Transcription factor that recognizes and binds to the enhancer heptamer motif 5'-TGA[CG]TCA-3' (PubMed:1696724, PubMed:2116361). Plays a role in dorsal closure (PubMed:9224723). Heterodimer with kay/Fra (PubMed:1696724, PubMed:2116361). The kay-Jra complex is bound more stably to the AP-1 site than either of the two proteins alone (PubMed:2116361). Interacts with Atf3; the interaction enhances the DNA-binding activity of Atf3 (PubMed:20023169). During embryogenesis, expression is elevated in the amnioserosa, in the cells of the dorsolateral epidermis during and following germ-band retraction, in the cells at the leading dorsal edge of the epidermis and in the cells along the cephalic furrow (at protein level). Expressed during embryonic development. Death in mid to late embryogenesis with large anterior and dorsal holes. Belongs to the bZIP family. Jun subfamily.