Figure 4.

H₂O₂-mediated EGF signaling in the brain. H₂O₂ production in live rat hippocampal neuron cultures can be assayed using PG1. Binding of EGF to its cognate receptor results in upregulation of receptor tyrosine kinase activity and downstream activation of PI3K. Phosphorylation of PIP2 to PIP3 ultimately results in assembly of an active NADPH oxidase complex (NOX) to produce H₂O₂, which is detected by PG1. Addition of small molecule inhibitors such as PD153035, wortmannin, or apocynin results in loss of H₂O₂ production, as indicated by a relative decrease in PG1 fluorescence.