Breast cancer is the most prevalent cancer type in women worldwide. It proliferates rapidly and can metastasize into farther tissues at any stage due to the gradual invasiveness and motility of the tumor cells. These crucial properties are the outcome of the weakened intercellular adhesion, regulated by small guanosine triphosphatases (GTPases), which hydrolyze to the guanosine diphosphate (GDP)-bound conformation. We investigated the inactivating effect of ARHGAP1 on Rho GTPases involved signaling pathways after treatment with a high dose of doxorubicin. Label-free quantitative proteomic analysis of the proteome isolated from the MCF-7 breast cancer cell line, treated with 1 μM of doxorubicin, identified RAC1, CDC42, and RHOA GTPases that were inactivated by the ARHGAP1 protein. Upregulation of the GTPases involved in the transforming growth factor-beta (TGF-beta) signaling pathway initiated epithelial-mesenchymal transitions. These findings demonstrate a key role of the ARHGAP1 protein in the disruption of the cell adhesion and simultaneously allow for a better understanding of the molecular mechanism of the reduced cell adhesion leading to the subsequent metastasis. The conclusions of this study corroborate the hypothesis that chemotherapy with doxorubicin may increase the risk of metastases in drug-resistant breast cancer cells.

• Klíčová slova
• breast cancer, cell adhesion, doxorubicin, mass spectrometry, metastases, proteomics,
• MeSH
• cdc42 protein vázající GTP metabolismus   MeSH
• doxorubicin farmakologie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• nádory prsu * farmakoterapie   MeSH
• proteiny aktivující GTPasu * metabolismus   MeSH
• proteomika MeSH
• rac1 protein vázající GTP metabolismus   MeSH
• rho proteiny vázající GTP * metabolismus   MeSH
• rhoA protein vázající GTP metabolismus   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ARHGAP1 protein, human MeSH Prohlížeč
• cdc42 protein vázající GTP MeSH
• doxorubicin MeSH
• proteiny aktivující GTPasu * MeSH
• rac1 protein vázající GTP MeSH
• rho proteiny vázající GTP * MeSH
• rhoA protein vázající GTP MeSH

The transmembrane adaptor protein NTAL (non-T-cell activation linker) participates in signalosome assembly in hematopoietic cells, but its exact role in cell physiology remains enigmatic. We report here that BM-derived mast cells from NTAL-deficient mice, responding to Ag alone or in combination with SCF, exhibit reduced spreading on fibronectin, enhanced filamentous actin depolymerization and enhanced migration towards Ag relative to WT cells. No such differences between WT and NTAL(-/-) BM-derived mast cells were observed when SCF alone was used as activator. We have examined the activities of two small GTPases, Rac and Rho, which are important regulators of actin polymerization. Stimulation with Ag and/or SCF enhanced activity of Rac(1,2,3) in both NTAL(-/-) and WT cells. In contrast, RhoA activity decreased and this trend was much faster and more extensive in NTAL(-/-) cells, indicating a positive regulatory role of NTAL in the recovery of RhoA activity. After restoring NTAL into NTAL(-/-) cells, both spreading and actin responses were rescued. This is the first report of a crucial role of NTAL in signaling, via RhoA, to mast cell cytoskeleton.

• MeSH
• adaptorové proteiny signální transdukční MeSH
• aktiny genetika   imunologie   metabolismus   MeSH
• antigeny imunologie   MeSH
• buňky kostní dřeně cytologie   imunologie   metabolismus   MeSH
• cytoskelet genetika   imunologie   metabolismus   MeSH
• mastocyty cytologie   imunologie   metabolismus   MeSH
• myši knockoutované MeSH
• myši MeSH
• proteiny genetika   imunologie   metabolismus   MeSH
• rac proteiny vázající GTP genetika   imunologie   metabolismus   MeSH
• rho proteiny vázající GTP genetika   imunologie   metabolismus   MeSH
• rhoA protein vázající GTP MeSH
• signální transdukce genetika   imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adaptorové proteiny signální transdukční MeSH
• aktiny MeSH
• antigeny MeSH
• LAT2 protein, mouse MeSH Prohlížeč
• proteiny MeSH
• rac proteiny vázající GTP MeSH
• rho proteiny vázající GTP MeSH
• rhoA protein vázající GTP MeSH
• RhoA protein, mouse MeSH Prohlížeč

