The chloride potassium symporter is a membrane transport protein of the solute carrier family 12 that is present in the S3-segment of the renal proximal tubule[1] and in the neuron.
[2] The concentrations of K+ and Cl− ions are high inside the cell due to the activities of Na+/K+ ATPase and NKCC cotransporter, respectively.
Hence, their net driving force acting on the K/Cl cotransporter favours the exit of both K+ and Cl− from the cell.
Chloride potassium symporter are classified into: Each is encoded by a separate gene of the solute carrier family 12, hence accounting for the numbers succeeding its name.
Notably, symporters prior to 4 in the same family are other types of ion pumps.