Academic literature on the topic 'Protein S'
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Journal articles on the topic "Protein S"
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Sorice, M., T. Griggi, A. Circella, L. Lenti, P. Arcieri, G. Domenico di Nucci, and G. Mariani. "Protein S antibodies in acquired protein S deficiencies [letter]." Blood 83, no. 8 (April 15, 1994): 2383–84. http://dx.doi.org/10.1182/blood.v83.8.2383b.2383b.
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Sorice, M., T. Griggi, A. Circella, L. Lenti, P. Arcieri, G. Domenico di Nucci, and G. Mariani. "Protein S antibodies in acquired protein S deficiencies [letter]." Blood 83, no. 8 (April 15, 1994): 2383–84. http://dx.doi.org/10.1182/blood.v83.8.2383b.bloodjournal8382383b.
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Sacchi, E., M. Pinotti, G. Marchetti, G. Merati, L. Tagliabue, P. M. Mannucci, and F. Bernardi. "Protein S mRNA in Patients with Protein S Deficiency." Thrombosis and Haemostasis 73, no. 05 (1995): 746–49. http://dx.doi.org/10.1055/s-0038-1653862.
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SummaryA protein S gene polymorphism, detectable by restriction analysis (BstXI) of amplified exonic sequences (exon 15), was studied in seven Italian families with protein S deficiency. In the 17 individuals heterozygous for the polymorphism the study was extended to platelet mRNA through reverse transcription, amplification and densitometric analysis. mRNA produced by the putative defective protein S genes was absent in three families and reduced to a different extent (as expressed by altered allelic ratios) in four families. The allelic ratios helped to distinguish total protein S deficiency (type I) from free protein S deficiency (type IIa) in families with equivocal phenotypes. This study indicates that the study of platelet mRNA, in association with phenotypic analysis based upon protein S assays in plasma, helps to classify patients with protein S deficiency.
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Kwaan, Hau. "Protein C and Protein S." Seminars in Thrombosis and Hemostasis 15, no. 03 (July 1989): 353–55. http://dx.doi.org/10.1055/s-2007-1002728.
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Esmon, Charles T. "Protein S and protein C." Trends in Cardiovascular Medicine 2, no. 6 (November 1992): 214–19. http://dx.doi.org/10.1016/1050-1738(92)90027-p.
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Rick, Margaret E. "Protein C and Protein S." JAMA 263, no. 5 (February 2, 1990): 701. http://dx.doi.org/10.1001/jama.1990.03440050095041.
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Nelson, R. M., and G. L. Long. "Binding of protein S to C4b-binding protein. Mutagenesis of protein S." Journal of Biological Chemistry 267, no. 12 (April 1992): 8140–45. http://dx.doi.org/10.1016/s0021-9258(18)42418-0.
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NAKAYAMA, Takayuki, and Tetsuhito KOJIMA. "Protein S Deficiency." Japanese Journal of Thrombosis and Hemostasis 12, no. 3 (2001): 235–39. http://dx.doi.org/10.2491/jjsth.12.235.
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Ratnaparkhi, Girish S., Satish Kumar Awasthi, P. Rani, P. Balaram, and R. Varadarajan. "Structural and thermodynamic consequences of introducing α-aminoisobutyric acid in the S peptide of ribonuclease S." Protein Engineering, Design and Selection 13, no. 10 (October 2000): 697–702. http://dx.doi.org/10.1093/protein/13.10.697.
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D'Angelo, A., and S. Vigano D'Angelo. "Protein S deficiency." Haematologica 93, no. 4 (April 1, 2008): 498–501. http://dx.doi.org/10.3324/haematol.12691.
Full textDissertations / Theses on the topic "Protein S"
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Hon, Jiří. "Vyhledávání příbuzných proteinů s modifikovanou funkcí." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2015. http://www.nusl.cz/ntk/nusl-234914.
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Protein engineering is a young dynamic discipline with great amount of potential practical applications. However, its success is primarily based on perfect knowledge and usage of all existing information about protein function and structure. To achieve that, protein engineering is supported by plenty of bioinformatic tools and analysis. The goal of this project is to create a new tool for protein engineering that would enable researchers to identificate related proteins with modified function in still growing biological databases. The tool is designed as an automated workflow of existing bioinformatic analyses that leads to identification of proteins with the same type of enzymatic function, but with slightly modified properties - primarily in terms of selectivity, reaction speed and stability.
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He, Xuhua. "Vitamin K-dependent anticoagulant protein S biochemical and histochemical studies /." Lund : Dept. of Clinical Chemistry, Wallenberg Laboratory, University of Lund, University Hospital MAS, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39693810.html.
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Radu, Claudia Maria. "Study of the origin of platelets coagulation protein S by human megakaryocyte cultures and characterization of platelets protein S in patients with inherited protein S deficiency." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426476.
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Protein S (PS) is a vitamin K dependent plasma glycoprotein with multiple functions in coagulation, inflammation and apoptosis. The molecular weight of PS is approximately 70 kDa and its concentration in plasma is about 25 mg/L. In human plasma 40% of PS circulates as free form and the remaining 60% is complexes with complement C4b-binding protein, a component of the complement system. PS circulating in plasma is mainly derived from liver synthesis but, in addition, endothelial cells, testicular Leydig cells and a megakaryocytic cell line (MEG 01) can synthesize PS. Platelet contain PS, but whether this is derived from megakaryocytic synthesis or from uptake of plasma PS by megakaryocyte (Mk) is not known. Free PS acts as a cofactor for activated protein C (APC) in the inactivation of procoagulant factors Va and VIIIa. However, PS also has APC-independent anticoagulant functions, probably through direct inhibition of both the prothrombinase and the tenase complexes. It is hypothesized that intra-platelets PS, release upon platelets stimulation, plays a crucial role in regulating thrombin generation and therefore controlling procoagulant activity. PS deficiency is inherited as an autosomal dominant disordered and is classified in three types: I) reduced plasma levels of total and free PS antigen (PSAg); II) normal concentration of total and free PSAg but with low PS activity; III) low free PSAg; and
normal total PSAg. Inherited PS deficiency is generally associated with increased risk of deep venous thrombosis, pulmonary embolism and some cases of arterial thrombosis. The risk of venous thrombosis in PS deficiency increased if 2 associated with other genetic or acquired conditions these includes factor V (FV) Leiden, HR2 aplotype of FV and prothrombin mutation. Several
factors influence the concentration of plasma PS, pregnancy, oral contraceptive and oral anticoagulant therapy decreased the levels of PS. To clarify the origin of intra-platelets PS, we development an in vitro model of human megakaryocyte cell culture. Hematopoietic stem cells were isolated by the histopaque system from whole blood of healthy and PS deficiency subjects. Mononuclear cells have been grown in a serum free medium in presence of thrombopoietin (TPO) and interleuchin-3 (IL-3) to stimulate the differentiation into megakaryocytes lineage. The morphology of differentiated mononuclear cells was similar to MKs, and their positive stain with anti-CD41 antibody allowed us to conclude that these cells were indeed Mk. Mk was labeled with ??-tubulin and ?-tubulin antibodies and we observed the cytoplasmatic extensions called proplatelets and the release of platelets. In addition, through immunofluorescence techniques,
we detected FV in their cytoplasm whereas protein C was not present as expected. As for PS, it was present in the cytoplasm of MKs obtained from healthy and PS deficiency individuals. Our study demonstrated the PS biosynthesis by megakaryocyte. To study the mechanisms that regulate the
