|   Send via email

Research

With the aging of society central nervous system disorders including conformational diseases (for example Parkinson’s and Alzheimer’s diseases) as well as multiple sclerosis become more and more widespread with serious health and socio-economic burden. The development of these diseases is a multi-step process initiated by aberrant homo- and/or hetero-associations of distinct proteins. The pathological interactions result in formation of aggregates leading to the destruction of specific groups of neuron/glia cells in the brain. Besides the classical hallmark proteins of these diseases such as alpha-synuclein and beta-amyloid playing crucial roles in the formation of inclusion bodies, identification of new players is indispensable to understand the pathomechanisms responsible for disease development, which is essential for design and development of highly specific drug molecules against these neurological disorders.

The Cell Architecture research group has recently discovered a brain-specific protein and denoted it as Tubulin Polymerization Promoting Protein (TPPP/p25) based on its function and molecular weight. It has been revealed that TPPP/p25 does not have a well-defined 3D structure similarly as the hallmark proteins of neurodegenerative diseases such as alpha-synuclein and beta-amyloid. Prediction and experimental analysis proved that the disordered regions are localized at the N- and C-termini of TPPP/p25, which straddle a highly flexible, middle region. This middle region involves different ligand- and protein-binding segments: it binds and specifically hydrolyses GTP; binds zinc ion inducing local structural alteration (molten globule); associates to tubulin as physiological and alpha-synuclein/beta-amyloid as pathological protein partners, respectively.

Atypical histone deacetylases, which exert their activities in the cytosol, are responsible for the removal of the acetyl-group on tubulin. These tubulin deacetylases are the NAD+-dependent SIRT2 and the histone deacetylase-6 (HDAC6). Acetylation-derived microtubule dynamics plays crucial roles physiologically in cell division, formation/destruction of the mitotic spindle, regulation of projection elongation during differentiation, as well as pathologically in aggresome formation which serves as a protective mechanism. The research group observed that the expression of TPPP/p25 significantly increased the acetylation level of tubulin, which influences the stability and dynamics of microtubules. The molecular mechanism responsible for this effect was identified, namely that TPPP/p25 interacts with HDAC6 and inhibits its deacetylase activity.

Under pathological conditions TPPP/p25 interacts with alpha-synuclein resulting in the formation of inclusion bodies; these two proteins are co-localized in human brain, which is characteristic for Parkinson’s disease and other synucleinopathies. The dysfunction of TPPP/p25 leads to the destruction of myelin sheath, consequently to the development of multiple sclerosis. Abnormally high TPPP/p25 level was found in the cerebrospinal fluid of patients suffering from multiple sclerosis, which may serve as a biomarker for the early diagnosis of the disease. TPPP/p25 is a prototype of the neomorphic moonlighting proteins which display distinct physiological and pathological functions without alterations at gene level.

The main task of the research group is to understand, characterize and specifically influence the regulation of these interactions both at molecular and cellular levels. The results of these studies provide valuable new information on the role of the interactions of TPPP/p25 in the formation of the microtubule ultra-structures with specific functions, contribute to the better understanding of the inhibitory/activating effects of the physiologically and pathologically relevant complexes at molecular and cellular levels, which opens a new perspective for the identification of drug targets, design of specific drug molecules, and treatment of distinct neurological diseases.

They deal with the in silico phylogenetic investigation of TPPP proteins. They defined family of TPPP-like proteins. Within this family, they identified and named a new protein, apicortin, which is one of the characteristic proteins of the phylum Apicomplexa. (The phylum Apicomplexa contains also the pathogens of malaria.) They clarified by synteny analysis (based on the identification of conservative gen blocks) that one of the three paralogues being present in fishes, the tppp3-like gene, is an orthologue of mammalian Tppp2 gene. In contrast to the other two paralogs, the genomic position of this gene is not constant either among vertebrates or in fishes. They highlighted the problem that host genome sequences can easily be contaminated with parasite sequences, which was shown by the example of two recently published vertebrate genomes. The systematic positions of the contaminating un-known apicomplexan parasites were identified by the analyses. One of them belongs to the Nephroisospora genus, for which only one member has been known before.

