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Full-Text Articles in Medicine and Health Sciences
Mechanisms Of Growth Hormone Action In Skeletal Muscle, Mahendra Devaraj Mavalli
Mechanisms Of Growth Hormone Action In Skeletal Muscle, Mahendra Devaraj Mavalli
All ETDs from UAB
Growth hormone (GH) and insulin like growth factor-1 (IGF-1) exert profound growth promoting actions during pre and postnatal skeletal muscle development. GH and IGF-1 seem to promote their anabolic actions by influencing skeletal muscle cell prolif-eration and fusion. However, because GH stimulates the production of IGF-1 from the liver and other GH-responsive peripheral tissues, including skeletal muscle, the individual contributions of these two growth factors to anabolic responses in skeletal muscle remains poorly defined. In this dissertation research, I sought to distinguish the mechanisms responsible for growth hormone's (GH) anabolic actions in skeletal muscle. To accomplish this, I analyzed the …
Development And Implementation Of Knock-In And Bac-In Il-2 Reporter Mouse Models To Characterize Il2 Gene Regulation In Cd4 T Cells, Rita Jeanne Luther
Development And Implementation Of Knock-In And Bac-In Il-2 Reporter Mouse Models To Characterize Il2 Gene Regulation In Cd4 T Cells, Rita Jeanne Luther
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Maintenance of immune homeostasis involves a balance between T cell effector responses to antigen stimulus and reciprocal downregulation of this response through peripheral tolerance mechanisms. Upon exposure to pathogen, cytokine production and signaling serve to tightly coordinate cell-mediated clearance of antigen followed by contraction of the immune response. Interkeukin-2 (IL-2) is a type I family cytokine critical for expansion of activated T cells in vitro and enhancement of T cell memory responses in vivo. Deficiency of IL-2 in vivo also revealed a critical role for IL-2 in immune tolerance through the maintenance of T regulatory cell populations (Treg) in peripheral …
The Significance Of Heavy Chain Cdr3 Diversity In The Antibody Response To Polysaccharides, Tamer Mahmoud
The Significance Of Heavy Chain Cdr3 Diversity In The Antibody Response To Polysaccharides, Tamer Mahmoud
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An understanding of the molecular mechanisms involved in the generation of protective antibody responses to polysaccharides associated with pathogenic microorganisms is of importance for improving vaccine design. The heavy chain third complementarity-determining region (HCDR3) of an antibody molecule is at the center of its antigen-binding site and plays a determinative role in antigen recognition. The goal of this dissertation was to investigate the role of HCDR3 diversity and composition on the antibody response to the polysaccharide α 1→3 Dextran (DEX). In the first study, we investigated the role of TdT, a DNA polymerase that plays a major role in generating …
Localization And Function Of Electrogenic Na/Bicarbonate Cotransporter Nbce1 In Rat Brain, Debeshi Majumdar
Localization And Function Of Electrogenic Na/Bicarbonate Cotransporter Nbce1 In Rat Brain, Debeshi Majumdar
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Na-Coupled Bicarbonate Transporters (NCBTs) are members of the bicarbonate transporter superfamily that play important roles in regulating intracellular pH (pHi) and extracellular pH (pHo) in the central nervous system. Electrogenic Na/bicarbonate Cotransporter 1 (NBCe1) is an NCBT that is expressed in different mammalian tissues including the brain. NBCe1 has three splice variants - NBCe1-A, -B and -C - that differ in the amino and carboxy termini. We have first performed a systematic characterization of the localization profiles of the three NBCe1 splice variants at mRNA and protein levels in rat brain. In these studies, we have used anti-sense probes and …
Intracellular Trafficking Of The Hantaviral Nucleocapsid Protein And Its Function In Modulation Of Immune Signaling, Steven Joe Ontiveros
Intracellular Trafficking Of The Hantaviral Nucleocapsid Protein And Its Function In Modulation Of Immune Signaling, Steven Joe Ontiveros
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Old World and New World hantaviruses, family Bunyaviridae, mature intracellularly within cellular compartments. Although it is generally accepted they assemble and bud in the Golgi apparatus the site remains controversial for New World hantaviruses, because some studies have raised the possibility of their maturation at the plasma membrane. Furthermore, the site of assembly hantaviruses still remains undetermined. The nucleocapsid (N) protein has been proposed to play a key role in facilitating assembly. To gain insight into the assembly pathways of Old World hantaviruses, we examine the intracellular trafficking of the Hantaan (HTN) virus N protein. We show progressive redistribution of …
Insulin Signaling And Function In Osteoblasts, Keertik S. Fulzele
Insulin Signaling And Function In Osteoblasts, Keertik S. Fulzele
