Download or read book A Novel RCC1 like Protein is a Crucial Regulator of the Intraerythrocytic Cycle of the Human Malaria Parasite Plasmodium Falciparum written by and published by . This book was released on 2015 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Malaria is a deadly infection caused by a single celled protozoan of the Plasmodium genus. Plasmodium spp. are transmitted to humans by mosquitoes, and initially invade the liver, but the disease is caused by the blood stage of the infection. Approximately 500 million cases of malaria are documented annually and over 1 million of those result in death. Plasmodium falciparum is the most lethal of five species known to infect humans. To further compound this problem, drug-resistant parasite strains have been documented for every currently available antimalarial drug, making the need to identify new drug targets more urgent than ever. Modern genetics have found that more than 50% of the Plasmodium genome codes for proteins of unknown functions, with no significant sequence homology to any known eukaryotic genes. Recent advances in forward genetics and the use of transposable elements to manipulate the genome of P. falciparum have made tremendous contributions to discovering the functions of these unknown genes, which is critical to rapidly advance antimalarial drug development. In this study we have identified a gene of unknown function, PF3D7_1143500, that is significant for intraerythrocytic development of Plasmodium. This gene exhibits weak similarities to the human regulator of chromatin condensation 1 protein (RCC1) and appears to belong to the class of RCC1-like proteins that perform diverse functions in eukaryotes. A thorough cellular and molecular analysis of an insertional knockout mutant of PF3D7_1143500 in P. falciparum has revealed a critical role for this gene in the production of merozoites during the intraerythrocytic cycle. The insertional mutant parasite strain displays a significant delay in initiating nuclear division, which results in a 40% reduction in the number of merozoites produced at the end of the intraerythrocytic cycle, thereby severely attenuating the parasite growth rate. PF3D7_1143500 localizes to the microtubule organization centers within the nucleus during the early stages of parasite development, suggesting it functions in regulating mitosis. Since cell cycle regulatory mechanisms are largely unknown in Plasmodium, the identification of this novel RCC1-like protein promises to offer new insights into this critical biological pathway that has high potential as an antimalarial drug target.

Download or read book Understanding Phospholipid Biosynthesis in the Human Malaria Parasite Plasmodium Falciparum Using Saccharomyces Cerevisiae as a Surrogate System written by Teresa C. Santiago and published by . This book was released on 2005 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Exported Malaria Protein Regulates Glucose Uptake During Intraerythrocytic Infection written by Tamira K. Butler and published by . This book was released on 2014 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Malaria is the world's second biggest infectious killer after tuberculosis. It accounts for 219 million cases each year, with an estimated 660,000 deaths. The majority of these deaths occur in sub-Saharan Africa, in children under 5 years old. In addition to Africa, malaria is endemic to Asia, Central and South America, the Caribbean and the Middle East. Plasmodium falciparum (P. falciparum) is the protozoan parasite that is responsible for the deadliest form of human malaria. Plasmodia are carried by the female Anopheles mosquito and infected into humans during a blood meal. The parasites invade liver cells and form merozoites which erupt from liver cells to invade red blood cells. The intraerythrocytic cycle of infection is responsible for the clinical manifestations of malaria, namely fever and chills. The intraerythrocytic cycle is also the stage of disease that is most studied and targeted for treatment. Although treatment for malaria is available, drug-resistant forms of the parasite are increasingly rampant. For this reason, new, more effective treatments for malaria are necessary. To develop these treatments, we must have a better understanding of the biological processes that the parasite employs to survive in the host to cause disease. In 1996, an international effort was launched to sequence the genome of P. falciparum with the expectation that the genome sequence could be exploited in the search for new drugs and vaccines to fight malaria. In 2002, the genome sequence was published with gaps in some chromosomes. Approximately 5,300 protein-encoding genes were identified; of these about 60% were labeled as hypothetical proteins. Our studies focus on determining the function of one hypothetical protein, PFB0923c, that we now call Glucose Uptake Restoration Protein (GURP). We show that GURP localizes to novel double membrane vesicles in the RBC cytosol and is essential during P. falciparum intraerythrocytic infection. GURP interacts with and sequesters the host protein stomatin, which is known to depress glucose uptake in mammalian cells. Knockdown of GURP decreases glucose uptake and impairs parasite growth in RBCs. This phenotype can be rescued with antioxidants, suggesting that hexose monophosphate/pentose phosphate pathway impairment is lethal in the knockdown parasites. GURP C183 is essential to parasite viability and trafficking of GURP vesicles to the RBC cytosol. Together, these data demonstrate that GURP is essential to P. falciparum viability and glucose uptake during infection of red blood cells.

