title: Disordered TPPP/p25 binds GTP and displays Mg2+-dependent GTPase activity.
abstract: The disordered Tubulin Polymerization Promoting Protein/p25 (TPPP/p25) modulates the dynamics and stability of the microtubule system and plays a crucial role in differentiation of oligodendrocytes. Here we first demonstrated by multinuclear NMR that the extended disordered segments are localized at the N- and C-terminals straddling a flexible region. We showed by affinity chromatography, fluorescence spectroscopy and circular dichroism that GTP binds to TPPP/p25 likely within the flexible region; neither positions nor intensities of the peaks in the assigned terminals were affected by GTP. In addition, we demonstrated that TPPP/p25 specifically hydrolyses GTP in an Mg(2+)-dependent manner. The GTPase activity is comparable with the intrinsic activities of small G proteins suggesting its potential role in multiple physiological processes.
authors.affiliation: Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, H-1113 Budapest, Hungary.
authors.forename: Agnes
authors.initials: A
authors.lastname: Zotter
authors.forename: Andrea
authors.initials: A
authors.lastname: Bodor
authors.forename: Judit
authors.initials: J
authors.lastname: Oláh
authors.forename: Emma
authors.initials: E
authors.lastname: Hlavanda
authors.forename: Ferenc
authors.initials: F
authors.lastname: Orosz
authors.forename: András
authors.initials: A
authors.lastname: Perczel
authors.forename: Judit
authors.initials: J
authors.lastname: Ovádi
mesh_terms: D020558:GTP Phosphohydrolases / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D008274:Magnesium / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D055550:Protein Stability / Q000187:drug effects
chemical_list: D009419:Nerve Tissue Proteins; C118136:TPPP protein, human; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D008274:Magnesium