On the cover: Model of aldosterone action in the principal cell of the aldosterone-sensitive distal nephron (ASDN). Aldosterone binds to its cognate mineralocorticoid receptor (MR) and is translocated into the nucleus, where it binds to the promotor of specific genes leading to the repression (ART) or induction (AIT) of mRNA transcripts (ENaC, NaK-ATPase, and Sgk-1). Sgk-1, in turn, regulates the activity of E3 ubiquitin ligase (Nedd4-2), leading to increased ENaC activity at the cell surface. (See page 596.)