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

Verrastro, Ivan, Tveen Jensen, Karina, Spickett, Corinne M and Pitt, Andrew R (2018). The effect of HOCl-induced modifications on phosphatase and tensin homolog (PTEN) structure and function. Free Radical Research , pp. 1-471.

Abstract

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.

Publication DOI: https://doi.org/10.1080/10715762.2018.1424333
Dataset DOI: https://doi.org/10.17036/researchdata.aston.ac.uk.00000317
Divisions: Life & Health Sciences > Pharmacy
Life & Health Sciences > Biosciences
Life & Health Sciences
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: http://www.tandfonline.com/10.1080/10715762.2018.1424333. 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
Full Text Link: https://www.tan ... 62.2018.1424333
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Published Date: 2018-01-03
Authors: Verrastro, Ivan
Tveen Jensen, Karina
Spickett, Corinne M ( 0000-0003-4054-9279)
Pitt, Andrew R ( 0000-0003-3619-6503)

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