|
| |
|
|
The role of NG2 glycoprotein in regulation of Rho/ROCK signaling
Kratochvílová, Magdalena ; Rösel, Daniel (advisor) ; Kuželová, Kateřina (referee)
NG2 is a transmembrane glycoprotein, which takes part in cellular processes such as adhesion, migration or invasivity, i.e., in processes important in tissue development but also in tumor and metastasis formation. Among other things, NG2 leads to an inhibition of neurite growth, and probably plays an important role in amoeboid type of cell invasion. These processes are in many respects similar. Both in inhibition of neurite growth and in mesenchymal-amoeboid transition occur morphological changes which lead to a loss of cell protrusions and a transition to a rounded shape. In both of these processes Rho/ROCK signaling also plays a crucial role. Connection between NG2 and the Rho/ROCK signaling pathway has been indicated in the process of inhibition of neurite growth. The mechanism of Rho/ROCK signaling regulation by NG2 glycoprotein is, however, still unknown. In this thesis is proposed a molecular mechanism of Rho/ROCK pathway activation by glycoprotein NG2 which relies on the NG2/MUPP1/Syx signaling complex where the scaffold protein MUPP1, bound to activated NG2, enables binding and activation of the Syx protein. Syx then as RhoGEF activates Rho/ROCK signaling, and the activated Rho/ROCK pathway leads to inhibition of neurite growth, increased cell contractility and traction forces. These processes are...
|
|
| |
|
| |
|
|
Crosstalk of integrin and mTOR signaling
Teglová, Lucie ; Rösel, Daniel (advisor) ; Libus, Jiří (referee)
iv Abstract Crosstalk of integrin and mTOR signalling is an essential process that monitors cellular interaction with extracellular matrix and transmits these inputs to cell growth signalling. Although adhesion status of the cell monitored by integrin signalling is clearly important for regulation of cellular growth, a little is known about the crosstalk of integrin and mTOR signalling. In this study, we employed two different approaches to describe and elucidate character of this crosstalk. p130Cas is an adaptor protein phosphorylated by Src kinase and focal adhesion kinase upon integrin ligand binding and implicated in cell adhesion, motility and survival in both Src-transformed and untransformed cells. Recently, p130Cas was also described in cellular pathology, mainly by its ability to stimulate cell invasion and metastasis. In this study, we described that p130Cas affects mTOR signalling in Src-transformed cells. Substrate domain of p130Cas was found to be indispensable for this effect and is also responsible for serum-induced activation of mTOR signalling. In addition, we prepared cell lines overexpressing various Rheb protein versions and characterized them in context of mTOR signalling, integrin signalling and cell cycle progression. Interestingly, a cell line overexpressing constitutively active...
|
|
|
Design and construction of Src biosensor
Pavlík, Vojtěch ; Rösel, Daniel (advisor) ; Brdička, Tomáš (referee)
Src kinase is a well-known proto-oncogene that contributes to cell migration and proliferation and is often found deregulated in tumors. Yet, biology of Src is not fully understood and great effort is made to find new tools for broadening knowledge about the kinase. In this thesis is described design and construction of a novel Src biosensor that exploits genetically encodable fluorophores derived from green fluorescent protein and Förster/fluorescence resonance energy transfer (FRET). The fluorophores are inserted directly into the structure of full-length c-Src in the way that should not impair the inner regulatory mechanisms of Src. The created biosensor proved to be sensitive to various stimuli, which also activate c-Src, by increase of activating autophosphorylation on Tyr4162 and decrease in FRET. Preliminary experiments indicate that the Src biosensor can be used to reflect Src activation in fixed cell as well.
