Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat
<p>Abstract</p> <p>Background</p> <p>During HIV-1 infection, the Tat protein plays a key role by transactivating the transcription of the HIV-1 proviral DNA. In addition, Tat induces apoptosis of non-infected T lymphocytes, leading to a massive loss of immune competence...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2008-07-01
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| Series: | Retrovirology |
| Online Access: | http://www.retrovirology.com/content/5/1/62 |
| _version_ | 1819026391416438784 |
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| author | Muller Sylviane Chaloin Olivier Allegro Diane Piémont Etienne Didier Pascal Barbier Pascale Egelé Caroline Peyrot Vincent Mély Yves |
| author_facet | Muller Sylviane Chaloin Olivier Allegro Diane Piémont Etienne Didier Pascal Barbier Pascale Egelé Caroline Peyrot Vincent Mély Yves |
| author_sort | Muller Sylviane |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>During HIV-1 infection, the Tat protein plays a key role by transactivating the transcription of the HIV-1 proviral DNA. In addition, Tat induces apoptosis of non-infected T lymphocytes, leading to a massive loss of immune competence. This apoptosis is notably mediated by the interaction of Tat with microtubules, which are dynamic components essential for cell structure and division. Tat binds two Zn<sup>2+ </sup>ions through its conserved cysteine-rich region <it>in vitro</it>, but the role of zinc in the structure and properties of Tat is still controversial.</p> <p>Results</p> <p>To investigate the role of zinc, we first characterized Tat apo- and holo-forms by fluorescence correlation spectroscopy and time-resolved fluorescence spectroscopy. Both of the Tat forms are monomeric and poorly folded but differ by local conformational changes in the vicinity of the cysteine-rich region. The interaction of the two Tat forms with tubulin dimers and microtubules was monitored by analytical ultracentrifugation, turbidity measurements and electron microscopy. At 20°C, both of the Tat forms bind tubulin dimers, but only the holo-Tat was found to form discrete complexes. At 37°C, both forms promoted the nucleation and increased the elongation rates of tubulin assembly. However, only the holo-Tat increased the amount of microtubules, decreased the tubulin critical concentration, and stabilized the microtubules. In contrast, apo-Tat induced a large amount of tubulin aggregates.</p> <p>Conclusion</p> <p>Our data suggest that holo-Tat corresponds to the active form, responsible for the Tat-mediated apoptosis.</p> |
| first_indexed | 2024-12-21T05:25:50Z |
| format | Article |
| id | doaj.art-21f52bcc906c4ee3b4511efa31c476e1 |
| institution | Directory Open Access Journal |
| issn | 1742-4690 |
| language | English |
| last_indexed | 2024-12-21T05:25:50Z |
| publishDate | 2008-07-01 |
| publisher | BMC |
| record_format | Article |
| series | Retrovirology |
| spelling | doaj.art-21f52bcc906c4ee3b4511efa31c476e12022-12-21T19:14:42ZengBMCRetrovirology1742-46902008-07-01516210.1186/1742-4690-5-62Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to TatMuller SylvianeChaloin OlivierAllegro DianePiémont EtienneDidier PascalBarbier PascaleEgelé CarolinePeyrot VincentMély Yves<p>Abstract</p> <p>Background</p> <p>During HIV-1 infection, the Tat protein plays a key role by transactivating the transcription of the HIV-1 proviral DNA. In addition, Tat induces apoptosis of non-infected T lymphocytes, leading to a massive loss of immune competence. This apoptosis is notably mediated by the interaction of Tat with microtubules, which are dynamic components essential for cell structure and division. Tat binds two Zn<sup>2+ </sup>ions through its conserved cysteine-rich region <it>in vitro</it>, but the role of zinc in the structure and properties of Tat is still controversial.</p> <p>Results</p> <p>To investigate the role of zinc, we first characterized Tat apo- and holo-forms by fluorescence correlation spectroscopy and time-resolved fluorescence spectroscopy. Both of the Tat forms are monomeric and poorly folded but differ by local conformational changes in the vicinity of the cysteine-rich region. The interaction of the two Tat forms with tubulin dimers and microtubules was monitored by analytical ultracentrifugation, turbidity measurements and electron microscopy. At 20°C, both of the Tat forms bind tubulin dimers, but only the holo-Tat was found to form discrete complexes. At 37°C, both forms promoted the nucleation and increased the elongation rates of tubulin assembly. However, only the holo-Tat increased the amount of microtubules, decreased the tubulin critical concentration, and stabilized the microtubules. In contrast, apo-Tat induced a large amount of tubulin aggregates.</p> <p>Conclusion</p> <p>Our data suggest that holo-Tat corresponds to the active form, responsible for the Tat-mediated apoptosis.</p>http://www.retrovirology.com/content/5/1/62 |
| spellingShingle | Muller Sylviane Chaloin Olivier Allegro Diane Piémont Etienne Didier Pascal Barbier Pascale Egelé Caroline Peyrot Vincent Mély Yves Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat Retrovirology |
| title | Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat |
| title_full | Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat |
| title_fullStr | Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat |
| title_full_unstemmed | Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat |
| title_short | Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat |
| title_sort | modulation of microtubule assembly by the hiv 1 tat protein is strongly dependent on zinc binding to tat |
| url | http://www.retrovirology.com/content/5/1/62 |
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