Limits...
Self protein-protein interactions are involved in TPPP/p25 mediated microtubule bundling.

DeBonis S, Neumann E, Skoufias DA - Sci Rep (2015)

Bottom Line: However, the C-terminally truncated TPPP/p25 shows a lower Bmax for microtubule binding, suggesting that it may bind to a site of tubulin that is masked in microtubules.Bimolecular fluorescent complementation assays in cells expressing combinations of various TPPP/p25 fragments, but not that of the central folded domain, resulted in the generation of a fluorescence signal colocalized with perinuclear microtubule bundles insensitive to microtubule inhibitors.The data suggest that the central folded domain of TPPP/p25 following binding to microtubules can drive s homotypic protein-protein interactions leading to bundled microtubules.

View Article: PubMed Central - PubMed

Affiliation: Université de Grenoble Alpes, F-38044 Grenoble, France.

ABSTRACT
TPPP/p25 is a microtubule-associated protein, detected in protein inclusions associated with various neurodegenerative diseases. Deletion analysis data show that TPPP/p25 has two microtubule binding sites, both located in intrinsically disordered domains, one at the N-terminal and the other in the C-terminal domain. In copolymerization assays the full-length protein exhibits microtubule stimulation and bundling activity. In contrast, at the same ratio relative to tubulin, truncated forms of TPPP/p25 exhibit either lower or no microtubule stimulation and no bundling activity, suggesting a cooperative phenomenon which is enhanced by the presence of the two binding sites. The binding characteristics of the N- and C-terminally truncated proteins to taxol-stabilized microtubules are similar to the full-length protein. However, the C-terminally truncated TPPP/p25 shows a lower Bmax for microtubule binding, suggesting that it may bind to a site of tubulin that is masked in microtubules. Bimolecular fluorescent complementation assays in cells expressing combinations of various TPPP/p25 fragments, but not that of the central folded domain, resulted in the generation of a fluorescence signal colocalized with perinuclear microtubule bundles insensitive to microtubule inhibitors. The data suggest that the central folded domain of TPPP/p25 following binding to microtubules can drive s homotypic protein-protein interactions leading to bundled microtubules.

No MeSH data available.


Related in: MedlinePlus

Microtubule bundle cold stability induced by TPPP/p25.Microtubules were assembled from tubulin solutions (15 μM) in the absence or presence of TPPP/p25 fragments (15 μM) to steady state and then the temperature was dropped to 4 °C. EM images of the solutions were taken at the indicated times (scale bars = 50 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4542545&req=5

f2: Microtubule bundle cold stability induced by TPPP/p25.Microtubules were assembled from tubulin solutions (15 μM) in the absence or presence of TPPP/p25 fragments (15 μM) to steady state and then the temperature was dropped to 4 °C. EM images of the solutions were taken at the indicated times (scale bars = 50 nm).

Mentions: We then tested the stability of the TPPP/p25-induced MT bundles to cold treatment. At a TPPP/p25 : tubulin stoichiometry of 1:1, the MT bundles in the presence of full length protein were stable after incubation for 1 h at 4 °C (Fig. 2). In contrast, the single MTs observed in the control were depolymerized and protein aggregates were observed. Therefore, we conclude that TPPP/p25 not only has MT bundling activity but also confers cold stability to MT bundles.


Self protein-protein interactions are involved in TPPP/p25 mediated microtubule bundling.

DeBonis S, Neumann E, Skoufias DA - Sci Rep (2015)

Microtubule bundle cold stability induced by TPPP/p25.Microtubules were assembled from tubulin solutions (15 μM) in the absence or presence of TPPP/p25 fragments (15 μM) to steady state and then the temperature was dropped to 4 °C. EM images of the solutions were taken at the indicated times (scale bars = 50 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542545&req=5

f2: Microtubule bundle cold stability induced by TPPP/p25.Microtubules were assembled from tubulin solutions (15 μM) in the absence or presence of TPPP/p25 fragments (15 μM) to steady state and then the temperature was dropped to 4 °C. EM images of the solutions were taken at the indicated times (scale bars = 50 nm).
Mentions: We then tested the stability of the TPPP/p25-induced MT bundles to cold treatment. At a TPPP/p25 : tubulin stoichiometry of 1:1, the MT bundles in the presence of full length protein were stable after incubation for 1 h at 4 °C (Fig. 2). In contrast, the single MTs observed in the control were depolymerized and protein aggregates were observed. Therefore, we conclude that TPPP/p25 not only has MT bundling activity but also confers cold stability to MT bundles.

Bottom Line: However, the C-terminally truncated TPPP/p25 shows a lower Bmax for microtubule binding, suggesting that it may bind to a site of tubulin that is masked in microtubules.Bimolecular fluorescent complementation assays in cells expressing combinations of various TPPP/p25 fragments, but not that of the central folded domain, resulted in the generation of a fluorescence signal colocalized with perinuclear microtubule bundles insensitive to microtubule inhibitors.The data suggest that the central folded domain of TPPP/p25 following binding to microtubules can drive s homotypic protein-protein interactions leading to bundled microtubules.

View Article: PubMed Central - PubMed

Affiliation: Université de Grenoble Alpes, F-38044 Grenoble, France.

ABSTRACT
TPPP/p25 is a microtubule-associated protein, detected in protein inclusions associated with various neurodegenerative diseases. Deletion analysis data show that TPPP/p25 has two microtubule binding sites, both located in intrinsically disordered domains, one at the N-terminal and the other in the C-terminal domain. In copolymerization assays the full-length protein exhibits microtubule stimulation and bundling activity. In contrast, at the same ratio relative to tubulin, truncated forms of TPPP/p25 exhibit either lower or no microtubule stimulation and no bundling activity, suggesting a cooperative phenomenon which is enhanced by the presence of the two binding sites. The binding characteristics of the N- and C-terminally truncated proteins to taxol-stabilized microtubules are similar to the full-length protein. However, the C-terminally truncated TPPP/p25 shows a lower Bmax for microtubule binding, suggesting that it may bind to a site of tubulin that is masked in microtubules. Bimolecular fluorescent complementation assays in cells expressing combinations of various TPPP/p25 fragments, but not that of the central folded domain, resulted in the generation of a fluorescence signal colocalized with perinuclear microtubule bundles insensitive to microtubule inhibitors. The data suggest that the central folded domain of TPPP/p25 following binding to microtubules can drive s homotypic protein-protein interactions leading to bundled microtubules.

No MeSH data available.


Related in: MedlinePlus