concentration of plasma and platelets PS we analyzed plasma and platelets PS from normal and PS deficiency subjects. PS contained in platelets have the same immunoblotting pattern respect to plasma PS. Plasma and platelet PS immunoblotting pattern demonstrated different molecular weight of PS in some deficient PS individuals as compared to normal control, suggesting different mutations in PS gene. We analyzed the presence of mutation and the presence of PS Heerlen allele. We investigated platelets PS antigen levels in type I and type III PS deficient patients. In type I subjects total and plasma free PS antigen levels were (PSAg) 62±7% and 37±12% 3 respectively. In carries of type III defect total and free PSAg levels were 85±13% and 41±13% respectively. Platelets PSAg in type I and type III were 66 ±32% and 80±37%.In a subgroup of healthy individuals total, free and platelet PSAg levels were 119±17%, 110±17% and 101±30%, respectively. The results indicate that type I and III subject’s total and plasma free PSAg levels were lower than normal individuals. Intra-platelets PSAg levels in type I and type III were lower than of healthy individuals. Our analysis demonstrates a strict correlation between total and free plasma PS and Plts PS. The reduction of platelet PS mirrors the reduced levels of free and total PSAg present in carries of the defect even though PS levels in Plts appears unexpectedly higher than the free PS counterpart. Moreover, we study the interaction of anticoagulant drugs on PSAg levels on 35 patient treatments with warfarin. The levels of total and free plasma PS decreased during treatment with oral anticoagulant, since PS is a vitamin K-dependent protein. Our study demonstrated significant decreased levels of platelet PS respectively plasma free and total PS. We valuated the effect of
anticoagulant drugs (warfarin) and of vitamin K on Mk cells. The Mk were treatment with 1?g/ml of warfarin or 1?g/ml of vitamin K and analyze synthesis of PS. We observed decreased PS synthesis on MKs with warfarin than control MKs; on the contrary, MKs cultured under vitamin K treatment increase PS synthesis.La proteina S (PS) è una glicoproteina plasmatica, vitamina K-dipendente, con molteplici funzioni nell’ambito della coagulazione, infiammazione e apoptosi. Il suo peso molecolare è di 70 kDa e la sua concentrazione plasmatica di circa 25 mg/L. Nel plasma umano il 40% della PS circola in forma libera, mentre il restante 60% è legato alla C4b-binding-protein, una proteina del sistema del complemento. La PS circolante nel plasma viene sintetizzata principalmente nel fegato ma anche le cellule endoteliali, le cellule di Leydig e una linea cellulare di megacariociti sono in grado di sintetizzarla. Le piastrine contengono PS, anche se la sua origine non è ancora stata chiarita. Si ipotizza che derivi dalla sintesi dei megacariociti o che siano gli stessi megacariociti ad assumerla dal pool plasmatico mediante un meccanismo di endocitosi. La PS libera agisce da cofattore per la proteina C attivata (APC) nell’inattivazione dei fattori procoagulanti Va (FVa ) e VIIIa (FVIIIa). La PS esercita anche un’azione anticoagulante APC-indipendente, probabilmente inibendo direttamente i complessi tenase e protrombinase. Si suppone che la PS rilasciata dalle piastrine in seguito alla loro attivazione regoli la generazione di trombina, controllando perciò l’attività procoagulante. I difetti di PS sono a trasmissione autosomica dominante e vengono classificati in tre tipi: – difetto di tipo I, caratterizzato da ridotti livelli plasmatici di PS totale e libera; – difetto di tipo II, caratterizzato da livelli fisiologici di PS totale e libera associati ad una ridotta attività; 6 – difetto di tipo III, presenta una PS libera ridotta ed una PS totale nella norma. I difetti di PS sono generalmente associati ad un aumentato rischio di trombosi venosa profonda, embolismo polmonare ed, in qualche caso, a trombosi arteriosa. Nei deficit di PS il rischio di trombosi venosa aumenta se associato ad altre condizioni di carattere genetico o acquisito quali il FV Leiden, l’aplotipo HR2 del FV e mutazioni a carico del gene che codifica per la protrombina. Molteplici fattori, tra cui la gravidanza, la terapia anticoncezionale e anticoagulante orale, riducono la concentrazione plasmatica della PS. Al fine di chiarire l’origine della PS piastrinica, abbiamo messo a punto un modello in vitro di colture di megacariociti umani. Le cellule staminali ematopoietiche sono state isolate con histopaque da sangue intero di soggetti sani e con difetto di PS. Le cellule mononucleate sono state coltivate in un terreno privo di siero ed in presenza di trombopoietina (TPO) e interleuchina 3 (IL3) per stimolarne la differenziazione in una linea magacariocitaria. Le cellule mononucleate differenziate presentavano una morfologia simile a quella dei megacariociti e risultavano positive all’anticorpo anti-CD41; questi elementi ci hanno permesso di confermare che si trattasse effettivamente di megacariociti. Inoltre, la marcatura dei megacariociti con anticorpi anti ??-tubulina e ?-tubulina ha evidenziato sia la presenza di estensioni citoplasmatiche denominate “proplatelets” sia il rilascio di piastrine da parte dei megacariociti. In aggiunta, mediante tecniche di immunofluorescenza, abbiamo rilevato la presenza del FV a livello citoplasmatico, mentre la PC era assente. La PS era presente nel citoplasma dei megacariociti isolati da individui sani e con difetto di PS. La nostra ricerca ha così dimostrato la sintesi di PS da parte dei megacariociti. 7 Per studiare il meccanismo che regola i livelli di PS presenti nel plasma e all’interno delle piastrine, abbiamo determinato la concentrazione di PS plasmatica e piastrinica in soggetti sani e portatori di difetto di PS. La PS piastrinica mostrava lo stesso pattern elettroforetico di quella isolata dal plasma. L’analisi immunologica ha inoltre evidenziato, per alcuni soggetti portatori del difetto, una PS plasmatica con differente peso molecolare rispetto ai controlli sani; questo ci ha suggerito la presenza di mutazioni nel gene della PS. Abbiamo quindi testato la presenza di eventuali mutazioni e dell’allele Heerlen. In soggetti portatori di difetto di PS di tipo I i livelli di PS totale plasmatici, e libera erano: 62±7% e 37±12% . In soggetti portatori di difetto di PS di tipo III i livelli di PS totale e libera nel plasma erano di 85±13% e 41±13%. I livelli di PS nelle piastrine nei soggetti portatori di difetto di PS di tipo I e di tipo III erano di 66 ±32% e 80±37%. In un gruppo di persone sane i livelli di PS totale, libera e piastrinica erano di 119±17%, 110±17% e 101±30%, rispettivamente. Dall’analisi dei livelli plasmatici e piastrinici di PS in soggetti portatori del difetto di tipo I e III è emerso che a) nei pazienti con difetto i livelli di PS totale e libera erano più bassi rispetto ai soggetti sani; b) i pazienti con difetto presentavano livelli di PS piastrinica ridotti rispetto agli individui sani utilizzati come controllo. La nostra analisi ha dimostrato una stretta correlazione tra la PS plasmatica (libera e totale) e quella piastrinica. La diminuzione della concentrazione di PS piastrinica, osservata negli individui portatori del difetto, riflette l’abbassamento del livello di PS plasmatica, sebbene la quota di PS all’interno delle piastrine risulti maggiore rispetto a quella della PS presente nel plasma in forma libera. In seguito abbiamo studiato l’effetto di sostanze anticoagulanti sui livelli plasmatici e piastrinici di PS in pazienti 8 sani in trattamento con warfarina. E’ noto che la warfarina abbassa i livelli plasmatici di PS in quanto quest’ultima è una proteina vitamina Kdipendente. Anche i livelli di PS plasmatica, (totale e libera), e piastrinica dei medesimi soggetti in terapia con warfarina risultano ridotti rispetto alla norma ma l’abbassamento della concentrazione di PS appare molto più marcata all’interno delle piastrine piuttosto che nel plasma. Infine abbiamo valutato l’effetto della warfarina e della vitamina K sulla sintesi di PS da parte dei megacariociti. Mediante tecniche di immunofluorescenza abbiamo osservato una ridotta sintesi della PS nei megacariociti trattati con warfarina rispetto alle cellule di controllo; al contrario, i megacariociti coltivati in un terreno supplementato con vitamina K mostravano un incremento della sintesi di PS.
