Bcl-6: Proteins and Enzymes

Bcl-6 (B-cell lymphoma protein 6; also ZFP51, LAZ-3 and Bcl-5) is an 80 kDa member of the Kruppel-like family of zinc finger proteins. It is expressed in germinal center B cells, neutrophils, monocytes, and immature dendritic cells, and serves as a potent transcriptional repressor of genes such as p53. Human Bcl-6 is 706 amino acids (aa) in length and contains an N-terminal BTB/POZ protein interaction domain (aa 32-99) and a series of six C2H2-type C-terminal zinc finger domains that bind DNA (aa 518-681). Centrally located are three PEST sequences (aa 336-430) that undergo phosphorylation by MAPK. This increases the molecular weight of Bcl-6 to 97 kDa and induces its degradation. Human Bcl-6 is about 99% aa identical to mouse and canine Bcl-6.