Highly conserved α- and β-tubulin heterodimers assemble into dynamic microtubules and perform multiple important cellular functions such as structural support, pathway for transport and force generation in cell division. Tubulin exists in different forms of isotypes expressed by specific genes with spatially- and temporally-regulated expression levels. Some tubulin isotypes are differentially expressed in normal and neoplastic cells, providing a basis for cancer chemotherapy drug development. Moreover, specific tubulin isotypes are overexpressed and localized in the nuclei of cancer cells and/or show bioenergetic functions through the regulation of the permeability of mitochondrial ion channels. It has also become clear that tubulin isotypes are involved in multiple cellular functions without being incorporated into microtubule structures. Understanding the mutations of tubulin isotypes specifically expressed in tumors and their post-translational modifications might help to identify precise molecular targets for the design of novel anti-microtubular drugs. Knowledge of tubulin mutations present in tubulinopathies brings into focus cellular functions of tubulin in brain pathologies such as Alzheimer's disease. Uncovering signaling pathways which affect tubulin functions during antigen-mediated activation of mast cells presents a major challenge in developing new strategies for the treatment of inflammatory and allergic diseases. γ-tubulin, a conserved member of the eukaryotic tubulin superfamily specialized for microtubule nucleation is a target of cell cycle and stress signaling. Besides its microtubule nucleation role, γ-tubulin functions in nuclear and cell cycle related processes. This special issue "Tubulin: Structure, Functions and Roles in Disease" contains eight articles, five of which are original research papers and three are review papers that cover diverse areas of tubulin biology and functions under normal and pathological conditions.

• Klíčová slova
• cancer regulation, chemotherapy drugs, isoforms, microtubules, tubulin,
• MeSH
• Alzheimerova nemoc genetika   metabolismus   patologie   MeSH
• lidé MeSH
• mikrotubuly genetika   metabolismus   patologie   MeSH
• mutace MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory genetika   metabolismus   MeSH
• protein - isoformy MeSH
• tubulin genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• úvodní články MeSH
• úvodníky MeSH
• Názvy látek
• nádorové proteiny MeSH
• protein - isoformy MeSH
• tubulin MeSH

The antigen-mediated activation of mast cells initiates signaling events leading to their degranulation, to the release of inflammatory mediators, and to the synthesis of cytokines and chemokines. Although rapid and transient microtubule reorganization during activation has been described, the molecular mechanisms that control their rearrangement are largely unknown. Microtubule nucleation is mediated by γ-tubulin complexes. In this study, we report on the regulation of microtubule nucleation in bone marrow-derived mast cells (BMMCs) by Src homology 2 (SH2) domain-containing protein tyrosine phosphatase 1 (SHP-1; Ptpn6). Reciprocal immunoprecipitation experiments and pull-down assays revealed that SHP-1 is present in complexes containing γ-tubulin complex proteins and protein tyrosine kinase Syk. Microtubule regrowth experiments in cells with deleted SHP-1 showed a stimulation of microtubule nucleation, and phenotypic rescue experiments confirmed that SHP-1 represents a negative regulator of microtubule nucleation in BMMCs. Moreover, the inhibition of the SHP-1 activity by inhibitors TPI-1 and NSC87877 also augmented microtubule nucleation. The regulation was due to changes in γ-tubulin accumulation. Further experiments with antigen-activated cells showed that the deletion of SHP-1 stimulated the generation of microtubule protrusions, the activity of Syk kinase, and degranulation. Our data suggest a novel mechanism for the suppression of microtubule formation in the later stages of mast cell activation.

• Klíčová slova
• SHP-1 tyrosine phosphatase, bone marrow-derived mast cells, cell activation, microtubule nucleation, γ-tubulin complexes,
• MeSH
• degranulace buněk MeSH
• HEK293 buňky MeSH
• kinasa Syk metabolismus   MeSH
• lidé MeSH
• mastocyty cytologie   metabolismus   MeSH
• MFC-7 buňky MeSH
• mikrotubuly metabolismus   MeSH
• myši MeSH
• tubulin metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 6 antagonisté a inhibitory   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kinasa Syk MeSH
• Ptpn6 protein, mouse MeSH Prohlížeč
• Syk protein, mouse MeSH Prohlížeč
• tubulin MeSH
• tyrosinfosfatasa nereceptorového typu 6 MeSH

The microtubule cytoskeleton is critically important for spatio-temporal organization of eukaryotic cells. The nucleation of new microtubules is typically restricted to microtubule organizing centers (MTOCs) and requires γ-tubulin that assembles into multisubunit complexes of various sizes. γ-Tubulin ring complexes (TuRCs) are efficient microtubule nucleators and are associated with large number of targeting, activating and modulating proteins. γ-Tubulin-dependent nucleation of microtubules occurs both from canonical MTOCs, such as spindle pole bodies and centrosomes, and additional sites such as Golgi apparatus, nuclear envelope, plasma membrane-associated sites, chromatin and surface of pre-existing microtubules. Despite many advances in structure of γ-tubulin complexes and characterization of γTuRC interacting factors, regulatory mechanisms of microtubule nucleation are not fully understood. Here, we review recent work on the factors and regulatory mechanisms that are involved in centrosomal and non-centrosomal microtubule nucleation.

