VHL ligand binding increases intracellular level of VHL

Frost, Julianty ORCID: 0000-0001-8209-2575, Rocha, Sonia ORCID: 0000-0002-2413-4981 and Ciulli, Alessio ORCID: 0000-0002-8654-1670 (2021) VHL ligand binding increases intracellular level of VHL. Journal of Biological Chemistry, 297 (2). 2021.04.12.439487-.

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Official URL: http://dx.doi.org/10.1101/2021.04.12.439487

Abstract

The von–Hippel Lindau (VHL) protein is a tumour suppressor protein frequently mutated in the VHL disease, which functions as substrate recognition subunit of a Cul2 E3 ubiquitin ligase (CRL2 VHL ). CRL2 VHL plays an important role in oxygen sensing, by binding and targeting Hypoxia Inducible Factor-alpha subunits (HIF-alpha) for ubiquitination and degradation. VHL is also commonly hijacked by heterobifunctional degrader molecules known as proteolysis-targeting chimeras (PROTACs). In previous work we reported the structure-based design and functional characterisation of VHL inhibitors (VH032 and VH298) that induce the HIF response in cells. Here, we use unbiased quantitative mass spectrometry to identify the proteomic changes elicited by the VHL inhibitor and compare this to hypoxia or broad-spectrum prolyl-hydroxylase domain (PHD) enzyme inhibitor IOX2. Our results demonstrate the VHL inhibitor selectively activates the HIF response that is also present in the hypoxia- and IOX2-induced proteomic changes. Interestingly, VHL inhibitors were found to selectively upregulate a single protein, which is VHL itself. Our analysis revealed that this occurs via protein stabilisation of VHL isoforms and not via changes in transcript levels. Increased VHL levels upon VH298 treatment resulted in turn to reduced levels of HIF-1α protein. Our results demonstrate the high specificity of VHL inhibitors and suggest that use of these inhibitors would not produce overtly side effects due to prolonged HIF stabilisation. They also exemplify the concept that small-molecule binding induced protein stabilisation can increase protein levels inside cells.

Item Type:	Article
Uncontrolled Keywords:	1 Underpinning research, 5.1 Pharmaceuticals, 2 Aetiology, 5 Development of treatments and therapeutic interventions, 1.1 Normal biological development and functioning, 2.1 Biological and endogenous factors, Cancer, Generic health relevance
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User:	Symplectic Admin
Date Deposited:	05 Apr 2022 14:31
Last Modified:	15 Mar 2024 14:51
DOI:	10.1101/2021.04.12.439487
Open Access URL:	https://www.jbc.org/article/S0021-9258(21)00710-9/...
Related URLs:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3152173