Strategic Communications and Marketing News Bureau

Scientists identify molecular cause for one form of deafness

Gerard Wong, a professor of materials science and engineering, of physics, and of bioengineering at Illinois, and colleagues have found an underlying molecular cause for one form of deafness, while exploring the physics of hearing.

Gerard Wong, a professor of materials science and engineering, of physics, and of bioengineering at Illinois, and colleagues have found an underlying molecular cause for one form of deafness, while exploring the physics of hearing.

CHAMPAIGN, Ill. – 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.

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 deafness.

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 Urbana-Champaign.

“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.

Editor’s note: To reach Gerard Wong, call 217-265-5254; e-mail: gclwong@illinois.edu.

Read Next

Life sciences Portrait of the research team posing together.

Minecraft players can now explore whole cells and their contents

CHAMPAIGN, Ill. — Scientists have translated nanoscale experimental and computational data into precise 3D representations of bacteria, yeast and human epithelial, breast and breast cancer cells in Minecraft, a video game that allows players to explore, build and manipulate structures in three dimensions. The innovation will allow researchers and students of all ages to navigate […]

Arts Photo of seven dancers onstage wearing blue tops and orange or yellow flowing skirts. The backdrop is a Persian design.

February Dance includes works experimenting with live music, technology and a ‘sneaker ballet’

CHAMPAIGN, Ill. — The dance department at the University of Illinois Urbana-Champaign will present February Dance 2025: Fast Forward this week at Krannert Center for the Performing Arts. February Dance will be one of the first performances in the newly renovated Colwell Playhouse Theatre since its reopening. The performances are Jan. 30-Feb. 1. Dance professor […]

Honors portraits of four Illinois researchers

Four Illinois researchers receive Presidential Early Career Award

CHAMPAIGN, Ill. — Four researchers at the University of Illinois Urbana-Champaign were named recipients of the Presidential Early Career Award for Scientists and Engineers, the highest honor bestowed by the U.S. government on young professionals at the outset of their independent research careers. The winners this year are health and kinesiology professor Marni Boppart, physics professor Barry Bradlyn, chemical and biomolecular engineering professor Ying […]

Strategic Communications and Marketing News Bureau

507 E. Green St
MC-426
Champaign, IL 61820

Email: stratcom@illinois.edu

Phone (217) 333-5010