Basic-leucine zipper transcription factors

Basic-leucine zipper transcription factors (bZIP transcription factors) are a superfamily of transcription factors that play key roles in many biological processes in eukaryotes. They are characterized by the presence of a basic region and a leucine zipper motif.

Structure

The bZIP transcription factors are characterized by two structural features: a basic region and a leucine zipper. The basic region is responsible for DNA binding, while the leucine zipper is involved in dimerization.

Basic Region

The basic region of bZIP transcription factors is a stretch of approximately 16 amino acids that is rich in basic residues such as lysine and arginine. This region is responsible for DNA binding and specificity. It recognizes and binds to specific DNA sequences, known as bZIP domains, in the promoter regions of target genes.

Leucine Zipper

The leucine zipper is a structural motif that facilitates dimerization of bZIP transcription factors. It consists of a series of heptad repeats, with leucine residues occurring every seventh position. These leucine residues align along one face of an alpha helix and interact with the leucine residues of a second alpha helix, forming a coiled-coil structure.

Function

bZIP transcription factors regulate gene expression by binding to specific DNA sequences in the promoter regions of target genes. They can function as activators or repressors of transcription, depending on the context. They are involved in a wide range of biological processes, including cell proliferation, differentiation, apoptosis, and response to stress.

Classification

bZIP transcription factors are classified into several subfamilies based on sequence similarities and functional characteristics. These include the CREB/ATF subfamily, the C/EBP subfamily, the AP-1 subfamily, and the NFE2 subfamily, among others.

Clinical Significance

Alterations in the function of bZIP transcription factors have been implicated in a number of diseases, including cancer, neurodegenerative diseases, and immune disorders. As such, they are potential targets for therapeutic intervention.