Chronic myelogenous leukemia (CML) is a hematological malignancy that is characteristic by as expansion of myeloid cells and their premature release into the circulation. The molecular cause of CML is the fusion oncoprotein Bcr-Abl whose constitutive tyrosine-kinase (TK) activity maintains enhanced signaling through multiple signal transduction pathways and confers proliferative and survival advantage to CML cells. These effects can be largely suppressed by TK inhibitor Imatinib mesylate, currently the leading drug in CML treatment. However, Bcr-Abl contains also additional functional domains, in particular a DBL homology (DH) domain with guanine-exchange function (GEF) which can activate small GTPases of Rho family and a Src-homology3 (SH3) domain which recruits other proteins with GEF activity. Bcr-Abl affects among others the RhoA/ROCK/LIM/cofilin pathway that regulates the actin cytoskeleton assembly and thereby the cellular adhesion and migration. This review deals in detail with the known points of interference between Bcr-Abl and Rho kinase pathways and with the effects of Imatinib mesylate on Rho signaling and cell adhesion to the extracellular matrix (ECM) components. The potential protein targets related to Bcr-Abl non-kinase activity are discussed.

• MeSH
• antitumorózní látky farmakologie   MeSH
• bcr-abl fúzové proteiny účinky léků   metabolismus   MeSH
• benzamidy MeSH
• buněčná adheze účinky léků   MeSH
• chronická myeloidní leukemie farmakoterapie   patofyziologie   MeSH
• imatinib mesylát MeSH
• kinázy asociované s rho účinky léků   metabolismus   MeSH
• lidé MeSH
• piperaziny farmakologie   MeSH
• pyrimidiny farmakologie   MeSH
• rho proteiny vázající GTP metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• src homologní domény MeSH
• systémy cílené aplikace léků MeSH
• výměnné faktory guaninnukleotidů metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• antitumorózní látky MeSH
• bcr-abl fúzové proteiny MeSH
• benzamidy MeSH
• imatinib mesylát MeSH
• kinázy asociované s rho MeSH
• piperaziny MeSH
• pyrimidiny MeSH
• rho proteiny vázající GTP MeSH
• výměnné faktory guaninnukleotidů MeSH

The tyrosine kinase Src acts as a key regulator of cell motility by phosphorylating multiple protein substrates that control cytoskeletal and adhesion dynamics. In an earlier phosphotyrosine proteomics study, we identified a novel Rho-GTPase activating protein, now known as ARHGAP42, as a likely biologically relevant Src substrate. ARHGAP42 is a member of a family of RhoGAPs distinguished by tandem BAR-PH domains lying N-terminal to the GAP domain. Like other family members, ARHGAP42 acts preferentially as a GAP for RhoA. We show that Src principally phosphorylates ARHGAP42 on tyrosine 376 (Tyr-376) in the short linker between the BAR-PH and GAP domains. The expression of ARHGAP42 variants in mammalian cells was used to elucidate its regulation. We found that the BAR domain is inhibitory toward the GAP activity of ARHGAP42, such that BAR domain deletion resulted in decreased active GTP-bound RhoA and increased cell motility. With the BAR domain intact, ARHGAP42 GAP activity could be activated by phosphorylation of Tyr-376 to promote motile cell behavior. Thus, phosphorylation of ARHGAP42 Tyr-376 is revealed as a novel regulatory event by which Src can affect actin dynamics through RhoA inhibition.

• Klíčová slova
• Focal adhesion, GAP, GRAF, Motility, RhoA, Src, Tyrosine phosphorylation,
• MeSH
• fokální adheze metabolismus   MeSH
• fosforylace MeSH
• lidé MeSH
• myši MeSH
• pohyb buněk fyziologie   MeSH
• proteiny aktivující GTPasu genetika   metabolismus   MeSH
• rho proteiny vázající GTP antagonisté a inhibitory   metabolismus   MeSH
• rhoA protein vázající GTP antagonisté a inhibitory   metabolismus   MeSH
• skupina kinas odvozených od src-genu metabolismus   MeSH
• tyrosin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ARHGAP42 protein, human MeSH Prohlížeč
• proteiny aktivující GTPasu MeSH
• rho proteiny vázající GTP MeSH
• rhoA protein vázající GTP MeSH
• RHOA protein, human MeSH Prohlížeč
• RhoA protein, mouse MeSH Prohlížeč
• skupina kinas odvozených od src-genu MeSH
• tyrosin MeSH