Collaborations

Prof. Perczel András, Eötvös Loránd Tudományegyetem,Kémiai Intézet

Prof. Magyar Anna, Eötvös Loránd Tudományegyetem,Kémiai Intézet

Prof. Fidy Judit, Semmelweis Egyetem, Biofizikai Intézet

Prof. Berki Timea, Pécsi Tudományegytem, Immunológiai Intézet

Prof. Dombrádi Viktor, Debreceni Tudományegyetem, Orvosi Vegytani intézet

Prof. Penke Botond, Szegedi Tudományegyetem, Orvosi Kémiai Intézet

Prof. Vécsei László, Szegedi Tudományegyetem, Neurológiai Intézet

Prof. Kovács G. Gábor, Institute of Neurology, Medical University of Vienna, Austria

Prof. Manfed Jung, Albert-Ludwigs-Universität Freiburg, Germany

Prof. Marival Bermejo, Institute of Pharmacology, Miguel Hernández University, Spain

Dr. Pierre Lau, National Institute of Neurological Disorders, NIH, Bethesda, USA

Prof. Victor Norris, Faculty of Science, University of Rouen, France

Equipment

NuAire biological safety cabinet, Biosafe II level (Class II),

NuAire air jacketed CO2-incubator,

with Hepa-filter and automatic CO2 control,

ESCO Class II BSC Airstream biological safety cabinet, Biosafe II level

Olympus inverse CKX41 microscope,

Olympus C5050 with automatic camera (5.0 MP)

Cary 50 UV-visible spectrophotometer (Varian)

Cary 100 UV- visible spectrophotometer (Varian)

Equipment for preparation and characterisation of proteins

Amicon protein concentrator cells, gel electrophoresis and Western-blot equipment, chromatography columns

Eppendorf centrifuge.

Mathematica software, v. 4.1. (Wolfram Research)

Common equipment:: Zeiss LSM 710 confocal microscope

Configuration:

Lasers:

diode laser (405 nm), 30mW

Ar-laser (458, 488, 514 nm), 25 mW

HeNe-laser (543 nm), 1 mW

HeNe-laser (633 nm), 5 mW

Objectives

Plan Apo 10x, N.A.=0.3

Plan Apo 20x, N.A.=0.8 (DIC)

Plan Apo 40x, N.A.=1.4

Plan Apo 63x, N.A.=1.4 (DIC)

Software:

ZEN 2011 basic software r

FRET module license

FRAP module license

Detector:

Spectral detection: Standard: 2, simultaneous confocal fluorescence channels

 

Actual grants

Physiological and pathological interactions of the disordered TPPP/p25 :mapping of the binding motifs

OTKAK-101039 (2012-2016)

Project leader: Ovádi Judit

THE ROLE OF THE TUBULIN POLYMERIZATION PROMOTING PROTEIN (TPPP/p25) IN THE CELL PROTECTING PROCESSES OF THE NERVOUS SYSTEM, IN THE AUTOPHAGY AND IN THE PROTEASOME AND AGGRESOME SYSTEMS. A peptidomimetic foldamer as potential drug against synucleinopathies

OTKA K-112144 (2015-2017)

Project leader: Ovádi Judit

Zinc-Net: the Network for the Biology of Zinc

EU COST Action TD1304 (2013-2017)

Epigenetic Chemical Biology (EPICHEM)

EU COSTAction -TD0905 (2014-2018)

Group leader

Dr. Ferenc Orosz, scientific advisor

Publications

Members

Dr. Judit Ovádi , professor emerita

Publications

Dr. Judit Oláh, senior research fellow

Publications

Dr. Attila Lehotzky , research fellow

Publications

Dr. Orsolya Vincze , research fellow

Publications

Dr. Tibor Szénási, junior research fellow

Publications

Sándor  Szunyogh, junior research fellow

Adél Szabó, PhD student, BME

Marianna Csaplár, MSc student, BME

Kinga Kovács  MSc student, BME