We analyzed earlier time points after infection to determine the minimal threshold below which lung endothelial cells become sensitive to VEGF and confirmed that a reduction of endoglin expression by half is indeed required for endothelial cells to respond inadequately to VEGF stimulation, as shown by an increase in Akt and p42/p44 Mitogen Activated Protein Kinase (MAPK) phosphorylation (Figure 5E). Here, AKT1 is linked to infection.