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Basic leucine zipper (bZIP) domain of CCAAT/enhancer-binding protein epsilon (CEBPE): a DNA-binding and dimerization domain CEBPE is a critical regulator of terminal granulocyte differentiation or granulopoiesis. It is expressed only in myeloid cells. Mice deficient with CEBPE are normal at birth and fertile, but they do not produce normal neutrophils or eosinophils, and show impaired inflammatory and bacteriocidal responses. Functional loss of CEBPE causes the rare congenital disorder, Neutrophil-specific granule deficiency (SGD), which is characterized by patients' neutrophils with atypical nuclear morphology, abnormal migration and bactericidal activity, and the lack of specific granules. Patients with SGD suffer from severe and frequent bacterial infections. CEBPs (or C/EBPs) are Basic leucine zipper (bZIP) transcription factors that regulate many cellular processes. There are six CEBP proteins in mammalian cells including CEBPA (alpha), CEBPB (beta), CEBPG (gamma), CEBPD (delta), and CEBPE (epsilon), which all contain highly conserved bZIP domains at their C-termini and variations at their N-terminal regions. 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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