P-type potassium:proton transporter activity

Definition

Target type: molecularfunction

Enables the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: ATP + H2O + H+(in) + K+(out) = ADP + phosphate + H+(out) + K+(in). [RHEA:22044]

P-type potassium:proton transporter activity describes the molecular function of a protein that actively transports potassium ions (K+) across a biological membrane, coupled with the simultaneous movement of protons (H+). This transport mechanism is driven by the hydrolysis of ATP, hence the "P-type" designation.

The transporter utilizes the energy released from ATP hydrolysis to create a transmembrane electrochemical gradient of potassium ions, which is essential for various physiological processes including:

- **Maintaining cellular pH**: By exporting protons out of the cell, these transporters help regulate intracellular pH, ensuring optimal conditions for enzymatic activity and other cellular processes.

- **Regulation of membrane potential**: The movement of potassium ions across the membrane contributes to the establishment and maintenance of membrane potential, which is crucial for nerve impulse transmission, muscle contraction, and other cellular signaling events.

- **Ion homeostasis**: P-type potassium:proton transporters play a role in maintaining the proper balance of potassium ions within cells, contributing to overall ion homeostasis.

The molecular mechanism of this transport involves multiple steps, including:

1. **Binding of potassium and protons**: The transporter protein has specific binding sites for both potassium and proton ions.

2. **Phosphorylation**: ATP hydrolysis leads to the phosphorylation of a specific amino acid residue within the transporter protein. This phosphorylation event is crucial for conformational changes that facilitate ion translocation.

3. **Conformational change**: Phosphorylation induces a conformational change in the transporter, exposing the bound potassium and proton ions to the opposite side of the membrane.

4. **Release of ions**: The conformational change facilitates the release of potassium and protons into the extracellular space or into the lumen of a cellular compartment.

5. **Dephosphorylation**: After the ions are released, the transporter protein undergoes dephosphorylation, returning to its original conformation and ready for another cycle of ion transport.

Overall, P-type potassium:proton transporter activity is an essential process that contributes to multiple cellular functions, including pH regulation, membrane potential control, and ion homeostasis.'
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Proteins (4)

Compounds (6)