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Wardlaw, Christopher. "Protein-protein interactions underlying damage checkpoint activation in S. pombe." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/48121/.
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DNA damage can lead to the accumulation of mutations and diseases such as cancer. It is therefore integral for cells to identify this damaged DNA and promote its repair. To carry out this function eukaryotic cells have evolved signal transduction pathways known as the DNA structure checkpoints. Much of the molecular mechanism underlying these pathways is still far from understood. The work in this thesis uses the model organism Schizosaccharomyces pombe to investigate these mechanisms, with a particular focus on the TopBP1 homolog Rad4. TopBP1 plays an essential scaffolding role in the initiation of DNA replication, but is also a key protein in the DNA structure checkpoints. It has previously been shown in metazoans and budding yeast to stimulate the kinase activity of ATR, via its ATR Activation Domain (AAD), an early event in checkpoint activation. The work presented in here, along with initial work carried by previous members of the Carr Laboratory; Su-Jiun Lin and Valerie Garcia, shows that the Rad4TopBP1 AAD acts in a chromatin dependent pathway to amplify the checkpoint signal in G1/S-phase, where DNA resection is limited. A second AAD is also identified in the checkpoint clamp protein Rad9, which acts redundantly with the Rad4 AAD. As well as its AAD function, Rad4 also plays a scaffolding role in the DNA structure checkpoint pathways. The work in this thesis, in collaboration with the Laurence Pearl and Li Lin Du laboratories, identifies the molecular mechanism of the interaction between Rad4 and the mediator protein Crb253BP1. It is shown that sequential phosphorylation of Crb2 by Cdc2CDK is required for the interaction with BRCT domains 1 and 2 of Rad4 and checkpoint activation. It is also shown that Rad4 most likely does not interact with Mrc1 or Slx4 in the S. pombe checkpoint pathways.
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Simmonds, Rachel Elizabeth. "Protein S deficiency and familial thrombophilia." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267993.
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Hamel, Laura Dawn. "Targeting Autopalmitoylation to Modulate Protein S-Palmitoylation." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5960.
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Palmitoylation refers to the covalent attachment of fatty acids, such as palmitate, onto the cysteine residues of proteins. This process may subsequently alter their localization and function. Nearly all of the enzymes that catalyze palmitoylation, zDHHC protein acyl transferases (PATs), are implicated in neurological disorders, infectious diseases, and cancer in humans. Of particular interest to those who study palmitoylation are Ras family GTPas and zDHHC9-GCP16, the zDHHC PAT that palmitoylates Ras proteins. Erf2-Erf4 is the zDHHC PAT that palmitoylates Ras proteins in Saccharomyces cerevisiae. Currently, there are no methods to therapeutically target palmitoylation for the treatment of disease. One of the barriers to identifying a modulator of palmitoylation is the lack of a reliable high-throughput screening system. To date, few assay systems have been developed to examine the kinetics and mechanism of that palmitoylation reaction. This lab has developed a fluorescence-based coupled assay to gain insight into the enzymology, biochemical mechanism, and kinetics of the palmitoylation reaction. This assay may be used to identify specific inhibitors of autopalmitoylation. In the first step of this reaction, the palmitoyl-moiety from palmitoyl-CoA is transferred to the zDHHC9 PAT cysteine side chain to form a palmitoyl:enzyme intermediate. The second step of palmitoylation is the subsequent transfer of the palmitoyl-moiety from the palmitoyl:enzyme intermediate to the cysteine residue of the substrate protein. This fluorescence-based coupled assay was utilized to screen a natural products library and a unique synthetic compound library for inhibitors of Erf2 autopalmitoylation. These screens led to the identification of fungal metabolite extracts and ten bis-cyclic piperazine compounds that inhibit Erf2 autopalmitoylation in the low micromolar range. This effect is similar to known inhibitors of palmitoylation that lack specificity for the palmitoylation reaction itself.
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Hughes, Qunitin William. "Hormonal regulation of the anticoagulant Protein S." University of Western Australia. School of Surgery and Pathology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0247.
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[Truncated abstract] Every year thousands of individuals suffer from thrombotic related complications that in some cases can be fatal and every year millions of women take some form of hormonal contraceptive. In some cases, there is a cause and effect relationship between the two as users of the combined oral contraceptive pill have an increased risk of developing a thrombotic event. Increased circulating levels of oestrogen cause a prothrombotic shift in the coagulation cascade resulting from upregulation of several procoagulant proteins and a decrease of key anticoagulant proteins. One of the most oestrogen sensitive anticoagulants is Protein S (PS), a product of the PROS1 gene. PS acts as a cofactor to activated protein C (aPC) and the PS-aPC complex serves to downregulate clot formation by deactivating the tenase and prothrombinase complexes via proteolytic cleavage of activated factors VIII and V, respectively. As such, low PS levels are associated with an increased risk of developing thrombotic disorders such as pulmonary embolism, stroke or coronary thrombosis and deep vein thrombosis. During pregnancy when oestrogen levels increase, a steady decline in PS is evident in the early weeks of gestation and continues to decrease to below the normal range in the 2nd trimester, remaining there until post-partum. In addition, reduced free and total PS levels are observed in users of the combined oral contraceptive (COC) pill that contains an oestrogen and a progestin. Interestingly, users of 3rd generation COCs have significantly greater reductions of PS than do 2nd generation COC users. The difference between the two forms is the type of progestin, not the oestrogen, which is predominantly ethinyl oestradiol in the majority of commercially available preparations. At present, a mechanism to describe the relationship between oestrogen and/or progesterone associated with the observed in vivo changes in the levels of PS has not been identified. The aim of this thesis was to define the molecular mechanisms involved in the regulation of PS expression by oestrogen and progesterone. In this study, a Combined Single-stranded conformational analysis and Heteroduplex Analysis (CSHA) iv methodology was optimised for screening both PROS1 DNA and mRNA for the detection of mutations. '...' This may explain why users of 3rd generation COCs display a greater reduction in circulating PS levels compared to 2nd generation users. To investigate potential PS interactions with other proteins that could be hormonally regulated, a yeast-2-hybrid (Y-2-H) screen was performed using the PS molecule as a 'bait' against molecules derived from liver and bone marrow cDNA libraries. A clone that contained a portion of another haemostatic protein, Protein Z (PZ) was isolated and confirmed via sequencing. As no full length PZ clones were identified, a second Y-2-H screen was performed once again using the PS molecule as bait and the PZ molecule as the fish. Interaction between the two proteins was shown to be possible via the successful growth of colonies on triple knock out selective media and by positive ß-galactosidase activity.
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Zheng, Bin. "RGS proteins : bridging the "GAP"s between G protein signaling and membrane trafficking /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3059905.
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Rezende, Suely Meireles. "The molecular basis of hereditary protein S deficiency." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289821.
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Grundy, Nicholas Matthew. "Protein S-thiolation and oxidative stress in plants." Thesis, Durham University, 2002. http://etheses.dur.ac.uk/3950/.
