Srebp2: A master regulator of sterol and fatty acid synthesis

Sterol regulatory element-binding proteins (SREBPs, including SREBP1a, SREBP1c, and SREBP2) are basic-helix-loop-helix leucine zipper (bHLH-Zip) transcription factors that regulate the synthesis and cellular uptake of two major building blocks of cell membranes: cholesterol and fatty acids. For cholesterol biosynthesis, SREBPs activate expression of genes such as HMG-CoA reductase (HMGCR), HMG-CoA synthase (HMGCS), and mevalonate kinase (MVK). For cholesterol uptake, SREBPs activate expression of the LDL receptor (LDLR).