Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 14 de 14
Filter
1.
J Sports Med Phys Fitness ; 55(11): 1354-62, 2015 Nov.
Article in English | MEDLINE | ID: mdl-25303167

ABSTRACT

AIM: The aim of this study was to compare tennis players with and without low back pain (LBP) and healthy sedentary participants regarding the trunk muscle strength and flexibility. METHODS: Thirty-eight male elite tennis players and 22 healthy sedentary male students (24.8±4.0 years) participated in this investigation. Tennis players were divided into two groups: 11 players (27.8±5.5 years) with current LBP and 27 players (24.3±5.9 years) without LBP. Maximal isometric strength of trunk extensor, rotator, flexor and lateralflexor muscles was assessed by means of specific trunk dynamometers. Pelvic and lumbar flexion mobility were measured by means of inclinometer technique. RESULTS: Comparison of tennis players with and without LBP revealed no significant difference regarding trunk muscle strength and ratio or lumbar spine flexibility (all P>0.05). In comparison with sedentary participants, the tennis players showed a sport-specific profile determined by a non-dominant trunk lateralflexors (P=0.02, F=4.05) and rotators (P=0.03, F=3.62) strength significantly higher than the dominant side. CONCLUSION: In the current study, comparison of tennis players with and without LBP showed no significant difference regarding trunk strength and spine flexibility. Trunk profile of tennis players showed selective unilateral strength increase of the non-dominant trunk lateralflexors and rotators. This finding could result from the forehand and the service action which involves simultaneously left trunk rotators and lateralflexors, in right-handed players, to generate power. In order to confirm that trunk muscle imbalance has no influence on LBP, further studies should study the effectiveness of a programme aiming to normalize strength ratios in tennis players with LBP.


Subject(s)
Exercise Tolerance/physiology , Low Back Pain/physiopathology , Muscle Strength/physiology , Muscle, Skeletal/physiopathology , Tennis/physiology , Adult , Humans , Lumbosacral Region , Male
2.
Biochem Biophys Res Commun ; 287(3): 688-95, 2001 Sep 28.
Article in English | MEDLINE | ID: mdl-11563850

ABSTRACT

DENN domains are found in a variety of signaling proteins but their exact function remains undefined. Some of the DENN-containing proteins, such as rat Rab3GEP (Rab3 GDP/GTP exchange protein) or mouse Rab6IP1 (Rab6 interacting protein 1) interact with GTPases of the Rab family. Others, such as human MADD (MAP (Mitogen-activated protein) kinase activating protein containing death domain) and human ST5 (Suppressor of tumoreginicity 5) gene products are involved in regulation of MAPKs (Mitogen-activated protein kinases) signaling pathways. Using a combination of profile-based and bidimensional analyses, we show here that DENN domains are much larger than described to date in domain databases, always encircled on both sides by more divergent domains, that we called uDENN and dDENN. These however share conserved amino acids which could play a key role in the DENN functions.


Subject(s)
Guanine Nucleotide Exchange Factors/chemistry , MAP Kinase Signaling System , rab1 GTP-Binding Proteins/chemistry , Algorithms , Amino Acid Motifs , Amino Acid Sequence , Animals , Cluster Analysis , Conserved Sequence , Databases, Factual , Death Domain Receptor Signaling Adaptor Proteins , Drosophila , Humans , Mice , Molecular Sequence Data , Protein Structure, Tertiary , Rats , Sequence Homology, Amino Acid , Signal Transduction
3.
Virology ; 286(1): 72-82, 2001 Jul 20.
Article in English | MEDLINE | ID: mdl-11448160

ABSTRACT

Viruses of the family Luteoviridae are ssRNA plant viruses that have particles that exhibit icosahedral symmetry. To identify the residues that might be exposed on the surface of the Potato leafroll virus (PLRV; genus Polerovirus, family Luteoviridae) capsid, and therefore involved in biological interactions, we performed a structural analysis of the PLRV coat protein (CP) on the basis of comparisons with protein sequences and known crystal structures of CPs of other viruses. The CP of PLRV displays 33% sequence similarity with that of Rice yellow mottle virus (genus Sobemovirus) when the sequences were aligned by using the hidden Markov model method. A structure model for PLRV CP was designed by protein homology modeling, using the crystal structure of RYMV as a template. The resulting model is consistent with immunological and site-directed mutagenesis data previously reported. On the basis of this model it is possible to predict some surface properties of the PLRV CP and also speculate about the structural evolution of small icosahedral viruses.