|
|
|
The search for novel interaction partners of SH3 domain of an adaptor protein p130Cas
Gemperle, Jakub ; Rösel, Daniel (advisor) ; Forstová, Jitka (referee)
Protein p130Cas is the major tyrosine phosphorylated protein in cells transformed by v-crk and v-src oncogenes. P130Cas plays an important role in invasiveness and metastasis of Src-transformed cells. In breast cancer patients, high p130Cas levels are associated with higher recurrence of disease, poor response to tamoxifen treatment and lower overall survival. In non-transformed cells, after the stimulation of integrins, protein p130Cas is phosphorylated in substrate domain affecting cell migration and cytoskeletal dynamics. For this signalling is the SH3 domain of p130Cas indispensable. In this thesis, was for the first time using the Phage display method analysed and subsequently characterized the binding motif of SH3 domain of p130Cas. Based on this high-affinity motif [AP]-P-[APMS]-K-P-[LPST]-[LR]- [LPST], we predicted new interaction partners of protein p130Cas and subsequently confirmed the interaction with the Ser/Thr kinase PKN3. This kinase colocalizes with p130Cas in the nucleus and perinuclear region and could phosphorylate p130Cas. In this thesis, we also analysed the effect of phosphomimicking mutation of tyrosine from sequence ALYD, which is conserved in the sequence of SH3 domains, on ability of these domains to bind ligands. This mutation reduced binding by about 3 orders of...
|
|
|
The role of 53BP1 in the cellular response to double-strand DNA breaks
Liďák, Tomáš ; Macůrek, Libor (advisor) ; Rösel, Daniel (referee)
DNA damage may result in various pathological conditions and contributes to aging and development of cancer. Evolutionarily conserved DNA damage response prevents the acumulation of mutations and protects against genomic instability. Tumor suppressor p53-binding protein 1 (53BP1) is an important regulator of the cellular response to DNA double-strand breaks (DSB) and is a canonical component of ionizing radiation-induced foci which are formed at DNA DSB following radiation exposure. Recently, new insights have been gained into its functions in the DNA damage response. Apart from its subtle role in the DNA damage checkpoints signaling, 53BP1 is a well established player in the DNA DSB repair pathway choice. The outcome of DNA repair is influenced by 53BP1 in several contexts. 53BP1 controls 5' end resection at DNA ends, improves DSB repair in heterochromatin, promotes the mobility of uncapped telomeres and mediates synapsis of DNA ends during V(D)J and class switch recombination. 53BP1 contributes to repair defect in BRCA1 (breast cancer type 1 susceptibility protein)-deficient cells, which may have an impact on the treatment of some types of breast cancer. The aim of this bachelor's thesis is to summarize new findings about the role of 53BP1 in the cellular response to DNA DSB. Powered by TCPDF (www.tcpdf.org)
|
|
|
Analyzing the role of the p130Cas SH3 domain in p130Cas-mediated signaling
Gemperle, Jakub ; Rösel, Daniel (advisor) ; Vomastek, Tomáš (referee) ; Truksa, Jaroslav (referee)
The adaptor protein p130Cas (CAS, BCAR1) represents a nodal signaling platform for integrin and growth factor receptor signaling, and influences normal development and tissue homeostasis. Its altered expression drives many pathological conditions including tumor growth, metastasis and drug resistance in many cancer types. How p130Cas contributes to many of these pathologies is still poorly understood. Therefore, the overall aim of my PhD work was to provide new insights to p130Cas signaling and its regulation. The SH3 domain is indispensable for p130Cas signaling, but the ligand binding characteristics of the p130Cas SH3 domain, and the structural determinants of its regulation were not well understood. To be able to study various aspects of p130Cas signaling we identified an atypical binding motif in p130Cas SH3 domain by establishing collaborations with Dr Veverka (Structural biology) and Dr Lepšík (Computational biochemistry; Academy of Sciences, CZ) which gave new insight into this binding interface. Through these collaborations I generated chimeras of p130Cas SH3 domain with its ligands for structural NMR analysis and learned how to visualize and analyze structures. Furthermore, my work expanded our knowledge of p130Cas SH3 ligand binding regulation and led to a novel model of Src-p130Cas- FAK...
|
|
| |
guest ::
