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Expression and characterisation of homologs of human glutamate carboxypeptidase II
Bäumlová, Adriana ; Konvalinka, Jan (advisor) ; Vaněk, Ondřej (referee)
English abstract Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a membrane bound glycoprotein that belongs to the metallopeptidase M28 family. Two physiological substrates were found for GCPII. The first one, N-acetyl-aspartylglutamate (NAAG), serves as a neurotransmiter in the brain and GCPII hydrolyzes it to yield free glutamate in the synaptic cleft. Excess glutamate might be cytotoxic and eventually lead to excitoxic nerve cells death. Inhibition of NAAG hydrolyzing activity has been shown to be neuroprotective. Therefore, GCPII inhibition was suggested as a therapeutic target in treatment of neurological disorders where excess glutamate is involved. The second substrate, polyglutamyl folate, is a precursor of folic acid which is required for cell growth and development. GCPII cleaves off glutamate from dietary folates and thus facilitates their absorption in small intestine. Although GCPII biological relevance is known only in the brain and the small intestine, its role in the prostate is also important. GCPII has been described as a prostate cancer marker as it is expressed on the membrane of prostate cancer cells. Since GCPII is type II transmembrane protein, it is enzymatically active and undergoes internalization, it has been suggested as a promising tool for specific anticancer-drug...
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Preparation, expression and characterization of mouse GCPIII
Bäumlová, Adriana ; Konvalinka, Jan (advisor) ; Šebo, Peter (referee)
English abstract Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a type II transmembrane glycoprotein which has been discovered in nervous system as an enzyme responsible for the hydrolysis of neuropeptide N-acetyl-L-aspartyl-L-glutamate to N-acetyl-L-aspartate and L-glutamate and that has been hypothesized to influence glutamatergic signaling processes. Except for brain, GCPII was mainly found in prostate, kidney, and small intestine. In small intestine, GCPII cleaves terminal glutamates from polyglutamylated folates facilitating thus absorption of dietary folates. In prostate, this enzyme is known as prostate-specific membrane antigen and is used as a cancer marker. Mus musculus is an important model for studing GCPII and its homologs as a therapeutic target. While human GCPII and its paralog GCPIII are relatively well characterized, no biochemical study of their mouse orthologs is available. That is why mouse glutamate carboxypeptidase III (mGCPIII) was cloned, prepared by recombinant expression in insect cells and characterized. We show that pure mouse GCPIII possesses α-glutamate carboxypeptidase activity which is effectively inhibited by specific inhibitor GCPII, 2-PMPA. We also analyzed sensitivity and specifity of monoclonal antibodies against mouse GCPIII. Immunoblots demonstrate that...
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The crystal structure of PI4 kinase
Bäumlová, Adriana ; Bouřa, Evžen (advisor) ; Obšil, Tomáš (referee) ; Bařinka, Cyril (referee)
Phosphatidylinositol 4-kinases (PI4K/PI4-kinases) catalyse the production of phosphatidylinositol 4-phosphate (PtdIns4P), the first step in the generation of higher phosphoinositides. PtdIns4P is an essential precursor in the production of second messengers, Ins(1,4,5)P3 and diacylglycerol, in a receptor activated phospholipase C signalling pathway. Moreover, PtdIns4P itself regulates conserved compartment-specific biological processes, mainly via recruiting a broad spectra of effector proteins. Because PI4-kinases have a central position in PtdIns4P synthesis on a surface of intracellular membranes, they are implicated in a wide range of PtdIns4P-induced processes such as lipid transport and metabolism, intracellular trafficking processes and cargo sorting, membrane and cytoskeleton remodelling events, signal transduction and many others. In mammals, two types of PI4-kinases were identified: type II and type III. Both types do not bear high sequence similarity to each other and, therefore, they possess diverse biochemical properties. In order to elucidate their structural relationship to other lipid kinases, structural analysis is highly demanded. The structural characterisation of individual PI4-kinases could also clarify the catalytic mechanism of PtdIns4P synthesis. Furthermore, information...
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The crystal structure of PI4 kinase
Bäumlová, Adriana
Phosphatidylinositol 4-kinases (PI4K/PI4-kinases) catalyse the production of phosphatidylinositol 4-phosphate (PtdIns4P), the first step in the generation of higher phosphoinositides. PtdIns4P is an essential precursor in the production of second messengers, Ins(1,4,5)P3 and diacylglycerol, in a receptor activated phospholipase C signalling pathway. Moreover, PtdIns4P itself regulates conserved compartment-specific biological processes, mainly via recruiting a broad spectra of effector proteins. Because PI4-kinases have a central position in PtdIns4P synthesis on a surface of intracellular membranes, they are implicated in a wide range of PtdIns4P-induced processes such as lipid transport and metabolism, intracellular trafficking processes and cargo sorting, membrane and cytoskeleton remodelling events, signal transduction and many others. In mammals, two types of PI4-kinases were identified: type II and type III. Both types do not bear high sequence similarity to each other and, therefore, they possess diverse biochemical properties. In order to elucidate their structural relationship to other lipid kinases, structural analysis is highly demanded. The structural characterisation of individual PI4-kinases could also clarify the catalytic mechanism of PtdIns4P synthesis. Furthermore, information...
