Phosphatidylinositol 4,5-bisphosphate, cholesterol, and fatty acids modulate the calcium-activated chloride channel TMEM16A (ANO1)

• Type of Material: Article
• Authors: Jose J. De Jesus-Perez, Universidad Autónoma de San Luis Potosí; Silvia Cruz-Rangel, Universidad Autónoma de San Luis Potosí; Angeles E. Espino-Saldana, Universidad Nacional Autónoma de México; Ataulfo Martinez-Torres, Universidad Nacional Autónoma de México; Zhiqiang Qu, Qingdao University; Criss Hartzell Jr., Emory University; Nancy E. Corral-Fernandez, Universidad Autónoma de San Luis Potosí; Patricia Perez-Cornejo, Universidad Autónoma de San Luis Potosí; Jorge Arreola, Universidad Autónoma de San Luis Potosí
• Language: English
• Date: 2018-03-01
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Elsevier B.V.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.bbalip.2017.12.009
• Title of Journal or Parent Work: Biochimica et Biophysica Acta Molecular and Cell Biology of Lipids
• ISSN: 1388-1981
• Volume: 1863
• Issue: 3
• Start Page: 299
• End Page: 312
• Grant/Funding Information: Silvia Cruz-Rangel was supported by Postdoctoral Fellowships 256034 and 290807 from CONACYT, México.; J. J. De Jesús-Pérez was supported by Student Fellowship 234820 from CONACYT, México.; This work was supported by grants 219949, and FDC 2016-01-1955 from CONACYT, México to J. Arreola and P. Pérez-Cornejo, by grants 220224 from CONACYT and IN206616 from PAPIIT-DGAPA, UNAM, Mexico to A. Martinez-Torres and by grants R01-EY0114852 and R01-AR067786 from the National Institutes of Health to H. Criss Hartzell.
• Keywords: Poly-unsaturated fatty acids; Biophysics; ION CHANNELS; SECRETION; CONTRIBUTES; Patch clamp; PROTEINS; Biochemistry & Molecular Biology; Regulation; PIP2; VOLTAGE; LIPID RAFTS; CA2+-ACTIVATED CL-CHANNEL; Science & Technology; Cell Biology; Fluorescence microscopy; TMEM16A; Anoctamin; Life Sciences & Biomedicine; ANOCTAMIN 1; PLASMA-MEMBRANE; Lipids
• Research Categories: Biophysics, Medical; Biology, Cell; Biology, Physiology

Abstract

The TMEM16A-mediated Ca2+-activated Cl− current drives several important physiological functions. Membrane lipids regulate ion channels and transporters but their influence on members of the TMEM16 family is poorly understood. Here we have studied the regulation of TMEM16A by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), cholesterol, and fatty acids using patch clamp, biochemistry and fluorescence microscopy. We found that depletion of membrane PI(4,5)P2 causes a decline in TMEM16A current that is independent of cytoskeleton, but is partially prevented by removing intracellular Ca2+. On the other hand, supplying PI(4,5)P2 to inside-out patches attenuated channel rundown and/or partially rescued activity after channel rundown. Also, depletion (with methyl-β-cyclodextrin M-βCD) or restoration (with M-βCD + cholesterol) of membrane cholesterol slows down the current decay observed after reduction of PI(4,5)P2. Neither depletion nor restoration of cholesterol change PI(4,5)P2 content. However, M-βCD alone transiently increases TMEM16A activity and dampens rundown whereas M-βCD + cholesterol increases channel rundown. Thus, PI(4,5)P2 is required for TMEM16A function while cholesterol directly and indirectly via a PI(4,5)P2-independent mechanism regulate channel function. Stearic, arachidonic, oleic, docosahexaenoic, and eicosapentaenoic fatty acids as well as methyl stearate inhibit TMEM16A in a dose- and voltage-dependent manner. Phosphatidylserine, a phospholipid whose hydrocarbon tails contain stearic and oleic acids also inhibits TMEM16A. Finally, we show that TMEM16A remains in the plasma membrane after treatment with M-βCD, M-βCD + cholesterol, oleic, or docosahexaenoic acids. Thus, we propose that lipids and fatty acids regulate TMEM16A channels through a membrane-delimited protein-lipid interaction.