BACKGROUND: Poor semen quality is one of the main causes of infertility. We have generated a set of monoclonal antibodies to human sperm and used them to investigate sperm quality. Some of these antibodies found differences in the expression of proteins between normal sperm and pathological sperm displaying severe defects. One of them was the Hs-14 antibody. The aim of this paper was to determine the target protein of the Hs-14 monoclonal antibody and to investigate the expression of the Hs-14-reacting protein on the sperm of asthenozoospermic men with sperm motility defect and of healthy normozoospermic men. METHODS: Indirect immunofluorescence, one-dimensional and two-dimensional polyacrylamide gel electrophoresis, immunoblotting and mass spectrometry. RESULTS: The Hs-14 antibody binds fibronectin, β-tubulin and valosin-containing protein - new name for this protein is transitional endoplasmic reticulum ATPase (TERA). Since the Hs-14 reaction with TERA remained the strongest at the highest antibody dilution, and Hs-14 consistently labelled the same spot or band as the monospecific anti-TERA antibody on immunoblots, we assume that TERA is an Hs-14-specific protein. Binding of fibronectin and β-tubulin might represent nonspecific cross-reactivity or Hs-14 reaction with similar epitopes of these proteins. A significant difference (P < 0.001) in immunofluorescence staining with Hs-14 was found between the normozoospermic and asthenozoospermic men. CONCLUSION: The Hs-14 antibody enables discrimination between sterile or subfertile asthenozoospermic and fertile normozoospermic men. Decreased levels of TERA in men can be used as a biomarker of reduced fertility.

INTRODUCTION: La pauvre qualité de la semence est l’une des causes d’infertilité. Nous avons généré une série d’anticorps monoclonaux contre le sperme humain et nous l’avons utilisée pour examiner la qualité du sperme. Certains de ces anticorps ont montré des différences d’ expression des protéines entre le sperme normal et le sperme pathologique qui a des défauts sévères. L’un d’eux a été l’anticorps Hs-14. Le but de cet article était de déterminer la protéine cible de l’anticorps monoclonal Hs-14 et d’établir l’expression de la protéine réagissant avec Hs-14 sur le sperme des hommes asthénozoospermiques qui ont des défauts de la mobilité du sperme et sur celui des hommes normozoospermiques. MÉTHODES: Immunofluorescence indirecte, electrophorèse sur gel polyacrylamide à une ou deux dimensions, immunoblotting et spectrométrie de masse. RÉSULTATS: L’anticorps Hs-14 s’attache à la fibronectine, à la β-tubuline et à la protéine TERA (ATPase transitoire de réticulum endoplasmique). Etant donné que la réaction du Hs-14 avec TERA a été la plus forte à la dilution la plus grande de l’anticorps, et que Hs-14 marquait systématiquement la même tache ou bande que l’anticorps mono-spécifique anti-TERA sur les immunoblots, nous supposons que TERA est une protéine spécifique pour Hs-14. L’attachement à la fibronectine et à la β-tubuline pourrait représenter une réaction croisée non spécifique ou la réaction du Hs-14 avec des épitopes similaires de ces protéines. Une différence significative (P < 0.001) en immunofluorescence avec Hs-14 a été révélée entre hommes normozoospermiques et asthénozoospermiques. CONCLUSIONS: L’anticorps Hs-14 permet de différencier les hommes stériles ou subfertiles asthénozoospermiques des hommes fertiles normozoospermiques. Les niveaux de la TERA chez les hommes pourraient être utilisés comme un marqueur biologique d’une fertilité réduite.

• Keywords
• Acrosome, Asthenozoospermia, Human spermatozoa, Monoclonal antibody, Transitional endoplasmic reticulum ATPase,
• Publication type
• Journal Article MeSH

We studied the expression and distribution of the microtubule-severing enzyme spastin in 3 human glioblastoma cell lines (U87MG, U138MG, and T98G) and in clinical tissue samples representative of all grades of diffuse astrocytic gliomas (n = 45). In adult human brains, spastin was distributed predominantly in neuronsand neuropil puncta and, to a lesser extent, in glia. Compared with normal mature brain tissues, spastin expression and cellular distribution were increased in neoplastic glial phenotypes, especiallyin glioblastoma (p < 0.05 vs low-grade diffuse astrocytomas). Overlapping punctate and diffuse patterns of localization wereidentified in tumor cells in tissues and in interphase and mitotic cells ofglioblastoma cell lines. There was enrichment of spastin in the leading edges of cells in T98G glioblastoma cell cultures and in neoplastic cell populations in tumor specimens. Real-time polymerase chain reaction and immunoblotting experiments revealed greater levels of spastin messenger RNA and protein expression in theglioblastoma cell lines versus normal human astrocytes. Functional experiments indicated that spastin depletion resulted in reduced cell motility and higher cell proliferation of T98G cells. Toour knowledge, this is the first report of spastin involvement incellmotility. Collectively, our results indicate that spastinexpression in glioblastomas might be linked to tumor cell motility, migration, and invasion.

