Eva Csosz

Publications

• 3.04

  Impact points

  Functional significance of five noncanonical Ca-binding sites of human transglutaminase 2 characterized by site-directed mutagenesis.

  Róbert Király, Eva Csősz, Tibor Kurtán, Sándor Antus, Krisztián Szigeti, Zsófia Simon-Vecsei, Ilma Rita Korponay-Szabó, Zsolt Keresztessy, László Fésüs

  The FEBS journal. 10/2009;

  The multifunctional tissue transglutaminase 2 (TG2) has a four-domain structure with several Ca(2+)-regulated biochemical activities, including transglutamylation and GTP hydrolysis. The structure of the Ca(2+)-binding form of the human enzyme is not known, and its Ca(2+)-binding sites have not been... [more] The multifunctional tissue transglutaminase 2 (TG2) has a four-domain structure with several Ca(2+)-regulated biochemical activities, including transglutamylation and GTP hydrolysis. The structure of the Ca(2+)-binding form of the human enzyme is not known, and its Ca(2+)-binding sites have not been fully characterized. By mutagenesis, we have targeted its active site Cys, three sites based on homology to Ca(2+)-binding residues of epidermal transglutaminase and factor XIIIa (S1-S3), and two regions with negative surface potentials (S4 and S5). CD spectroscopy, antibody-binding assay and GTPase activity measurements indicated that the amino acid substitutions did not cause major structural alterations. Calcium-45 equilibrium dialysis and isothermal calorimetric titration showed that both wild-type and active site-deleted enzymes (C277S) bind six Ca(2+). Each of the S1-S5 mutants binds fewer than six Ca(2+), S1 is a strong Ca(2+)-binding site, and mutation of one site resulted in the loss of more than one bound Ca(2+), suggesting cooperativity among sites. All mutants were deficient in transglutaminase activity, and GTP inhibited remnant activities. Like those of the wild-type enzyme, the GTPase activities of the mutants were inhibited by Ca(2+), except in the case of the S4 and S5 mutants, which exhibited increased activity. TG2 is the major autoantigen in celiac disease, and testing the reactivity of mutants with autoantibodies from celiac disease patients revealed that S4 strongly determines antigenicity. It can be concluded that five of the Ca(2+)-binding sites of TG2 influence its transglutaminase activity, two sites are involved in the regulation of GTPase activity, and one determines antigenicity for autoantibodies in celiac patients.
• 3.87

  Impact points

  Substrate Preference of Transglutaminase 2 Revealed by Logistic Regression Analysis and Intrinsic Disorder Examination.

  Eva Csosz, Peter Bagossi, Zoltan Nagy, Zsuzsanna Dosztanyi, Istvan Simon, Laszlo Fesus

  Journal of molecular biology. 09/2008;

  Tissue transglutaminase (TG2) catalyzes the Ca(2+)-dependent posttranslational modification of proteins via formation of isopeptide bonds between their glutamine and lysine residues. Although substrate specificity of TG2 has been studied repeatedly at the sequence level, no clear consensus sequences... [more] Tissue transglutaminase (TG2) catalyzes the Ca(2+)-dependent posttranslational modification of proteins via formation of isopeptide bonds between their glutamine and lysine residues. Although substrate specificity of TG2 has been studied repeatedly at the sequence level, no clear consensus sequences have been determined so far. With the use of the extensive structural information on TG2 substrate proteins listed in TRANSDAB Wiki databasedagger, a slight preference of TG2 for glutamine and lysine residues situated in turns could be observed. When the spatial environment of the favored glutamine and lysine residues was analyzed with logistic regression, the presence of specific amino acid patterns was identified. By using the occurrence of the predictor amino acids as selection criteria, several polypeptides were predicted and later identified as novel in vitro substrates for TG2. By studying the sequence of TG2 substrate proteins lacking available crystal structure, the strong favorable influence on substrate selection of the presence of substrate glutamine and lysine residues in intrinsically disordered regions could also be revealed. The collected structural data have provided novel understanding of how this versatile enzyme selects its substrates in various cell compartments and tissues.
• 3.88

  Impact points

  Transdab wiki: the interactive transglutaminase substrate database on web 2.0 surface.

