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Proteomics to Identify Proteins Interacting with P2X2 Ligand-Gated Cation Channels
Published on: May 18, 2009
Expression level dependent changes in the properties of P2X2 receptors
J D Clyne1, T C Brown, R I Hume
1Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3095 Natural Science Building, 830 N. University Avenue, Ann Arbor, MI 48109-1048, USA.
Neuropharmacology
|February 27, 2003
Summary
Cell-to-cell variability in P2X(2) receptors is linked to expression levels. Higher expression correlates with increased sensitivity to ATP, impacting potentiation by zinc and pH.
Area of Science:
- Neuroscience
- Molecular Biology
- Biophysics
Background:
- P2X(2) receptors exhibit significant variability in cellular responses.
- Factors influencing this variability, such as expression levels, remain unclear.
Purpose of the Study:
- To investigate the relationship between P2X(2) receptor expression levels and functional variability.
- To determine if expression levels affect potentiation by zinc and acidic pH.
Main Methods:
- Xenopus oocytes were injected with varying concentrations of P2X(2) receptor RNA.
- Maximum current amplitudes and potentiation ratios by zinc/acidic pH were measured.
- EC(50) for ATP and Hill coefficient were analyzed in relation to expression levels.
Main Results:
- A wide range of potentiation ratios (1.4- to 25-fold) was observed.
- Oocytes with lower ATP-induced currents showed higher potentiation ratios.
- An inverse correlation was found between EC(50) for ATP and maximum current amplitude, with higher expression decreasing EC(50).
Conclusions:
- P2X(2) receptor expression levels significantly influence functional properties, including ATP sensitivity.
- Expression-dependent changes involve domains near amino acid position H397.
- Understanding these relationships is crucial for interpreting P2X(2) receptor function.
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