EGFR and infection: Nevertheless, several questions concerning the TMPS mechanism remain to be clarified for complete elucidation of the mechanisms underlying EGFR activation in response to meningitic E. coli invasion, such as identification of the specific member in the metalloproteinase family, the functional domain of metalloproteinases required for ligand precursor cleavage, and the manner in which activation occurs through GPCR signaling in HBMEC upon infection.