Autores: <div class="autor_fcen" id="3633">Gerez, J.</div>; Fuertes, M.; Tedesco, L.; <div class="autor_fcen" id="8107">Silberstein, S.</div>; Sevlever, G.; <div class="autor_fcen" id="6349">Paez-Pereda, M.</div>; Holsboer, F.; <div class="autor_fcen" id="8715">Turjanski, A.G.</div>; Arzt, E.
Fecha de publicación: 2013.
RSUME (RWD-containing SUMO Enhancer) is a small protein that increases SUMO conjugation to proteins. To date, four splice variants that codify three RSUME isoforms have been described, which differ in their C-terminal end. Comparing the structure of the RSUME isoforms we found that, in addition to the previously described RWD domain in the N-terminal, all these RSUME variants also contain an intermediate domain. Only the longest RSUME isoform presents a C-terminal domain that is absent in the others. Given these differences, we used the shortest and longest RSUME variants for comparative studies. We found that the C-terminal domain is dispensable for the SUMO-conjugation enhancer properties of RSUME. We also demonstrate that these two RSUME variants are equally induced by hypoxia. The NF-κB signaling pathway is inhibited and the HIF-1 pathway is increased more efficiently by the longest RSUME, by means of a greater physical interaction of RSUME267 with the target proteins. In addition, the mRNA and protein levels of these isoforms differ in human glioma samples; while the shortest RSUME isoform is expressed in all the tumors analyzed, the longest variant is expressed in most but not all of them. The results presented here show a degree of redundancy of the RSUME variants on the SUMO pathway. However, the increased inhibition conferred by RSUME267 over the NF-κB signaling pathway, the increased activation over the HIF-1 pathway and the different expression of the RSUME isoforms suggest specific roles for each RSUME isoform which may be relevant in certain types of brain tumors that express RSUME, like human pituitary adenomas and gliomas. © 2013 Gerez et al.
Afiliación de los autores: Gerez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Silberstein, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Paez-Pereda, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Turjanski, A.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Palabras claves: hypoxia inducible factor 1; immunoglobulin enhancer binding protein; messenger RNA; protein variant; regulator protein; RWD containing SUMO enhancer protein; SUMO protein; unclassified drug; article; brain cancer; carboxy terminal sequence; computer model; controlled study; gene expression; human; human tissue; molecular pathology; molecular weight; nucleotide sequence; protein domain; protein expression; protein function; protein processing; protein protein interaction; regulator gene; RWD containing SUMO enhancer gene; signal transduction; structure activity relation; structure analysis.
Autores: <div class="autor_fcen" id="6922">Presman, D.M.</div>; <div class="autor_fcen" id="223">Alvarez, L.D.</div>; <div class="autor_fcen" id="4951">Levi, V.</div>; Eduardo, S.; Digman, M.A.; <div class="autor_fcen" id="5439">Martí, M.A.</div>; <div class="autor_fcen" id="8885">Veleiro, A.S.</div>; <div class="autor_fcen" id="1252">Burton, G.</div>; <div class="autor_fcen" id="6520">Pecci, A.</div>
Fecha de publicación: 2010.
Background: The glucocorticoid receptor (GR) is a transcription factor that regulates gene expression in a ligand-dependent fashion. This modular protein is one of the major pharmacological targets due to its involvement in both cause and treatment of many human diseases. Intense efforts have been made to get information about the molecular basis of GR activity. Methodology/Principal Findings: Here, the behavior of four GR-ligand complexes with different glucocorticoid and antiglucocorticoid properties were evaluated. The ability of GR-ligand complexes to oligomerize in vivo was analyzed by performing the novel Number and Brightness assay. Results showed that most of GR molecules form homodimers inside the nucleus upon ligand binding. Additionally, in vitro GR-DNA binding analyses suggest that ligand structure modulates GRDNA interaction dynamics rather than the receptor's ability to bind DNA. On the other hand, by coimmunoprecipitation studies we evaluated the in vivo interaction between the transcriptional intermediary factor 2 (TIF2) coactivator and different GR-ligand complexes. No correlation was found between GR intranuclear distribution, cofactor recruitment and the homodimerization process. Finally, Molecular determinants that support the observed experimental GR LBD-ligand/TIF2 interaction were found by Molecular Dynamics simulation. Conclusions/Significance: The data presented here sustain the idea that in vivo GR homodimerization inside the nucleus can be achieved in a DNA-independent fashion, without ruling out a dependent pathway as well. Moreover, since at least one GR-ligand complex is able to induce homodimer formation while preventing TIF2 coactivator interaction, results suggest that these two events might be independent from each other. Finally, 21-hydroxy-6,19-epoxyprogesterone arises as a selective glucocorticoid with potential pharmacological interest. Taking into account that GR homodimerization and cofactor recruitment are considered essential steps in the receptor activation pathway, results presented here contribute to understand how specific ligands influence GR behavior. © 2010 Presman et al.
Afiliación de los autores: Presman, D.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Alvarez, L.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Levi, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Martí, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Veleiro, A.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Burton, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Pecci, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Palabras claves: 21 hemisuccinate 6,19 epoxyprogesterone; 21 hydroxy 6,19 epoxyprogesterone; dexamethasone; glucocorticoid receptor; glucocorticoid receptor antagonist; mifepristone; nuclear receptor coactivator 2; unclassified drug; DNA; glucocorticoid receptor; steroid; article; binding affinity; cell assay; cell culture; cell strain BHK; cell strain COS7; cell strain L 929; cell type; computer model; conformational transition; controlled study; dissociation; DNA drug complex; drug mechanism; drug receptor binding; genetic transfection; in vitro study; in vivo study; incubation time; ligand binding; modulation; molecular dynamics; oligomerization; protein DNA binding; protein DNA interaction; protein function; steroid binding; structure activity relation; animal; cell line; cell strain COS1; Cercopithecus; chemical structure; dimerization; gel mobility shift assay; immunoprecipitation; metabolism; protein binding; Animals; Cell Line; Cercopithecus aethiops; COS Cells; Dimerization; DNA; Electrophoretic Mobility Shift Assay; Immunoprecipitation; Models, Molecular; Molecular Dynamics Simulation; Protein Binding; Receptors, Glucocorticoid; Steroids.
