title: Phosphoenolpyruvate-dependent tubulin-pyruvate kinase interaction at different organizational levels.
abstract: Evidence for the direct binding of pyruvate kinase to tubulin/microtubule and for the inhibitory effect of phosphoenolpyruvate on tubulin-enzyme hetero-association were provided by surface plasmon resonance and pelleting experiments. Electron microscopy revealed that pyruvate kinase induces depolymerization of paclitaxel-stabilized microtubules into large oligomeric aggregates and bundles the tubules in a salt concentration-dependent manner. The C-terminal "tail"-free microtubules did not bind pyruvate kinase, suggesting the crucial role of the C-terminal segments in the binding of kinase. Immunoblotting and polymerization experiments with cell-free brain extract revealed that pyruvate kinase specifically binds to microtubules, the binding of pyruvate kinase impedes microtubule assembly, and phosphoenolpyruvate counteracts the destabilization of microtubules induced by pyruvate kinase. We also showed by immunostaining the juxtanuclear localization of pyruvate kinase in intact L929 cells and that this localization was influenced by treatments with paclitaxel or vinblastine. These findings suggest that the distribution of the enzyme may be controlled by the microtubular network in vivo.
authors.affiliation: Department of General Zoology, Eötvös Loránd University, P.O. Box 330, H-1445 Budapest, Hungary.
authors.forename: Janos
authors.initials: J
authors.lastname: Kovacs
authors.forename: Peter
authors.initials: P
authors.lastname: Low
authors.forename: Anita
authors.initials: A
authors.lastname: Pacz
authors.forename: Istvan
authors.initials: I
authors.lastname: Horvath
authors.forename: Judit
authors.initials: J
authors.lastname: Olah
authors.forename: Judit
authors.initials: J
authors.lastname: Ovadi
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D002474:Cell-Free System; D015151:Immunoblotting; D007150:Immunohistochemistry; D007700:Kinetics; D051379:Mice; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology; D010728:Phosphoenolpyruvate / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011770:Pyruvate Kinase / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism*; D014747:Vinblastine / Q000494:pharmacology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D014404:Tubulin; D014747:Vinblastine; D010728:Phosphoenolpyruvate; D011770:Pyruvate Kinase; D017239:Paclitaxel