The asparaginyl hydroxylase factor inhibiting HIF-1 (FIH-1) is an important suppressor of hypoxia-inducible factor (HIF) activity. In addition to HIF-α, FIH-1 was previously shown to hydroxylate other substrates within a highly conserved protein interaction domain, termed the ankyrin repeat domain (ARD). However, to date, the biological role of FIH-1-dependent ARD hydroxylation could not be cla...

OBJECTIVE It has been shown that Mindbomb (Mib), an E3 Ubiquitin ligase, is an essential modulator of Notch signaling during development. However, its effects on vascular development remain largely unknown. APPROACHES AND RESULTS We identified a number of novel proteins that physically interact with Mib, including the Factor Inhibiting Hypoxia Inducible Factor 1 (FIH-1, also known as HIF1AN) ...

Factor-inhibiting hypoxia-inducible factor (FIH) is an Fe(II)/2-oxoglutarate-dependent dioxygenase that acts as a negative regulator of the hypoxia-inducible factor (HIF) by catalysing β-hydroxylation of an asparaginyl residue in its C-terminal transcriptional activation domain (CAD). In addition to the hypoxia-inducible factor C-terminal transcriptional activation domain (HIF-CAD), FIH also ca...

Notch plays a critical role in the transition from proliferation to differentiation in the epidermis and corneal epithelium. Furthermore, aberrant Notch signaling is a feature of diseases like psoriasis, eczema, nonmelanoma skin cancer, and melanoma where differentiation and proliferation are impaired. Whereas much is known about the downstream events following Notch signaling, factors responsi...

BACKGROUND Despite the increase in the number of clinical trials in low and middle income countries (LMICs), there has been little serious discussion of whether First in Human (FIH; phase 0 and phase 1) clinical trials should be conducted in LMICs, and if so, under what conditions. Based on our own experience, studies and consultations, this paper aims to stimulate debate on our contention that...

Glioblastoma multiforme (GBM) accounts for about 38% of primary brain tumors in the United States. GBM is characterized by extensive angiogenesis induced by vascular growth factors and cytokines. The transcription of these growth factors and cytokines is regulated by the Hypoxia-Inducible-Factor-1(HIF-1), which is a key regulator mediating the cellular response to hypoxia. It is known that Fact...

Hypoxia-inducible transcription factor (HIF) is regulated by two oxygen-dependent events that are catalyzed by the HIF prolyl 4-hydroxylases (HIF-P4Hs) and HIF asparaginyl hydroxylase (FIH). We have purified the three recombinant human HIF-P4Hs to near homogeneity and characterized their catalytic properties and inhibition and those of FIH. The specific activities of the HIF-P4Hs were at least ...

Precise regulation of the evolutionarily conserved hypoxia-inducible transcription factor (HIF) ensures proper adaptation to variations in oxygen availability throughout development and into adulthood. Oxygen-dependent regulation of HIF stability and activity are mediated by hydroxylation of conserved proline and asparagine residues, respectively. Because the relevant prolyl and asparginyl hydr...

Post-translational hydroxylation has been considered an unusual modification on intracellular proteins. However, following the recognition that oxygen-sensitive prolyl and asparaginyl hydroxylation are central to the regulation of the transcription factor hypoxia-inducible factor (HIF), interest has centered on the possibility that these enzymes may have other substrates in the proteome. In sup...

Bortezomib (PS-341), a proteasome inhibitor, has been examined clinically for the treatment of multiple myeloma and several solid tumors. Bortezomib directly induces tumor cell death and has also been reported to inhibit tumor adaptation to hypoxia by functionally inhibiting hypoxia-inducible factor-1alpha (HIF-1alpha). However, the mechanism underlying HIF-1 inhibition by bortezomib remains ob...