Redox modulation of thimet oligopeptidase activity by hydrogen peroxide

Author(s)

Icimoto, Marcelo Y. ; Ferreira, Juliana C. ; Yokomizo, Cesar H. ; Bim, Larissa V. ; Marem, Alyne ; Gilio, Joyce M. ; Oliveira, Vitor ; Nantes, Iseli L.

• Document type: Journal article
• Source: FEBS OPEN BIO; v. 7, n. 7, p. 1037-1050, JUL 2017.
• Web of Science Citations: 2

Abstract

Thimet oligopeptidase (EC 3.4.24.15, TOP) is a cytosolic mammalian zinc protease that can process a diversity of bioactive peptides. TOP has been pointed out as one of the main postproteasomal enzymes that process peptide antigens in the MHC class I presentation route. In the present study, we describe a fine regulation of TOP activity by hydrogen peroxide (H2O2). Cells from a human embryonic kidney cell line (HEK293) underwent an ischemia/reoxygenation-like condition known to increase H2O2 production. Immediately after reoxygenation, HEK293 cells exhibited a 32% increase in TOP activity, but no TOP activity was observed 2 h after reoxygenation. In another model, recombinant rat TOP (rTOP) was challenged by H2O2 produced by rat liver mitoplasts (RLMt) alone, and in combination with antimycin A, succinate, and antimycin A plus succinate. In these conditions, rTOP activity increased 17, 30, 32 and 38%, respectively. Determination of H2O2 concentration generated in reoxygenated cells and mitoplasts suggested a possible modulation of rTOP activity dependent on the concentration of H2O2. The measure of pure rTOP activity as a function of H2O2 concentration corroborated this hypothesis. The data fitted to an asymmetrical bell-shaped curve in which the optimal activating H2O2 concentration was 1.2 nM, and the maximal inhibition (75% about the control) was 1 mu M. Contrary to the oxidation produced by aging associated with enzyme oligomerization and inhibition, H2O2 oxidation produced sulfenic acid and maintained rTOP in the monomeric form. Consistent with the involvement of rTOP in a signaling redox cascade, the H2O2-oxidized rTOP reacted with dimeric thioredoxin-1 (TRx-1) and remained covalently bound to one subunit of TRx-1. (AU)

• FAPESP's process: 12/07456-7 - Flow cytometry studies of cell death and protection promoted by porphyrinoid compounds, phenothiazines and Teluranes associated to nanostructures in a cell biology multiuser lab
• Grantee: Iseli Lourenço Nantes Cardoso
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/20847-0 - Site-specific incorporation of non-natural amino acids in proteins: development of new incorporation technologies and the use in the study of proteins
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• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/05986-6 - Meanings given by users about the results in psychotherapy of psychoanalytic orientation in clinic-school: a clinical-qualitative research
• Grantee: Cássia Regina Rodrigues
• Support Opportunities: Regular Research Grants