Ecdysone receptor

The ecdysone receptor is a nuclear receptor found in arthropods, where it controls development and contributes to other processes such as reproduction. The receptor is a non-covalentheterodimer of two proteins, the ecdysone receptor (EcR) protein and ultraspiracle protein (USP). It binds to and is activated by ecdysteroids. Insect ecdysone receptors are currently better characterized than those from other arthropods, and mimics of ecdysteroids are used commercially as caterpillar-selective insecticides.

EcR and USP are the insect orthologs of the mammalianfarnesoid X receptor (FXR) and retinoid X receptor (RXR) proteins, respectively. Based on sequence homology considerations, some researchers reserve the term USP for the EcR partner from lepidopteran and dipteran insects, and use RXR in all other instances.