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Insulin and insulin-like growth factor-1 (IGF-1) are evolutionarily conserved hormonal signaling pathways with structurally similar ligands and receptors. Recent stu-dies suggest that that insulin and IGF-1 exert distinct as well as overlapping functions to regulate different aspects of skeletal development. A major problem in distinguishing the actions of insulin and IGF-1 is the fact that the receptors are co-expressed in many cell types and each ligand is able to cross-activate the other ligands' receptor. To distinguish direct skeletal actions of insulin from that of IGF-1, we have conditionally disrupted each receptor in vitro and in vivo specifically in osteoblasts. Studies …
Mitochondrial Bioenergetics And Cellular Stress, Brian Dranka
Mitochondrial Bioenergetics And Cellular Stress, Brian Dranka
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Mitochondria are responsible for most of the energy produced in human tissues, and this is dependent on the reduction of oxygen (O2) to water by the mitochondrial respiratory chain. Defects in mitochondrial energy production are now recognized to be involved in diabetes, cancer, cardiovascular disease, and other pathologies. To date, studies of these defects have employed quantification of O2 consumption in isolated, purified mitochondria. By using this strategy however, the cellular context, role of glycolysis, and normal regulation of mitochondrial function by metabolite availability are lost. Thus, an understanding of how mitochondria function and respond to stimuli in an intact …
The Peptidyl-Prolyl Isomerase Pin1 Promotes Nf-Kappab And Stat3 Signaling In Glioblastoma, George Prescott Atkinson
The Peptidyl-Prolyl Isomerase Pin1 Promotes Nf-Kappab And Stat3 Signaling In Glioblastoma, George Prescott Atkinson
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Glioblastoma (GBM) is an incurable tumor of the central nervous system (CNS). Over the past 50 years, little progress has made in improving the quality of life and median lifespans of patients who are diagnosed with this devastating disease. However, new insights into the aberrant signaling pathways at the root of GBM pathology are providing new targets for next generation cancer therapies. Two signaling pathways that are commonly upregulated in GBM are NF-kappaB and STAT3. Importantly, tumor models in which NF-kappaB and STAT3 signaling are inhibited have demonstrated the importance of these pathways to GBM growth and proliferation. Therefore, better …
Oncostatin M-Induced Gene Expression And Regulation In Astrocytes And Microglia, Brandi Janece Baker
Oncostatin M-Induced Gene Expression And Regulation In Astrocytes And Microglia, Brandi Janece Baker
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Astrocytes and microglia are specialized glial cells of the Central Nervous System (CNS) that modulate neural activity and regulate immunological and inflammatory events. These cells perform their functions, in part, through the secretion of soluble mediators such as cytokines and chemokines. However, in response to the same neurological insult or inflammatory stimuli, the responses of these cells can vary greatly. This notion of differential responses was examined in our studies using Oncostatin M (OSM). OSM is a member of the IL-6 family of cytokines, which can be produced by microglia, astrocytes, neurons, and infiltrating leukocytes in the CNS, and is …
Regulation Of Neural Precursor Cell Apoptosis And Proliferation By Glycogen Synthase Kinase-3, Tae-Yeon Eom
Regulation Of Neural Precursor Cell Apoptosis And Proliferation By Glycogen Synthase Kinase-3, Tae-Yeon Eom
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Neurogenesis is a crucial process for development, plasticity, and regenerative capacity of the developing and adult brain. Impairment of neurogenesis has been implicated in the etiology of psychiatric disorders. Although substantial studies have shown that therapeutic interventions enhance neurogenesis, much less is known about what factors impair neurogenesis. Thus, the present work examined if glycogen synthase kinase-3 (GSK3) has a role in impaired neurogenesis, focusing on apoptosis and proliferation of neural precursor cells (NPCs). This investigation found that GSK3 promotes apoptotic signaling in cultured NPCs subjected to two insults, trophic factor withdrawal and genotoxic stress. Both stimuli activated GSK3, Bax, …
The Role Of The Ss2-Integrin Family On T Cell Subsets, Jillian E. Wohler
The Role Of The Ss2-Integrin Family On T Cell Subsets, Jillian E. Wohler
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Members of the ß2-integrin family of adhesion molecules, CD11a, CD11b, and CD11c, have all been shown to play a role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE). CD11d had yet to be studied in demyelinating disease and its functions remained unclear. We report here that CD11d is the only member of the ß2-integrin family of adhesion molecules that fails to protect against the development of EAE. Surprisingly, the EAE studies suggested that CD11a, CD11b, and CD11c were all contributing to T cell activity during disease development by mechanisms beyond the migration of these cells into the CNS. However, the …
