Involved in transepithelial sodium transport. Regulates aldosterone-induced and epithelial sodium channel (ENaC)-mediated sodium transport through regulation of ENaC cell surface expression. Acts as a scaffold protein coordinating the assembly of an ENaC-regulatory complex (ERC). Interacts with epithelial sodium channel ENaC. Interacts directly with SCNN1A (ENaC subunit alpha) and SCNN1B (ENaC subunit beta) C-terminal tails. Interacts with ENaC regulatory proteins NEDD4L, RAF1 and SGK1. Up-regulated by aldosterone (at protein level). The PDZ domain is required for interaction with ENaC and SGK1, but not for interaction with NEDDL4 and RAF1. Belongs to the CNKSR family. The gene name MAGI1, shown in this entry as a synonym, is an obsolete human gene nomenclature committee-approved name. It should be noted that MAGI1 currently is the official name for the unrelated membrane-associated guanylate kinase, WW and PDZ domain-containing protein 1.