WNK Kinases and Renal Sodium Transport in Health and Disease

Abstract

The with no lysine (WNK) kinases comprise a novel branch of the human kinome that plays a central role in regulating renal sodium, potassium, and chloride transport, and, therefore, blood pressure. Mutations of two WNK kinases, WNK1 and WNK4, cause familial hyperkalemic hypertension (Gordon’s syndrome or Type II pseudohypoaldosteronism), a rare monogenic disease. Many aspects of WNK action have been elucidated during the past seven years. WNKs are all expressed along a short segment of renal distal tubule, where they modulate the activity of a wide variety of transport proteins. These diverse effects, however, make it difficult to describe an integrated model of WNK function within the kidney. Recently, work in vivo and in vitro has begun to clarify this picture. The present review emphasizes recent insights into mechanism by which WNK kinases interact to modulate sodium and potassium transport along the aldosterone-sensitive distal nephron. We describe a potential mechanism by which WNK4 mutations convert the action of WNK4 from inhibiting renal sodium chloride retention to stimulating it, thereby affecting both blood pressure and potassium balance. An explanation for how WNK kinases can alter the effects of aldosterone from primarily kaliuretic to primarily sodium chloride retentive, according to physiological need, is also described.