Phospho-c-Myc (Thr244) Antibody recognizes endogenous levels of c-Myc protein only when phosphorylated at Thr244. Thr244 is equivalent to Thr259 in canonical isoform 2 of c-Myc protein.

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Thr244 of human c-Myc protein. Antibodies are purified by peptide affinity chromatography.

Members of the Myc/Max/Mad network function as transcriptional regulators with roles in various aspects of cell behavior, including proliferation, differentiation, and apoptosis (1). These proteins share a common basic-helix-loop-helix leucine zipper (bHLH-ZIP) motif required for dimerization and DNA-binding. Max was originally discovered based on its ability to associate with c-Myc and found to be required for the ability of Myc to bind DNA and activate transcription (2). Subsequently, Max has been viewed as a central component of the transcriptional network, forming homodimers as well as heterodimers with other members of the Myc and Mad families (1). The association between Max and either Myc or Mad can have opposing effects on transcriptional regulation and cell behavior (1). The Mad family consists of four related proteins; Mad1, Mad2 (Mxi1), Mad3, and Mad4, and the more distantly related members of the bHLH-ZIP family, Mnt and Mga. Like Myc, the Mad proteins are tightly regulated with short half-lives. In general, Mad family members interfere with Myc-mediated processes, such as proliferation, transformation, and prevention of apoptosis by inhibiting transcription (3,4).
Phosphorylation of c-Myc at Thr58 and Ser62 can control proteasomal-dependent degradation of the transcription factor. Phosphorylation of c-Myc at these sites is a stepwise process, whereby mitogens, mitosis, or cellular stress induce phosphorylation at Ser62, which serves as a priming site for GSK-3 phosphorylation of Thr58 (5-9). A second phosphodegron was identified at Thr244/Thr248 that acts cooperatively with Thr58/Ser62 to promote c-Myc ubiquitination and proteasomal degradation (10).