title: Differential expression of human γ-tubulin isotypes during neuronal development and oxidative stress points to a γ-tubulin-2 prosurvival function.
abstract: γ-Tubulins are highly conserved members of the tubulin superfamily essential for microtubule nucleation. Humans possess 2 γ-tubulin genes. It is thought that γ-tubulin-1 represents a ubiquitous isotype, whereas γ-tubulin-2 is found predominantly in the brain, where it may be endowed with divergent functions beyond microtubule nucleation. The molecular basis of the purported functional differences between γ-tubulins is unknown. We report discrimination of human γ-tubulins according to their electrophoretic and immunochemical properties.In vitromutagenesis revealed that the differences in electrophoretic mobility originate in the C-terminal regions of the γ-tubulins. Using epitope mapping, we discovered mouse monoclonal antibodies that can discriminate between human γ-tubulin isotypes. Real time quantitative RT-PCR and 2-dimensional-PAGE showed that γ-tubulin-1 is the dominant isotype in fetal neurons. Although γ-tubulin-2 accumulates in the adult brain, γ-tubulin-1 remains the major isotype in various brain regions. Localization of γ-tubulin-1 in mature neurons was confirmed by immunohistochemistry and immunofluorescence microscopy on clinical samples and tissue microarrays. Differentiation of SH-SY5Y human neuroblastoma cells by all-transretinoic acid, or oxidative stress induced by mitochondrial inhibitors, resulted in upregulation of γ-tubulin-2, whereas the expression of γ-tubulin-1 was unchanged. Fractionation experiments and immunoelectron microscopy revealed an association of γ-tubulins with mitochondrial membranes. These data indicate that in the face of predominant γ-tubulin-1 expression, the accumulation of γ-tubulin-2 in mature neurons and neuroblastoma cells during oxidative stress may denote a prosurvival role of γ-tubulin-2 in neurons.-Dráberová, E., Sulimenko, V., Vinopal, S., Sulimenko, T., Sládková, V., D'Agostino, L., Sobol, M., Hozák, P., Křen, L., Katsetos, C. D., Dráber, P. Differential expression of human γ-tubulin isotypes during neuronal development and oxidative stress points to γ-tubulin-2 prosurvival function.
authors.affiliation: Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Eduarda
authors.initials: E
authors.lastname: Dráberová
authors.affiliation: Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Vadym
authors.initials: V
authors.lastname: Sulimenko
authors.affiliation: Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Vinopal
authors.affiliation: Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Tetyana
authors.initials: T
authors.lastname: Sulimenko
authors.affiliation: Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Vladimíra
authors.initials: V
authors.lastname: Sládková
authors.affiliation: Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children and Hahnemann University Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: Luca
authors.initials: L
authors.lastname: D'Agostino
authors.affiliation: Department of the Nucleus, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Margaryta
authors.initials: M
authors.lastname: Sobol
authors.affiliation: Department of the Nucleus, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hozák
authors.affiliation: Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, St. Christopher's Hospital for Children and Hahnemann University Hospital, Philadelphia, Pennsylvania, USA; and.
authors.forename: Leoš
authors.initials: L
authors.lastname: Křen
authors.affiliation: Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children and Hahnemann University Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: Christos D
authors.initials: CD
authors.lastname: Katsetos
authors.affiliation: Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic; paveldra@img.cas.cz.
authors.forename: Pavel
authors.initials: P
authors.lastname: Dráber
mesh_terms: D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism*
chemical_list: C582625:TUBG1 protein, human; C000619121:TUBG2 protein, human; D014404:Tubulin
keywords: microtubules; mitochondria; neuroblastoma differentiation; neurons