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The invention relates to an isolated or recombinant Na + /H + exchanger comprising an isolated or recombinant Na + /H + exchanger, particularly to the PBO-4 Na + /H + exchanger. Also disclosed is an isolated or recombinant protein component of an H + -gated channel which can be affected by extracellular Ca 2+ concentration. In particular, the invention relates to PBO-5 and/or PBO-8 and/or a H + -gated channel composed of PBO-5 and PBO-8. The invention relates to compounds isolated from a vertebrate organism, wherein said compounds comprise at least a part of a H + -gated channel or Na + /H + exchanger. The invention also relates to a method for identifying a component of a H + -gated channel in a vertebrate organism.
1. An isolated or recombinant component of a H + -gated channel, comprising a component having at least 80% identity to PBO-5 (SEQ ID NO:2) or PBO-8 (SEQ ID NO:3 or SEQ ID NO:4).
2. The isolated or recombinant component of a H+-gated channel of claim 1 , wherein said H + -gated cation channel has a Hill coefficient of approximately 9 and a pH 10 at approximately pH 7.0.
3. The isolated or recombinant component of a H + -gated channel of claim 1 comprising SEQ ID NO:2.
4. The isolated or recombinant component of a H + -gated channel of claim 1 , wherein the protein component comprises SEQ ID NO:3 or SEQ ID NO:4.
5. An isolated ligand-gated cation channel, comprising a H + ion activated heteromultimeric cation channel, wherein at least two components of the heteromultimeric cation channel have at least 80% identity to PBO-5 (SEQ ID NO:2) and PBO-8 (SEQ ID NO:3 or SEQ ID NO:4).
6. The isolated ligand-gated cation channel of claim 5 , comprising PBO-5 (SEQ ID NO: 2) and PBO-8 (SEQ ID NO:3 or SEQ ID NO: 4).
7. The isolated ligand-gated cation channel of claim 5 , having 10% maximal activation at approximately pH 7.0.
8. The isolated ligand-gated cation channel of claim 5 , having a Hill coefficient of approximately 9.
9. The isolated ligand-gated cation channel of claim 5 , wherein said ligand-gated cation channel is isolated from a vertebrate organism.