WNK1 (WNK Lysine Deficient Protein Kinase 1) is a serine/threonine kinase that plays a crucial role in regulating electrolyte balance and blood pressure. It affects sodium and potassium transport in the kidneys, helping to maintain fluid balance and vascular function. Variants in WNK1 can disrupt this regulation, leading to hereditary hypertension and electrolyte disorders.