Prestin, a motor protein of cochlear outer hair cells, is the basis for cochlear amplification. Prestin belongs to a distinct anion transporter family called solute carrier protein 26A, or SLC26A. Individual members of this 11-member family serve two fundamentally distinct functions. While all prestin paralogs (i.e., all other members in this family) transport different anion substrates across a variety of epithelia, prestin (SLC26A5) is the only member serving as a molecular motor. The goal of the proposed research is to investigate the molecular mechanisms of how prestin works. We have identified two regions (residues 158-168 and residues 256-276) that are well conserved among mammalian species but highly variable among prestin orthologs and SLC26A paralogs. Our overall hypothesis is that these amino acid sequences represent the essential motif for motor function. This project has three specific aims:
Aim 1 will determine whether residues 158-168, located in the external loop 2 of the prestin molecule, represent the essential motif for motor function.
Aim 2 will determine whether the length and constitution of the 11-amino acid sequence are critical for voltage-sensing/motor function.
Aim 3 will determine whether residues 256-276, located in the transmembrane domain 6 of the prestin molecule, are important for enhancing motor function. Site-directed mutagenesis will be used to swap these regions between gerbil prestin and human pendrin. Pendrin (SLC26A4), one of the paralogs, is a sodium-independent chloride/iodide transporter. Mutations in this gene are associated with Pendred syndrome, the second most common form of syndromic deafness. Nonlinear capacitance and somatic motility, two hallmarks of the motor function of prestin, will be measured from chimeric pendrin-transfected HEK cells, using the voltage-clamp technique and a photodiode-based displacement measurement system. A gain of motor function is expected in the chimeric pendrin. A radioisotope uptake technique will be used to determine whether the chimeric pendrin retains its transport function. The proposed experiments are significant for the fundamental understanding of how prestin and pendrin work.
A mutation in the prestin gene causes non-syndromic deafness, while mutations in the pendrin gene are associated with Pendred syndrome, one of the most common forms of syndromic deafness, an autosomal-recessive disorder characterized by sensorineural deafness and goiter. Understanding how the two molecules work and why mutations in the genes can cause hearing loss can guide diagnosis and prevention, and possible future gene therapy treatments.
|Li, Yi; Liu, Huizhan; Barta, Cody L et al. (2016) Transcription Factors Expressed in Mouse Cochlear Inner and Outer Hair Cells. PLoS One 11:e0151291|
|Lovas, SÃ¡ndor; He, David Z Z; Liu, Huizhan et al. (2015) Glutamate transporter homolog-based model predicts that anion-Ï€ interaction is the mechanism for the voltage-dependent response of prestin. J Biol Chem 290:24326-39|
|Li, Yi; Liu, Huizhan; Li, Jun et al. (2014) Morphology and ciliary motion of mucosa in the Eustachian tube of neonatal and adult gerbils. PLoS One 9:e99840|
|Zhang, Qian; Liu, Huizhan; Soukup, Garrett A et al. (2014) Identifying microRNAs involved in aging of the lateral wall of the cochlear duct. PLoS One 9:e112857|
|Liu, Huizhan; Pecka, Jason L; Zhang, Qian et al. (2014) Characterization of transcriptomes of cochlear inner and outer hair cells. J Neurosci 34:11085-95|
|He, David Z Z; Lovas, Sandor; Ai, Yu et al. (2014) Prestin at year 14: progress and prospect. Hear Res 311:25-35|
|Zhang, Qian; Liu, Huizhan; McGee, Joann et al. (2013) Identifying microRNAs involved in degeneration of the organ of corti during age-related hearing loss. PLoS One 8:e62786|
|Tang, Jie; Pecka, Jason L; Fritzsch, Bernd et al. (2013) Lizard and frog prestin: evolutionary insight into functional changes. PLoS One 8:e54388|
|Mao, Zhongping; Zhao, Lijun; Pu, Lichun et al. (2013) How well can centenarians hear? PLoS One 8:e65565|
|Tan, Xiaodong; Pecka, Jason L; Tang, Jie et al. (2012) A motif of eleven amino acids is a structural adaptation that facilitates motor capability of eutherian prestin. J Cell Sci 125:1039-47|
Showing the most recent 10 out of 28 publications