The Outer Pore and Selectivity Filter of TRPA1.
TRPA1 (transient-receptor-potential-related ion channel with ankyrin domains) is a direct receptor or indirect effector for a wide variety of nociceptive signals, and thus is a compelling target for development of analgesic pharmaceuticals such as channel blockers. Recently, the structure of TRPA1 was reported, providing insights into channel assembly and pore architecture. Here we report whole-cell and single-channel current recordings of wild-type human TRPA1 as well as TRPA1 bearing point mutations of key charged residues in the outer pore. These measurements demonstrate that the glutamate at position 920 plays an important role in collecting cations into the mouth of the pore, by changing the effective surface potential by ~16 mV, while acidic residues further out have little effect on permeation. Electrophysiology experiments also confirm that the aspartate residue at position 915 represents a constriction site of the TRPA1 pore and is critical in controlling ion permeation.
Program in Neuroscience, Harvard Medical School, 220 Longwood Ave, Boston, Massachusetts, United States of America.|Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Ave, Boston, Massachusetts, United States of America.
Adam P
AP
Christensen
Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Ave, Boston, Massachusetts, United States of America.
Nurunisa
http://orcid.org/0000-0002-6340-1915
N
Akyuz
Program in Neuroscience, Harvard Medical School, 220 Longwood Ave, Boston, Massachusetts, United States of America.|Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Ave, Boston, Massachusetts, United States of America.
David P
DP
Corey
D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid / Q000235:genetics; D016466:CHO Cells; D015220:Calcium Channels / Q000235:genetics*; D003412:Cricetulus; D018698:Glutamic Acid / Q000235:genetics; D006801:Humans; D015640:Ion Channel Gating / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010539:Permeability; D017354:Point Mutation / Q000235:genetics; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000235:genetics*
D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels; D001224:Aspartic Acid; D018698:Glutamic Acid