Download or read book DNA Sequence Context and the Chromatin Landscape Differentiate Sequence specific Transcription Factor Binding in the Human Malaria Parasite Plasmodium Falciparum written by Victoria Bonnell and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Malaria, caused by protozoan parasites of the genus Plasmodium, remains a major global health burden, with 247 million cases and killing 619,000 in 2021 alone. In Plasmodium falciparum, the deadliest human malaria parasite, about 90% of the protein-coding genes are transcribed in a periodic fashion over the 48-hour intraerythrocytic development cycle (IDC), with the peak transcript abundance generally occurring just before the protein is required. The periodicity of transcription forms a genome-wide cascade of continuous gene expression, which is believed to be finely regulated by a limited number of transcriptional regulators, including the 30-member Apicomplexan APETALA2 (ApiAP2) family of sequence-specific transcription factors (TFs). Interestingly, this family of proteins has AP2 DNA-binding domains only evolutionarily conserved in plant-linage genomes and Apicomplexan parasites, making them potential drug targets for novel antimalarial therapeutics in humans. The current literature is focused only on identifying regulatory networks controlled by the ApiAP2 TFs; however, dissecting the molecular mechanisms of their genome-wide binding pattern is still understudied. Knowing mechanisms of binding site selection of putative drug targets is critical to identifying essential interactions or features to be blocked. This dissertation elucidates the biological function and binding specificity of a subset of ApiAP2 TFs, which each recognize similar DNA sequence motifs in vitro, along with their chromatin-remodeling interaction partners. This project applies in vitro, in vivo, and in silico approaches to identify how sequence preferences are established during parasite development by probing the effects of cis- and trans- regulation on TF binding, in addition to dissecting the function of these TFs in parasite development. In higher eukaryotes, TFs with similar binding preferences can carry out different regulatory functions in a given cell type, work synergistically or antagonistically, perform similar functions in different cell types, or can be fully redundant and only necessary in the event that the primary factor cannot function. The occurrence of multiple TFs recognizing similar DNA sequence motifs in P. falciparum is intriguing since functional gene redundancy is not often evolutionarily conserved in pathogens. Therefore, despite the similar DNA binding motifs of these proteins, we predict that they carry out distinct regulatory functions in the parasite. There are several established features investigated by this work that can modulate binding specificity of a TF such as: DNA sequence context/intrinsic DNA shape, interaction with cofactors, histone post-translational modification, and chromatin accessibility. It is critical to understand which features, or combinations thereof, influence binding specificity of transcriptional regulators in P. falciparum to inform future antimalarial drug development.

Download or read book Integrative Transcriptome and Phenome Analysis Reveals Unique Regulatory Cascades Controlling the Intraerythrocytic Asexual and Sexual Development of Human Malaria Parasites written by RieÌ8tte Andele̹ Van Biljon and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Plasmodium falciparum parasite, the major causative agent of malaria on the African continent, has evolved numerous cellular adaptations to effectively propagate its species. The parasite can proliferate asexually, producing mass amounts of progeny to subsist in the human host or differentiate into sexual forms (gametocytes) that, once mature, can transmit to a feeding Anopheles mosquito. Key to our ability to effectively develop chemical candidates that interfere with either of these processes is the identification and understanding of critical factors that regulate parasite development. This is particularly true for the development of antimalarials that can be used in malaria elimination strategies by targeting both parasite proliferation and transmission. We therefore hypothesized that parasite proliferation and differentiation use divergent mechanisms for gene expression that could be observed through a thorough investigation of the functional genome of these different parasite forms. This doctoral study therefore set out to increase our knowledge base on three crucial aspects of parasite development: 1) the atypical cell cycle that allows the rapid proliferation of asexual parasites; 2) the full molecular profile of gametocytogenesis enabling the cellular differentiation that allows the parasite to transmit; and 3) the metabolic differences between these proliferating and differentiating parasites that results from their strategy-specific mechanisms of developmental control. The atypical cell cycle of the parasite, associated with the massive cell number expansion in asexual development, is notoriously difficult to study. Here, we contributed a novel system by developing a cell cycle synchronization tool that reversibly blocks the development of asexual parasites at the G1/S transition. This results in an inescapable arrest of the cell cycle that