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The tripeptides glutathione (GSH; γglutamyl-cysteinyl-glycine) and homoglutathione (hGSH; γglutamyl-cysteinyl-β-alanine) are abundant cytosolic tripeptides in legumes. The reactive cysteinyl sulphydryl group enables GSH or hGSH to act as the major cellular redox buffer through the formation of disulphides with other GSH/hGSH molecules. GSH can also form disulphides with cysteinyl groups within proteins, which is termed 5-thiolation, a reversible modification, protecting proteins from irreversible inactivation of thiol residues, as well as being important in regulating protein activity. Following treatment with fungal cell wall elicitors, plant cells produce reactive oxygen species (ROS) which results in cellular oxidative stress. In animal cells ROS generation induces antioxidant defences which include the accumulation of glutathione (GSH) and the formation of mixed disulphides between proteins and GSH. It was hypothesised that following treatment with a fringal elicitor, plant cells also thiolate proteins. It was of interest to determine how protein thiolation changed in response to changes in thiol metabolism known to occur during elicitation, as well as identifying proteins which underwent this modification. Using cell cultures of alfalfa (Medicago saliva L.), a leguminous plant containing both GSH and hGSH, changes in thiol content upon treatment with a fungal cell wall preparation elicitor were determined. By inhibiting protein synthesis and labelling the thiol pools with L-[(^35)S]cysteine, the degree and rate of protein mixed disulphide formation could be monitored in-vivo. To induce the elicitation response, alfalfa cell cultures were treated with a fungal cell-wall elicitor. Following elicitor treatment GSH, but not hGSH, was found to accumulate, with an associated increase in GSH, but not hGSH, forming mixed disulphide with protein. In order to use proteomic tools to identify thiolated proteins, the oxidative stress response in cell cultures of Arabidopsis, a GSH containing species, was then characterised. The level of protein-bound GSH was found to increase following treatment of cell cultures with the oxidant tert-hutyl hydroperoxide and this was associated with changes in cellular thiols. When proteins S-thiolated either in-vivo, or in-vitro, with [(^35)S]-GSH were resolved by SDS-PAGE under non-reducing conditions, a large number of radiolabelled polypeptides were identified in oxidatively stressed preparations. Testing the hypothesis that GSH-dependent enzymes may undergo S-thiolation, proteins which bound GSH were isolated from Arabidopsis using GSH-afFinity chromatography. A number of 30 kDa polypeptides were isolated and found to be S-thiolated under oxidative conditions in-vitro. Several of these were subsequently identified, notably members of the glutathione transferase (GST) superfamily. Representative recombinant GSTs from Arabidopsis, maize and soybean were expressed, Violated in-vitro and the effect on activity determined. Several thiolatable GSTs were identified from Arabidopsis, notably the members of the family of dehydroascorbate reductases (DHAR I, 11, III) and lambda GSTs. Further analysis by elecfrospray mass-spectroscopy confirmed the covalent binding of GSH to DHAR isoenzymes during in-vitro thiolation. It was concluded that S-thiolation of proteins is a commonly observed reversible modification of proteins in plants exposed to oxidative stress with potentially important consequences in cytoprotection and regulation.
Books on the topic "Protein S"
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M, Bertina Rogier, ed. Protein C and related proteins: Biochemical and clinical aspects. Edinburgh: Churchill Livingstone, 1988.
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Adhezivni molekuli, S-100 protein in ishemijska bolest mozga. Beograd: Zadužbina Andrejević, 2002.
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Cheung, Ricky W. K. The role of G-protein gbsgcs subunits in the invertebrate visual system. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1999.
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Trigazis, Leonidas. Involvement of cholecystokininbAs receptors in protein-induced satiety in rats. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1997.
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Statistik, Indonesia Biro Pusat, ed. Konsumsi kalori dan protein penduduk Indonesia per provinsi, 1987: Consumption of calorie and protein of Indonesian[s] by province, 1987. Jakarta, Indonesia: Biro Pusat Statistik, 1989.
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Hearn, Melanie Jane. Identification and characterisation of a binding protein from pollen membranes for the Papaver rhoeas stigmatic self-incompatability [(S-)] proteins. Birmingham: University of Birmingham, 1998.
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Abdel-Gawad, Yehia Mohamed. Nuclear protein changes in a murine model of myocarditis: The down regulation of histone H1ps, a differentiation - dependent protein. Ottawa: National Library of Canada, 1993.
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D'Agrosa, Raffaele Michael. The gbs galactosidase-neuraminidase-protective protein complex and associated lysosomal storage disorders. Ottawa: National Library of Canada, 1990.
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Bibby, Ashley C. Characterization of novel autoinhibitory site(s) within the protein kinase C alpha regulatory domain. Sudbury, Ont: Laurentian University, 2002.
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Cutz, Jean-Claude. Effect of amygdala kindling on G protein-coupled gas-subunit levels: Immunobolt and functional analysis. Ottawa: National Library of Canada, 1993.
Find full textBook chapters on the topic "Protein S"
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Pötzsch, B. "Protein S." In Hämostaseologie, 351–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-07673-6_41.
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Stief, T. "Protein S." In Lexikon der Medizinischen Laboratoriumsdiagnostik, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-49054-9_2559-1.
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Stief, T. "Protein S." In Springer Reference Medizin, 1981–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-48986-4_2559.
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Hepner, Mirta, and Vasiliki Karlaftis. "Protein S." In Haemostasis, 373–81. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-339-8_30.
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Bertina, R. M. "Protein S antigen." In ECAT Assay Procedures A Manual of Laboratory Techniques, 99–108. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2992-3_12.
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Bertina, R. M. "Protein S antigen." In Laboratory Techniques in Thrombosis - a Manual, 141–51. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4722-4_15.
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Faioni, E. M. "Protein S activity." In Laboratory Techniques in Thrombosis - a Manual, 153–62. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4722-4_16.
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Ward, Tony Milford. "Protein S-100." In Proteins and Tumour Markers May 1995, 1364–65. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0681-8_73.
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Nakamura, Tomohiro, and Stuart A. Lipton. "Protein S-Nitrosylation." In Encyclopedia of Molecular Pharmacology, 1–8. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-21573-6_10041-1.
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Nakamura, Tomohiro, and Stuart A. Lipton. "Protein S-Nitrosylation." In Encyclopedia of Molecular Pharmacology, 1302–9. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57401-7_10041.
Full textConference papers on the topic "Protein S"
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Walker, F. J. "REGULATION OF THE ANTICOAGULANT ACTIVITY OF ACTIVATED PROTEIN C BY PROTEIN S AND PROTEIN S BINDING PROTEIN." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642964.
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Protein S is a vitamin K-dependent protein that acts as a cofactor for the anticoagulant activity of activated protein C both in the proteolytic inactivation of factor V and VIII. Protein S is a single chain protein with a molecular weight of approximately 62 kDa. When the molecular weight of protein S in plasma was determined it was found to be much larger than the single chain protein. The molecular weight of functional protein S when measured by sedimentation equilibrium with the air-driven ultracentrifuge was observed to be between 115 and 130 kDa. In high salt or in the presence of copper ions this was observed to be reduced to approximately 62 kDa. Frontal analysis of plasma indicated that the functional protein by exist in as many as three molecular weight foras. Gel filtration of radiolabeled protein S also indicates heterogeneity in the molecular weight. In order to isolate the binding protein, bovine plasma was fractionated first on a column of immobilized iminodiacetic acid that had been equilibrated with copper ions. The proteins that eluted in the 0.6 M NaCl wash were passed over a column of protein S immobilized on agarose beads. A single protein was observed to elute from the protein S agarose at high salt. Fractionation of human plasma indicated the presence of several proteins. One major component isolated was C4-binding protein. A second major component has also been isolated that appears to correspond to protein S-binding protein that has been isolated from bovine plasma. When added to plasma depleted of both protein S and the binding protein, the binding protein was observed to enhance the anticoagulant activity of activated protein C only in the presence of protein S. Protein S-binding protein was also observed to enhance the rate of factor Va inactivation by activated protein C and protein S.
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Malm, J., R. Bennhagen, L. Holmberg, and B. Dahlbäck. "LOW PLASMA CONCENTRATIONS OF C4b-BINDING PROTEIN AND VITAMIN K-DEPENDENT PROTEIN S IN PRETERM INFANTS WITH DECREASED FORMATION OF PROTEIN S-C4b-BINDING PROTEIN COMPLEXES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644265.