• MeSH
• Adenosine Triphosphatases genetics   metabolism   MeSH
• Child MeSH
• Glioblastoma enzymology   pathology   MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• RNA, Messenger metabolism   MeSH
• Microtubules MeSH
• Young Adult MeSH
• Brain enzymology   pathology   MeSH
• Cell Line, Tumor MeSH
• Brain Neoplasms enzymology   pathology   MeSH
• Cell Count methods   MeSH
• Cell Movement physiology   MeSH
• Cell Proliferation * MeSH
• Gene Expression Regulation, Neoplastic physiology   MeSH
• Spastin MeSH
• Age Factors MeSH
• Check Tag
• Child MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Names of Substances
• Adenosine Triphosphatases MeSH
• RNA, Messenger MeSH
• SPAST protein, human MeSH Browser
• Spastin MeSH

BACKGROUND: The function of the cortical microtubules, composed of alphabeta-tubulin heterodimers, is linked to their organizational state which is subject to spatial and temporal modulation by environmental cues. The role of tubulin posttranslational modifications in these processes is largely unknown. Although antibodies against small tubulin regions represent useful tool for studying molecular configuration of microtubules, data on the exposure of tubulin epitopes on plant microtubules are still limited. RESULTS: Using homology modeling we have generated an Arabidopsis thaliana microtubule protofilament model that served for the prediction of surface exposure of five beta-tubulin epitopes as well as tyrosine residues. Peptide scans newly disclosed the position of epitopes detected by antibodies 18D6 (beta1-10), TUB2.1 (beta426-435) and TU-14 (beta436-445). Experimental verification of the results by immunofluorescence microscopy revealed that the exposure of epitopes depended on the mode of fixation. Moreover, homology modeling showed that only tyrosines in the C-terminal region of beta-tubulins (behind beta425) were exposed on the microtubule external side. Immunofluorescence microscopy revealed tyrosine phosphorylation of microtubules in plant cells, implying that beta-tubulins could be one of the targets for tyrosine kinases. CONCLUSIONS: We predicted surface exposure of five beta-tubulin epitopes, as well as tyrosine residues, on the surface of A. thaliana microtubule protofilament model, and validated the obtained results by immunofluorescence microscopy on cortical microtubules in cells.The results suggest that prediction of epitope exposure on microtubules by means of homology modeling combined with site-directed antibodies can contribute to a better understanding of the interactions of plant microtubules with associated proteins.

• MeSH
• Arabidopsis immunology   MeSH
• Epitopes immunology   MeSH
• Microscopy, Fluorescence MeSH
• Epitope Mapping methods   MeSH
• Microtubules immunology   MeSH
• Models, Molecular MeSH
• Antibodies, Monoclonal immunology   MeSH
• Arabidopsis Proteins immunology   MeSH
• Tubulin immunology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Epitopes MeSH
• Antibodies, Monoclonal MeSH
• Arabidopsis Proteins MeSH
• Tubulin MeSH

Many of the highly organized microtubular arrangements in ciliates are located in the cortical area containing membrane vesicles and vacuoles. In Tetrahymena thermophila and Paramecium caudatum, immunofluorescence microscopy with the monoclonal antibody TU-06, directed against beta-tubulin, revealed distinct staining of this cortical region alone, while the cilia and other microtubular structures were unstained. The specificity of the antibody was confirmed by immunoblotting and by preabsorption of the antibody with purified tubulin. Double-label immunofluorescence with antibodies against gamma-tubulin, detyrosinated alpha-tubulin, and centrin showed that the TU-06 epitope is localized outside the basal body region. This was also confirmed by immunogold electron microscopy of thin sections. Proteolytic digestion of porcine brain beta-tubulin combined with a peptide scan of immobilized, overlapping peptides disclosed that the epitope was in the beta-tubulin region beta81-95, a region which is phylogenetically highly conserved. As known posttranslational modifications of beta-tubulin are located outside this area, the observed staining pattern cannot be interpreted as evidence of subcellular sequestration of modified tubulin. The limited distribution of the epitope could rather reflect the dependence of TU-06 epitope exposition on conformations of tubulin molecules in microtubule arrangements or on differential masking by interacting proteins.