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The crystal structure of PI4 kinase
Bäumlová, Adriana ; Bouřa, Evžen (advisor) ; Obšil, Tomáš (referee) ; Bařinka, Cyril (referee)
Phosphatidylinositol 4-kinases (PI4K/PI4-kinases) catalyse the production of phosphatidylinositol 4-phosphate (PtdIns4P), the first step in the generation of higher phosphoinositides. PtdIns4P is an essential precursor in the production of second messengers, Ins(1,4,5)P3 and diacylglycerol, in a receptor activated phospholipase C signalling pathway. Moreover, PtdIns4P itself regulates conserved compartment-specific biological processes, mainly via recruiting a broad spectra of effector proteins. Because PI4-kinases have a central position in PtdIns4P synthesis on a surface of intracellular membranes, they are implicated in a wide range of PtdIns4P-induced processes such as lipid transport and metabolism, intracellular trafficking processes and cargo sorting, membrane and cytoskeleton remodelling events, signal transduction and many others. In mammals, two types of PI4-kinases were identified: type II and type III. Both types do not bear high sequence similarity to each other and, therefore, they possess diverse biochemical properties. In order to elucidate their structural relationship to other lipid kinases, structural analysis is highly demanded. The structural characterisation of individual PI4-kinases could also clarify the catalytic mechanism of PtdIns4P synthesis. Furthermore, information...
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The crystal structure of PI4 kinase
Bäumlová, Adriana
Phosphatidylinositol 4-kinases (PI4K/PI4-kinases) catalyse the production of phosphatidylinositol 4-phosphate (PtdIns4P), the first step in the generation of higher phosphoinositides. PtdIns4P is an essential precursor in the production of second messengers, Ins(1,4,5)P3 and diacylglycerol, in a receptor activated phospholipase C signalling pathway. Moreover, PtdIns4P itself regulates conserved compartment-specific biological processes, mainly via recruiting a broad spectra of effector proteins. Because PI4-kinases have a central position in PtdIns4P synthesis on a surface of intracellular membranes, they are implicated in a wide range of PtdIns4P-induced processes such as lipid transport and metabolism, intracellular trafficking processes and cargo sorting, membrane and cytoskeleton remodelling events, signal transduction and many others. In mammals, two types of PI4-kinases were identified: type II and type III. Both types do not bear high sequence similarity to each other and, therefore, they possess diverse biochemical properties. In order to elucidate their structural relationship to other lipid kinases, structural analysis is highly demanded. The structural characterisation of individual PI4-kinases could also clarify the catalytic mechanism of PtdIns4P synthesis. Furthermore, information...
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Expression and characterisation of homologs of human glutamate carboxypeptidase II
Bäumlová, Adriana ; Konvalinka, Jan (advisor) ; Vaněk, Ondřej (referee)
English abstract Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a membrane bound glycoprotein that belongs to the metallopeptidase M28 family. Two physiological substrates were found for GCPII. The first one, N-acetyl-aspartylglutamate (NAAG), serves as a neurotransmiter in the brain and GCPII hydrolyzes it to yield free glutamate in the synaptic cleft. Excess glutamate might be cytotoxic and eventually lead to excitoxic nerve cells death. Inhibition of NAAG hydrolyzing activity has been shown to be neuroprotective. Therefore, GCPII inhibition was suggested as a therapeutic target in treatment of neurological disorders where excess glutamate is involved. The second substrate, polyglutamyl folate, is a precursor of folic acid which is required for cell growth and development. GCPII cleaves off glutamate from dietary folates and thus facilitates their absorption in small intestine. Although GCPII biological relevance is known only in the brain and the small intestine, its role in the prostate is also important. GCPII has been described as a prostate cancer marker as it is expressed on the membrane of prostate cancer cells. Since GCPII is type II transmembrane protein, it is enzymatically active and undergoes internalization, it has been suggested as a promising tool for specific anticancer-drug...
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Preparation, expression and characterization of mouse GCPIII
Bäumlová, Adriana ; Šebo, Peter (referee) ; Konvalinka, Jan (advisor)
English abstract Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a type II transmembrane glycoprotein which has been discovered in nervous system as an enzyme responsible for the hydrolysis of neuropeptide N-acetyl-L-aspartyl-L-glutamate to N-acetyl-L-aspartate and L-glutamate and that has been hypothesized to influence glutamatergic signaling processes. Except for brain, GCPII was mainly found in prostate, kidney, and small intestine. In small intestine, GCPII cleaves terminal glutamates from polyglutamylated folates facilitating thus absorption of dietary folates. In prostate, this enzyme is known as prostate-specific membrane antigen and is used as a cancer marker. Mus musculus is an important model for studing GCPII and its homologs as a therapeutic target. While human GCPII and its paralog GCPIII are relatively well characterized, no biochemical study of their mouse orthologs is available. That is why mouse glutamate carboxypeptidase III (mGCPIII) was cloned, prepared by recombinant expression in insect cells and characterized. We show that pure mouse GCPIII possesses α-glutamate carboxypeptidase activity which is effectively inhibited by specific inhibitor GCPII, 2-PMPA. We also analyzed sensitivity and specifity of monoclonal antibodies against mouse GCPIII. Immunoblots demonstrate that...
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