241 |
Studies on the blockade of interferon action by rinderpest virus and other morbillivirusesChinnakannan, Senthil Kumar January 2012 (has links)
No description available.
|
242 |
eIF4E Phosphorylation Influences Bdnf mRNA Translation in Mouse Dorsal Root Ganglion NeuronsMoy, Jamie K., Khoutorsky, Arkady, Asiedu, Marina N., Dussor, Gregory, Price, Theodore J. 06 February 2018 (has links)
Plasticity in dorsal root ganglion (DRG) neurons that promotes pain requires activity-dependent mRNA translation. Protein synthesis inhibitors block the ability of many pain-promoting molecules to enhance excitability in DRG neurons and attenuate behavioral signs of pain plasticity. In line with this, we have recently shown that phosphorylation of the 5' cap-binding protein, eIF4E, plays a pivotal role in plasticity of DRG nociceptors in models of hyperalgesic priming. However, mRNA targets of eIF4E phosphorylation have not been elucidated in the DRG. Brain-derived neurotrophic factor (BDNF) signaling from nociceptors in the DRG to spinal dorsal horn neurons is an important mediator of hyperalgesic priming. Regulatory mechanisms that promote pain plasticity via controlling BDNF expression that is involved in promoting pain plasticity have not been identified. We show that phosphorylation of eIF4E is paramount for Bdnf mRNA translation in the DRG. Bdnf mRNA translation is reduced in mice lacking eIF4E phosphorylation (eIF4E(S209A)) and pro-nociceptive factors fail to increase BDNF protein levels in the DRGs of these mice despite robust upregulation of Bdnf-201 mRNA levels. Importantly, bypassing the DRG by giving intrathecal injection of BDNF in eIF4E(S209A) mice creates a strong hyperalgesic priming response that is normally absent or reduced in these mice. We conclude that eIF4E phosphorylation-mediated translational control of BDNF expression is a key mechanism for nociceptor plasticity leading to hyperalgesic priming.
|
243 |
Receptor tyrosine kinase expression and phosphorylation in canine nasal carcinomaHocker, Samuel January 1900 (has links)
Master of Science in Biomedical Sciences / Department of Clinical Sciences / Mary Lynn Higginbotham / This study evaluated sixteen canine nasal carcinoma and five normal nasal epithelium samples for expression and phosphorylation of known targets of toceranib [vascular endothelial growth factor receptor-2 (VEGR2), platelet derived growth factor alpha (PDGFR-[alpha]), platelet derived growth factor receptor beta (PDGFR-[beta]), and stem cell factor receptor (c-KIT)] and epidermal growth factor receptor 1 (EGFR1) using immunohistochemistry, RT-PCR and a receptor tyrosine kinase (RTK) phosphorylation panel. Protein for VEGFR2 was expressed in neoplastic cells of all carcinomas, PDGFR-[alpha] was noted in 15/16, whereas PDGFR-[beta] was detected in 3/16 samples, but showed primarily stromal staining. Protein expression for c-KIT was present in 4/16 and EGFR1 was noted in 14/16 samples. Normal tissue showed variable protein expression of the RTKs. Messenger RNA for VEGFR2, PDGFR-[beta], and c-KIT were noted in all samples. Messenger RNA for PDGFR-[alpha] and EGFR1 were detected in 15/16 samples. All normal nasal tissue detected messenger RNA for all RTKs of interest. Constitutive phosphorylation of VEGFR2, PDGFR-[alpha], PDGFR-[beta] and c-KIT was not observed in any carcinoma or normal nasal sample, but phosphorylation of EGFR1 was noted in 10/16 carcinoma and 3/5 normal samples. The absence of major phosphorylated RTK targets of toceranib suggests the clinical effect of toceranib may occur through inhibition of alternative and currently unidentified RTK pathways in canine nasal carcinomas. The observed protein and message expression and phosphorylation of EGFR1 in the nasal carcinoma samples merits further inquiry into EGFR1 as a therapeutic target for this cancer.
|
244 |
Docking proteins p130<sup>Cas</sup> and p120<sup>Cbl</sup> in integrin and growth factor receptor signallingOjaniemi, M. (Marja) 23 June 1999 (has links)
Abstract
Adhesive interactions between cells and extracellular matrix
proteins play a vital role in biological processes such as cell
proliferation, differentiation and survival. Integrins comprise
a major family of cell surface receptors that mediate these interactions.
Integrin engagement triggers adhesion-dependent intracellular signalling
cascades that include the phosphorylation of tyrosines in intracellular
signalling proteins. Integrin-dependent signals act in concert
with signals from growth factors and other signalling receptors.
The objective of this thesis was to study how cell adhesion and growth
factors interact with intracellular components to regulate cell
behavior in normal and transformed cells.
One of the main proteins phosphorylated following integrin
ligation in several different cell types is the docking protein
p130Cas (Cas), which is tyrosine phosphorylated
after stimulation of cells with low concentrations of epidermal
growth factor (EGF). Tyrosine-phosphorylated Cas associates with
an adapter protein c-Crk, the main binding protein for Cas, suggesting
a novel role for EGF in Cas signalling. The interaction of cells
with a variety of agonists such as growth factors and integrin ligation
results in stimulation of mitogen-activated protein kinases (MAPKs),
which control the expression of genes important for many cell functions.
