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Updated: Jun 20, 2026

A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters
Published on: April 20, 2015
Bestrophin and TMEM16-Ca(2+) activated Cl(-) channels with different functions
Karl Kunzelmann1, Patthara Kongsuphol, Fadi Aldehni
1Institut für Physiologie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany. karl.kunzelmann@vkl.uni-regensburg.de
Two protein families, bestrophins and TMEM16 proteins, now reliably replicate calcium-activated chloride currents. TMEM16A (anoctamin 1) is crucial for epithelial function and a potential cystic fibrosis therapy target.
Area of Science:
- Cellular and Molecular Physiology
- Ion Channel Biology
- Epithelial Transport
Background:
- Calcium-activated chloride currents are vital for cellular functions.
- Bestrophins and TMEM16 proteins are the primary candidates for these currents.
- Bestrophin 1 influences intracellular calcium signaling, particularly in epithelial cells.
Purpose of the Study:
- To review the roles of bestrophins and TMEM16 proteins in calcium-activated chloride currents.
- To highlight TMEM16A's function in epithelial secretion and its therapeutic potential.
- To explore the activation mechanisms and channel properties of TMEM16 family members.
Main Methods:
- Literature review of studies on bestrophins and TMEM16 proteins.
- Analysis of protein expression patterns in various tissues.
- Examination of biophysical and pharmacological properties of identified channels.
Main Results:
- Bestrophins, like Bestrophin 1, are expressed in the retinal pigment epithelium and may modulate intracellular calcium signaling.
- TMEM16A (anoctamin 1) exhibits properties consistent with calcium-dependent chloride channels and is essential for epithelial secretion.
- TMEM16A is broadly expressed and plays a key role in electrolyte transport in respiratory and intestinal epithelia.
Conclusions:
- Bestrophins and TMEM16 proteins are key players in calcium-activated chloride channel function.
- TMEM16A is a critical protein for epithelial function and a promising therapeutic target for cystic fibrosis.
- Further research is needed to elucidate the activation mechanisms and channel properties of the TMEM16 family.
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