• Klíčová slova
• Centrosomes, Microtubule nucleation, Microtubule-organizing centers, Non-centrosomal nucleation sites, Spindle pole bodies, γ-Tubulin complexes,
• MeSH
• centrozom metabolismus   MeSH
• Golgiho aparát metabolismus   MeSH
• jaderný obal metabolismus   MeSH
• lidé MeSH
• mikrotubuly metabolismus   MeSH
• multiproteinové komplexy metabolismus   MeSH
• pólová tělíska vřeténka metabolismus   MeSH
• proteiny asociované s mikrotubuly metabolismus   MeSH
• tubulin metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• multiproteinové komplexy MeSH
• proteiny asociované s mikrotubuly MeSH
• tubulin MeSH

Mast cell activation mediated by the high affinity receptor for IgE (FcεRI) is a key event in allergic response and inflammation. Other receptors on mast cells, as c-Kit for stem cell factor and G protein-coupled receptors (GPCRs) synergistically enhance the FcεRI-mediated release of inflammatory mediators. Activation of various signaling pathways in mast cells results in changes in cell morphology, adhesion to substrate, exocytosis, and migration. Reorganization of cytoskeleton is pivotal in all these processes. Cytoskeletal proteins also play an important role in initial stages of FcεRI and other surface receptors induced triggering. Highly dynamic microtubules formed by αβ-tubulin dimers as well as microfilaments build up from polymerized actin are affected in activated cells by kinases/phosphatases, Rho GTPases and changes in concentration of cytosolic Ca(2+). Also important are nucleation proteins; the γ-tubulin complexes in case of microtubules or Arp 2/3 complex with its nucleation promoting factors and formins in case of microfilaments. The dynamic nature of microtubules and microfilaments in activated cells depends on many associated/regulatory proteins. Changes in rigidity of activated mast cells reflect changes in intermediate filaments build up from vimentin. This review offers a critical appraisal of current knowledge on the role of cytoskeleton in mast cells signaling.

• Klíčová slova
• actins, intermediate filaments, mast cell activation, microfilaments, microtubules, signal transduction, tubulins, vimentin,
• Publikační typ
• časopisecké články MeSH

gamma-Tubulin is assumed to participate in microtubule nucleation in acentrosomal plant cells, but the underlying molecular mechanisms are still unknown. Here, we show that gamma-tubulin is present in protein complexes of various sizes and different subcellular locations in Arabidopsis and fava bean. Immunoprecipitation experiments revealed an association of gamma-tubulin with alphabeta-tubulin dimers. gamma-Tubulin cosedimented with microtubules polymerized in vitro and localized along their whole length. Large gamma-tubulin complexes resistant to salt treatment were found to be associated with a high-speed microsomal fraction. Blue native electrophoresis of detergent-solubilized microsomes showed that the molecular mass of the complexes was >1 MD. Large gamma-tubulin complexes were active in microtubule nucleation, but nucleation activity was not observed for the smaller complexes. Punctate gamma-tubulin staining was associated with microtubule arrays, accumulated with short kinetochore microtubules interacting in polar regions with membranes, and localized in the vicinity of nuclei and in the area of cell plate formation. Our results indicate that the association of gamma-tubulin complexes with dynamic membranes might ensure the flexibility of noncentrosomal microtubule nucleation. Moreover, the presence of other molecular forms of gamma-tubulin suggests additional roles for this protein species in microtubule organization.

