Related Experiment Video
Updated: Jun 11, 2025
Demonstration of Heterologous Complexes formed by Golgi-Resident Type III Membrane Proteins using Split Luciferase Complementation Assay
Published on: September 10, 2020
SLC26A4-AP-2 mu2 interaction regulates SLC26A4 plasma membrane abundance in the endolymphatic sac
Hyun Jae Lee1, Cristina Fenollar-Ferrer1,2, Kevin Isgrig3
1Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.
Abstract:
Decreased presence or activity of human SLC26A4 at the plasma membrane is a common cause of hearing loss. SLC26A4 (Pendrin) is necessary for normal reabsorption of endolymph, the fluid bathing the inner ear. We identified the μ2 subunit of adaptor protein 2 (AP-2) complex required for clathrin-mediated endocytosis as a protein-partner of SLC26A4 involved in regulating its plasma membrane abundance. We showed that, in the endolymphatic sac, where fluid reabsorption occurs, SLC26A4 is localized along the apical microvilli of mitochondria-rich cells, in contact with the endolymph, and associated with clathrin-coated pits where μ2 and AP-2 are present. Based on SLC26A4 structure, the elements involved in SLC26A4-μ2 interaction were identified and validated experimentally, allowing modeling of this interaction at the atomic level. Pharmacological inhibition of clathrin-mediated endocytosis led to an increased plasma membrane abundance of hemagglutinin-tagged SLC26A4 virally or endogenously expressed in mitochondria-rich cells. These results indicate that the SLC26A4-μ2 interaction regulates SLC26A4 abundance at the apical surface of mitochondria-rich cells.
Insights
The micro2 subunit of adaptor protein 2 (AP-2) complex regulates the abundance of SLC26A4 (Pendrin) at the plasma membrane. This interaction is crucial for normal inner ear fluid reabsorption and preventing hearing loss.
Area of Science:
- Cell Biology
- Otolaryngology
- Molecular Biology
Background:
- Reduced human SLC26A4 (Pendrin) at the plasma membrane causes hearing loss.
- SLC26A4 is vital for endolymph reabsorption in the inner ear.
Purpose of the Study:
- To identify proteins interacting with SLC26A4 and regulating its plasma membrane abundance.
- To elucidate the mechanism controlling SLC26A4 localization in the inner ear.
Main Methods:
- Investigated the interaction between SLC26A4 and the micro2 subunit of AP-2.
- Utilized immunofluorescence microscopy to observe SLC26A4 localization in mitochondria-rich cells.
- Performed structural analysis and experimental validation of the SLC26A4-micro2 interaction.
- Assessed the effect of inhibiting clathrin-mediated endocytosis on SLC26A4 plasma membrane levels.
Main Results:
- Identified micro2 (AP-2 complex) as a SLC26A4-interacting protein.
- SLC26A4 localizes to apical microvilli and clathrin-coated pits in the endolymphatic sac.
- Atomic-level modeling of the SLC26A4-micro2 interaction was achieved.
- Inhibiting endocytosis increased SLC26A4 plasma membrane abundance.
Conclusions:
- The SLC26A4-micro2 interaction regulates SLC26A4 abundance at the apical surface of mitochondria-rich cells.
- This mechanism is critical for maintaining inner ear fluid balance and preventing hearing loss.
More Related Videos
11:55Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution
Published on: August 16, 2016
08:06Preparation of Synaptic Plasma Membrane and Postsynaptic Density Proteins Using a Discontinuous Sucrose Gradient
Published on: September 3, 2014
