Introduction of a disulfide bond into ricin A chain decreases the cytotoxicity of the ricin holotoxin.

Argent, Richard H.; Roberts, Lynne M.; Wales, Richard; Robertus, Jon D.; Lord, J. Michael

doi:10.1016/s0021-9258(18)47076-7

Cited by 46 publications

(7 citation statements)

References 29 publications

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“…In the same experiment, we incubated the cells with the chemically cross-linked mutant CC3-DBB with and without the inhibitor LY294002. CC3-DBB was recovered from the cytosolic (Figure 8, lanes 13,14) and nuclear fractions (lanes 20, 21) in the absence, but not in the presence, of the inhibitor. Thus, even the irreversibly cross-linked mutant CC3-DBB appears to be transported from the cell surface to the cytosol, and it can partly be recovered from the nuclear fraction.…”

Section: Characterization Of Afgf Mutants Containing Internalmentioning

confidence: 97%

“…Falnes et al have shown that introduction of artificial disulfide bonds in the diphtheria toxin A-fragment blocks the translocation step, apparently due to the inability of the protein to unfold sufficiently (12). Also, the toxicity of a mutant of the plant toxin ricin containing an internal disulfide bridge was lower than that of wild-type ricin (13). Experiments with a fusion protein of anthrax toxin and diphtheria toxin A-fragment containing an internal disulfide bond demonstrated that unfolding was also necessary for translocation of anthrax toxin (14).…”

mentioning

confidence: 99%

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Externally Added aFGF Mutants Do Not Require Extensive Unfolding for Transport to the Cytosol and the Nucleus in NIH/3T3 Cells

et al. 2000

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Acidic fibroblast growth factor (aFGF) is transported to the cytosol and the nucleus when added to cells expressing FGF receptors, implying that aFGF must cross cellular membranes. Since protein translocation across membranes commonly requires extensive unfolding of the protein, we were interested in testing whether this is also necessary for membrane translocation of aFGF. We therefore constructed mutant growth factors with intramolecular disulfide bonds to prevent complete unfolding. Control experiments demonstrated that translocation of aFGF by the diphtheria toxin pathway, which requires extensive unfolding of the protein, was prevented by disulfide bond formation, indicating that the introduced disulfide bonds interfered with the unfolding of the growth factor. On the other hand, when the growth factor as such was added to cells expressing FGF receptors, the disulfide-bonded mutants were translocated to the cytosol and the nucleus equally well as wild-type aFGF. The possibility that the translocation of the mutants was due to reduction of the disulfide bonds prior to translocation was tested in experiments using an irreversibly cross-linked mutant. Also this mutant was transported to the cytosol and to the nucleus. The results suggest that extensive unfolding is not required for membrane translocation of aFGF.

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Section: Characterization Of Afgf Mutants Containing Internalmentioning

confidence: 97%

mentioning

confidence: 99%

Externally Added aFGF Mutants Do Not Require Extensive Unfolding for Transport to the Cytosol and the Nucleus in NIH/3T3 Cells

et al. 2000

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“…Other toxins like ricin, Pseudomonas exotoxin A or diphtheria toxin have two separated domains: one with catalytic activity and the other with the ability to cross particular biological membranes. Since these toxins interact with the Sec61 protein-conducting pore, 48 which is responsible for translocation of proteins across the rough endoplasmic reticulum membrane, and since their translocation requires previous unfolding, 49 it has been proposed that these toxins also use Sec61 to reach the cytosol. Several facts indicate that RNases do not follow the same mechanism to cross the lipid bilayer.…”

Section: Lipid Bilayer Translocationmentioning

confidence: 99%

On the track of antitumour ribonucleases

2005

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Ribonucleases (RNases) are potential alternatives to non-mutagenic antitumour drugs. Among these enzymes, onconase, bovine-seminal ribonuclease and the Rana catesbeiana and Rana japonica lectins exert a cytotoxic activity that is selective for tumour cells. A model for the mechanism of cytotoxicity of these RNases which involves different steps is generally accepted. The model predicts that cytotoxicity requires interaction of the RNases with the cell membrane and internalisation to occur by endocytosis. Then, at a precise point, the RNases are translocated to the cytosol where they cleave cellular RNA if they have been able to preserve their ribonucleolytic activity. The cleavage of cellular RNA induces apoptosis but there is evidence suggesting that RNase-triggered apoptosis does not entirely result from the inhibition of protein synthesis. How efficiently a particular RNase carries out each of the steps determines its potency as a cytotoxin.

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“…The members of the RIP family are classified as type I RIPs, which include a single polypeptide chain (~30 kDa) with RNA- N -glycosidase enzyme activity, and type II RIPs that include a lectin domain (ricin toxin B_chain, RTB) and a glycosidase domain (ricin toxin A_chain, RTA) [ 6 ]. These two chains are connected by a single interchain disulfide bond [ 7 ]. Pokeweed antiviral protein (PAP) and trichosanthin (TCS) belong to the subfamily of type I RIP, but abrin and RT are typical type II RIPs [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Integrated Transcriptome and Proteome Analysis Provides Insight into the Ribosome Inactivating Proteins in Plukenetia volubilis Seeds

Yan

Shang

et al. 2022

IJMS

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Plukenetia volubilis is a highly promising plant with high nutritional and economic values. In our previous studies, the expression levels of ricin encoded transcripts were the highest in the maturation stage of P. volubilis seeds. The present study investigated the transcriptome and proteome profiles of seeds at two developmental stages (Pv-1 and Pv-2) using RNA-Seq and iTRAQ technologies. A total of 53,224 unigenes and 6026 proteins were identified, with functional enrichment analyses, including GO, KEGG, and KOG annotations. At two development stages of P. volubilis seeds, 8815 unique differentially expressed genes (DEGs) and 4983 unique differentially abundant proteins (DAPs) were identified. Omics-based association analysis showed that ribosome-inactivating protein (RIP) transcripts had the highest expression and abundance levels in Pv-2, and those DEGs/DAPs of RIPs in the GO category were involved in hydrolase activity. Furthermore, 21 RIP genes and their corresponding amino acid sequences were obtained from libraries produced with transcriptome analysis. The analysis of physicochemical properties showed that 21 RIPs of P. volubilis contained ricin, the ricin_B_lectin domain, or RIP domains and could be divided into three subfamilies, with the largest number for type II RIPs. The expression patterns of 10 RIP genes indicated that they were mostly highly expressed in Pv-2 and 4 transcripts encoding ricin_B_like lectins had very low expression levels during the seed development of P. volubilis. This finding would represent valuable evidence for the safety of oil production from P. volubilis for human consumption. It is also notable that the expression level of the Unigene0030485 encoding type I RIP was the highest in roots, which would be related to the antiviral activity of RIPs. This study provides a comprehensive analysis of the physicochemical properties and expression patterns of RIPs in different organs of P. volubilis and lays a theoretical foundation for further research and utilization of RIPs in P. volubilis.

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Introduction of a disulfide bond into ricin A chain decreases the cytotoxicity of the ricin holotoxin.

Cited by 46 publications

References 29 publications

Externally Added aFGF Mutants Do Not Require Extensive Unfolding for Transport to the Cytosol and the Nucleus in NIH/3T3 Cells

Externally Added aFGF Mutants Do Not Require Extensive Unfolding for Transport to the Cytosol and the Nucleus in NIH/3T3 Cells

On the track of antitumour ribonucleases

Integrated Transcriptome and Proteome Analysis Provides Insight into the Ribosome Inactivating Proteins in Plukenetia volubilis Seeds

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