Transcription factor AP-1 subunit c-Jun (c-Jun) (c-Jun)

Transcription factor AP-1 subunit c-Jun (c-Jun), encoded by the JUN proto-oncogene, is a pivotal component of the Activator Protein-1 (AP-1) transcription factor complex. It is a leucine zipper protein that forms homo- or heterodimers with other members of the Jun and Fos families to regulate the transcription of genes involved in cell proliferation, differentiation, apoptosis, and the cellular stress response [5, 17]. Under normal physiological conditions, c-Jun activity is transient and tightly controlled by the c-Jun N-terminal kinase (JNK) signaling pathway [9, 20]. However, in many pathological states, particularly various cancers like melanoma and breast cancer, c-Jun is frequently overexpressed or hyperactivated, driving tumor progression, metastasis, and therapeutic resistance [10, 18, 19]. Beyond oncology, c-Jun is an essential mediator in chronic inflammatory disorders such as rheumatoid arthritis and atopic dermatitis [11, 16]. Therapeutic intervention strategies for c-Jun include small molecules that block its DNA-binding capacity, DNAzymes that cleave its messenger RNA, and inhibitors of its upstream activating kinases, although maintaining selectivity without affecting healthy tissue remains a significant challenge [9, 13].

Other names

p39Jun proto-oncogeneActivator protein 1 subunit c-JunAP-1

The activity of c-Jun can be modulated through several distinct therapeutic mechanisms: (1) small molecule inhibitors like T-5224 selectively disrupt the DNA-binding activity of the c-Fos/c-Jun (AP-1) complex [7, 13]; (2) RNA-cleaving DNAzymes, such as DZ13, specifically bind to and cleave c-jun mRNA, thereby preventing protein translation and reducing expression levels [1, 11]; and (3) inhibition of upstream c-Jun N-terminal kinases (JNK) with agents like SP600125 prevents the essential N-terminal phosphorylation at Ser63 and Ser73 required for its transcriptional activation [5, 20].