Transcription factor involved in regulating gene activity following the primary growth factor response. Binds to the DNA sequence 5'-TGA[GC]TCA-3'. Heterodimerizes with proteins of the FOS family to form an AP-1 transcription complex, thereby enhancing its DNA binding activity to an AP-1 consensus sequence and its transcriptional activity (By similarity). Binds DNA as a homodimer or as a heterodimer with another member of the Jun/Fos family. Component of an AP-1 transcription factor complex composed of JUN-FOS heterodimers composed of JUN-FOS heterodimers (By similarity). As part of the AP-1 transcription factor complex, forms heterodimers with FOSB, thereby binding to the AP-1 consensus sequence and stimulating transcription (By similarity). Interacts with ITCH (via its WW domains). By growth factors. Ubiquitinated by ITCH, leading to its degradation. Belongs to the bZIP family. Jun subfamily.