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Protein S is a vitamin K-dependent plasmaprotein functioning as a non-enzymatic cofactor to the activated form of protein C in the degradation of coagulationfactors Va and VIIa. In the circulation approximately 60% of protein S is complexed to the complement protein C4b-binding protein (C4BP). Only the remaining, free fraction exhibits protein Ca cofactor activity.The plasma concentrations of protein S and C4BP were determined in 25 term and 26 preterm infants. Both proteins werequantified with radioimmunoassays. The free, functionally active form of proteinS and the total protein S concentration were determined separately. The level ofC4BP in preterm infants was found to be very low (mean 6% of the adult level). In term infants the level had increased to a mean of 18%. Also the total concentration of protein S was decreased in preterm as well as in term infants; 18% and 31% of the adult level, respectively. Free protein S was the predominant form in plasma representing 83 % of total protein S in preterm and 68 % in term infants. This was probably due to the very low C4BP levels. In adult controls the corresponding value was 34%. The plasma concentration of free protein S in preterm and term infants, when compared to the adult level, was 44% and 66%, respectively. These results demonstrate that although the total protein S concentration in preterm and term infants was very low when compared to adult levels, the difference in the concentration of free, functionally active protein S between infants and adults was less pronounced.
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Melissari, E., M. F. Scully, C. Parker, K. H. Nicolaides, and V. V. Kakkar. "PROTEIN C/PROTEIN S IN THE FOETAL BLOOD. ABSENCE OF BOUND PROTEINS AND C4 BINDING PROTEIN." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644290.
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Protein C, free and bound protein S and C4 binding protein levels (C4bp), were measured by electroimmunoassay in 7 pregnant women aged 22-29 years at 16-18 weeks of gestation, immediately prior to termination of pregnancy for social reasons. Protein C and protein S levels were also measured in their foetuses from blood taken through the umbilical cord. In this group of pregnant women the mean levels for protein C were 104% of normal adult mean (range 80-128%), for C4bp 100% (52-150%), for free protein S 66% (43-89%). In the foetuses the mean value for protein C was 15.3% (10.5-21%) and for free protein S 36.85% (27-47%) of the normal adult mean. Bound protein S and C4bp levels were zero. Conclusions: (1) free protein S is significantly decreased (< 2SD below the normal adult mean) in women after the first trimester of gestation whereas no change is seen in protein C concentration; (2) C4bp levels are at zero in the foetus as also are the levels of bound protein S; (3) foetal blood protein S level is approximately 2.5 times higher than protein C. Since all other vitamin K-dependent factors have been observed to be in the range of 10-20% of normal at this stage of gestation, our findings may be further proof of a non hepatic (endothelial) source of plasma protein S.
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Comp, P. C., and C. T. Esmon. "Defects in the protein C pathway." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643715.
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Activated protein C functions as an anticoagulant by enzymatically degrading factors Va and Villa in the clotting cascade. Protein C may be converted to its enzymatically active form bythrombin. The rate at which thrombin cleavage of the zymogen occurs is greatly enhanced when thrombin is bound to an endothelial cell receptor protein, thrombomodulin. Activated proteinC has a relatively long half-life in vivo and the formation of activated protein C in response to low level thrombin infusion suggests that the protein C system may provide a feedback mechanism to limit blood clotting. Clinical support for such a physiologic role for activated protein C includes an increased incidence of thrombophlebitis and pulmonary emboli in heterozygous deficient individuals, and severe, often fatal, cutaneous thrombosis in homozygous deficient newborns. A third thrombotic condition associated with protein C deficiency is coumarin induced skin (tissue) necrosis. This localized skin necrosis occurs shortly after the initiation of coumarin therapy and is hypothesized to bedue to the rapid disappearance of protein C activity in the plasma beforean adequate intensity of anticoagulation is achieved. Recent estimates of heterozygous protein C deficiency range as high as 1 in 300 individuals in the general population. Since coumarin compounds are in routine clinical use throughout the world and skin necrosis remains a relatively rare clinical finding, this suggests that factors other than protein C deficiency alone may be involved in the pathogenesis of the skin necrosis.The anticoagulant properties of activated protein C are greatly enhanced by another vitamin K-dependent plasma protein, protein S. Protein S functions by increasing the affinity of activated protein C for cell surfaces.Protein S is found in two forms in plasma: free and in complex with C4b-binding protein, "an inhibitor of the complement system. Free protein S is functionally active and the complexed protein S is not active. Individuals congenitally deficient in protein S ae subject to recurrent thromboembolicevents. At least two classes of protin S deficiency occur.Some patienshavedecreased levels of protein S antigen and reduced protein S functional activity. A second group of deficient individuals have normal levels of protein S antigen but most or all their protein S is complexed to C4b-binding protein and they have little or no functional protein S activity. Such a protein S distribution could result from abnormal forms of protein S or C4b-binding protein or some other abnormal plasma or cellular component. Patients with functionally inactive forms of protein S have yet to be identified. Identification of protein S deficient individuals is complicated by thepossible effect of sex hormones on plasma protein S levels. Total protein S antigen is reduced during pregnancyand during oral contraceptive administration. This finding is of practicalclinical importance since the decrease in protein S which occurs during pregnancy may be an added risk factor for congenitally protein S deficient women and may explain why some proteinS deficient women experience their first episode of thrombosis during pregnancy.In addition to having anticoagulant properties, activated protein C enhances fibrinolysis, at least in part,by inhibiting the inhibitor of tissueplasminogen activator. This profibrinolytic effect is enhanced by protein S and cell surfaces. This protection of plasminogen activator activity suggests that the combination of tissue plasminogen activator and activated protein C may be useful in the treatment of coronary artery thrombi. Tissueplasminogen activator would promote clot lysis while activated protein C protected the plasminogen activatorfrom inhibition and also prevented further clot deposition. There is no evidence at present that fibrinolytic activity is reduced in protein C deficient individuals. The possible clinical relevance of this aspect of protein Cfunction in the predisposition of protein C deficient individuals to thrombosis remains to be defined.
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Hopmeier, P., M. Halbmayer, H. P. Schwarz, F. Heuss, and M. Fischer. "PROTEIN C AND PROTEIN S IN MILD AND MODERATE PREECLAMPSIA." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644285.
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In normal pregnancy, total protein S antigen and activity have been reported to be markedly reduced, whereas protein C level was found unaltered. In contrast, in severe preeclampsia protein C antigen was found to be considerably reduced. The presentstudy was done to clarify whether similar changes in protein Cwould alsobe observed for the mildand moderatepreeclamptic state andwhether there would be any effects on the level ofprotein S, since nodata on this cofactor in preeclampsia have been reported to date. 4-0 women in the 3rd trimester of pregnancy - 20 with uncomplicated pregnancies and 20 who had developed a mild (n = 14-) or moderate (n = 6) preeclamptic condition - were included in the study. All groups were well matched in age and gestational age. In addition, 20 healthynon-pregnant women served as controls. All probands had normal liver (SGOT, SGPT) and kidney (BUN, creatinine) values and no other medication than oral vitamins was used. Classification of preeclampsia was done according to a modification of the gestosis index of Goecke using an 11 gradeindex system (0 - 11). ProteinC antigen was measured by an enzyme-linkedimmunosorbent assay and protein S by the Laurell rocket technique.For statistics, the Wilcoxon rank sum test was appliedWe conclude that in comparison tonormal pregnancies, protein S is found elevated at least in the moderate, and protein C in the moderateas well as in the mild preeclamptic state
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Marcovina, S., R. Coppola, M. P. Protti, C. Gelfi, and P. M. Mannucci. "EDTA-DEPENDENT MONOCLONAL ANTIBODIES TO HUMAN PROTEIN S." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644294.