Protein Trafficking And 4.1r Relocalization In Plamodium Falciparum-Infected Erythrocytes, Lindsay A. Parish
Protein Trafficking And 4.1r Relocalization In Plamodium Falciparum-Infected Erythrocytes, Lindsay A. Parish
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Malaria is a mosquito-borne infectious disease that is caused by parasites in the genus Plasmodium. There are four species of malaria that routinely infect humans, but it is P. falciparum that is responsible for the majority of the severe and fatal cases of malaria. P. falciparum has a complex life cycle involving a mosquito vector and intracellular stages in both hepatocytes and erythrocytes; however, it is only the intraerythrocytic stages that are the cause of the pathology associated with malaria. This pathology is largely due to the ability of infected erythrocytes to cytoadhere to host microvasculature. After invasion, the parasite …
Late Development Plasticity In The T Helper 17 Lineage, Yun Kyung Lee
Late Development Plasticity In The T Helper 17 Lineage, Yun Kyung Lee
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CD4 T cells are a principal component of the adaptive immune system that is required for the efficient elimination of foreign antigens, but dysregulated CD4 T cells responses may result in autoimmune and chronic inflammatory diseases. The differentiation of effector CD4 T cells is directed by cytokines elicited by pathogendriven innate immune responses. Therefore the coordinated innate and adaptive immune responses provide an efficient system for host protection. Our understanding of distinct differentiated CD4 T cells has recently expanded with the discovery of the Th17 lineage, a new subset of effector CD4 T cells that has been implicated in chronic …
Mouse Model Of Cooley's Anemia, Yongliang Huo
Mouse Model Of Cooley's Anemia, Yongliang Huo
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β thalassemia major or Cooley’s anemia (CA) is a heterogeneous group of inherited disorders characterized by deficient β globin chain production. Newborns with CA are healthy because of the high fetal hemoglobin (HbF) levels present in their red blood cells (RBCs). As HbF levels decline during the first year of life, patients develop severe anemia that necessitates regular blood transfusion to maintain life. CA has been difficult to model in the mouse due to the lack of a fetal hemoglobin equivalent in the mouse. By utilizing a human fetal to adult delayed hemoglobin switching cassette, I hypothesize that a CA …
The Protective Role Of Transglutaminase 2 In Ischemic Stroke, Anthony J. Filiano
The Protective Role Of Transglutaminase 2 In Ischemic Stroke, Anthony J. Filiano
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Stroke is a leading cause of long term disabilities in the US. Currently, administration of thrombolytics is the only approved therapy. Due to the variability, small management time window, and lack of options for effective treatment, there is a clear need for new compounds to alleviate cell death post-stroke. Transglutaminase 2 (TG2) can decrease apoptotic signaling during stroke and lead to increased neuronal survival making it a potential target for therapeutic intervention. TG2, a multifunction enzyme that has both transamidase (TG) and GTPase activities, amongst others, has recently been shown to be upregulated in numerous neurodegenerative conditions, including stroke. In …
Genetic Complexity And Population Diversity Of Plasmodium Falciparum In The Peruvian Amazon, Patrick Lee Sutton
Genetic Complexity And Population Diversity Of Plasmodium Falciparum In The Peruvian Amazon, Patrick Lee Sutton
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GENETIC COMPLEXITY AND POPULATION DIVERSITY OF PLASMODIUM FALCIPARUM IN THE PERUVIAN AMAZON PATRICK LEE SUTTON MICROBIOLOGY GRADUATE PROGRAM ABSTRACT Characterizing the genetic complexity of immunologically relevant proteins, expressed during the life cycle of P. falciparum, is essential for identifying and advancing potential vaccine candidates. The current malaria immunity paradigm is rooted in high transmission studies which have investigated the impact of high genetic diversity on the development of humoral responses. Given the dynamic nature of malaria parasites, especially their ability to acclimate to change, it is likely that regions of low transmission do not share the same malaria immunity paradigm …
The Role Of Gbf1 In Golgi Biogenesis And Secretory Traffic., Tomasz Szul
The Role Of Gbf1 In Golgi Biogenesis And Secretory Traffic., Tomasz Szul
