PUBLICATION
Polar residues in the second transmembrane domain of the rat P2X2 receptor that affect spontaneous gating, unitary conductance, and rectification
- Authors
- Cao, L., Broomhead, H.E., Young, M.T., and North, R.A.
- ID
- ZDB-PUB-091120-48
- Date
- 2009
- Source
- The Journal of neuroscience : the official journal of the Society for Neuroscience 29(45): 14257-14264 (Journal)
- Registered Authors
- Keywords
- none
- MeSH Terms
-
- Mutation
- Cell Line
- Molecular Sequence Data
- Amino Acid Sequence
- Blotting, Western
- Protein Conformation
- Patch-Clamp Techniques
- Receptors, Purinergic P2X2
- Adenosine Triphosphate/metabolism
- Animals
- Rats
- Models, Molecular
- Humans
- Receptors, Purinergic P2/chemistry*
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism*
- Time Factors
- Membrane Potentials/physiology
- Sequence Homology, Amino Acid
- PubMed
- 19906973 Full text @ J. Neurosci.
Citation
Cao, L., Broomhead, H.E., Young, M.T., and North, R.A. (2009) Polar residues in the second transmembrane domain of the rat P2X2 receptor that affect spontaneous gating, unitary conductance, and rectification. The Journal of neuroscience : the official journal of the Society for Neuroscience. 29(45):14257-14264.
Abstract
Membrane ion channels activated by extracellular ATP (P2X receptors) are widely distributed in the nervous system. Their molecular architecture is fundamentally distinct from that of the nicotinic or glutamate receptor families. We have measured single-channel currents, spontaneous gating, and rectification of rat P2X2 receptor in which polar and charged residues of the second transmembrane domain (TM2) were systematically probed by mutagenesis. The results suggest that Asn(333) and Asp(349) lie respectively in external and internal vestibules. Substitutions at Asn(333), Thr(336), and Ser(340) were particularly likely to cause spontaneously active channels. At Thr(336), Thr(339), and Ser(340), the introduction of positive charge (Arg, Lys, or His, or Cys followed by treatment with 2-aminoethyl methanethiosulphonate) greatly enhanced outward currents, suggesting that side-chains of these three residues are exposed in the permeation pathway of the open channel. These functional findings are interpreted in the context of the recently reported 3.1 A crystal structure of the zebrafish P2X4.1 receptor in the closed state. They imply that the gate is formed by residues Asn(333) to Thr(339) and that channel opening involves a counter-clockwise rotation and separation of the TM2 helices.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping