Factor Inhibiting HIF (FIH) Asparaginyl Hydroxylase Inhibitors inhibit the FIH pathway also catalyzed by Asparaginyl Hydroxylase inhibition. Before 2010s thought to be identical to HIF prolyl-hydroxylase pathway, studies have shown FIH to be the master regulator (relative to HIF) that controls HIF transcriptional activity in an oxygen-dependent manner.[1] and that HIF prolyl-hydroxylase inhibitors may only minimally inhibit FIH. Skeletal muscle expresses 50-fold higher levels of FIH than other tissues.[1]
The cytoplasmic tail of MT1-MMP, which can bind to FIH-1, promotes inhibition of FIH-1 during normoxia.[2]