Transmembrane 7 superfamily member 2 (TM7SF2, Sterol C14-reductase, 3beta-hydroxysterol Delta-reductase) is a 418 amino acid gene product that belongs to the ERG4/ERG24 family. TM7SF2 is a seven pass transmembrane protein that can localize to the membrane of the endoplasmic reticulum. TM7SF2 is involved in the conversion of lanosterol to cholesterol and, specifically, catalyzes the NADPH dependant reduction of 4,4-dimethyl-5-alpha-cholesta-8,14,24-trien-3-beta-ol to 4,4-dimethyl-5-alpha-cholesta-8,24-dien-3-beta-ol and NADP+.