Apoptosis Transcription Factors and Regulators

In addition to NFkB and p53, the STAT family of transcription factors and Mad, Max, and c-Myc are also involved in regulating proliferative and pro-apoptotic gene expression. The STAT family of transcription factors is activated by intracellular kinases such as Jak (1-3), TyK2, and Src. Upon activation, STATs are free to hetero- or homo-dimerize and translocate to the nucleus where they promote the expression of Bcl-2 and Bcl-xL. Mad, Max, and c-Myc belong to the basic helix-loop-helix/leucine zipper family of transcription factors. Both c-Myc and Mad form heterodimers with Max to regulate transcription. Mad-Max heterodimers are associated with transcriptional repression and cellular differentiation, while Myc-Max heterodimers are associated with transcriptional activation and cellular proliferation.