BACKGROUND: Shuffling of modular protein domains is an important source of evolutionary innovation. Formins are a family of actin-organizing proteins that share a conserved FH2 domain but their overall domain architecture differs dramatically between opisthokonts (metazoans and fungi) and plants. We performed a phylogenomic analysis of formins in most eukaryotic kingdoms, aiming to reconstruct an evolutionary scenario that may have produced the current diversity of domain combinations with focus on the origin of the angiosperm formin architectures. RESULTS: The Rho GTPase-binding domain (GBD/FH3) reported from opisthokont and Dictyostelium formins was found in all lineages except plants, suggesting its ancestral character. Instead, mosses and vascular plants possess the two formin classes known from angiosperms: membrane-anchored Class I formins and Class II formins carrying a PTEN-like domain. PTEN-related domains were found also in stramenopile formins, where they have been probably acquired independently rather than by horizontal transfer, following a burst of domain rearrangements in the chromalveolate lineage. A novel RhoGAP-related domain was identified in some algal, moss and lycophyte (but not angiosperm) formins that define a specific branch (Class III) of the formin family. CONCLUSION: We propose a scenario where formins underwent multiple domain rearrangements in several eukaryotic lineages, especially plants and chromalveolates. In plants this replaced GBD/FH3 by a probably inactive RhoGAP-like domain, preserving a formin-mediated association between (membrane-anchored) Rho GTPases and the actin cytoskeleton. Subsequent amplification of formin genes, possibly coincident with the expansion of plants to dry land, was followed by acquisition of alternative membrane attachment mechanisms present in extant Class I and Class II formins, allowing later loss of the RhoGAP-like domain-containing formins in angiosperms.

• MeSH
• fosfohydroláza PTEN genetika   MeSH
• fylogeneze MeSH
• genetická variace MeSH
• Magnoliopsida enzymologie   genetika   MeSH
• molekulární evoluce * MeSH
• molekulární sekvence - údaje MeSH
• pravděpodobnostní funkce MeSH
• proteiny aktivující GTPasu genetika   MeSH
• rho proteiny vázající GTP genetika   MeSH
• rostlinné geny * MeSH
• rostlinné proteiny genetika   MeSH
• sekvence aminokyselin MeSH
• sekvenční analýza proteinů MeSH
• sekvenční seřazení MeSH
• terciární struktura proteinů genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfohydroláza PTEN MeSH
• proteiny aktivující GTPasu MeSH
• rho GTPase-activating protein MeSH Prohlížeč
• rho proteiny vázající GTP MeSH
• rostlinné proteiny MeSH

The aim of this study was to analyze the potential role of NG2 chondroitin sulfate proteoglycan in amoeboid morphology and invasiveness of cancer cells. In the highly metastatic amoeboid cell lines A3 and A375M2, siRNA-mediated down-regulation of NG2 induced an amoeboid-mesenchymal transition associated with decreased invasiveness in 3D collagen and inactivation of the GTPase Rho. Conversely, the expression of NG2 in mesenchymal sarcoma K2 cells as well as in A375M2 cells resulted in an enhanced amoeboid phenotype associated with increased invasiveness and elevated Rho-GTP levels. Remarkably, the amoeboid-mesenchymal transition in A375M2 cells triggered by NG2 down-regulation was associated with increased extracellular matrix-degrading ability, although this was not sufficient to compensate for the decreased invasive capability caused by down-regulated Rho/ROCK signaling. Conversely, in K2 cells with overexpression of NG2, the ability to degrade the extracellular matrix was greatly reduced. Taken together, we suggest that NG2-mediated activation of Rho leading to effective amoeboid invasiveness is a possible mechanism through which NG2 could contribute to tumor cell invasion and metastasis.

• MeSH
• chondroitinsulfát proteoglykany genetika   metabolismus   MeSH
• down regulace MeSH
• extracelulární matrix metabolismus   MeSH
• invazivní růst nádoru MeSH
• kinázy asociované s rho metabolismus   MeSH
• kolagen chemie   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• malá interferující RNA MeSH
• membránové proteiny genetika   metabolismus   MeSH
• molekulární konformace MeSH
• nádorové buněčné linie MeSH
• nádory metabolismus   patologie   ultrastruktura   MeSH
• pohyb buněk * MeSH
• rho proteiny vázající GTP metabolismus   MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chondroitinsulfát proteoglykany MeSH
• CSPG4 protein, human MeSH Prohlížeč
• kinázy asociované s rho MeSH
• kolagen MeSH
• malá interferující RNA MeSH
• membránové proteiny MeSH
• rho proteiny vázající GTP MeSH

Tunnelling nanotubes (TNTs) are an emerging route of long-range intercellular communication that mediate cell-to-cell exchange of cargo and organelles and contribute to maintaining cellular homeostasis by balancing diverse cellular stresses. Besides their role in intercellular communication, TNTs are implicated in several ways in health and disease. Transfer of pathogenic molecules or structures via TNTs can promote the progression of neurodegenerative diseases, cancer malignancy, and the spread of viral infection. Additionally, TNTs contribute to acquiring resistance to cancer therapy, probably via their ability to rescue cells by ameliorating various pathological stresses, such as oxidative stress, reactive oxygen species (ROS), mitochondrial dysfunction, and apoptotic stress. Moreover, mesenchymal stem cells play a crucial role in the rejuvenation of targeted cells with mitochondrial heteroplasmy and oxidative stress by transferring healthy mitochondria through TNTs. Recent research has focussed on uncovering the key regulatory molecules involved in the biogenesis of TNTs. However further work will be required to provide detailed understanding of TNT regulation. In this review, we discuss possible associations with Rho GTPases linked to oxidative stress and apoptotic signals in biogenesis pathways of TNTs and summarize how intercellular trafficking of cargo and organelles, including mitochondria, via TNTs plays a crucial role in disease progression and also in rejuvenation/therapy.