is completely and functionally reversible; parasites re-initiate cell cycle progression and continue to S phase within 6 h. This system provided the opportunity to characterize cell cycle phases in the parasite and additionally evaluate molecular mechanisms associated with cell cycle arrest or re-initiation. During cell cycle arrest, the parasite enters a quiescent state reminiscent of a mitogen-activated restriction point. This arrest is unique and solely attributed to the removal of the specific mitogens within this system, polyamines. These analyses indicate the close interaction between transcriptional regulation and signal transduction cascades in the progression through the parasite℗þs cell cycle and for the first time highlight aspects of controlled cell cycle regulation in Plasmodium. In contrast to proliferation, the process of sexual differentiation only started receiving attention in the past few years. As such, we lack fundamental understanding of the mechanisms driving the unique gametocyte differentiation of P. falciparum parasites. This study contributes a detailed analysis of gametocyte differentiation that revealed distinct developmental transitions demarcating the start of gametocytogenesis, intermediate gametocyte development and finally maturation to produce the transmissible mature gametocytes. The study provides evidence for coordinated regulation of gene expression on a transcriptional level. We propose a model for regulation of gametocytogenesis in malaria parasites that involves active repression of gene sets mediated through epigenetics and RNA destabilization as well as active transcription of gene sets through successive ApiAP2 transcription factor activity. This data provides the most detailed framework of coordinated gene regulation events underlying development of P. falciparum gametocytes to date, a unique resource for the malaria community. The comprehensive and complex transcriptional regulation described for the proliferation and differentiation of the parasite led us to evaluate the functional consequence thereof. A whole cell phenotype microarray system was evaluated for its ability to measure the metabolic processes that define asexual and sexual stage metabolism as a functional consequence of changed gene expression profiles during proliferation and differentiation. The study provided metabolic profiles detailing carbon and nitrogen metabolism in asexual parasites, mature and immature gametocyte stages. The data highlighted dipeptide metabolism as a distinguishing feature in mature gametocytes and showed the presence of a low, delayed metabolic state concurrent with reduced transcriptional activity observed in this stage. These results show that gene expression changes associated with differentiation compared to proliferation translate to an observable metabolic phenotype and that transcriptional regulation shapes the molecular landscape underlying crucial events that enable the parasite℗þs intraerythrocytic asexual and sexual development.

Download or read book Integrative Transcriptome and Phenome Analysis Reveals Unique Regulatory Cascades Controlling the Intraerythrocytic Asexual and Sexual Development of Human Malaria Parasites written by Ri tte Andel Van Biljon and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Plasmodium falciparum parasite, the major causative agent of malaria on the African continent, has evolved numerous cellular adaptations to effectively propagate its species. The parasite can proliferate asexually, producing mass amounts of progeny to subsist in the human host or differentiate into sexual forms (gametocytes) that, once mature, can transmit to a feeding Anopheles mosquito. Key to our ability to effectively develop chemical candidates that interfere with either of these processes is the identification and understanding of critical factors that regulate parasite development. This is particularly true for the development of antimalarials that can be used in malaria elimination strategies by targeting both parasite proliferation and transmission. We therefore hypothesized that parasite proliferation and differentiation use divergent mechanisms for gene expression that could be observed through a thorough investigation of the functional genome of these different parasite forms. This doctoral study therefore set out to increase our knowledge base on three crucial aspects of parasite development: 1) the atypical cell cycle that allows the rapid proliferation of asexual parasites; 2) the full molecular profile of gametocytogenesis enabling the cellular differentiation that allows the parasite to transmit; and 3) the metabolic differences between these proliferating and differentiating parasites that results from their strategy-specific mechanisms of developmental control. The atypical cell cycle of the parasite, associated with the massive cell number expansion in asexual development, is notoriously difficult to study. Here, we contributed a novel system by developing a cell cycle synchronization tool that reversibly blocks the development of asexual parasites at the G1/S transition. This results in an inescapable arrest of the cell cycle that is completely and functionally reversible; parasites re-initiate cell cycle progression and continue to S phase within 6 h. This system provided the opportunity to characterize cell cycle phases