Hypoxia Inducible Factor-α Binding and Ubiquitylation by the von Hippel-Lindau Tumor Suppressor Protein

pVHL, the product of von Hippel-Lindau (VHL) tumor suppressor gene, functions as the substrate recognition component of an E3-ubiquitin ligase complex that targets hypoxia inducible factor α (HIF-α) for ubiquitination and degradation. Besides HIF-α, pVHL also interacts with other proteins and has multiple functions. Here, we report that pVHL inhibits ribosome biogenesis and protein synthesis. We find that pVHL associates with the 40S ribosomal protein S3 (RPS3) but does not target it for destruction. Rather, the pVHL-RPS3 association interferes with the interaction between RPS3 and RPS2. Expression of pVHL also leads to nuclear retention of pre-40S ribosomal subunits, diminishing polysomes and 18S rRNA levels. We also demonstrate that pVHL suppresses both cap-dependent and cap-independent protein synthesis. Our findings unravel a novel function of pVHL and provide insight into the regulation of ribosome biogenesis by the tumor suppressor pVHL.

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Oxygen-Dependent Ubiquitination and Degradation of Hypoxia-Inducible Factor Requires Nuclear-Cytoplasmic Trafficking of the von Hippel-Lindau Tumor Suppressor Protein

Molecular and Cellular Biology ◽

10.1128/mcb.22.15.5319-5336.2002 ◽

2002 ◽

Vol 22 (15) ◽

pp. 5319-5336 ◽

Cited By ~ 112

Author(s):

Isabelle Groulx ◽

Stephen Lee

Keyword(s):

Tumor Suppressor ◽

Rna Polymerase Ii ◽

Nuclear Export ◽

Hypoxia Inducible Factor ◽

Tumor Suppressor Protein ◽

Nuclear Compartment ◽

Von Hippel Lindau ◽

Substrate Protein ◽

Subsequent Degradation ◽

Substrate Proteins

ABSTRACT It is becoming increasingly evident that the degradation of nuclear proteins requires nuclear-cytoplasmic trafficking of both the substrate proteins, as well as the E3 ubiquitin-ligases. Here, we show that nuclear-cytoplasmic trafficking of the von Hippel-Lindau tumor suppressor protein (VHL) is required for oxygen-dependent ubiquitination and degradation of the alpha subunits of hypoxia-inducible factor (HIF-α). VHL engages in a constitutive transcription-sensitive nuclear-cytoplasmic shuttle unaffected by oxygen tension or levels of nuclear substrate HIF-α. Ubiquitinated forms of HIF-α, as well as VHL/ubiquitinated HIF-α complexes, are found solely in the nuclear compartment of normoxic or reoxygenated VHL-competent cells. HIF-α localizes exclusively in the nucleus of hypoxic cells but is exported to the cytoplasm upon reoxygenation. Oxygen-dependent nuclear ubiquitination and nuclear export of HIF-α can be prevented by treatment with an HIF-specific prolyl hydroxylase inhibitor. Treatment with inhibitors of RNA polymerase II activity, which interfere with the ability of VHL to engage in nuclear export, also prevents cytoplasmic accumulation of HIF-α in reoxygenated cells. This caused a marked increase in the HIF-α half-life without affecting its nuclear ubiquitination. We present a model by which VHL-mediated ubiquitination of HIF-α and its subsequent degradation are dependent upon dynamic nuclear-cytoplasmic trafficking of both the E3 ubiquitin-ligase and the nuclear substrate protein.

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Proline hydroxylation at different sites in hypoxia-inducible factor 1α modulates its interactions with the von Hippel–Lindau tumor suppressor protein

Physical Chemistry Chemical Physics ◽

10.1039/c8cp01964a ◽

2018 ◽

Vol 20 (27) ◽

pp. 18756-18765

Author(s):

Hongsheng Qian ◽

Yu Zou ◽

Yiming Tang ◽

Yehong Gong ◽

Zhenyu Qian ◽

...

Keyword(s):

Tumor Suppressor ◽

Conformational Change ◽

Hypoxia Inducible Factor ◽

Tumor Suppressor Protein ◽

Von Hippel Lindau ◽

Hypoxia Inducible Factor 1Α ◽

Proline Hydroxylation

Proline hydroxylation of HIF-1α affects the interaction affinity between pVHL and HIF-1α and allosterically induces the conformational change of pVHL.

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