Expression of Cas and Crk induces activation of C-Jun N-terminal
kinases (JNKs), which are members of MAPK family. JNK activation
induced by integrin ligand binding is blocked by the expression
of a dominant-negative mutant of Cas or Crk demonstrating an important
role for the Cas-Crk complex in integrin-mediated JNK activation.
The proto-oncogene product p120Cbl (Cbl)
was identified as the main tyrosine-phosphorylated protein following
integrin ligation in hematopoietic cells of myeloid lineage. Tyrosine-phosphorylated
Cbl interacts with and activates other signalling proteins, such
as Src tyrosine kinase and phosphatidylinositol 3"-kinase
(PI 3-kinase), thereby mediating adhesion-dependent signals in hematopoietic
cells. Unlike the cellular Cbl, the transforming mutants of Cbl
were tyrosine-phosphorylated in an adhesion-independent manner
and interacted with and activated signalling molecules both in
suspended and in adherent cells. Further, the oncogenic forms of
Cbl induced anchorage-independent but serum-dependent proliferation
of cells. These results support the view that transformation by
Cbl results from constitutive activation of integrin-dependent
rather than growth factor-dependent signalling events.
|
245 |
Phosphorylation of multiwalled carbon nanotubesNdzimandze, Thembinkosi Mpendulo 07 May 2009 (has links)
M.Sc. / Carbon nanotubes are among the most exciting new materials being investigated and synthesized, owing to their outstanding mechanical, electronic and optical properties. For more than a decade, the translation of these properties into realistic applications has been hindered by solubility and processing difficulties. Recently the development of efficient methodologies for covalent chemical modification has raised hope for the use of these materials in various fields of application such as biosensors, vaccine and drug delivery systems, medical imaging, biomaterials, water purification, etc... Phosphorylation of functionalized and unfunctionalized multiwalled carbon nanotubes (MWCNTs) is reported in this dissertation. This was achieved by the incorporation of phosphorus moieties on the end and side walls of the MWCNTs. Pristine MWCNTs were functionalized through oxidation by sodium hypochlorite and with a mixture of sulphuric and nitric acids, a diazonium coupling method and by reduction of amide functions on the surface of MWCNTs. Then condensation reactions with alkyl or aryl chlorophosphates were undertaken to obtain compounds 7 to 12. Phosphorylation of pristine MWCNTs was achieved by a 1, 3 dipolar cyclo addition of diphenyl phosphoryl azide. Characterization of the phosphorylated multiwalled carbon nanotubes has been performed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy X-Ray Dispersive Spectroscopy (EXDS), Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) and Raman Spectroscopy. These techniques together gave evidence for surface, structure and chemical modifications of the synthesized material.
|
246 |
A new method of phosphorylation and the synthesis of some phosphate esters of biological interestMoffatt, John Gilbert January 1956 (has links)
Tetra-p-nitrophenyl pyrophosphate, generated in situ by the reaction of di-p-nitrophenyl phosphate with di-p-tolyl carbodiimide in anhydrous dioxane, has been shown to be a new and powerful phosphorylating agent, it has been used for the phosphorylation of various aliphatic alcohols and carbohydrate derivatives, particularly nucleosides, as well as of aliphatic amines and mercaptans. The removal of the protecting groups from the initially formed di-p-nitrophenyl alkyl phosphates has been accomplished by both alkaline hydrolysis and catalytic hydrogenolysis. Various other chemical reactions of the intermediate neutral esters, as typified by di-p-nitrophenyl methyl phosphate, have been studied in considerable detail. Included in these are: mild alkaline hydrolysis, partial hydrogenolysis, the action of anhydrous amines, acidic hydrolysis, base catalysed transesterification, and reductive cleavage with sodium in liquid ammonia.
The method has been specifically applied, to the phosphorylation of 2',3'-0-isopropylidine guanosine and has led to the first efficient synthesis of the biologically interesting guanosine-5'-phosphate. Also the enzymatic-ally useful guanosine-5’-mono-p-nitrophenyl phosphate and uridine-5’-mono-p-nitrophenyl phosphate have been prepared and the formation of 3,5’-cyclo-guanosine quaternary salts observed.
