Because both KLF2 and KLF4 were shown to be downstream of increased MEKK3-MEK5-ERK5 signaling in cerebral cavernous malformations,64,65 we next examined the expression of KLF2 and KLF4 in shear stress-exposed HUVECs. Here, MAP3K3 is linked to famililal cerebral cavernous malformations.