VHL and endothelial dysfunction: AKT, which is regulated by PHD2/VHL independent of HIF2α (19), and AIP1 (ASK1-interacting protein 1, official symbol DAB2IP), a Ras GTPase-activating (GAP) scaffolding protein that regulates a number of signaling pathways including AKT, ERK, JNK, and STAT (24), were investigated to determine the mechanistic underpinnings of pseudohypoxic endothelial dysfunction.