• MeSH
• Cell Membrane immunology   MeSH
• 3T3 Cells MeSH
• Epitopes analysis   immunology   metabolism   MeSH
• Immunoblotting MeSH
• Epitope Mapping MeSH
• Mice MeSH
• Paramecium immunology   MeSH
• Tetrahymena thermophila immunology   MeSH
• Tubulin immunology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Epitopes MeSH
• Tubulin MeSH

Neither the molecular mechanism by which plant microtubules nucleate in the cytoplasm nor the organization of plant mitotic spindles, which lack centrosomes, is well understood. Here, using immunolocalization and cell fractionation techniques, we provide evidence that gamma-tubulin, a universal component of microtubule organizing centers, is present in both the cytoplasm and the nucleus of plant cells. The amount of gamma-tubulin in nuclei increased during the G(2) phase, when cells are synchronized or sorted for particular phases of the cell cycle. gamma-Tubulin appeared on prekinetochores before preprophase arrest caused by inhibition of the cyclin-dependent kinase and before prekinetochore labeling of the mitosis-specific phosphoepitope MPM2. The association of nuclear gamma-tubulin with chromatin displayed moderately strong affinity, as shown by its release after DNase treatment and by using extraction experiments. Subcellular compartmentalization of gamma-tubulin might be an important factor in the organization of plant-specific microtubule arrays and acentriolar mitotic spindles.

• MeSH
• Cell Nucleus chemistry   MeSH
• Cell Cycle MeSH
• Centrioles MeSH
• Fabaceae chemistry   metabolism   MeSH
• Fluorescent Antibody Technique MeSH
• Microscopy, Confocal MeSH
• Plants, Medicinal MeSH
• Mitosis * MeSH
• Plants chemistry   metabolism   MeSH
• Tubulin metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Tubulin MeSH

Distribution of post-translationally modified tubulins in cells of Nicotiana tabacum L. was analysed using a panel of specific antibodies. Polyglutamylated, tyrosinated, nontyrosinated, acetylated and delta 2-tubulin variants were detected on alpha-tubulin subunits; polyglutamylation was also found on beta-tubulin subunits. Modified tubulins were detected by immunofluorescence microscopy in interphase microtubules, preprophase bands, mitotic spindles as well as in phragmoplasts. They were, however, located differently in the various microtubule structures. The antibodies against tyrosinated, acetylated and polyglutamylated tubulins gave uniform staining along all microtubules, while antibodies against nontyrosinated and delta 2-tubulin provided dot-like staining of interphase microtubules. Additionally, immunoreactivity of antibodies against acetylated and delta 2-tubulins was strong in the pole regions of mitotic spindles. High-resolution isoelectric focusing revealed 22 tubulin charge variants in N. tabacum suspension cells. Immunoblotting with antibodies TU-01 and TU-06 against conserved antigenic determinants of alpha- and beta-tubulin molecules, respectively, revealed that 11 isoforms belonged to the alpha-subunit and 11 isoforms to the beta-subunit. Whereas antibodies against polyglutamylated, tyrosinated and acetylated tubulins reacted with several alpha-tubulin isoforms, antibodies against nontyrosinated and delta 2-tubulin reacted with only one. The combined data demonstrate that plant tubulin is extensively post-translationally modified and that these modifications participate in the generation of plant tubulin polymorphism.

• MeSH
• Acetylation MeSH
• Chromatography, Ion Exchange MeSH
• Electrophoresis, Polyacrylamide Gel MeSH
• Genetic Variation MeSH
• Immunoblotting MeSH
• Isoelectric Focusing MeSH
• Plants, Toxic * MeSH
• Cells, Cultured MeSH
• Microtubules metabolism   ultrastructure   MeSH
• Antibodies, Monoclonal MeSH
• Mice MeSH
• Protein Processing, Post-Translational * MeSH
• Nicotiana metabolism   MeSH
• Tubulin analysis   isolation & purification   metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antibodies, Monoclonal MeSH
• Tubulin MeSH

Individual beta-tubulin isoforms in developing mouse brain were characterized using immunoblotting, after preceding high-resolution isoelectric focusing, with monoclonal antibodies against different structural regions of beta-tubulin. Some of the antibodies reacted with a limited number of tubulin isoforms in all stages of brain development and in HeLa cells. The epitope for the TU-14 antibody was located in the isotype-defining domain and was present on the beta-tubulin isotypes of classes I, II and IV, but absent on the neuron-specific class-III isotype. The data suggest that non-class-III beta-tubulins in mouse brain are substrates for developmentally regulated post-translational modifications and that beta-tubulins of non-neuronal cells are also post-translationally modified.

• MeSH
• Epitopes analysis   MeSH
• HeLa Cells MeSH
• Immunoblotting MeSH
• Isoelectric Focusing MeSH
• Isomerism MeSH
• Humans MeSH
• Molecular Sequence Data MeSH
• Antibodies, Monoclonal MeSH
• Brain growth & development   immunology   metabolism   MeSH
• Mice, Inbred BALB C MeSH
• Mice MeSH
• Protein Processing, Post-Translational physiology   MeSH
• Amino Acid Sequence MeSH
• Tubulin immunology   metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Epitopes MeSH
• Antibodies, Monoclonal MeSH
• Tubulin MeSH