in the parasite and additionally evaluate molecular mechanisms associated with cell cycle arrest or re-initiation. During cell cycle arrest, the parasite enters a quiescent state reminiscent of a mitogen-activated restriction point. This arrest is unique and solely attributed to the removal of the specific mitogens within this system, polyamines. These analyses indicate the close interaction between transcriptional regulation and signal transduction cascades in the progression through the parasite s cell cycle and for the first time highlight aspects of controlled cell cycle regulation in Plasmodium. In contrast to proliferation, the process of sexual differentiation only started receiving attention in the past few years. As such, we lack fundamental understanding of the mechanisms driving the unique gametocyte differentiation of P. falciparum parasites. This study contributes a detailed analysis of gametocyte differentiation that revealed distinct developmental transitions demarcating the start of gametocytogenesis, intermediate gametocyte development and finally maturation to produce the transmissible mature gametocytes. The study provides evidence for coordinated regulation of gene expression on a transcriptional level. We propose a model for regulation of gametocytogenesis in malaria parasites that involves active repression of gene sets mediated through epigenetics and RNA destabilization as well as active transcription of gene sets through successive ApiAP2 transcription factor activity. This data provides the most detailed framework of coordinated gene regulation events underlying development of P. falciparum gametocytes to date, a unique resource for the malaria community. The comprehensive and complex transcriptional regulation described for the proliferation and differentiation of the parasite led us to evaluate the functional consequence thereof. A whole cell phenotype microarray system was evaluated for its ability to measure the metabolic processes that define asexual and sexual stage metabolism as a functional consequence of changed gene expression profiles during proliferation and differentiation. The study provided metabolic profiles detailing carbon and nitrogen metabolism in asexual parasites, mature and immature gametocyte stages. The data highlighted dipeptide metabolism as a distinguishing feature in mature gametocytes and showed the presence of a low, delayed metabolic state concurrent with reduced transcriptional activity observed in this stage. These results show that gene expression changes associated with differentiation compared to proliferation translate to an observable metabolic phenotype and that transcriptional regulation shapes the molecular landscape underlying crucial events that enable the parasite s intraerythrocytic asexual and sexual development.

Download or read book The Role of Autophagy in the Human Malaria Parasite Plasmodium Falciparum written by Serena Stacie Cervantes and published by . This book was released on 2013 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: The human malaria parasite remains a major public health burden in developing nations. Despite many years of research, the mechanisms controlling gene expression in the parasite are still poorly understood. While the P. falciparum genome lacks more than fifty percent of the transcription factors anticipated to regulate its 6372 genes, it encodes a large amount of genes involved in RNA metabolism and chromatin remodeling. Furthermore, preliminary data in the laboratory showed extensive nucleosome remodeling during the parasite's asexual cycle. Therefore, we hypothesized that change in chromatin structure plays an important role in controlling parasite development. To understand the role of histone post-translational modifications (PTMs) in transcriptional regulation and histone turnover, we used a shotgun proteomic approach. A total of 246 histone PTMs were identified with 126 being novel. Parasite histones were highly acetylated and methylation marks associated with transcriptional silencing were detected at low levels. To elucidate the mechanism regulating histone turnover, we treated parasite cultures with inhibitors of two distinct pathways that degrade bulk amounts of protein; the ubiquitin-proteasome system and the autophagosome-lysosome pathway. Parasites treated with inhibitors of the autophagy pathway displayed an accumulation of histone protein. The autophagy pathway was overlooked in the parasite; thus, we investigated it at the comparative genomic, cellular, biological and genetic levels. PfATG8, an autophagosome membrane marker, was detected throughout the erythrocytic stages in the apicoplast and the cytoplasm. Proteins associated with PfAtg8 were isolated by immunoprecipitation and identified by mass spectrometry. Gene ontology enrichment showed an enrichment of proteins involved with the digestive food vacuole, the phagolysosome, and the nucleus. In summary, we determined that the autophagy pathway is multifunctional and is likely involved in vesicle traffic, apicoplast biogenesis, and protein catabolism. To further validate its role in histone turnover, we took a cellular approach and colocalized histones and PfATG8 vesicles. Collectively, our work provides key information of mechanism regulating epigenetic and its effects on gene expression in the human malaria parasite.

