AP-1 binding and c-Jun activation in synovial cells from mice with collagen-induced arthritis (CIA) after vasoactive intestinal peptide (VIP) treatment. (a) EMSA results from nuclear extracts of synovial cells from CIA or VIP-treated CIA mice, using a radiolabeled oligonucleotide containing the AP-1 consensus binding site. (b) Supershift assay on nuclear extracts of CIA mice using anti-c-Jun, anti-c-Fos or anti-Jun B. (c) Supershift assay on nuclear extracts of VIP-treated CIA mice using anti-c-Jun, anti-c-Fos or anti-Jun B. (d) Western blot analysis showing immunoreactive phosphorylated c-Jun (39 kDa) in cytoplasmic fractions of synovial cells from CIA and VIP-treated CIA mice. A representative experiment of three is shown.