  Eva Csősz, Bertalan Meskó, László Fésüs

  Amino acids. 08/2008;

  TRANSDAB wiki is a database of transglutaminase substrate proteins. This wiki is designed to provide quality content of all the details (including synonyms, structures, references) about transglutaminase substrate proteins and interaction partners. Currently TRANSDAB contains 243 articles about subs... [more] TRANSDAB wiki is a database of transglutaminase substrate proteins. This wiki is designed to provide quality content of all the details (including synonyms, structures, references) about transglutaminase substrate proteins and interaction partners. Currently TRANSDAB contains 243 articles about substrate proteins for 6 transglutaminase types in a user-friendly, editable format. Our aim was to collect structural information about substrate proteins and this information is provided in form of images, videos and links. The scientific community is invited to edit the database and besides providing up-to-date information, this wiki should serve as a platform for valuable discussions.
• 2.94

  Impact points

  Phage display selection of efficient glutamine-donor substrate peptides for transglutaminase 2.

  Zsolt Keresztessy, Eva Csosz, Jolán Hársfalvi, Krisztián Csomós, Joe Gray, Robert N Lightowlers, Jeremy H Lakey, Zoltán Balajthy, László Fésüs

  Protein science : a publication of the Protein Society. 12/2006; 15(11):2466-80.

  Understanding substrate specificity and identification of natural targets of transglutaminase 2 (TG2), the ubiquitous multifunctional cross-linking enzyme, which forms isopeptide bonds between protein-linked glutamine and lysine residues, is crucial in the elucidation of its physiological role. As a... [more] Understanding substrate specificity and identification of natural targets of transglutaminase 2 (TG2), the ubiquitous multifunctional cross-linking enzyme, which forms isopeptide bonds between protein-linked glutamine and lysine residues, is crucial in the elucidation of its physiological role. As a novel means of specificity analysis, we adapted the phage display technique to select glutamine-donor substrates from a random heptapeptide library via binding to recombinant TG2 and elution with a synthetic amine-donor substrate. Twenty-six Gln-containing sequences from the second and third biopanning rounds were susceptible for TG2-mediated incorporation of 5-(biotinamido)penthylamine, and the peptides GQQQTPY, GLQQASV, and WQTPMNS were modified most efficiently. A consensus around glutamines was established as pQX(P,T,S)l, which is consistent with identified substrates listed in the TRANSDAB database. Database searches showed that several proteins contain peptides similar to the phage-selected sequences, and the N-terminal glutamine-rich domain of SWI1/SNF1-related chromatin remodeling proteins was chosen for detailed analysis. MALDI/TOF and tandem mass spectrometry-based studies of a representative part of the domain, SGYGQQGQTPYYNQQSPHPQQQQPPYS (SnQ1), revealed that Q(6), Q(8), and Q(22) are modified by TG2. Kinetic parameters of SnQ1 transamidation (K(M)(app) = 250 microM, k(cat) = 18.3 sec(-1), and k(cat)/K(M)(app) = 73,200) classify it as an efficient TG2 substrate. Circular dichroism spectra indicated that SnQ1 has a random coil conformation, supporting its accessibility in the full-length parental protein. Added together, here we report a novel use of the phage display technology with great potential in transglutaminase research.
• 0.42

  Impact points

  Structure-function relationships of transglutaminases--a contemporary view.

  Zoltán Nemes, Goran Petrovski, Eva Csosz, László Fésüs

  Progress in experimental tumor research. Fortschritte der experimentellen Tumorforschung. Progrès de la recherche expérimentale des tumeurs. 02/2005; 38:19-36.