CREB

CREB (cAMP response element-binding protein) is a cellular transcription factor. It binds to certain DNA sequences called cAMP response elements (CRE), thereby increasing or decreasing the transcription of the downstream genes. CREB was first described in 1987 as a cAMP-responsive transcription factor regulating the somatostatin gene.

CREB (top) is a transcription factor capable of binding DNA (bottom) and regulating gene expression.  See image on Thought. Image left below.

The 'leucine zipper' is a structure that is believed to mediate the function of several eukaryotic gene regulatory proteins. The zipper consists of a periodic repetition of leucine residues at every seventh position, and regions containing them appear to span 8 turns of alpha-helix. The leucine side chains that extend from one helix interact with those from a similar helix, hence facilitating dimerisation in the form of a coiled-coil. Leucine zippers are present in many gene regulatory proteins, including the CREB proteins, Jun/AP1 transcription factors, fos oncogene and fos-related proteins, C-myc, L-myc and N-myc oncogenes, and so on.

Below right side:--Neuronal activity mediates the formation of neuronal circuits in the cerebral cortex. These processes are regulated by the transcription factor CREB, which regulates gene expression in neuronal activity-dependent processes. Neuronal activity enhances CREB-mediated transcription but the mechanisms remain unclear. CREB binds to a cAMP response element (CRE) in the promoter region of its target genes. Assembly and disassembly of CREB-CRE interactions control spatiotemporal gene expression in the nucleus. However, how CREB interacts with CRE in activity-dependent mechanisms is not known.

The overall structure of the CREB transcription factor. The region in red is the dimerization domain called the leucine zipper. The magnesium ion is in grey and the DNA is multicolored. Rendering of PDB 1DH3.

CREB

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