Subject(s)
Capsid/chemistry , Plant Viruses/chemistry , Solanum tuberosum/virology , Amino Acid Sequence , Capsid/genetics , Models, Molecular , Molecular Sequence Data , Protein Conformation , Sequence Alignment
4.
Cell Mol Biol (Noisy-le-grand) ; 47(2): 285-96, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11355003

ABSTRACT

The (Na+,K+)-ATPase is a plasma membrane protein complex composed of at least three subunits (alpha,beta,gamma) that couples the exchange of three cytoplasmic Na+ ions with two extracellular K+ ions, to the hydrolysis of one molecule ofATP in most animal cells. The gamma-subunit is a 66 residue membrane protein associated with the active alpha/beta binary complex. It can be considered as an archetype of single transmembrane proteins (type I) which may play a modulatory role upon association with functional membrane partners. This paper highlights similar associations observed with other ATPases such as the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA1/SERCA 2a), but also with Cl- and/or K+ currents, ionic channels (HERG, KCNQ1) and G-protein coupled receptors (adrenomedullin, CGRP and calcitonin) which are of particular interest in the cardiovascular field. Here is reviewed the assessed or suggested regulatory role of a family of small plasma/SR associated membrane proteins including gamma-subunit, phospholemman, Mat 8, KCNE (type 1, 2 and 3), RAMP (type 1, 2 and 3), sarcolipin and phospholamban, mainly found in muscular and vascular tissues. These proteins are critical in controlling important biological processes which derive from specific associations with a binding partner and particular subcellular localizations.


Subject(s)
Membrane Proteins/chemistry , Protein Structure, Tertiary , Sarcoplasmic Reticulum/chemistry , Sodium-Potassium-Exchanging ATPase/chemistry , Amino Acid Motifs , Animals , Humans , Membrane Proteins/genetics , Membrane Proteins/metabolism , Models, Molecular , Phylogeny , Protein Subunits , Sarcoplasmic Reticulum/enzymology , Sodium-Potassium-Exchanging ATPase/genetics , Sodium-Potassium-Exchanging ATPase/metabolism
5.
FEBS Lett ; 477(1-2): 99-105, 2000 Jul 14.
Article in English | MEDLINE | ID: mdl-10899318

ABSTRACT

Structural comparisons of the two GTPase activating proteins (GAPs) p120 and p50 in complex with Ras and Rho, respectively, allowed us to decipher the functional role of specific structural features, such as helix alpha8c of p120 and helix A1 of p50, necessary for small GTPase recognition. We identified important residues that may be critical for stabilization of the GAP/GTPase binary complexes. Detection of topohydrophobic positions (positions which are most often occupied by hydrophobic amino acids within a family of protein domains) conserved between the two GAP families led to the characterization of a common flexible four-helix bundle. Altogether, these data are consistent with a rearrangement of several helices around a common core, which strongly supports the assumption that p50 and p120 GAPs derive from a unique fold. Considered as a whole, the remarkable plasticity of GAPs appears to be a means used by nature to accurately confer functional specificity.


Subject(s)
GTPase-Activating Proteins/chemistry , GTPase-Activating Proteins/metabolism , p120 GTPase Activating Protein/chemistry , p120 GTPase Activating Protein/metabolism , ras Proteins/metabolism , rho GTP-Binding Proteins/metabolism , Amino Acid Sequence , Binding Sites , Conserved Sequence , Crystallography, X-Ray , Models, Molecular , Molecular Sequence Data , Pliability , Protein Binding , Protein Structure, Secondary , Protein Structure, Tertiary , Sequence Alignment , Substrate Specificity , ras Proteins/chemistry , rho GTP-Binding Proteins/chemistry
6.
Fetal Diagn Ther ; 15(1): 41-5, 2000.
Article in English | MEDLINE | ID: mdl-10705213

