EGF (Epidermal Growth Factor) protein, of the superfamily with the same name, is synthesized as a large precursor molecule that is proteolytically cleaved to generate the 53-amino acid epidermal growth factor peptide. This protein acts a potent mitogenic factor that plays an important role in the growth, proliferation and differentiation of numerous cell types. It is a magnesiotropic hormone that stimulates magnesium reabsorption in the renal distal convoluted tubule via engagement of EGFR and activation of the magnesium channel TRPM6. This protein acts by binding the high affinity cell surface receptor, epidermal growth factor receptor. Defects in this gene are the cause of hypomagnesemia type 4 (HOMG4). Dysregulation of this gene has been associated with the growth and progression of certain cancers. Alternate splicing results in multiple transcript variants. This protein exists in the membrane as a single-pass type I membrane protein, and contains 9 EGF-like domains as well as 9 LDL-receptor class B repeats. It is significantly expressed in kidney, salivary gland, cerebrum and prostate.