Fecha de publicación: 2004.
This report describes a new set of macromolecular descriptors of relevance to protein QSAR/QSPR studies, protein's quadratic indices. These descriptors are calculated from the macromolecular pseudograph's α-carbon atom adjacency matrix. A study of the protein stability effects for a complete set of alanine substitutions in Arc repressor illustrates this approach. Quantitative Structure-Stability Relationship (QSSR) models allow discriminating between near wild-type stability and reduced-stability A-mutants. A linear discriminant function gives rise to excellent discrimination between 85.4% (35/41) and 91.67% (11/12) of near wild-type stability/reduced stability mutants in training and test series, respectively. The model's overall predictability oscillates from 80.49 until 82.93, when n varies from 2 to 10 in leave-n-out cross validation procedures. This value stabilizes around 80.49% when n was > 6. Additionally, canonical regression analysis corroborates the statistical quality of the classification model (Rcanc = 0.72, p-level <0.0001). This analysis was also used to compute biological stability canonical scores for each Arc A-mutant. On the other hand, nonlinear piecewise regression model compares favorably with respect to linear regression one on predicting the melting temperature (t m) of the Arc A-mutants. The linear model explains almost 72% of the variance of the experimental tm (R = 0.85 and s = 5.64) and LOO press statistics evidenced its predictive ability (q2 = 0.55 and s cv = 6.24). However, this linear regression model falls to resolve tm predictions of Arc A-mutants in external prediction series. Therefore, the use of nonlinear piecewise models was required. The tm values of A-mutants in training (R = 0.94) and test (R = 0.91) sets are calculated by piecewise model with a high degree of precision. A break-point value of 51.32°C characterizes two mutants' clusters and coincides perfectly with the experimental scale. For this reason, we can use the linear discriminant analysis and piecewise models in combination to classify and predict the stability of the mutants' Arc homodimers. These models also permit the interpretation of the driving forces of such a folding process. The models include protein's quadratic indices accounting for hydrophobic (z1), bulk-steric (z2), and electronic (z3) features of the studied molecules. Preponderance of z1 and z3 over z 2 indicates the higher importance of the hydrophobic and electronic side chain terms in the folding of the Arc dimer. In this sense, developed equations involve short-reaching (k ≤ 3), middle- reaching (3 < k ≤ 7) and far-reaching (k = 8 or greater) z1, 2, 3-protein's quadratic indices. This situation points to topologic/topographic protein's backbone interactions control of the stability profile of wild-type Arc and its A-mutants. Consequently, the present approach represents a novel and very promising way to mathematical research in biology sciences.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)
Palabras claves: Ciencias Exactas; Química; Farmacia; protein; amino acid substitution; macromolecule; mutant; quantitative structure activity relation; alanine; dimerization; stereoisomerism; alanine-substitution mutant; arc repressor; protein quadratic indices; protein stability; QSPR; TOMOCOMD software.
Repositorio: SEDICI (UNLP). Universidad Nacional de La Plata
Autores: <div class="autor_fcen" id="1816">Chemes, L.B.</div>; Glavina, J.; <div class="autor_fcen" id="184">Alonso, L.G.</div>; Marino-Buslje, C.; <div class="autor_fcen" id="2390">de Prat-Gay, G.</div>; Sánchez, I.E.
Fecha de publicación: 2012.
In the present work, we have used the papillomavirus E7 oncoprotein to pursue structure-function and evolutionary studies that take into account intrinsic disorder and the conformational diversity of globular domains. The intrinsically disordered (E7N) and globular (E7C) domains of E7 show similar degrees of conservation and co-evolution. We found that E7N can be described in terms of conserved and coevolving linear motifs separated by variable linkers, while sequence evolution of E7C is compatible with the known homodimeric structure yet suggests other activities for the domain. Within E7N, inter-residue relationships such as residue co-evolution and restricted intermotif distances map functional coupling and co-occurrence of linear motifs that evolve in a coordinate manner. Within E7C, additional cysteine residues proximal to the zinc-binding site may allow redox regulation of E7 function. Moreover, we describe a conserved binding site for disordered domains on the surface of E7C and suggest a putative target linear motif. Both homodimerization and peptide binding activities of E7C are also present in the distantly related host PHD domains, showing that these two proteins share not only structural homology but also functional similarities, and strengthening the view that they evolved from a common ancestor. Finally, we integrate the multiple activities and conformations of E7 into a hierarchy of structure-function relationships. © 2012 Chemes et al.
Afiliación de los autores: Chemes, L.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Alonso, L.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: de Prat-Gay, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Palabras claves: cysteine; protein E7; zinc; article; binding site; coevolution; dimerization; molecular evolution; nonhuman; oxidation reduction reaction; Papilloma virus; peptide mapping; protein analysis; protein conformation; protein domain; protein function; protein motif; protein structure; sequence alignment; sequence analysis; structural homology; structure activity relation; Amino Acid Motifs; Amino Acid Sequence; Binding Sites; Dimerization; Evolution, Molecular; Humans; Papillomavirus E7 Proteins; Protein Conformation; Protein Structure, Tertiary; Sequence Alignment; Structure-Activity Relationship; Zinc; Papillomaviridae.