FIGURE 1

Interactions between the STAT3 and NFB pathways. U-STAT3, induced to a high level due to activation of the STAT3 gene in response to ligands such as IL-6, competes with IB for p65/p50. The U-STAT3:U-NFB complex activates the RANTES promoter plus a subset of other promoters that have B elements. U-STAT3 also drives the expression of some genes that do not have B elements, by an unknown mechanism. The B element of the IL-6 gene is driven by canonical NFB signaling in response to ligands such as TNF- or IL-1, setting up a positive feedback loop that is driven by the activation of STAT3 in response to secreted IL-6, leading to an increased level of U-STAT3 that sustains the activation of genes such as RANTES.