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Splenocytes from a Balb/c mouse immunized with purified human protein S (PS) were fused with murine hybridoma cell line SP2/0-Agl4 and cultured in Iscove's medium without addition of fetal bovine serum. Hybrid supernatants were screened for the presence of specific antibodies by solid-phase ELISA and cloned by the limiting dilution technique. Pour clones, named S2, S3, S8, and S10, were selected, recloned several times, and injected intraperitoneally into Balb/c mice for the production of antibody-rich ascitic fluid. The monoclonal antibodies (Mabs), all of IgGl subclass with k light chain, were purified from ascitic fluid by Protein-A chromatography. The specificity of Mabs was controlled by the immunoblotting technique: the Mabs appeared to react only with two plasma proteins, one with a MW of about 70.000 dal tons comigrating with purified PS, and the other with a MW >300.000 da that is likely to be the C4b-binding protein-PS complex. No interaction has been observed with PS-depleted plasma. As tested by a fluid phase radio immunoassay, the binding of Mabs to PS was significantly higher in the presence of EDTA while was totally inhibited in the presence of Ca2+. Scatchard plot analysis of the binding between 125I-PS and Mabs showed that the binding affinity of the antibodies ranged from 108 to 109 1/mol. Each EDTA-dependent Mab was then immobilized on Sepharose 4B-CNBr and used to purify PS from barium precipitation of citrated plasma. The fraction eluted with 2 mmol of CaCl2 from the immunoadsorbent appeared to contain only two proteins when stained with Cocmassie Blue. By immuno blotting, all Mabs reacted with both proteins, one comigrating with purified PS and the other with a MW >300.000. Essentially homogeneous PS, free from the high MW component, was obtained when the barium citrate adsorbate was applied to a DEAE-Sephadex column and the protein peack containing the balk of PS was sussequently applied to the immunoadsorbent and eluted with 2 mmol CaCl2.In summary, we have described an unusual set of EDTA-dependent monoclonal antibodies to PS and their use for the purification of homogeneous protein S from human plasma.
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Vigano D'Angelo, S., F. Gilardoni, M. P. Seveso, A. Marassi, G. Mari, and A. D'Angelo. "REDUCTION OF THE ANTICOAGULANT ACTIVITY OF PROTEIN C AND PROTEIN S DURING THE POSTOPERATIVE PERIOD." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644287.
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Protein S circulates in plasma as free protein S and in complex with C4b-binding protein, an inhibitor of complement activation. Only free protein S functions as the cofactor for the anticoagulant and profibrinolytic effects of activated protein C. Since isolated reductions of protein C and protein S result in increased thrombotic risk, only measurement of both proteins permits comprehensive evaluation of the antithrombotic potential of the protein C system. No information is available on protein C and protein S functional levels during the postoperative period, an established prothrombotic condition. The plasma changes of protein C, protein S and C4b-binding protein were followed in 40 patients with no malignancy undergoing abdominal surgery. No significant change of protein C and protein S activi ty was observed following minor operations. After major surgery, protein C anticoagulant activity dropped to 80% of preoperative levels during the first postoperative week (p<0.00l). Significant increase of both total protein S antigen (110%, p< 0.01) and C4b-binding protein (130%, p<0.001) were observed after major surgery resulting in reduction of free protein S antigen to 86% of pre operative values (p<0.001). Protein S anticoagulant activity matched the changes of free protein S antigen.Albeit transient and moderate, the observed reductions of both protein C and protein S may act synergistically to cause significant impairment of the antithrombotic potential during the postoperative period. The effect of heparin prophylaxis on protein C and protein S postoperative levels is currently under investigation.
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D'Angelo, A., F. Gilardoni, M. P. Seveso, P. Poli, R. Quintavalle, and C. Manotti. "ANTICOAGULANT AND ANTIGENIC LEVELS OF PROTEIN C AND PROTEIN S IN PATIENTS ON STABILIZED ORAL ANTICOAGULANT TREATMENT." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644286.
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Isolated deficiencies of protein C and protein S, two vitamin K-dependent plasma proteins, constitute about 70% of the congenital abnormalities of blood coagulation observed in patients with recurrent venous thrombosis beLow the age of 40. The laboratory diagnosis of congenital deficiency of these proteins represents a major problem since a large proportion of patients are on oral anticoagulation (OA) at the time the deficiencies are suspected.Under these circumstances the availability of a reference interval obtained in patients on stabilized OA has proven useful.Functional (C) and antigenic levels (Ag) of protein C, protein S, factor IX and II were estimated in 136 patients on stabilized OA, subdivided according to the degree of anticoagulation (Internatio nal Normalized Ratio, INR).The results indicate that with increasing anticoagulation the activity levels of all the vitamin K-dependent factors decrease to a greater extent than the corresponding antigenic levels. At variance with the other factors, total protein S antigen levels are only moderately reduced by OA with protein S anticoagulant activi ty comparing well to factor IX clotting activity. These data suggest the possibility of identifying both quantitative and qualita tive deficiencies of protein C and protein S in patients on oral anticoagulant treatment.
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Schwarz, H. P., and W. Muntean. "LOW TOTAL PROTEIN S ANTIGEN BUT HIGH PROTEIN S ACTIVITY DUE TO DECREASED C4b-BINDING PROTEIN (C4b-BP) LEVELS IN NEWBORNS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643610.
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Vitamin K-dependent coagulation proteins are known to be decreased in the neonatal period. So far no data have been published on protein S (PS), the vitamin K-dependent cofactor for the antithrombotic enzyme, activated protein C (APC) in this period. We determined, therefore, PS antigen, PS activity and C4b-BP,a regulatory protein of the classical complement pathway to which PS is complexed, in 36 neonates. Total PS antigen in newborns was below the range associated with thromboembolism in patients congenitally deficient in this protein (22±9.6%, mean±SD). None of these infants had clinical or laboratory evidence of thromboembolism or DIC. In contrast to the PS antigen level PS activity measured by the ability of APC to prolong the clotting time of a modified APTT assay using PS-immunodep1eted plasma was significantly higher (77.6±14%, mean±SD, p< 0,001), suggesting a shift in PS to the free form. In fact two dimensional immunoe1ectrophoresis studies revealed the absence of protein S-C4b-BP complexes and only one precipitation indicating free PS was seen in 15 out of the 36 infants. In these 15 neonates C4b-BP was below the limit of detection by sensitive quantitative immunob1otting techniques using monoclonal or polyclonal antibodies. In the remaining 21 infants PS-C4b-BP complexes were detected, but in contrast to adult normal plasma approximately 80% of PS was found in the free form. Mixing experiments with normal human plasma and newborn’s plasma indicate that PS in neonate deficient of C4b-BP can bind normally to C4bp. Absence of C4b-BP did not correlate to gestational age. If an equilibrium distribution of PS between bound and free form regulates the cofactor activity of PS for the anticoagulant and profibrino 1ytic properties of APC in normal adults, our study demonstrates that the absence of PS-C4b-BP complexes in newborns and the presence of free PS only may contribute to the increased bleeding risk of premature infants.
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Schwarz, H. P., M. J. Heeb, R. Lottenberg, H. Roberts, and J. H. Griffin. "FAMILIAL PROTEIN S DEFICIENCY WITH A VARIANT PROTEIN S MOLECULE IN PLASMA AND PLATELETS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644636.
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Deficiency of protein S (PS), the cofactor for the antithrombotic protease, activated protein C (APC), was first described in 1984 in families with venous thrombotic disease. We describe here a PS deficient family with venous thrombotic disease presenting an abnormal PS molecule in plasma and platelets. The propositus, 20 years old, and two older siblings suffered from severe venous thrombosis and pulmonary emboli documented by imaging techniques. All laboratory studies were normal except for PS. The propositus while taking oral anticoagulant had a PS antigen (ag) level of 17% and PS functional activity of > 5% as measured by the ability of APC to prolong the clotting time of a modified APTT assay using PS-immunodepleted plasma. One brother had PS ag of 42% and PS activity of 7%. As demonstrated by immunoblotting using SDS gels, both the propositus and this brother presented an abnormal PS molecule in plasma at 65,000 apparent MW versus normal PS at 70,000 apparent MW. The mother had normal PS levels (93% ag/100% activity) but had both normal (70,000 MW) and variant (65,000 MW) forms of the PS molecule in plasma as well as in platelet lysates. One clinically affected PS heterozygous deficient brother (64% ag/11% activity), two asymptomatic siblings (68% ag/9% activity and 104% ag/114% activity) and the asymptomatic PS heterozygous deficient father (59% ag/10% activity) had only normal PS molecules (70,000 MW) on PS immunoblots. Two dimensional immunoelectrophoresis studies showed that the variant PS bound to C4b-binding protein in plasma. Since PS is in platelets and megakaryocytes and synthesized by the latter cells, immunoblotting analysis of platelet lysates was done and showed that platelets of each family member contained the same pattern of normal and variant PS forms as found in plasma. This is consistent with the hypothesis that PS gene expression is similar in those cells, presumably megakaryocytes, hepatocytes and endothelial cells, that control the synthesis of both platelet and plasma forms of PS.
