Figure 2. Domain structure of Nrf2 and Keap1.

Keap1 possesses four characteristic domains: the Broad complex, Tramtrack, and Bric-a-Brac (BTB); the intervening region (IVR); the double glycine repeat or Kelch repeat (DGR); and the C-terminal region (CTR). The DGR and CTR domains, also known as DC domain, mediate interaction with Neh2 domain of Nrf2. Nrf2 can be divided into six highly homologous regions (Neh1 to Neh6 domains) through comparing the human and chicken Nrf2 amino acid sequences. Neh2 is responsible for interacting with Keap1.