c-Jun is the name of a gene and protein that, in combination with c-Fos, forms the AP-1 early response transcription factor. It was first identified as the Fos-binding protein p39 and only later rediscovered as the product of the c-jun gene. It is activated through double phosphorylation by the JNK pathway but has also a phosphorylation-independent function. c-Jun knockout is lethal, but transgenic animals with a mutated c-Jun that cannot be phosphorylated (termed c-JunAA) can survive.
A recent study was carried out to evaluate the role of c-Jun in cellular proliferation and apoptosis of the endometrium throughout the menstrual cycle. Results suggest that the cyclic change of the c-jun protein levels is significant in the proliferation and apoptosis of glandular epithelial cells. The persistent stromal expression of c-jun protein may prevent stromal cells from entering into apoptosis during the late secretory phase.
This gene is the putative transforming gene of avian sarcoma virus 17. It encodes a protein that is highly similar to the viral protein, and that interacts directly with specific target DNA sequences to regulate gene expression. This gene is intronless and is mapped to 1p32-p31, a chromosomal region involved in both translocations and deletions in human malignancies.
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