Reports on the topic "Protein S"
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Furbert-Harris, Paulette. Eosinophil Granular Protein(s) Modulate Tumor Metastasis Marker Gene Expression. Fort Belvoir, VA: Defense Technical Information Center, May 2007. http://dx.doi.org/10.21236/ada473779.
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Marquart, Grant. Biomimetic Model Membranes to Study Protein-membrane Interactions and their Role in Alzheimer?s Disease. Portland State University Library, January 2015. http://dx.doi.org/10.15760/honors.154.
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Bercovier, Herve, Raul Barletta, and Shlomo Sela. Characterization and Immunogenicity of Mycobacterium paratuberculosis Secreted and Cellular Proteins. United States Department of Agriculture, January 1996. http://dx.doi.org/10.32747/1996.7573078.bard.
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Our long-term goal is to develop an efficient acellular vaccine against paratuberculosis based on protein antigen(s). A prerequisite to achieve this goal is to analyze and characterize Mycobacterium paratuberculosis (Mpt) secreted and cellular proteins eliciting a protective immune response. In the context of this general objective, we proposed to identify, clone, produce, and characterize: the Mpt 85B antigen and other Mpt immunoreactive secreted proteins, the Mpt L7/L12 ribosomal protein and other immunoreactive cellular proteins, Mpt protein determinants involved in invasion of epithelial cells, and Mpt protein antigens specifically expressed in macrophages. Paratuberculosis is still a very serious problem in Israel and in the USA. In the USA, a recent survey evaluated that 21.6% of the dairy herd were infected with Mpt resulting in 200-250 million dollars in annual losses. Very little is known on the virulence factors and on protective antigens of Mpt. At present, the only means of controlling this disease are culling or vaccination. The current vaccines do not allow a clear differentiation between infected and vaccinated animals. Our long-term goal is to develop an efficient acellular paratuberculosis vaccine based on Mpt protein antigen(s) compatible with diagnostic tests. To achieve this goal it is necessary to analyze and characterize secreted and cellular proteins candidate for such a vaccine. Representative Mpt libraries (shuttle plasmid and phage) were constructed and used to study Mpt genes and gene products described below and will be made available to other research groups. In addition, two approaches were performed which did not yield the expected results. Mav or Mpt DNA genes that confer upon Msg or E. coli the ability to invade and/or survive within HEp-2 cells were not identified. Likewise, we were unable to characterize the 34-39 kDa induced secreted proteins induced by stress factors due to technical difficulties inherent to the complexity of the media needed to support substantial M. pt growth. We identified, isolated, sequenced five Mpt proteins and expressed four of them as recombinant proteins that allowed the study of their immunological properties in sensitized mice. The AphC protein, found to be up regulated by low iron environment, and the SOD protein are both involved in protecting mycobacteria against damage and killing by reactive oxygen (Sod) and nitrogen (AhpC) intermediates, the main bactericidal mechanisms of phagocytic cells. SOD and L7/L12 ribosomal proteins are structural proteins constitutively expressed. 85B and CFP20 are both secreted proteins. SOD, L7/L12, 85B and CFP20 were shown to induce a Th1 response in immunized mice whereas AphC was shown by others to have a similar activity. These proteins did not interfere with the DTH reaction of naturally infected cows. Cellular immunity provides protection in mycobacterial infections, therefore molecules inducing cellular immunity and preferentially a Th1 pathway will be the best candidate for the development of an acellular vaccine. The proteins characterized in this grant that induce a cell-mediated immunity and seem compatible with diagnostic tests, are good candidates for the construction of a future acellular vaccine.
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Gontar, I. P., O. A. Rusanova, O. I. Emelyanova, and I. A. Zborovskaya. ASSOCIATION BETWEEN NEUROLOGICAL STATUS OF RHEUMATOID ARTHRITIS PATIENTS WITH SPECIFIC ANTIBODIES TO MYELIN AND S-100 PROTEIN. Планета, 2018. http://dx.doi.org/10.18411/978-5-907109-24-7-2018-xxxv-89-95.
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Citovsky, Vitaly, and Yedidya Gafni. Suppression of RNA Silencing by TYLCV During Viral Infection. United States Department of Agriculture, December 2009. http://dx.doi.org/10.32747/2009.7592126.bard.
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The Israeli isolate of Tomato yellow leaf curl geminivirus (TYLCV-Is) is a major tomato pathogen, causing extensive (up to 100%) crop losses in Israel and in the south-eastern U.S. (e.g., Georgia, Florida). Surprisingly, however, little is known about the molecular mechanisms of TYLCV-Is interactions with tomato cells. In the current BARD project, we have identified a TYLCV-Is protein, V2, which acts as a suppressor of RNA silencing, and showed that V2 interacts with the tomato (L. esculentum) member of the SGS3 (LeSGS3) protein family known to be involved in RNA silencing. This proposal will use our data as a foundation to study one of the most intriguing, yet poorly understood, aspects of TYLCV-Is interactions with its host plants – possible involvement of the host innate immune system, i.e., RNA silencing, in plant defense against TYLCV-Is and the molecular pathway(s) by which TYLCV-Is may counter this defense. Our project sought two objectives: I. Study of the roles of RNA silencing and its suppression by V2 in TYLCV-Is infection of tomato plants. II. Study of the mechanism by which V2 suppresses RNA silencing. Our research towards these goals has produced the following main achievements: • Identification and characterization of TYLCV V2 protein as a suppressor of RNA silencing. (#1 in the list of publications). • Characterization of the V2 protein as a cytoplasmic protein interacting with the plant protein SlSGS3 and localized mainly in specific, not yet identified, bodies. (#2 in the list of publications). • Development of new tools to study subcellular localization of interacting proteins (#3 in the list of publications). • Characterization of TYLCV V2 as a F-BOX protein and its possible role in target protein(s) degradation. • Characterization of TYLCV V2 interaction with a tomato cystein protease that acts as an anti-viral agent. These research findings provided significant insights into (I) the suppression of RNA silencing executed by the TYLCV V2 protein and (II) characterization some parts of the mechanism(s) involved in this suppression. The obtained knowledge will help to develop specific strategies to attenuate TYLCV infection, for example, by blocking the activity of the viral suppressor of gene silencing thus enabling the host cell silencing machinery combat the virus.
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Nasrallah, J. B. Characterization of a putative S-locus encoded receptor protein kinase and its role in self-incompatibility. Progress report. Office of Scientific and Technical Information (OSTI), May 1994. http://dx.doi.org/10.2172/10148217.
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Morrison, Mark, and Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7695844.bard.
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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Yalovsky, Shaul, and Julian Schroeder. The function of protein farnesylation in early events of ABA signal transduction in stomatal guard cells of Arabidopsis. United States Department of Agriculture, January 2002. http://dx.doi.org/10.32747/2002.7695873.bard.
