Publications

Reductive activation of ricin and ricin A-chain immunotoxins by protein disulfide isomerase and thioredoxin reductase.  (2004)

Authors:
G. Bellisola; G. Fracasso; R. Ippoliti; G. Menestrina; A. Rosén; S. Soldà; S. Udali; R. Tomazzolli; G. Tridente; M. Colombatti
Title:
Reductive activation of ricin and ricin A-chain immunotoxins by protein disulfide isomerase and thioredoxin reductase.
Year:
2004
Type of item:
Articolo in Rivista
Tipologia ANVUR:
Articolo su rivista
Nations of authors:
ITALIA
Language:
Inglese
Format:
A Stampa
Referee:
Name of journal:
Biochemical Pharmacology
ISSN of journal:
0006-2952
N° Volume:
67
Page numbers:
1721-1731
Code PMID:
15081871
Keyword:
Ricin, Immunotoxin, Disulfide reduction, Protein disulfide isomerase, Thioredoxin, Thioredoxin reductase
Short description of contents:
Intracellular activation of ricin and of the ricin A-chain (RTA) immunotoxins requires reduction of their intersubunit disulfide(s). This crucial event is likely to be catalyzed by disulfide oxidoreductases and precedes dislocation of the toxic subunit to the cytosol. We investigated the role of protein disulfide isomerase (EC 5.3.4.1, PDI), thioredoxin (Trx), and thioredoxin reductase (EC 1.8.1.9, TrxR) in the reduction of ricin and of a ricin A-chain immunotoxin by combining enzymatic assays, SDSPAGE separation and immunoblotting. We found that, whereas PDI, Trx, and TrxR used separately were unable to directly reduce ricin and the immunotoxin, PDI and Trx in the presence ofTrxR andNADPHcould reduce both ricin and immunotoxin invitro. PDI functioned only after pre-incubation withTrxR and the reductive activation of ricin was more efficient in the presence of glutathione. Similar results were obtained with microsomal membranes or crude cell extracts. Pre-incubation with the gold(I) compound auranofin, which irreversibly inactivates TrxR, resulted in a dose-dependent inhibition of ricin and immunotoxin reduction. Reductive activation of ricin and immunotoxin decreased or was abolished in microsomes depleted of TrxR and in cell extracts depleted of both PDI and Trx. Pre-incubation of U-937, Molt-3, Jurkat, and DU145 cells with auranofin significantly decreased ricin cytotoxicity with respect to mock-treated controls (P < 0:05). Conversely, auranofin failed to protect cells from the toxicity of pre-reduced ricin which does not require intracellular reduction of disulfide between the two ricin subunits.We conclude that TrxR, by activating disulfide reductase activity of PDI, can ultimately lead to reduction/activation of ricin and immunotoxin in the cell.
 
Reductive activation of ricin [pdf]
Product ID:
20209
Handle IRIS:
11562/303413
Deposited On:
October 19, 2007
Last Modified:
November 2, 2016
Bibliographic citation:
G. Bellisola; G. Fracasso; R. Ippoliti; G. Menestrina; A. Rosén; S. Soldà; S. Udali; R. Tomazzolli; G. Tridente; M. Colombatti, Reductive activation of ricin and ricin A-chain immunotoxins by protein disulfide isomerase and thioredoxin reductase. «Biochemical Pharmacology» , vol. 672004pp. 1721-1731

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