The effect of HOCl-induced modifications on phosphatase and tensin homolog (PTEN) structure and function


Oxidation by reactive species can cause changes in protein function and affect cell signaling pathways. Phosphatase and tensin homolog (PTEN) is a negative regulator of the PI3K/AKT pathway and is known to be inhibited by oxidation, but its oxidation by the myeloperoxidase-derived oxidant hypochlorous acid (HOCl) has not previously been investigated. PTEN-GST was treated with HOCl:protein ratios from 15:1 to 300:1. Decreases in PTEN phosphatase activity were observed at treatment ratios of 60:1 and higher, which correlated with the loss of the intact protein band and appearance of high molecular weight aggregates in SDS-PAGE. LC-MSMS was used to map oxidative modifications (oxPTMs) in PTEN-GST tryptic peptides and label-free quantitative proteomics used to determine their relative abundance. Twenty different oxPTMs of PTEN were identified, of which 14 were significantly elevated upon HOCl treatment in a dose-dependent manner. Methionine and cysteine residues were the most heavily oxidized; the percentage modification depended on their location in the sequence, reflecting differences in susceptibility. Other modifications included tyrosine chlorination and dichlorination, and hydroxylations of tyrosine, tryptophan, and proline. Much higher levels of oxidation occurred in the protein aggregates compared to the monomeric protein for certain methionine and tyrosine residues located in the C2 and C-terminal domains, suggesting that their oxidation promoted protein destabilization and aggregation; many of the residues modified were classified as buried according to their solvent accessibility. This study provides novel information on the susceptibility of PTEN to the inflammatory oxidant HOCl and its effects on the structure and activity of the protein.

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Divisions: College of Health & Life Sciences > Aston Pharmacy School
College of Health & Life Sciences > School of Biosciences
College of Health & Life Sciences
College of Health & Life Sciences > Chronic and Communicable Conditions
College of Health & Life Sciences > Aston Medical School
College of Health & Life Sciences > School of Biosciences > Cellular and Molecular Biomedicine
Additional Information: © 2018 Informa UK Limited, publishing as Taylor & Francis. This is an Accepted Manuscript of an article published by Taylor & Francis in Free Radical Research on 3rd January 2018, available online: Funding: Engineering and Physical Sciences Research Council (EP/I017887/1 Cross-Disciplinary Research Landscape Award)
Uncontrolled Keywords: Cysteine Oxidation,hypochlorous acid, mass spectrometry, oxidative post-translational modifications,protein aggregation,tyrosine chlorination
Publication ISSN: 1029-2470
Last Modified: 01 Apr 2024 07:23
Date Deposited: 04 Jan 2018 12:40
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Related URLs: https://www.tan ... 62.2018.1424333 (Publisher URL)
PURE Output Type: Article
Published Date: 2018-02-01
Published Online Date: 2018-01-03
Accepted Date: 2018-01-02
Authors: Verrastro, Ivan
Tveen Jensen, Karina
Spickett, Corinne M (ORCID Profile 0000-0003-4054-9279)
Pitt, Andrew R (ORCID Profile 0000-0003-3619-6503)



Version: Accepted Version

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