Up-regulation of c-fos expression in PRL-3 depleted cells. (A) Cell lysates prepared from the indicated cell lines were examined for the protein levels of c-fos, c-jun and Sp1 by immunoblot. GAPDH was used as a loading control. (B) Total RNA extracted from the indicated cell lines was used for semi-quantitative RT-PCR assay with c-fos-, c-jun- and Sp1-specific primer pairs. GAPDH was used as a control. (C) Model of PRL-3 mediated regulation of integrin α2 via c-Fos.