Full textAbstract:
Loss of function mutations in the farnesyltransferase β subunit gene ERA1 (enhanced response to abscisic acid), cause abscisic acid hypersensitivity in seedlings and in guard cells. This results in slowed water loss of plants in response to drought. Farnesyltransferase (PFT) catalyses the attachment of the 15-carbon isoprenoid farnesyl to conserved cysteine residues located in a conserved C-terminal domain designated CaaX box. PFT is a heterodimeric protein comprised of an a and b sununits. The a subunit is shared between PFT and geranylgeranyltransferase-I (PGGTI) which catalyses the attachemt of the 20-carbon isoprenoid geranylgeranyl to CaaX box proteins in which the last amino acid is almost always leucine and in addition have a polybasic domain proximal to the CaaL box. Preliminary data presented in the proposal showed that increased cytoplasmic Ca2+ concentration in stomal guard cells in response to non-inductive ABA treatements. The goals set in the proposal were to characterize better how PFT (ERA1) affects ABA induced Ca2+ concentrations in guard cells and to identify putative CaaX box proteins which function as negative regulators of ABA signaling and which function is compromised in era1 mutant plants. To achieve these goals we proposed to use camelion Ca2+ sensor protein, high throughput genomic to identify the guard cell transcriptome and test prenylation of candidate proteins. We also proposed to focus our efforts of RAC small GTPases which are prenylated proteins which function in signaling. Our results show that farnesyltransferaseprenylates protein/s that act between the points of ABA perception and the activation of plasma membrane calcium influx channels. A RAC protein designated AtRAC8/AtRop10 also acts in negative regulation of ABA signaling. However, we discovered that this protein is palmitoylated and not prenylated although it contains a C-terminal CXXX motif. We further discovered a unique C-terminal sequence motif required for membrane targeting of palmitoylatedRACs and showed that their function is prenylation independent. A GC/MS based method for expression in plants, purification and analysis of prenyl group was developed. This method would allow highly reliable identification of prenylated protein. Mutants in the shared α subunit of PFT and PGGT-I was identified and characterized and was shown to be ABA hypersensitive but less than era1. This suggested that PFT and PGGT-I have opposing functions in ABA signaling. Our results enhanced the understanding of the role of protein prenylation in ABA signaling and drought resistance in plants with the implications of developing drought resistant plants. The results of our studies were published 4 papers which acknowledge support from BARD.
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Christopher, David A., and Avihai Danon. Plant Adaptation to Light Stress: Genetic Regulatory Mechanisms. United States Department of Agriculture, May 2004. http://dx.doi.org/10.32747/2004.7586534.bard.
Full textAbstract:
Original Objectives: 1. Purify and biochemically characterize RB60 orthologs in higher plant chloroplasts; 2. Clone the gene(s) encoding plant RB60 orthologs and determine their structure and expression; 3. Manipulate the expression of RB60; 4. Assay the effects of altered RB60 expression on thylakoid biogenesis and photosynthetic function in plants exposed to different light conditions. In addition, we also examined the gene structure and expression of RB60 orthologs in the non-vascular plant, Physcomitrella patens and cloned the poly(A)-binding protein orthologue (43 kDa RB47-like protein). This protein is believed to a partner that interacts with RB60 to bind to the psbA5' UTR. Thus, to obtain a comprehensive view of RB60 function requires analysis of its biochemical partners such as RB43. Background & Achievements: High levels of sunlight reduce photosynthesis in plants by damaging the photo system II reaction center (PSII) subunits, such as D1 (encoded by the chloroplast tpsbAgene). When the rate of D1 synthesis is less than the rate of photo damage, photo inhibition occurs and plant growth is decreased. Plants use light-activated translation and enhanced psbAmRNA stability to maintain D1 synthesis and replace the photo damaged 01. Despite the importance to photosynthetic capacity, these mechanisms are poorly understood in plants. One intriguing model derived from the algal chloroplast system, Chlamydomonas, implicates the role of three proteins (RB60, RB47, RB38) that bind to the psbAmRNA 5' untranslated leader (5' UTR) in the light to activate translation or enhance mRNA stability. RB60 is the key enzyme, protein D1sulfide isomerase (Pill), that regulates the psbA-RN :Binding proteins (RB's) by way of light-mediated redox potentials generated by the photosystems. However, proteins with these functions have not been described from higher plants. We provided compelling evidence for the existence of RB60, RB47 and RB38 orthologs in the vascular plant, Arabidopsis. Using gel mobility shift, Rnase protection and UV-crosslinking assays, we have shown that a dithiol redox mechanism which resembles a Pill (RB60) activity regulates the interaction of 43- and 30-kDa proteins with a thermolabile stem-loop in the 5' UTR of the psbAmRNA from Arabidopsis. We discovered, in Arabidopsis, the PD1 gene family consists of II members that differ in polypeptide length from 361 to 566 amino acids, presence of signal peptides, KDEL motifs, and the number and positions of thioredoxin domains. PD1's catalyze the reversible formation an disomerization of disulfide bonds necessary for the proper folding, assembly, activity, and secretion of numerous enzymes and structural proteins. PD1's have also evolved novel cellular redox functions, as single enzymes and as subunits of protein complexes in organelles. We provide evidence that at least one Pill is localized to the chloroplast. We have used PDI-specific polyclonal and monoclonal antisera to characterize the PD1 (55 kDa) in the chloroplast that is unevenly distributed between the stroma and pellet (containing membranes, DNA, polysomes, starch), being three-fold more abundant in the pellet phase. PD1-55 levels increase with light intensity and it assembles into a high molecular weight complex of ~230 kDa as determined on native blue gels. In vitro translation of all 11 different Pill's followed by microsomal membrane processing reactions were used to differentiate among PD1's localized in the endoplasmic reticulum or other organelles. These results will provide.1e insights into redox regulatory mechanisms involved in adaptation of the photosynthetic apparatus to light stress. Elucidating the genetic mechanisms and factors regulating chloroplast photosynthetic genes is important for developing strategies to improve photosynthetic efficiency, crop productivity and adaptation to high light environments.
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Grafi, Gideon, and Brian Larkins. Endoreduplication in Maize Endosperm: An Approach for Increasing Crop Productivity. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575285.bard.
Full textAbstract:
The focus of this research project is to investigate the role of endoreduplication in maize endosperm development and the extent to which this process contributes to high levels of starch and storage protein synthesis. Although endoreduplication has been widely observed in many cells and tissues, especially those with high levels of metabolic activity, the molecular mechanisms through which the cell cycle is altered to produce consecutive cycles of S-phase without an intervening M-phase are unknown. Our previous research has shown that changes in the expression of several cell cycle regulatory genes coincide with the onset of endoreduplication. During this process, there is a sharp reduction in the activity of the mitotic cyclin-dependent kinase (CDK) and activation of the S-phase CDK. It appears the M-phase CDK is stable, but its activity is blocked by a proteinaceous inhibitor. Coincidentally, the S-phase checkpoint protein, retinoblastoma (ZmRb), becomes phosphorylated, presumably releasing an E2F-type transcriptional regulator which promotes the expression of genes responsible for DNA synthesis. To investigate the role of these cell cycle proteins in endoreduplication, we have created transgenic maize plants that express various genes in an endosperm-specific manner using a storage protein (g-zein) promoter. During the first year of the grant, we constructed point mutations of the maize M-phase kinase, p34cdc2. One alteration replaced aspartic acid at position 146 with asparagine (p3630-CdcD146N), while another changed threonine 161 to alanine (p3630-CdcT161A). These mutations abolish the activity of the CDK. We hypothesized that expression of the mutant forms of p34cdc2 in endoreduplicating endosperm, compared to a control p34cdc2, would lead to extra cycles of DNA synthesis. We also fused the gene encoding the regulatory subunit of the M- phase kinase, cyclin B, under the g-zein promoter. Normally, cyclin B is expected to be destroyed prior to the onset of endoreduplication. By producing high levels of this protein in developing endosperm, we hypothesized that the M-phase would be extended, potentially reducing the number of cycles of endoreduplication. Finally, we genetically engineered the wheat dwarf virus RepA protein for endosperm-specific expression. RepA binds to the maize retinoblastoma protein and presumably releases E2F-like transcription factors that activate DNA synthesis. We anticipated that inactivation of ZmRb by RepA would lead to additional cycles of DNA synthesis.