Figure 6.

Model of PCB 95-induced synaptogenesis. Under basal conditions, p250GAP suppresses Rac1 activation to repress synaptogenesis. PCB 95 exposure sensitizes RyR1 and RyR2 to increase release of internal Ca²⁺ stores. Increased cytoplasmic Ca²⁺ triggers phosphorylation of CREB, stimulating CREB-dependent transcription. CREB activation increases transcription of miR132, a transcriptional repressor that suppresses p250GAP translation. The decreased translation of p250GAP effectively releases inhibition on Rac1 activity to increase synaptogenesis.