Download or read book An Exploration of Transcriptional Regulation in the Human Malaria Parasite Plasmodium Falciparum written by Xueqing Lu and published by . This book was released on 2017 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approximately half of the world's population is at risk of malaria transmission, and this number can be expected to grow as drug resistant strains continue to develop. Among the human infectious Plasmodium species, Plasmodium falciparum causes the most severe and lethal form of malaria. This parasite has an extreme AT-rich genome and a complex life cycle that is likely to be regulated by coordinate changes in gene expression. However, the mechanisms behind this fine-tuned gene expression and regulation system remain elusive. For instance, only a limited number of transcription factors have been identified. Recent studies suggest that epigenetic and post-transcriptional regulation may be used as alternative regulation strategies to compensate for the lack of transcription factors in this parasite. Therefore, in this dissertation work, we further explored the transcriptome, epigenome, and the proteome to better understand the transcriptional mechanisms in P. falciparum. In chapter 1, we demonstrated that genes are usually defined by unique nucleosomal features and that nucleosome landscape alone could be used to identify novel genes in organisms with a nucleotide bias. Next, we investigated nascent RNA expression profiles and observed that the majority of genes are transcribed at the trophozoite stage in response to the open chromatin structure of that stage. These results helped us link chromatin reorganization events to transcriptional activity and highlighted the importance of epigenetic and post-transcriptional regulation in this parasite. Therefore, in the latter two chapters, we further examined the proteasome and transcriptome isolated from both nuclear and cytoplasmic fractions to identify potential chromatin regulators. As a result, we identified a large number of chromatin-associated proteins and lncRNAs that are likely to have important roles in chromatin regulation and post-transcriptional and translational regulations. Collectively, data and results from these studies will become stepping-stones for future malaria studies and further assist the identification of promising anti-malarial drug targets.

Download or read book Identificatin of Physiological Substrates of Plasmodium Falciparum PfPK5 a CDK like Kinase written by Catherine Sullenberger and published by . This book was released on 2011 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Malaria is one of the most devastating infectious diseases causing 1-3 million fatalities a year. The majority of these cases occur amongst children in developing countries. Malarial strains in these areas are exhibiting increasing resistance to canonical treatments proving the importance of new drug targets for anti-malarials. Identification of new drug targets is dependent upon a better understanding of the molecular biology of the parasitic agent of malaria, Plasmodium. The regulation of Plasmodium's complex life cycle is still not well understood. Elucidation of signaling pathways involved in Plasmodium cell cycle regulation will provide insights into how the parasite thrives in human cells. A subset of kinases, referred to as cyclin-dependent kinases (CDKs), are crucial regulators of eukaryotic cell cycle progression. In silico studies show high homology between mammalian CDK's and a group of CDK-like Plasmodium kinases including PfPK5 (Plasmodium falciparum protein kinase 5). Plasmodium homologues to CDK regulators, cyclins, have also been identified. Understanding the role of PfPK5 in cell cycle regulation would require analysis of subcellular localization and cell cycle-dependent expression. Immunofluorescence assays demonstrate that PfPK5 is localized in the nucleus. PfPK5's expression profile, as determined by western blotting, shows highest expression in the schizont stage, the stage when the atypical multiple nucleated form of the parasite is observed. Possible PfPK5 interacting partners were detected by performing an anti-PfPK5 immunoprecipitation assay. Additionally, a hemagglutinin (HA)-tagged PfPK5 construct was made to increase the sensitivity of immunoprecipitation assay and identification of PfPK5 interacting partners. The characterization of PfPK5 and its interacting partners may prove useful in identification of novel drug targets in the future.

