Role of distinct mitogen-activated protein kinase pathways and cooperationbetween Ets-2, ATF-2 and jun family members in human urokinase-type plasminogen activator gene induction by interleukin-1 and tetradecanoyl phorbol acetate

We have investigated the in vivo and in vitro regulation of the human uroki nase-type plasminogen activator (uPA) gene by interleukin-1 (IL-1) and anal yzed the transcription factors and signalling pathways involved in the resp onse of the -2.0-kb uPA enhancer to IL-1 induction and to tetradecanoyl pho rbol acetate (TPA) induction. Mutational analysis showed the cooperative ac tivity of the Ets-binding site (EBS) and the two AP-1 elements of the enhan cer. The results reveal that the EBS is required for the response to both i nducers mediated by Ets-2, which is regulated at a level subsequent to DNA binding, by an IL-1- and phorbol ester-inducible transactivation domain. Bo th the IL-1 and the TPA-mediated induction result in a drastic increase of AP-1 binding to the downstream site of the enhancer (uPA 3' TPA-responsive element), while a mostly qualitative change, resulting from the interplay b etween ATF-2 homodimers and c-Jun-ATF-2 heterodimers, takes place at the up stream AP-1 element. The analysis of two distinct mitogen-activated protein kinase pathways shows that stress-activated protein kinase-Jun N-terminal kinase activation, resulting in the phosphorylation of ATF-2, c-Jun, and Ju nD, is required not only for the IL-1 but also for the TPA-dependent induct ion, while the extracellular signal-related kinase 1 (ERK-1) and ERK-2 acti vation is involved in the TPA-but not in the IL-1-dependent stimulation of the uPA enhancer.