Fig 9.

Model of the regulation of proinflammatory cytokine and chemokine production by MAPKs in THP-1 cells. After retrotranslocation of the Stx A₁ fragment (purple circle) across the ER membrane, depurination of a single adenine in the 28S rRNA ribosomal subunit (blue circles) may lead to a conformational change that allows PKR and possibly other kinases to bind the ribosome. ERK, p38, and JNK MAPKs are activated, resulting in differential regulation of cytokine and chemokine expression. ERK and p38 activation is negatively regulated by DUSP1, while DUSP1 mRNA expression is regulated by p38 MAPKs, creating an autoregulatory loop. Asterisks denote statistical significance. (Adapted from reference 55 with permission of the publisher, John Wiley & Sons.) The figure was made using the Pathway Builder (version 2.0) software.