Activating transcription factor, ATF, is a group of bZIP transcription factors, which act as homodimers or heterodimers with a range of other bZIP factors. [1] First, they have been described as members of the CREB/ATF family, [2] whereas it turned out later that some of them might be more similar to AP-1-like factors such as c-Jun or c-Fos. [3] In general, ATFs are known to respond to extracellular signals and this suggests an important role that they have in maintaining homeostasis. Some of these ATFs, such as ATF3, ATF4, and ATF6 are known to play a role in stress responses. [4] Another example of ATFs function would be ATFx that can suppress apoptosis. [5]
Genes include ATF1, ATF2, ATF3, ATF4, ATF5, ATF6, ATF7, ATFx.
CREB-TF is a cellular transcription factor. It binds to certain DNA sequences called cAMP response elements (CRE), thereby increasing or decreasing the transcription of the genes. CREB was first described in 1987 as a cAMP-responsive transcription factor regulating the somatostatin gene.
A leucine zipper is a common three-dimensional structural motif in proteins. They were first described by Landschulz and collaborators in 1988 when they found that an enhancer binding protein had a very characteristic 30-amino acid segment and the display of these amino acid sequences on an idealized alpha helix revealed a periodic repetition of leucine residues at every seventh position over a distance covering eight helical turns. The polypeptide segments containing these periodic arrays of leucine residues were proposed to exist in an alpha-helical conformation and the leucine side chains from one alpha helix interdigitate with those from the alpha helix of a second polypeptide, facilitating dimerization.
Protein c-Fos is a proto-oncogene that is the human homolog of the retroviral oncogene v-fos. It is encoded in humans by the FOS gene. It was first discovered in rat fibroblasts as the transforming gene of the FBJ MSV. It is a part of a bigger Fos family of transcription factors which includes c-Fos, FosB, Fra-1 and Fra-2. It has been mapped to chromosome region 14q21→q31. c-Fos encodes a 62 kDa protein, which forms heterodimer with c-jun, resulting in the formation of AP-1 complex which binds DNA at AP-1 specific sites at the promoter and enhancer regions of target genes and converts extracellular signals into changes of gene expression. It plays an important role in many cellular functions and has been found to be overexpressed in a variety of cancers.
Transcription factor Jun is a protein that in humans is encoded by the JUN gene. c-Jun, in combination with protein c-Fos, forms the AP-1 early response transcription factor. It was first identified as the Fos-binding protein p39 and only later rediscovered as the product of the JUN gene. c-jun was the first oncogenic transcription factor discovered. The proto-oncogene c-Jun is the cellular homolog of the viral oncoprotein v-jun. The viral homolog v-jun was discovered in avian sarcoma virus 17 and was named for ju-nana, the Japanese word for 17. The human JUN encodes a protein that is highly similar to the viral protein, which interacts directly with specific target DNA sequences to regulate gene expression. This gene is intronless and is mapped to 1p32-p31, a chromosomal region involved in both translocations and deletions in human malignancies.
Activator protein 1 (AP-1) is a transcription factor that regulates gene expression in response to a variety of stimuli, including cytokines, growth factors, stress, and bacterial and viral infections. AP-1 controls a number of cellular processes including differentiation, proliferation, and apoptosis. The structure of AP-1 is a heterodimer composed of proteins belonging to the c-Fos, c-Jun, ATF and JDP families.
Jun dimerization protein 2 (JUNDM2) is a protein that in humans is encoded by the JDP2 gene. The Jun dimerization protein is a member of the AP-1 family of transcription factors.
Transcription factor JunD is a protein that in humans is encoded by the JUND gene.
Transcription factor jun-B is a protein that in humans is encoded by the JUNB gene. Transcription factor jun-B is a transcription factor involved in regulating gene activity following the primary growth factor response. It binds to the DNA sequence 5'-TGA[CG]TCA-3'.
Cyclic AMP-dependent transcription factor ATF-3 is a protein that, in humans, is encoded by the ATF3 gene.
Cyclic AMP-dependent transcription factor ATF-1 is a protein that in humans is encoded by the ATF1 gene.
Activating transcription factor 4 , also known as ATF4, is a protein that in humans is encoded by the ATF4 gene.
Activating transcription factor 6, also known as ATF6, is a protein that, in humans, is encoded by the ATF6 gene and is involved in the unfolded protein response.
Activating transcription factor 2, also known as ATF2, is a protein that, in humans, is encoded by the ATF2 gene.
DNA damage-inducible transcript 3, also known as C/EBP homologous protein (CHOP), is a pro-apoptotic transcription factor that is encoded by the DDIT3 gene. It is a member of the CCAAT/enhancer-binding protein (C/EBP) family of DNA-binding transcription factors. The protein functions as a dominant-negative inhibitor by forming heterodimers with other C/EBP members, preventing their DNA binding activity. The protein is implicated in adipogenesis and erythropoiesis and has an important role in the cell's stress response.
Fos-related antigen 1 (FRA1) is a protein that in humans is encoded by the FOSL1 gene.
Activating transcription factor 5, also known as ATF5, is a protein that, in humans, is encoded by the ATF5 gene.
Cyclic AMP-dependent transcription factor ATF-7 is a protein that in humans is encoded by the ATF7 gene.
Mitogen-activated protein kinase 10 also known as c-Jun N-terminal kinase 3 (JNK3) is an enzyme that in humans is encoded by the MAPK10 gene.
The ATF/CREB family is a group of transcription factors, consisting of different ATFs, CREB, CREM and related proteins. Among the transcription factors assigned to this group, some are more related to CREB-like, factors, whereas other exhibit closer similarity with the AP-1 transcription factor components c-Jun or c-Fos.
The Basic Leucine Zipper Domain is found in many DNA binding eukaryotic proteins. One part of the domain contains a region that mediates sequence specific DNA binding properties and the leucine zipper that is required to hold together (dimerize) two DNA binding regions. The DNA binding region comprises a number of basic amino acids such as arginine and lysine. Proteins containing this domain are transcription factors.