Figure 5
From: Novel STAT binding elements mediate IL-6 regulation of MMP-1 and MMP-3
Proposed model for the regulation of MMPs by IL-6/PMA and IFN-γ. Fos/Jun and non-phosphorylated STAT-1 bind constitutively to AP-1 and SBEs elements in the MMP-1 and MMP-3 proximal promoters, maintaining a basal level of gene expression (A). In the presence of IL-6 or PMA, MMP expression is enhanced (green arrow) (B). In response to IFN-γ, STAT-1 is phosphorylated, increasing its affinity for binding to GAS elements in the promoters of IFN-γ responsive genes, displacing STAT-1 from the HDLCs in the MMP gene promoters, resulting in a reduction in expression of these genes (C).
