Further evidence for microtubule-independent dimerization of TPPP/p25

Abstract

Tubulin Polymerization Promoting Protein (TPPP/p25) is a brain-specific disordered protein that modulates the dynamics and stability of the microtubule network by its assembly promoting, cross-linking and acetylation enhancing activities. In normal brain it is expressed primarily in differentiated oligodendrocytes; however, at pathological conditions it is enriched in inclusions of both neurons and oligodendrocytes characteristic for Parkinson’s disease and multiple system atrophy, respectively. The objective of this paper is to highlight a critical point of a recently published Skoufias’s paper in which the crucial role of the microtubules in TPPP/p25 dimerization leading to microtubule bundling was suggested. However, our previous and present data provide evidence for the microtubule-independent dimerization of TPPP/p25 and its stabilization by disulphide bridges. In addition, our bimolecular fluorescence complementation experiments revealed the dimerization ability of both the full length and the terminal-free (CORE) TPPP/p25 forms, however, while TPPP/p25 aligned along the bundled microtubule network, the associated CORE segments distributed mostly homogeneously within the cytosol. Now, we identified a molecular model from the possible ones suggested in the Skoufias’s paper that could be responsible for stabilization of the microtubule network in the course of the oligodendrocyte differentiation, consequently in the constitution of the myelin sheath.

Interactions between two regulatory proteins of microtubule dynamics, HDAC6, TPPP/p25, and the hub protein, DYNLL/LC8

“…Control experiments revealed that neither the empty Venus vectors [42] nor the Venus fusion constructs of LC8-2 and -synuclein produce a BiFC signal ( Supplementary Fig. 7A), that concerns with the in vitro ELISA data (cf.…”

“…The BiFC plasmids (pBiFC-V N1-173 , pBiFC-V C155-238 ) were a gift of Prof. Péter Várnai (Semmelweis University, Budapest). The V N -TPPP/p25 plasmid containing the insert for human FL TPPP/p25 was prepared as described previously [42]. Plasmid V C -LC8-2 was produced by inserting the LC8-2 coding region in frame into pBiFC-V C155-238 by EcoRI and SalI restriction enzymes.…”

“…The unstructured, multifunctional protein, TPPP/p25 has been extensively characterized concerning its structural and functional features [4,14,42]. Distinct binding segments, its flexible CORE region and the extended unstructured termini were identified that are involved in multifarious interactions including its dimerization coupled with physiological function [4,14,42].…”

Modulation Of Microtubule Acetylation By The Interplay Of TPPP/p25, SIRT2 And New Anticancer Agents With Anti-SIRT2 Potency

“…The BiFC plasmids (pBiFC-VN1-173, pBiFC-VC155-238) were a gift of Prof. Péter Várnai (Semmelweis University, Budapest). The V C -TPPP/p25 plasmid containing the insert for human full length TPPP/p25 was prepared as described previously 14 , 43 . Plasmid V N -SIRT2 was produced by inserting the SIRT2 coding region in frame 25 into pBiFC-VN1-173 by XhoI and BamHI restriction enzymes.…”

A Variation in FGF14 Is Associated with Downbeat Nystagmus in a Genome-Wide Association Study

“…The remaining 7 variants were localized in genes involved in the cytoskeleton (MAST4, TPPP), iron homeostasis (FTMT), lysosomal degradation of sulfate esters (IDS), glutamate carboxypeptidases (NAALADL2), and fertility according to their sole expression in reproductive organs (DSCR4, SPATA19). Of these, MAST4 [62], TPPP [63], FTMT [64], and IDS [65] have been linked to pathological processes in the brain.…”