ABSTRACT

The fetal iliac wings angle was studied in 255 fetuses before amniocentesis at 16.7 weeks (+/- 1.3), using a sonographic axial view of the fetal pelvis. The measurement could be performed in 208 fetuses (81.6%), of whom 4 had trisomy 21 (T 21). The mean iliac angle was greater in fetuses with T 21 than in normal fetuses (69.8 degrees vs. 88.7 degrees; p = 0.03). This measurement is subject to significant intra- and interexaminer variability (interclass correlation coefficient: 0.65 and 0.23, respectively). When a 90 degrees value is used as a threshold, specificity, sensitivity, positive and negative predictive values are, respectively, 80, 75, 7. 0 and 99.4%. The 20% rate of false-positives rules out the use of this measurement as the sole criterion for the indication of amniocentesis for T 21 antenatal diagnosis.


Subject(s)
Down Syndrome/diagnostic imaging , Ilium/diagnostic imaging , Ultrasonography, Prenatal , Down Syndrome/pathology , Female , Gestational Age , Humans , Ilium/pathology , Predictive Value of Tests , Pregnancy , Sensitivity and Specificity
7.
J Biol Chem ; 274(51): 36592-600, 1999 Dec 17.
Article in English | MEDLINE | ID: mdl-10593960

ABSTRACT

Starting with computational tools that search for tissue-selective expression of assembled expressed sequenced tags, we have identified by focusing on heart libraries a novel small stress protein of 170 amino acids that we named cvHsp. cvHsp was found as being computationally selectively and highly (0.3% of the total RNA) expressed in human heart. The cvHsp gene mapped to 1p36.23-p34.3 between markers D1S434 and D1S507. The expression of cvHsp was analyzed with RNA dot, Northern blots, or reverse transcription-polymerase chain reaction: expression was high in heart, medium in skeletal muscle, and low in aorta or adipose tissues. In the heart of rat models of cardiac pathologies, cvHsp mRNA expression was either unchanged (spontaneous hypertension), up-regulated (right ventricular hypertrophy induced by monocrotaline treatment), or down-regulated (left ventricular hypertrophy following aortic banding). In obese Zucker rats, cvHsp mRNA was increased in skeletal muscle, brown, and white adipose tissues but remained unchanged in the heart. Western blot analysis using antipeptide polyclonal antibodies revealed two specific bands at 23 and 25 kDa for cvHsp in human heart. cvHsp interacted in both yeast two-hybrid and immunoprecipitation experiments with alpha-filamin or actin-binding protein 280. Within cvHsp, amino acid residues 56-119 were shown to be important for its specific interaction with the C-terminal tail of alpha-filamin.


Subject(s)
Cardiovascular System/metabolism , Heat-Shock Proteins/biosynthesis , Heat-Shock Proteins/genetics , Insulin/metabolism , Amino Acid Sequence , Animals , Base Sequence , Cloning, Molecular , DNA, Complementary/genetics , DNA, Complementary/isolation & purification , Gene Expression Regulation , Humans , Molecular Sequence Data , Organ Specificity , Rats , Sequence Alignment
8.
J Mol Biol ; 294(2): 443-56, 1999 Nov 26.
Article in English | MEDLINE | ID: mdl-10610770

