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Asp residues of the Glu-Glu-Asp-Asp pore filter contribute to ion permeation and selectivity of the Ca(v)3.2 T-type channel.
- Source :
-
Cell calcium [Cell Calcium] 2013 Sep; Vol. 54 (3), pp. 226-35. Date of Electronic Publication: 2013 Jul 09. - Publication Year :
- 2013
-
Abstract
- Voltage-activated Ca2+ channels are membrane protein machinery performing selective permeation of external calcium ions. The main Ca2+ selective filters of all high-voltage-activated Ca2+ channel isoforms are commonly composed of four Glu residues (EEEE), while those of low-voltage-activated T-type Ca2+ channel isoforms are made up of two Glu and two Asp residues (EEDD). We here investigate how the Asp residues at the pore loops of domains III and IV affect biophysical properties of the Ca(v)3.2 channel. Electrophysiological characterization of the pore mutant channels in which the pore Asp residue(s) were replaced with Glu, showed that both Asp residues critically control the biophysical properties of Ca(v)3.2, including relative permeability between Ba2+ and Ca2+, anomalous mole fraction effect (AMFE), voltage dependency of channel activation, Cd2+ blocking sensitivity, and pH effects, in distinctive ways.<br /> (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Subjects :
- Amino Acid Sequence
Animals
Barium metabolism
Cadmium metabolism
Calcium metabolism
Calcium Channels, T-Type chemistry
Calcium Channels, T-Type genetics
Female
Humans
Hydrogen-Ion Concentration
Mutagenesis
Oligopeptides chemistry
Oocytes physiology
Patch-Clamp Techniques
Protein Isoforms chemistry
Protein Isoforms genetics
Protein Isoforms metabolism
Xenopus growth & development
Xenopus physiology
Aspartic Acid chemistry
Calcium Channels, T-Type metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1532-1991
- Volume :
- 54
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Cell calcium
- Publication Type :
- Academic Journal
- Accession number :
- 23849427
- Full Text :
- https://doi.org/10.1016/j.ceca.2013.06.006