• MeSH
• antinukleární protilátky genetika   metabolismus   MeSH
• Arabidopsis metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• cytosol metabolismus   MeSH
• dimerizace MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• fluorescenční protilátková technika MeSH
• mikrotubuly metabolismus   MeSH
• mikrozomy metabolismus   MeSH
• mitóza fyziologie   MeSH
• precipitinové testy MeSH
• proteiny huseníčku metabolismus   MeSH
• tubulin chemie   imunologie   metabolismus   MeSH
• vazba proteinů MeSH
• Vicia faba metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antinukleární protilátky MeSH
• proteiny huseníčku MeSH
• tubulin MeSH

gamma-Tubulin is necessary for nucleation and polar orientation of microtubules in vivo. The molecular mechanism of microtubule nucleation by gamma-tubulin and the regulation of this process are not fully understood. Here we show that there are two gamma-tubulin forms in the brain that are present in complexes of various sizes. Large complexes tend to dissociate in the presence of a high salt concentration. Both gamma-tubulins co-polymerized with tubulin dimers, and multiple gamma-tubulin bands were identified in microtubule protein preparations under conditions of non-denaturing electrophoresis. Immunoprecipitation experiments with monoclonal antibodies against gamma-tubulin and alpha-tubulin revealed interactions of both gamma-tubulin forms with tubulin dimers, irrespective of the size of complexes. We suggest that, besides small and large gamma-tubulin complexes, other molecular gamma-tubulin form(s) exist in brain extracts. Two-dimensional electrophoresis revealed multiple charge variants of gamma-tubulin in both brain extracts and microtubule protein preparations. Post-translational modification(s) of gamma-tubulins might therefore have an important role in the regulation of microtubule nucleation in neuronal cells.

• MeSH
• dimerizace MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• frakcionace buněk MeSH
• mozek - chemie * MeSH
• prasata MeSH
• protein - isoformy MeSH
• tkáňové extrakty chemie   metabolismus   MeSH
• tubulin chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protein - isoformy MeSH
• tkáňové extrakty MeSH
• tubulin MeSH

The first step in immunoreceptor signaling is represented by ligand-dependent receptor aggregation, followed by receptor phosphorylation mediated by tyrosine kinases of the Src family. Recently, sphingolipid- and cholesterol-rich plasma membrane microdomains, called lipid rafts, have been identified and proposed to function as platforms where signal transduction molecules may interact with the aggregated immunoreceptors. Here we show that aggregation of the receptors with high affinity for immunoglobulin E (FcepsilonRI) in mast cells is accompanied by a co-redistribution of the Src family kinase Lyn. The co-redistribution requires Lyn dual fatty acylation, Src homology 2 (SH2) and/or SH3 domains, and Lyn kinase activity, in cis or in trans. Palmitoylation site-mutated Lyn, which is anchored to the plasma membrane but exhibits reduced sublocalization into lipid rafts, initiates the tyrosine phosphorylation of FcepsilonRI subunits, Syk protein tyrosine kinase, and the linker for activation of T cells, along with an increase in the concentration of intracellular Ca(2+). However, Lyn mutated in both the palmitoylation and myristoylation sites does not anchor to the plasma membrane and is incapable of initiating FcepsilonRI phosphorylation and early signaling events. These data, together with our finding that a constitutively tyrosine-phosphorylated FcepsilonRI does not exhibit an increased association with lipid rafts, suggest that FcepsilonRI phosphorylation and early activation events can be initiated outside of lipid rafts.

• MeSH
• aktivace enzymů MeSH
• antigeny metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• časové faktory MeSH
• cholesterol metabolismus   MeSH
• detergenty farmakologie   MeSH
• DNA metabolismus   MeSH
• fosforylace MeSH
• fosfotyrosin metabolismus   MeSH
• fragmentace DNA MeSH
• imunoblotting MeSH
• konfokální mikroskopie MeSH
• konformace proteinů MeSH
• krysa rodu Rattus MeSH
• kyselina myristová metabolismus   MeSH
• kyselina palmitová metabolismus   MeSH
• luminescentní proteiny metabolismus   MeSH
• membránové mikrodomény metabolismus   MeSH
• metabolismus lipidů MeSH
• myši MeSH
• oktoxynol farmakologie   MeSH
• precipitinové testy MeSH
• receptory IgE metabolismus   MeSH
• rekombinantní proteiny metabolismus   MeSH
• sfingolipidy metabolismus   MeSH
• signální transdukce MeSH
• skupina kinas odvozených od src-genu chemie   metabolismus   fyziologie   MeSH
• terciární struktura proteinů MeSH
• transfekce MeSH
• tyrosin metabolismus   MeSH
• vápník metabolismus   MeSH
• vazba proteinů MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zelené fluorescenční proteiny MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny MeSH
• cholesterol MeSH
• detergenty MeSH
• DNA MeSH
• fosfotyrosin MeSH
• kyselina myristová MeSH
• kyselina palmitová MeSH
• luminescentní proteiny MeSH
• lyn protein-tyrosine kinase MeSH Prohlížeč
• oktoxynol MeSH
• receptory IgE MeSH
• rekombinantní proteiny MeSH
• sfingolipidy MeSH
• skupina kinas odvozených od src-genu MeSH
• tyrosin MeSH
• vápník MeSH
• zelené fluorescenční proteiny MeSH