ABSTRACT

Mutations in human cardiac myosin-binding protein C (cMyBP-C) gene are associated with familial hypertrophic cardiomyopathy (FHC), and most of them are predicted to produce COOH-truncated proteins. To understand the molecular mechanism(s) by which such mutations cause FHC, we analyzed (i) the accumulation of human cMyBP-C mutants in fetal rat cardiomyocytes, and (ii) the protein sequence of the human wild-type (wt) cMyBP-C by hydrophobic cluster analysis with the aim of identifying new putative myosin-binding site(s). Accumulation and sarcomeric localization of the wt protein and of four FHC-mutant cMyBP-Cs (E542Q and three COOH-truncated proteins) were studied in cardiomyocytes by immunostaining and confocal microscopy after transfection with myc-tagged constructs. We found that: (i) 10 % of the cells expressing COOH-truncated mutants exhibit an incorporation into the A-band of the sarcomere without any alteration of the myofibrillar architecture versus 76 % of those expressing the wt or E542Q mutant cMyBP-Cs (p<0.001); (ii) 90 % of the cells expressing the truncated mutants show a diffuse localization of these proteins in the cardiomyocytes, out of which 45 % exhibit a significant alteration of the sarcomeric structure (p<0.0001 versus wt); and (iii) the two shortest mutant cMyBP-Cs accumulate at very low levels in fetal rat cardiomyocytes as compared to the wt (p<0.008). Protein sequence analysis indicated that a 45-residue sequence in the NH2-terminal C0 domain of cMyBP-C exhibits a consistent homology (sequence similarity score of 42 %) with a segment of the NH2-terminal domain of myomesin, another myosin-binding protein. This result suggests that the C0 domain of human cMyBP-C contains a novel putative myosin-binding site that could account for the A-band incorporation of the truncated mutants. In addition, the faint accumulation and the diffuse localization of truncated mutants could probably be explained by a low affinity of the C0 domain for myosin. We conclude that COOH-truncated cMyBP-Cs may act as poison polypeptides that disrupt the myofibrillar architecture and result in the defects observed in FHC.


Subject(s)
Cardiomyopathy, Hypertrophic/genetics , Cardiomyopathy, Hypertrophic/metabolism , Carrier Proteins/genetics , Carrier Proteins/metabolism , Myocardium/metabolism , Amino Acid Motifs , Amino Acid Sequence , Animals , Binding Sites , COS Cells/metabolism , Cells, Cultured , Connectin , Gene Expression , Heart/embryology , Humans , Molecular Sequence Data , Muscle Proteins/metabolism , Mutation , Myocardium/cytology , Myosins/metabolism , Rats , Rats, Wistar , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sarcomeres/metabolism , Sequence Analysis, Protein
9.
Protein Sci ; 8(12): 2570-9, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10631972

ABSTRACT

Protein phosphatase 1 (PP1) is widely distributed among tissues and species and acts as a regulator of many important cellular processes. By targeting the catalytic part of PP1 (PP1C) toward particular loci and substrates, regulatory subunits constitute key elements conferring specificity to the holoenzyme. Here, we report the identification of an (alpha/beta)8-barrel-like structure within the N-ter stretch of the human PP1 regulatory subunit hGM, which is part of the family of diverse proteins associated with glycogen metabolism. Protein homology modeling gave rise to a three-dimensional (3D) model for the 381 N-ter residue stretch of hGM, based on sequence similarity with Streptomyces olivochromogenes xylose isomerase, identified by using FASTA. The alignment was subsequently extended by using hydrophobic cluster analysis. The homology-derived model includes the putative glycogen binding area located within the 142-230 domain of hGM as well as a structural characterization of the PP1C interacting domain (segment 51-67). Refinement of the latter by molecular dynamics afforded a topology that is in agreement with previous X-ray studies (Egloff et al., 1997). Finite difference Poisson-Boltzmann calculations performed on the interacting domains of PP1C and hGM confirm the complementarity of the local electrostatic potentials of the two partners. This work highlights the presence of a conserved fold among distant species (mammalian, Caenorhabditis elegans, yeast) and, thus, emphasizes the involvement of PP1 in crucial basic cellular functions.


Subject(s)
Glycogen/metabolism , Phosphoprotein Phosphatases/chemistry , Amino Acid Motifs , Amino Acid Sequence , Humans , Models, Molecular , Molecular Sequence Data , Protein Phosphatase 1 , Protein Structure, Tertiary , Sequence Alignment , Sequence Analysis, Protein , Static Electricity
10.
FEBS Lett ; 439(3): 224-30, 1998 Nov 20.
Article in English | MEDLINE | ID: mdl-9845327

ABSTRACT

Regulation of the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA 2a) depends on the phosphorylation state of phospholamban (PLB). When PLB is phosphorylated, its inhibitory effect towards SERCA 2a is relieved, leading to an enhanced myocardial performance. This process is reversed by a sarcoplasmic reticulum (SR)-associated type 1 protein phosphatase (PP1) composed of a catalytic subunit PP1C and a regulatory subunit GM. Human GM and PLB have been produced in an in vitro transcription/translation system and used for co-immunoprecipitation and biosensor experiments. The detected interaction between the two partners suggests that cardiac PPI is targeted to PLB via GM and we believe that this process occurs with the identified transmembrane domains of the two proteins. Thus, the interaction between PLB and GM may represent a specific way to modulate the SR function in human cardiac muscle.


