Required for the expression of gene products mediating border cell migration (PubMed:1459454, PubMed:10949024, PubMed:23305818). Among the DNA sequences that this protein binds with high affinity is a conserved site within the promoter of its gene (PubMed:1459454). Binds DNA as a dimer and can form stable heterodimers (PubMed:1459454). Interacts with trbl (PubMed:23305818). At stage 9 detected in centrally located anterior polar cells, and in border cells before and as they migrate (at protein level). At stage 10, detected in centripetal cells and levels decrease in border cells as they finish migrating (at protein level). Ubiquitination/deubiquitination regulates border cell migration. Ubiquitination is stimulated by trbl, which leads to proteasomal degradation and inhibits border cell migration. Deubiquitination by Usp47, leads to its stabilization and promotes border cell migration. Belongs to the bZIP family. C/EBP subfamily.