Download or read book Functional Characterization of a Puf Protein Family Member in Malaria Parasite Plasmodium Falciparum written by Xiaoying Liang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Regulation of gene expression is important to cellular growth and differentiation of eukaryotes, as it plays key roles in determining the eventual expression levels and cellular localizations of a large number of proteins. RNA-binding proteins (RBPs) with conserved RNA-binding domains (RBDs) are key molecules in controlling gene expression. These conserved RBDs can specifically interact with target RNAs through specific sequences and structures to regulate mRNA stability, translation efficiency and subcellular localization. One of the well-studied RBPs is the Puf family RBPs. Members of the Puf family share a highly conserved Puf RBD, which typically consists of eight imperfect tandem repeats of ~36 amino acids (aa). Here I report the studies of two Puf members, PfPuf3 in Plasmodium falciparum and its ortholog PyPuf3 in Plasmodium yoelii. Both genes could not be disrupted, suggesting that they may be essential for the intraerythrocytic developmental cycle (IDC). A time-course study of both PfPuf3 mRNA and protein indicated that PfPuf3 was expressed during the entire IDC, with peak expression in early trophozoites. Cellular fractionation demonstrated that PfPuf3 preferentially partitioned to the nuclear than the cytoplasmic fractions. Interestingly, tagging of the endogenous of PfPuf3 and PyPuf3 with the green fluorescent protein showed that both proteins were limited to the nucleus, which is in contrast to the cytoplasmic localization of PfPuf1 and PfPuf2. Further, we found PfPuf3 co-localized with a well-known nucleolus maker PfNop1, demonstrating that PfPuf3 is a nucleolar protein. Using a parasite line with PfPuf3-tagged with PTP (ProtC-TEV-ProtA), we were able to affinity purify the PfPuf3 protein complex and the associated RNAs. Proteomic analysis of the PfPuf3 complex identified 32 proteins that are associated with the 60S ribosome subunit, suggesting that PfPuf3 might be involved in ribosomal biogenesis. RNA sequencing analysis of the purified PfPuf3 complex revealed significant enrichment of the 28S rRNA and ITS2 (internal transcribed spacer 2), implying that PfPuf3 may recognize and bind to these rRNA sequences. Taken together, these results demonstrated nucleolar localization of PfPuf3 and suggested an essential function of PfPuf3 in ribosomal biogenesis.

Download or read book Endogenous Insulin like Peptides and Control of Malaria Parasite Infection in the Mosquito Host written by Jose Enrique Pietri and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The deadliest human malaria parasite, Plasmodium falciparum, is transmitted by mosquitoes of the genus Anopheles, including Anopheles stephensi, the major malaria vector in India and southeast Asia. Recent efforts to enhance malaria control have focused on developing genetically modified Anopheles mosquitoes that are resistant to malaria parasite infection by manipulating proteins that are essential to the immune response, a strategy that requires a detailed understanding of the complex molecular mechanisms underlying immunity. Insulin/insulin-like growth factor signaling (IIS) is highly conserved from invertebrates to humans and a growing body of literature suggests the involvement of this pathway in regulating immunity. In this work, we show that endogenous insulin-like peptides (ILPs) produced during infection can regulate diverse aspects of mosquito physiology to impact malaria parasite growth and transmission. First, we identified five ILPs in A. stephensi, and characterized their tissue-specific expression patterns in response to various physiological conditions. Specifically, we showed that that ILP expression is not highly responsive to dietary changes, starvation, or ageing, but appears fine-tuned to ingested human insulin and infection with P. falciparum. Next, in order to probe the significance of ILP expression during P. falciparum infection, we developed a novel protocol for protein knockdown in the midgut using antisense morpholinos. We confirmed the effectiveness of this method by inhibiting the mitogen-activated protein kinase (MAPK) MEK-ERK signaling pathway, a known regulator of immunity in the A. stephensi midgut. Further, we utilized this knockdown technique to show that two infection induced ILPs negatively regulate mosquito immunity. We demonstrated that P. falciparum induces ILP expression through activation of feed-forward insulin signaling in the midgut to suppress expression NF-KB regulated immune genes and facilitate parasite growth. We also showed that ILP expression during infection regulates host-seeking and feeding behaviors in the mosquito, potentially increasing transmission in addition to parasite growth. Finally, we dissected the dynamics of ILP signaling using synthetic peptides to predict mechanisms by which induced ILPs function during infection to regulate P. falciparum development. We showed that two infection-induced ILPs produce distinct effects on cell signaling, immunity, metabolism, and midgut homeostasis, suggesting that that the kinetics of ILP regulation of P. falciparum infection are controlled through a diverse network of ILP-specific effects on midgut physiology. Collectively, this body of work provides a foundation for understanding a new gene target that could potentially be manipulated to engineer parasite resistant mosquitoes for disease control, while also unveiling novel aspects of fundamental biology that are controlled by the highly conserved insulin/insulin-like growth factor signaling cascade in a medically important disease vector.

