Effect of diphtheria toxin T-domain on endosomal pH
A key step in the mode of cytotoxic action of diphtheria toxin (DT) is the transfer of its catalytic domain (Cd) from endosomes into the cytosol. The main activity in this process is performed by the transport domain (Td), but the molecular mechanism of its action remains unknown. We have previously...
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| Format: | Article |
| Language: | English |
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National Academy of Sciences of Ukraine, Palladin Institute of Biochemistry
2015-08-01
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| Series: | The Ukrainian Biochemical Journal |
| Subjects: | |
| Online Access: | http://ukrbiochemjournal.org/wp-content/uploads/2015/07/Labyntsev_4-15.pdf |
| _version_ | 1797641736152940544 |
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| author | A. J. Labyntsev N. V. Korotkevych D. V. Kolybo S. V. Komisarenko |
| author_facet | A. J. Labyntsev N. V. Korotkevych D. V. Kolybo S. V. Komisarenko |
| author_sort | A. J. Labyntsev |
| collection | DOAJ |
| description | A key step in the mode of cytotoxic action of diphtheria toxin (DT) is the transfer of its catalytic domain (Cd) from endosomes into the cytosol. The main activity in this process is performed by the transport domain (Td), but the molecular mechanism of its action remains unknown. We have previously shown that Td can have some influence on the endosomal transport of DT. The aim of this work was to study the effect of diphtheria toxin on the toxin compartmentalization in the intracellular transporting pathway and endosomal pH. We used recombinant fragments of DT, which differed only by the presence of Td in their structure, fused with fluorescent proteins. It was shown that the toxin fragment with Td moved slower by the pathway early-late endosomes-lysosomes, and had a slightly different pattern of colocalization with endosomal markers than DT fragment without Td. In addition, endosomes containing DT fragments with Td had a constant pH of about 6.5 from the 10th to 50th minute of observation, for the same time endosomes containing DT fragments without Td demonstrated a decrease in pH from 6.3 to 5.5. These results indicate that Td inhibits acidification of endosomal medium. One of possible explanations for this may be the effect of the ion channel formed by the T-domain on the process of the endosomal acidification. This property of Td may not only inhibit maturation of endosomes but also inhibit activation of endosomal pH-dependent proteases, and this promotes successful transport of Cd into the cell cytosol. |
| first_indexed | 2024-03-11T13:49:55Z |
| format | Article |
| id | doaj.art-3261dd6cd47f4d9e9596cd4603a862dc |
| institution | Directory Open Access Journal |
| issn | 2409-4943 2409-4943 |
| language | English |
| last_indexed | 2024-03-11T13:49:55Z |
| publishDate | 2015-08-01 |
| publisher | National Academy of Sciences of Ukraine, Palladin Institute of Biochemistry |
| record_format | Article |
| series | The Ukrainian Biochemical Journal |
| spelling | doaj.art-3261dd6cd47f4d9e9596cd4603a862dc2023-11-02T09:08:07ZengNational Academy of Sciences of Ukraine, Palladin Institute of BiochemistryThe Ukrainian Biochemical Journal2409-49432409-49432015-08-01874132310.15407/ubj87.04.013Effect of diphtheria toxin T-domain on endosomal pHA. J. Labyntsev 0 N. V. Korotkevych1 D. V. Kolybo2 S. V. Komisarenko3Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;A key step in the mode of cytotoxic action of diphtheria toxin (DT) is the transfer of its catalytic domain (Cd) from endosomes into the cytosol. The main activity in this process is performed by the transport domain (Td), but the molecular mechanism of its action remains unknown. We have previously shown that Td can have some influence on the endosomal transport of DT. The aim of this work was to study the effect of diphtheria toxin on the toxin compartmentalization in the intracellular transporting pathway and endosomal pH. We used recombinant fragments of DT, which differed only by the presence of Td in their structure, fused with fluorescent proteins. It was shown that the toxin fragment with Td moved slower by the pathway early-late endosomes-lysosomes, and had a slightly different pattern of colocalization with endosomal markers than DT fragment without Td. In addition, endosomes containing DT fragments with Td had a constant pH of about 6.5 from the 10th to 50th minute of observation, for the same time endosomes containing DT fragments without Td demonstrated a decrease in pH from 6.3 to 5.5. These results indicate that Td inhibits acidification of endosomal medium. One of possible explanations for this may be the effect of the ion channel formed by the T-domain on the process of the endosomal acidification. This property of Td may not only inhibit maturation of endosomes but also inhibit activation of endosomal pH-dependent proteases, and this promotes successful transport of Cd into the cell cytosol.http://ukrbiochemjournal.org/wp-content/uploads/2015/07/Labyntsev_4-15.pdfconfocal microscopydiphtheria toxinendocytosisendosomal pHfluorescent proteinsT-domain of diphtheria toxin |
| spellingShingle | A. J. Labyntsev N. V. Korotkevych D. V. Kolybo S. V. Komisarenko Effect of diphtheria toxin T-domain on endosomal pH The Ukrainian Biochemical Journal confocal microscopy diphtheria toxin endocytosis endosomal pH fluorescent proteins T-domain of diphtheria toxin |
| title | Effect of diphtheria toxin T-domain on endosomal pH |
| title_full | Effect of diphtheria toxin T-domain on endosomal pH |
| title_fullStr | Effect of diphtheria toxin T-domain on endosomal pH |
| title_full_unstemmed | Effect of diphtheria toxin T-domain on endosomal pH |
| title_short | Effect of diphtheria toxin T-domain on endosomal pH |
| title_sort | effect of diphtheria toxin t domain on endosomal ph |
| topic | confocal microscopy diphtheria toxin endocytosis endosomal pH fluorescent proteins T-domain of diphtheria toxin |
| url | http://ukrbiochemjournal.org/wp-content/uploads/2015/07/Labyntsev_4-15.pdf |
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