Purdy at
the Advanced Photon Source and at the Stanford Synchrotron Radiation
Laboratory, allowed the researchers to solve the structure of various
espin-actin bundles.

"As the ability of espin to cross-link F-actin is decreased by using
genetically modified 'deafness' mutants with progressively more
damaged actin binding sites, the structure changes from a
well-ordered crystalline array of filaments to a nematic, liquid
crystal-like state," said Wong, who also is a researcher at the
Frederick Seitz Materials Research Laboratory on campus and at the
university's Beckman Institute for Advanced Science and Technology.

In the liquid crystalline state, the bundles maintain their
orientation order - that is, they point roughly along the same
direction - but lose their positional order. These nematic liquid
crystals are commonly used in watch displays and laptop displays.

Wong and his colleagues also found that a mixture of mutant espin and
normal espin would prevent the structural transition from occurring.
If gene expression could turn on the production of just a fraction of
normal espin linkers, a kind of rescue attempt at restoring hearing
could, in principle, be made.

"We have identified the underlying molecular cause for one form of
deafness, and we have identified a mechanism to potentially 'rescue'
this particular kind of pathology," Wong said. "Even so, this is
really the first step. This work has relevance to not just human
hearing, but also to artificial sensors."

The U.S. Department of Energy, National Institutes of Health and
National Science Foundation funded the work.


About University of Illinois
At Illinois, research shapes the campus identity, stimulates classroom instruction and serves as a springboard for public engagement activities throughout the world. Opportunities abound for graduate students to develop independent projects and launch their own careers as researchers while working alongside faculty and assisting in their research. Illinois continues its long tradition of groundbreaking accomplishments with remarkable new discoveries and achievements that inspire and enrich the lives of people around the world.

For more information, please click here

Gerard Wong

Copyright © University of Illinois

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press


Controllable protein gates deliver on-demand permeability in artificial nanovesicles October 9th, 2015

Performance of Polymeric Nanoparticles as Gene Carriers Studied by Iranian, Dutch Scientists October 9th, 2015

Room temperature magnetic skyrmions, a new type of digital memory? October 8th, 2015

A quantum simulator of impossible physics: In the experiment, developed by the UPV/EHU-University of the Basque Country in conjunction with the University of Tsinghua (China), the atoms simulate absurd actions "as if they were actors in a quantum theatre" October 8th, 2015


Controllable protein gates deliver on-demand permeability in artificial nanovesicles October 9th, 2015

Faster design -- better catalysts: New method facilitates research on fuel cell catalysts October 9th, 2015

Performance of Polymeric Nanoparticles as Gene Carriers Studied by Iranian, Dutch Scientists October 9th, 2015

Newly discovered 'design rule' brings nature-inspired nanostructures one step closer: Computer sims and microscopy research at Berkeley Lab yield first atomic-resolution structure of a peptoid nanosheet October 8th, 2015

Human Interest/Art

Bionic liver micro-organs explain off-target toxicity of acetaminophen (Tylenol): Israeli-German partnership aims to replace animal experiments with advanced liver-on-chip devices August 17th, 2015

Omni Nano and Time Warner Cable Partner to Provide Nanotechnology Education to the Boys & Girls Clubs of Los Angeles: A $10,000 Donation to Benefit Youth of Los Angeles County's Boys & Girls Clubs August 4th, 2015

Kalam: versatility personified August 1st, 2015

Pakistani Students Who Survived Terror Attack to Attend Weeklong “NanoDiscovery Institute” at SUNY Poly CNSE in Albany July 29th, 2015

The latest news from around the world, FREE

  Premium Products
Only the news you want to read!
 Learn More
University Technology Transfer & Patents
 Learn More
Full-service, expert consulting
 Learn More

Nanotechnology Now Featured Books


The Hunger Project

Car Brands
Buy website traffic