RPL10: Proteins and Enzymes

The c-Jun protein is a major component of the transcription factor AP-1, originally shown to mediate phorbol ester tumor promoter (TPA)-induced expression of responsive genes through the TPA-response element (TRE). The Jun proteins form homo- and heterodimers which bind the TRE, while Fos proteins are active only as heterodimers with any of the Jun proteins. Fos/Jun heterodimers have a much higher affinity for the TRE than Jun homodimers. A distant member of the MAP kinase family, designated c-Jun NH2-terminal kinase (JNK1) functions to regulate c-Jun by phosphorylation at the amino terminal serine regulatory sites, Ser 63 and Ser 73). QM has been described as a transcription factor that can function to bind DNA directly or alternatively can interact with c-Jun to inhibit transactivation of AP-1 promoter driven reporter vectors by Jun-Jun homodimers. QM is highly conserved throughout eukaryotic evolution and is apparently a member of a multi-gene family.