TRIM25, also known as estrogen responsive finger protein (EFP) is a member of the RING finger-B box-coiled coil family and is a downstream target of estrogen receptor a. Mice lacking this gene displayed an underdeveloped uterus and reduced estrogen responsiveness demonstrating that this protein is essential for estrogen dependent proliferation. TRIM25 expression is increased in breast carcinoma where it promotes the growth of breast tumor by functioning as an E3 ubiquitin ligase that targets the negative cell cycle checkpoint 14-3-3s. Recent reports have indicated that TRIM25 E3 ubiquitin ligase is essential for the retinoic-acid-inducible gene 1 (RIG-1) signaling pathway to elicit host antiviral innate immunity.