c-Myc Transcription Factor Assay Kit (Colorimetric) (ab207200)

c-Myc is a transcription factor that regulates cell growth and differentiation, glycolysis and apoptosis and deregulation of c-Myc has been implicated in the origin of diverse human cancers.

c-Myc was originally discovered as the cellular homolog of the retroviral v-myc oncogene, and is a transcription factor involved in a wide variety of cellular processes, including cell proliferation, replicative potential, growth, differentiation and apoptosis. Expression of c-Myc is induced by mitogenic signals and suppressed by growth-inhibitory signals. c-Myc is a member of the basic helix-loop-helix leucine zipper (bHLHzip) family, along with B-Myc, N-Myc, L-Myc and s-Myc. Upon dimerization with the bHLHzip protein Max, c-Myc can bind to the E box motif CACGTG and activate transcription. c-Myc is phosphorylated at Ser62, which has been shown to be a regulatory site of phosphorylation. The phosphorylation of c-Myc causes increased function of the NH2-terminal transactivation domain, and studies have indicated that the expression of MAP kinase is responsible for increased c-Myc phosphorylation at Ser62.

Because of the central role of c-Myc as an activator of diverse cellular processes, regulation of this transcription factor is crucial for proper cell function and ultimate survival. The main regulation of c-Myc occurs through its binding with the bHLHzip protein Max, which can also form heterodimers with members of the Mad family (Mad 1, 3, 4 and Mxi1). As c-Myc cannot bind to DNA without forming a heterodimer with Max, competition between c-Myc and Mad for the common partner Max is used to regulate c-Myc activity. While Max is a relatively stable protein, c-Myc degrades rapidly, with a half-life of 20-30 minutes.