Basic leucine zipper (bZIP) domain of Nuclear Factor, Erythroid-derived 2 (NFE2) and similar proteins: a DNA-binding and dimerization domain
This subfamily is composed of NFE2 and NFE2-like proteins including NFE2-like 1 or NFE2-related factor 1 (NFE2L1 or Nrf1), NFE2L2 (or Nrf2), and NFE2L3 (or Nrf3). These are Cap'n'Collar (CNC) Basic leucine zipper (bZIP) transcription factors that are defined by a conserved 43-amino acid region (called the CNC domain) located N-terminal to the bZIP DNA-binding domain. NFE2 functions in development; it is required for the proper development of platelets. The three Nrfs function in stress responses. Nrf2, the most extensively studied member of this subfamily, acts as a xenobiotic-activated receptor that regulates the adaptive response to oxidants and electrophiles. As the master regulator of the antioxidant defense pathway, it plays roles in the biology of inflammation, obesity, and cancer. Nrf1 is an essential protein that binds to the antioxidant response element (ARE) and is also involved in regulating oxidative stress. In addition, it also regulates genes involved in cell and tissue differentiation, inflammation, and hepatocyte homeostasis. bZIP factors act in networks of homo and heterodimers in the regulation of a diverse set of cellular processes. The bZIP structural motif contains a basic region and a leucine zipper, composed of alpha helices with leucine residues 7 amino acids apart, which stabilize dimerization with a parallel leucine zipper domain. Dimerization of leucine zippers creates a pair of the adjacent basic regions that bind DNA and undergo conformational change. Dimerization occurs in a specific and predictable manner resulting in hundreds of dimers having unique effects on transcription.
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