Renal Salt and Water Homeostasis: a New Regulatory Pathway Involving the Ser/Thr Kinase PIM-3

Since many years now, scientists believe that a great credit for the blood pressure regulation goes to the kidneys, as their inability in maintaining salt balance and water homeostasis can result in the development of hypertension, the most common disease in the human population. Aldosterone is the key hormone in the control of sodium balance, blood volume and blood pressure, acting in the aldosterone-sensitive distal nephron (ASDN) and stimulating a complex transcriptional, translational and cellular program. We have carried out a gene expression profiling in a mouse cortical collecting duct cell model (mpkCCD), stimulated or not by aldosterone and identified the PIM-3 Ser/Thr kinase as a novel aldosterone-induced protein. PIM kinases (PIM-1, -2 and -3), and in particular PIM-3, are overexpressed in different tumors and are known to be regulators of apoptosis, cell proliferation and cell metabolism. PIM-3, the PIM kinase family member most expressed in the kidney, has similar substrate specificities to o...