Topography and motion of acid-sensing ion channel intracellular domains

eLife

Dana L Kneisley¹  Paul Kammermeier¹  David M Maclean¹  Kyle Berger¹  Tyler W McCullock²  Tyler Couch² 

[1] Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, United States;Graduate Program in Cellular and Molecular Pharmacology and Physiology, Reno, United States;

关键词: ASIC;    FRET;    patch clamp fluorometry;    DPA;    fluorescence;    gating;    None;   

DOI  :  10.7554/eLife.68955

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Acid-sensing ion channels (ASICs) are trimeric cation-selective channels activated by decreases in extracellular pH. The intracellular N and C terminal tails of ASIC1 influence channel gating, trafficking, and signaling in ischemic cell death. Despite several X-ray and cryo-EM structures of the extracellular and transmembrane segments of ASIC1, these important intracellular tails remain unresolved. Here, we describe the coarse topography of the chicken ASIC1 intracellular domains determined by fluorescence resonance energy transfer (FRET), measured using either fluorescent lifetime imaging or patch clamp fluorometry. We find the C terminal tail projects into the cytosol by approximately 35 Å and that the N and C tails from the same subunits are closer than adjacent subunits. Using pH-insensitive fluorescent proteins, we fail to detect any relative movement between the N and C tails upon extracellular acidification but do observe axial motions of the membrane proximal segments toward the plasma membrane. Taken together, our study furnishes a coarse topographic map of the ASIC intracellular domains while providing directionality and context to intracellular conformational changes induced by extracellular acidification.

【 授权许可】

CC BY