• Klíčová slova
• Apoptosis, Cellular stress, Chemotherapy resistance, Intercellular transfer, Mesenchymal stem cells, Mitochondrial homeostasis, Reactive oxygen species (ROS), Rejuvenation,
• MeSH
• lidé MeSH
• mezibuněčná komunikace * MeSH
• mitochondrie metabolismus   MeSH
• nádory metabolismus   patologie   MeSH
• neurodegenerativní nemoci metabolismus   patologie   MeSH
• organely metabolismus   MeSH
• oxidační stres * MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rho proteiny vázající GTP fyziologie   MeSH
• virové nemoci metabolismus   patologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• reaktivní formy kyslíku MeSH
• rho proteiny vázající GTP MeSH

In many eukaryotic lineages, the RHO clade of small GTPases controls microfilament dynamics by direct binding to formin family actin nucleators. A new study in plants reveals that formin activity can also be regulated by a RHO cofactor rather than the GTPase itself.

• MeSH
• aktiny metabolismus   MeSH
• forminy * metabolismus   genetika   MeSH
• mikrofilamenta metabolismus   MeSH
• mikrofilamentové proteiny metabolismus   genetika   MeSH
• rho proteiny vázající GTP metabolismus   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aktiny MeSH
• forminy * MeSH
• mikrofilamentové proteiny MeSH
• rho proteiny vázající GTP MeSH

Mitochondria are organelles present in most eukaryotic cells, where they play major and multifaceted roles. The classical notion of the main mitochondrial function as the powerhouse of the cell per se has been complemented by recent discoveries pointing to mitochondria as organelles affecting a number of other auxiliary processes. They go beyond the classical energy provision via acting as a relay point of many catabolic and anabolic processes, to signaling pathways critically affecting cell growth by their implication in de novo pyrimidine synthesis. These additional roles further underscore the importance of mitochondrial homeostasis in various tissues, where its deregulation promotes a number of pathologies. While it has long been known that mitochondria can move within a cell to sites where they are needed, recent research has uncovered that mitochondria can also move between cells. While this intriguing field of research is only emerging, it is clear that mobilization of mitochondria requires a complex apparatus that critically involves mitochondrial proteins of the Miro family, whose role goes beyond the mitochondrial transfer, as will be covered in this review.

• Klíčová slova
• Miro proteins, Mitochondria, endoplasmic reticulum, intercellular transfer, mitophagy, motor proteins, respiration,
• MeSH
• aktivní transport fyziologie   MeSH
• lidé MeSH
• mitochondriální proteiny genetika   metabolismus   MeSH
• mitochondrie genetika   metabolismus   MeSH
• pyrimidiny biosyntéza   MeSH
• rho proteiny vázající GTP genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• audiovizuální média MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• mitochondriální proteiny MeSH
• pyrimidine MeSH Prohlížeč
• pyrimidiny MeSH
• rho proteiny vázající GTP MeSH

Certain pathogenic Escherichia coli strains elaborate a toxin, the cytotoxic necrotizing factor type 1 (CNF1). CNF1 covalently and specifically modifies the p21 Rho GTP-binding protein in mammalian cells by deamidation of the p21 Rho glutamine 63. CNF1 modification of Rho leads to permanent activation of the GTP-binding protein by blocking intrinsic and RhoGAP GTPase activities. Rho activation by CNF1 induces reorganization of the actin cytoskeleton into large stress fibers and the multiplication of focal contact points. Deamidation is a new catalytic activity described for an intracellularly acting toxin.

• MeSH
• bakteriální toxiny metabolismus   toxicita   MeSH
• cytoskelet metabolismus   mikrobiologie   MeSH
• cytotoxiny metabolismus   toxicita   MeSH
• Escherichia coli chemie   metabolismus   MeSH
• eukaryotické buňky metabolismus   mikrobiologie   MeSH
• lidé MeSH
• proteiny vázající GTP metabolismus   MeSH
• proteiny z Escherichia coli * MeSH
• rho proteiny vázající GTP MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• bakteriální toxiny MeSH
• cytotoxic necrotizing factor type 1 MeSH Prohlížeč
• cytotoxiny MeSH
• proteiny vázající GTP MeSH
• proteiny z Escherichia coli * MeSH
• rho proteiny vázající GTP MeSH