Copper(II) ions affect the gating dynamics of the 20S proteasome

A molecular and in cell study

Anna Maria Santoro, Irene Monaco, Francesco Attanasio, Valeria Lanza, Giuseppe Pappalardo, Marianna Flora Tomasello, Alessandra Cunsolo, Enrico Rizzarelli, Ada De Luigi, Mario Salmona, Danilo Milardi

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Due to their altered metabolism cancer cells are more sensitive to proteasome inhibition or changes of copper levels than normal cells. Thus, the development of copper complexes endowed with proteasome inhibition features has emerged as a promising anticancer strategy. However, limited information is available about the exact mechanism by which copper inhibits proteasome. Here we show that Cu(II) ions simultaneously inhibit the three peptidase activities of isolated 20S proteasomes with potencies (IC 50) in the micromolar range. Cu(II) ions, in cell-free conditions, neither catalyze red-ox reactions nor disrupt the assembly of the 20S proteasome but, rather, promote conformational changes associated to impaired channel gating. Notably, HeLa cells grown in a Cu(II)-supplemented medium exhibit decreased proteasome activity. This effect, however, was attenuated in the presence of an antioxidant. Our results suggest that if, on one hand, Cu(II)-inhibited 20S activities may be associated to conformational changes that favor the closed state of the core particle, on the other hand the complex effect induced by Cu(II) ions in cancer cells is the result of several concurring events including ROS-mediated proteasome flooding, and disassembly of the 26S proteasome into its 20S and 19S components.

Original languageEnglish
Pages (from-to)33444
JournalScientific Reports
Volume6
DOIs
Publication statusPublished - Sep 16 2016

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Proteasome Endopeptidase Complex
Copper
Ions
Cells
Enzyme inhibition
Metabolism
Peptide Hydrolases
Antioxidants

ASJC Scopus subject areas

  • General

Cite this

Santoro, A. M., Monaco, I., Attanasio, F., Lanza, V., Pappalardo, G., Tomasello, M. F., ... Milardi, D. (2016). Copper(II) ions affect the gating dynamics of the 20S proteasome: A molecular and in cell study. Scientific Reports, 6, 33444. https://doi.org/10.1038/srep33444

Copper(II) ions affect the gating dynamics of the 20S proteasome : A molecular and in cell study. / Santoro, Anna Maria; Monaco, Irene; Attanasio, Francesco; Lanza, Valeria; Pappalardo, Giuseppe; Tomasello, Marianna Flora; Cunsolo, Alessandra; Rizzarelli, Enrico; De Luigi, Ada; Salmona, Mario; Milardi, Danilo.

In: Scientific Reports, Vol. 6, 16.09.2016, p. 33444.

Research output: Contribution to journalArticle

Santoro, AM, Monaco, I, Attanasio, F, Lanza, V, Pappalardo, G, Tomasello, MF, Cunsolo, A, Rizzarelli, E, De Luigi, A, Salmona, M & Milardi, D 2016, 'Copper(II) ions affect the gating dynamics of the 20S proteasome: A molecular and in cell study', Scientific Reports, vol. 6, pp. 33444. https://doi.org/10.1038/srep33444
Santoro AM, Monaco I, Attanasio F, Lanza V, Pappalardo G, Tomasello MF et al. Copper(II) ions affect the gating dynamics of the 20S proteasome: A molecular and in cell study. Scientific Reports. 2016 Sep 16;6:33444. https://doi.org/10.1038/srep33444
Santoro, Anna Maria ; Monaco, Irene ; Attanasio, Francesco ; Lanza, Valeria ; Pappalardo, Giuseppe ; Tomasello, Marianna Flora ; Cunsolo, Alessandra ; Rizzarelli, Enrico ; De Luigi, Ada ; Salmona, Mario ; Milardi, Danilo. / Copper(II) ions affect the gating dynamics of the 20S proteasome : A molecular and in cell study. In: Scientific Reports. 2016 ; Vol. 6. pp. 33444.
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