Download or read book Investigating the Druggability and Biological Roles of Apicomplexan AP2 Transcription Factors in the Human Malaria Parasite Plasmodium Falciparum written by Timothy Russell and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmodium falciparum, the most virulent of the human infectious malaria parasites, caused over 600,000 deaths in 2020. Alarmingly, malaria deaths have increased since 2019 and resistance has been reported for every antimalarial drug deployed to date. Regulation of gene expression is critical for P. falciparum to complete its complex life cycle, which includes stages in the human host and Anopheles mosquito vector. Gene regulation in malaria parasites is primarily driven by the Apicomplexan AP2 (ApiAP2) proteins, a single expanded family of sequence specific DNA binding transcription factors. ApiAP2 proteins are plant derived and therefore have no homologs encoded in the human or mosquito genomes, making them potential drug targets. In order to exploit ApiAP2 proteins as antimalarial intervention targets, it is important to both identify ApiAP2 inhibitors and to probe the biological function of ApiAP2 proteins. In this thesis work, ApiAP2 proteins have been investigated to assess their biological functions and druggability. In Chapter 2, putative competitors of DNA binding by the ApiAP2 protein AP2-EXP were selected using an in silico screen. Several compounds were found to inhibit ApiAP2 DNA binding in vitro using DNA gel-shifts. An ApiAP2 competitor compound was then leveraged for use as a chemical genetic tool to interrogate the function of AP2-EXP. In Chapter 3, a potential cooperative interaction between the ApiAP2 proteins PfAP2-I and PfAP2-G during P. falciparum sexual development was interrogated by mapping the DNA binding occupancy of each protein. PfAP2-I genomic occupancy changes in the presence of PfAP2-G, indicating for the first time a causal relationship between two P. falciparum transcription factors that regulates DNA binding specificity. PfAP2-I and PfAP2-G co-occupancy coincides with the activation of P. falciparum sexual stage genes. In Chapter 4, the first indications of the gene regulatory functions of the ApiAP2 proteins PfAP2-HS and PfAP2-O3 were uncovered by mapping their genome-wide DNA binding occupancies. PfAP2-HS was found to regulate a transcription program that is required for P. falciparum to survive febrile host temperatures, while PfAP2-O3 primarily occupies the gene bodies of loci encoding tRNA and rRNA during sexual development. In aggregate, this thesis work describes efforts to further understand the unique ApiAP2 transcription factor proteins in the human malaria parasite P. falciparum.

Download or read book Identification of Plasmodium Falciparum Protein Kinase Substrates and Interacting Proteins written by Jessica C. Yap and published by . This book was released on 2012 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Malaria is a devastating disease that results in almost one million deaths annually. Most of the victims are children under the age of five in Sub-Saharan Africa. Malaria parasite strains throughout developing countries are continually building resistance to available drugs. Current therapies such as mefloquine, chloroquine, as well as artemisinin are becoming less effective, and this underscores the urgency for therapeutics directed against novel drug targets. In order to identify new drug targets, the molecular biology of the malaria parasite Plasmodium needs to be elucidated. Plasmodium exhibits a unique cell cycle in which it undergoes multiple rounds of DNA synthesis and mitosis without cytokinesis. Thus, cell cycle regulatory proteins are likely to be promising pathogen-specific drug targets. It is expected that fluctuating activity of key proteins, such as protein kinases, play an essential role in regulating the noncanonical life cycle of Plasmodium. Consequently, malarial kinases are a prime target for therapy. One way to better understand the role of malarial kinases in Plasmodium cell cycle regulation is to identify putative protein kinase substrates and interacting proteins. Two malarial kinases that have been implicated in regulating malaria parasite cell cycle stages were investigated in this study: P. falciparum CDK-like Protein Kinase 5 (PfPK5) and cAMP-Dependent Protein Kinase A (PfPKA). A transgenic P. falciparum line was created for the expression of epitope-tagged PfPK5 for pull-down analysis. Phospho-substrate antibodies were used to identify physiological substrates of both PfPK5 and PfPKA. Immunoblotting with these antibodies identified several potential substrates. Identities of the PfPKA physiological substrates were determined from the global P. falciparum phosphoproteome dataset that has recently been generated in our laboratory. Characterization of PfPKA and PfPK5 substrates, as well as the proteins they interact with, will help us to develop innovative therapies targeting binding sites.

