Following TBI, stimulation of BCR, TCR, cytokine receptors and toll-like receptors (TLRs) by signals that are released in response to brain trauma activate tyrosine kinase adaptor molecules that are present on the cell membrane to recruit the p85 subunit of PI3K, which contributes to the activation of PI3K to catalyze the transformation of phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol 3,4,5-triphosphate (PIP3)24. This evidence concerns the gene BCR and brain injury.