Figure 7.

Scheme depicting proposed intracellular signaling pathways and functional consequences in response to stimulation of human neutrophils with LPS. Binding of CD14 by LPS in the presence of LBP initiates a signal that passes though a transmembrane spanning protein and a series of yet unknown upstream signaling events, leading to activation of the MKK3–p38α MAPk cascade. The activator of MKK3 in this cell (MEKK-X) is not known. Activation of p38α MAPk then results in rapid responses such as adhesion and activation of NF-κB. Synthesis of the TNF-α peptide is also dependent on p38α MAPk activation, in part through activation of NF-κB, but primarily through regulation of translation. LBS, lipopolysaccharide-binding protein.