Several synthetic routes have been developed for the synthesis of 1,2-0-isopropylidine-D-xylofuranose-3,5-cyclic phosphate and of D-xylofuranose-3,5-cyclic phosphate. Hot alkaline hydrolysis of the former followed by acidic removal of the isopropylidine group has led to a mixture of D-xylofuranose-5-phosphate and D-xylopyranose-3-phosphate which were separated by ion exchange chromatography. Both products have been fully characterized and the method constitutes the first successful synthesis of D-xylose-3-phosphate. A previously reported isolation of the latter compound has been reexamined and shown to be in error. Reinterpretation of the data has shown the reported compound to be in fact D-xylulose-5-phosphate. / Science, Faculty of / Chemistry, Department of / Graduate
|
247 |
Post-translational Analysis of Arabidopsis thaliana Proteins in Response to Cyclic Guanosine Monophosphate TreatmentParrott, Brian 12 December 2011 (has links)
The introduction of mass spectrometry techniques to the field of biology has made possible the exploration of the proteome as a whole system as opposed to prior techniques, such as anti-body based assays or yeast two-hybrid studies, which were strictly limited to the study of a few proteins at a time. This practice has allowed for a systems biology approach of exploring the proteome, with the possibility of viewing entire pathways over increments of time. In this study, the effect of treating Arabidopsis thaliana suspension culture cells with 3’,5’-cyclic guanosine monophosphate (cGMP), which is a native second messenger, was examined. Samples were collected at four time points and proteins were extracted and enriched for both oxidation and phosphorylation before analysis via mass spectrometry. Preliminary results suggest a tendency towards an increased number of phosphorylated proteins as a result of cGMP treatment. The data also showed a sharp increase in methionine oxidation in response to the treatment, occurring within the first ten minutes. This finding suggests that cGMP may utilize methionine oxidation as a mechanism of signal transduction. As such, this study corroborates a growing body of evidence supporting the inclusion of methionine oxidation in intracellular signaling pathways.
|
248 |
Integration of Troponin I Phosphorylations to Modulate Cardiac FunctionSalhi, Hussam E., Salhi 10 August 2016 (has links)
No description available.
|
249 |
Role of the Phosphorylation of mTOR in the Differentiation of AML Cells Triggered with CD44 AntigenDarwish, Manar M. 05 1900 (has links)
Acute myeloid leukemia (AML) is a hematological disorder
characterized by blockage of differentiation of myeloblasts. To date, the
main therapy for AML is chemotherapy. Yet, studies are seeking a better
treatment to enhance the survival rate of patients and minimize the
relapsing of the disease. Since the major problem in these cells is that they
are arrested in cellular differentiation, drugs that could induce their
differentiation have proven to be efficient and of major interest for AML
therapy.
CD44 triggering appeared as a promising target for AML therapy as it
has been shown that specific monoclonal antibodies, such as A3D8 and
H90, reversed the blockage of differentiation, inhibited the proliferation of
all AML subtypes, and in some cases, induced cell apoptosis. Studies
conducted in our laboratory have added strength to these antibodies as
potential treatment for AML. Indeed, our laboratory found that treating HL60 cells with A3D8 shows a decrease in the phosphorylation of the
mammalian target of Rapamycin (mTOR) kinase correlated with the
inhibition of proliferation/induction of differentiation of AML cells.The
relationship between the induction of differentiation and the inhibition of
proliferation and the decrease of mTOR phosphorylation remains to be
clarified.
To study the importance of the de-phosphorylation of mTOR and the
observed effect of CD44 triggering on differentiation and/or proliferation,
we sought to prepare phospho-mimic mutants of the mTOR kinase that will
code for a constitutively phosphorylated form of mTOR and used two main
methods to express this mutant in HL60 cells: lentiviral and simple
transfection (cationic-liposomal transfection).
|
250 |
Autoregulatory and structural control of CaMKII substrate specificityJohnson, Derrick Ethan 06 July 2016 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Calcium/calmodulin (CaM)-dependent protein kinase II (CaMKII) is a multimeric
holoenzyme composed of 8–14 subunits from four closely related isoforms (α, β, γ, δ).
CaMKII plays a strategic, multifunctional role in coupling the universal second messenger
calcium with diverse cellular processes including metabolism, cell cycle control, and
synaptic plasticity. CaMKII exhibits broad substrate specificity, targeting numerous
substrates with diverse phosphorylation motifs. Binding of the calcium sensor CaM to the
autoregulatory domain (ARD) of CaMKII functions to couple kinase activation with calcium signaling. Important sites of autophosphorylation, namely T287 and T306/7 (δ
isoform numbering), reside within the ARD and control either CaM dependence or ability
to bind to CaMKII respectively, thus determining various activation states of the kinase.
Because autophosphorylation is critical to the function of CaMKII in vivo, we sought to
determine the relationship between the activation state of the kinase and substrate
selectivity. We show that the ARD of activated CaMKII tunes substrate selectivity by
competing for substrate binding to the catalytic domain, thus functioning as a selectivity filter. Specifically, in the absence of T287 autophosphorylation, substrate phosphorylation is limited to high-affinity, consensus substrates. T287 autophosphorylation restores maximal
kinase activation and broad substrate selectivity by disengaging ARD filtering. The unique
multimeric architecture of CaMKII is an ideal sensor which encodes calcium-spike
frequency into graded levels of subunit activation/autophosphorylation within the
holoenzyme. We find that differential activation states of the holoenzyme produce distinct substrate phosphorylation profiles. Maximal holoenzyme activation/autophosphorylation
leads to further broadening of substrate specificity beyond the effect of
autophosphorylation alone, which is consistent with multivalent avidity. Thus, the ability of calcium-spike frequency to regulate T287 autophosphorylation and holoenzyme
activation permits cellular activity to dictate switch-like behavior in substrate selectivity
that is required for diverse cellular responses by CaMKII.
|
Page generated in 0.1694 seconds