Download or read book The Cell Cycle and Cancer written by Renato Baserga and published by . This book was released on 1971 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biomolecular Simulations in Structure Based Drug Discovery written by Francesco L. Gervasio and published by John Wiley & Sons. This book was released on 2019-04-29 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to applying the power of modern simulation tools to better drug design Biomolecular Simulations in Structure-based Drug Discovery offers an up-to-date and comprehensive review of modern simulation tools and their applications in real-life drug discovery, for better and quicker results in structure-based drug design. The authors describe common tools used in the biomolecular simulation of drugs and their targets and offer an analysis of the accuracy of the predictions. They also show how to integrate modeling with other experimental data. Filled with numerous case studies from different therapeutic fields, the book helps professionals to quickly adopt these new methods for their current projects. Experts from the pharmaceutical industry and academic institutions present real-life examples for important target classes such as GPCRs, ion channels and amyloids as well as for common challenges in structure-based drug discovery. Biomolecular Simulations in Structure-based Drug Discovery is an important resource that: -Contains a review of the current generation of biomolecular simulation tools that have the robustness and speed that allows them to be used as routine tools by non-specialists -Includes information on the novel methods and strategies for the modeling of drug-target interactions within the framework of real-life drug discovery and development -Offers numerous illustrative case studies from a wide-range of therapeutic fields -Presents an application-oriented reference that is ideal for those working in the various fields Written for medicinal chemists, professionals in the pharmaceutical industry, and pharmaceutical chemists, Biomolecular Simulations in Structure-based Drug Discovery is a comprehensive resource to modern simulation tools that complement and have the potential to complement or replace laboratory assays for better results in drug design.

Download or read book Protein protein Complexes written by Martin Zacharias and published by World Scientific. This book was released on 2010 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: Given the immense progress achieved in elucidating protein-protein complex structures and in the field of protein interaction modeling, there is great demand for a book that gives interested researchers/students a comprehensive overview of the field. This book does just that. It focuses on what can be learned about protein-protein interactions from the analysis of protein-protein complex structures and interfaces. What are the driving forces for protein-protein association? How can we extract the mechanism of specific recognition from studying protein-protein interfaces? How can this knowledge be used to predict and design protein-protein interactions (interaction regions and complex structures)? What methods are currently employed to design protein-protein interactions, and how can we influence protein-protein interactions by mutagenesis and small-molecule drugs or peptide mimetics?The book consists of about 15 review chapters, written by experts, on the characterization of protein-protein interfaces, structure determination of protein complexes (by NMR and X-ray), theory of protein-protein binding, dynamics of protein interfaces, bioinformatics methods to predict interaction regions, and prediction of protein-protein complex structures (docking and homology modeling of complexes, etc.) and design of protein-protein interactions. It serves as a bridge between studying/analyzing protein-protein complex structures (interfaces), predicting interactions, and influencing/designing interactions.

Download or read book Chlamydial Infection written by C. M. Black and published by Karger Medical and Scientific Publishers. This book was released on 2013 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: New insights into one of the world's most common infectious diseases Chlamydiae are obligate intracellular bacteria that cause one of the most common sexually transmitted infectious diseases in the world. The infection disproportionately impacts women and the highest prevalence of infection is found in adolescents. Most chlamydial infections are asymptomatic. Untreated infections are sources of further spread of infection and can lead to serious consequences including pelvic inflammatory disease, infertility and chronic pelvic pain. Chlamydial infections also increase a person's susceptibility to HIV and other STDs. Featuring contributions by internationally recognized experts in epidemiology, infectious disease research and chlamydial biology, this book provides up-to-date reviews from a clinical and public health perspective on chlamydia epidemiology and control programs, genomics and pathogenicity, diagnosis, treatment, host immune responses, and the latest on the search for an effective vaccine. Also included are chapters on the impact of chlamydial infection on specific populations such as the lesbian, gay, bisexual and transgender community, and an update on the outbreak in Europe of the invasive chlamydial infection, lymphogranuloma venereum or LGV. This comprehensive publication is intended for clinicians, public health workers and scientists with interest in sexually transmitted diseases, medical microbiology, infectious diseases and clinical research.