Subject(s)
Calcium-Binding Proteins/metabolism , Phosphoprotein Phosphatases/metabolism , Amino Acid Sequence , Binding Sites , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/physiology , Calcium-Transporting ATPases/metabolism , Humans , Membrane Proteins/metabolism , Molecular Sequence Data , Phosphorylation , Precipitin Tests , Protein Binding , Protein Conformation , Protein Phosphatase 1 , Sarcoplasmic Reticulum/metabolism , Sarcoplasmic Reticulum/physiology
11.
FEBS Lett ; 426(2): 205-11, 1998 Apr 17.
Article in English | MEDLINE | ID: mdl-9599009

ABSTRACT

An extensive study of both sequence and recent 3D structural data concerning GTPase interacting domains of Ras- and Rho-specific GTPase-activating proteins (GAPs) shows that these two subfamilies share a same 3D scaffold and are thus related to each other. This relationship has heretofore remained undetected although these domains of similar size are both totally alpha-helical and activate nearly structurally identical targets (Ras and Rho proteins). In this report, sequence similarities correlated to 3D structures of p120rasGAP and p50rhoGAP were detected using the sensitive two-dimensional method hydrophobic cluster analysis (HCA). These patterns were further extended to other members in each subfamily and the geometry orientation of crucial arginines R789 in p120 and R282 in p50 and of important stabilizing residues like p120R903 and p50N391 was confirmed. This overall structural relationship is centered on an invariant motif of three consecutive helices that we suggest to name the 'cradle fold'. This observation opens new perspectives to understand how small GTPases are specifically regulated.


Subject(s)
GTP-Binding Proteins/ultrastructure , Proteins/ultrastructure , Amino Acid Sequence , Animals , GTPase-Activating Proteins , Humans , Models, Molecular , Molecular Sequence Data , Protein Structure, Secondary , Protein Structure, Tertiary , Sequence Alignment , Sequence Homology, Amino Acid , Structure-Activity Relationship , ras GTPase-Activating Proteins
12.
Bioorg Med Chem ; 6(11): 1993-2011, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9881092

ABSTRACT

Class III antiarrhythmic agents have been shown to prevent reentrant arrhythmias but also to be responsible for initiating arrhythmias characterised by afterdepolarizations and triggered activities. By combining potassium and calcium channel antagonistic actions, as with BRL-32872 (1), it might be possible to reduce the incidence of proarrhythmias albeit retaining antiarrhythmic efficacy. In the present study we synthesised and tested for their electrophysiological activity in guinea pig papillary muscle a wide panel of analogues of BRL-32872. Some qualitative relationships between compound structure and the inhibitory effect on the rapidly activating component of the delayed rectifier potassium current and/or the L-type calcium current will be presented. New derivatives depicting bell-shaped dose-response curves on action potential duration may therefore represent novel agents for improved antiarrhythmic therapy.


Subject(s)
Anti-Arrhythmia Agents/chemical synthesis , Benzamides/chemical synthesis , Benzamides/pharmacology , Calcium Channel Blockers/chemical synthesis , Potassium Channel Blockers , Potassium Channels, Voltage-Gated , Action Potentials/drug effects , Animals , Anti-Arrhythmia Agents/chemistry , Anti-Arrhythmia Agents/pharmacology , Benzamides/chemistry , Calcium Channel Blockers/chemistry , Calcium Channel Blockers/pharmacology , Calcium Channels/physiology , Delayed Rectifier Potassium Channels , Electrophysiology , Guinea Pigs , Hydrogen Bonding , Indicators and Reagents , Molecular Structure , Papillary Muscles/drug effects , Papillary Muscles/physiology , Potassium Channels/physiology , Structure-Activity Relationship
SELECTION OF CITATIONS
SEARCH DETAIL
...