The hearing-essential intracellular domain of PCDH15 reveals a new layer of auditory mechanotransduction
Current models of mechanotransduction in inner-ear hair cells explain how force is transmitted through the extracellular tip link but provide little insight into how force is propagated beneath the plasma membrane. Although the CD2 isoform of PCDH15 has been shown to be essential for hearing in mature mammalian hair cells, its structural and mechanical properties have remained largely unknown.…
Researchers have uncovered a new layer of auditory mechanotransduction by examining the intracellular domain of PCDH15. Current models explain force transmission through the extracellular tip link, but the propagation beneath the plasma membrane remains unclear. The CD2 isoform of PCDH15 is crucial for hearing in mature mammalian hair cells, yet its structural and mechanical properties have been largely unknown.
Using computational sequence analysis, biophysical characterization, and small-angle X-ray scattering, the study reveals that the CD2 intracellular domain is an intrinsically disordered region (IDR) that acts as a highly expanded acidic polyampholyte. Despite being predominantly monomeric in solution, it occupies a larger conformational space at physiological-like ionic strength.
The presence of a conserved regulatory interaction platform suggests a potential link between its polymer properties and cellular regulation. These findings position the CD2 intracellular domain as a polymer with biophysical characteristics suitable for functioning as a mechanically responsive structural element in auditory mechanotransduction.
This discovery offers a framework for investigating how intracellular polymer mechanics may contribute to force transmission and adaptation within the auditory system.
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