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The secretory pathway within a cell consists of series of membrane compartments connected by shuttling secretory vesicles containing cargo that travel from endoplasmic reticulum (ER) though ER-to-Golgi intermediate compartment (ERGIC), the Golgi apparatus, and endosomal compartment to the plasma membrane (PM). The Golgi specific brefeldin A (BFA)-resistant factor 1 GBF1 has been identified as an important factor involved in traffic between ER and Golgi and within the Golgi apparatus. GBF1 belongs to a family of guanine nucleotide exchange factors (GEFs) that stimulate the exchange of GDP for GTP on small GTPases, ADP-ribosylation factors (ARFs). The exchange of the nucleotide activates …
Polysaccharide Specific B Cells: A Study Of Their Development And Function, Jeremy B. Foote
Polysaccharide Specific B Cells: A Study Of Their Development And Function, Jeremy B. Foote
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Polysaccharides are important structural components of bacterial capsule and cell walls. Polysaccharide-specific antibodies are an important component of serologic memory capable of protecting against infection by pathogenic microorganisms. An understanding of the biology and function of polysaccharide specific B cells is necessary for formulation of vaccines designed to induce polysaccharide specific memory and long-lived antibody production. The goal of this dissertation was to examine the development of naïve DEX-specific B cells and examine their capacity to generate memory and long-lived plasma cells in response to polysaccharide α 1→3-dextran (DEX), which is expressed by the opportunistic pathogens Enterobacter cloacae, Histoplasma capsulatum …
The Role Of Transforming Growth Factor Beta-1 In Bone Remodeling, Yi Tang
The Role Of Transforming Growth Factor Beta-1 In Bone Remodeling, Yi Tang
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Bone remodeling depends on the precise coordination of bone resorption by the osteoclasts and bone formation by the osteoblasts. It is proposed that osteoclastic bone resorption releases factors to initiate bone formation, thereby, coupling the bone resorption and formation. Mesenchymal stem cells (MSCs) are progenitors of osteoblasts. Recruitment of MSCs in response to osteoclastic bone resorption may be an initial step for bone formation during bone remodeling process. Therefore, we have established an in vitro osteoclastic bone resorption system. Bone resorption condition medium have been tested to identify the factor inducing the migration of human bone marrow mesechymal stem cells …
Regulation Of Vh Replacement In Human Immature B Cells By B Cell Receptor (Bcr) - Mediated Signaling, Jing Liu
Regulation Of Vh Replacement In Human Immature B Cells By B Cell Receptor (Bcr) - Mediated Signaling, Jing Liu
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VH replacement occurs through RAG-mediated secondary recombination to change unwanted IgH genes. In this dissertation, I focused on studying the molecular mechanism that regulates VH replacement in human immature B cells. In part I, our results show that VH replacement is regulated by B cell antigen receptor (BCR) mediated signaling. Using the human EU12 mHC+ cells as an experimental model system, crosslinking BCR with F(ab')2 anti-IgM antibodies results in BCR internalization, cell proliferation arrest, and induction of VH replacement. Pretreatment of human EU12 mHC+ cells with the protein tyrosine kinase inhibitor Genistein, Syk kinase inhibitors, and a Src kinase inhibitor …
Cystic Fibrosis Transmembrane Conductance Regulator (Cftr) Modulators And Their Mechanistic Basis: Relevance To Emerging Therapies For Cystic Fibrosis, Louise Clare Pyle
Cystic Fibrosis Transmembrane Conductance Regulator (Cftr) Modulators And Their Mechanistic Basis: Relevance To Emerging Therapies For Cystic Fibrosis, Louise Clare Pyle
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Cystic fibrosis (CF) is a lethal genetic disorder leading to pulmonary decline and premature death. The gene responsible for CF, the cystic fibrosis transmembrane conductance regulator (CFTR), serves as a chloride and bicarbonate channel situated at the apical cell surface of epithelia. The discovery of small molecules that augment channel gating of mutant CFTR (so-called `potentiators') represents a major theme of CF research, and offers hope for new therapeutic interventions. High-throughput screening (HTS) provides a means to test millions of agents in an unbiased manner for CFTR potentiating properties. New agents identified by HTS have undergone extensive pre-clinical and clinical …
Biological Characterization Of Fc Receptor-Like 6 (Fcrl6), Daniel M. Schreeder
Biological Characterization Of Fc Receptor-Like 6 (Fcrl6), Daniel M. Schreeder
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Members of the Fc receptor-like (FCRL) family are cell-surface proteins with ancient conservation, distinct lymphocyte expression patterns, and tyrosine-based signaling capa-bilities that imply a fundamental role for them in modulating immune responses. Though they share many features with the Fc receptors (FCR) for IgG and IgE, FCRLs have not been found to bind immunoglobulin. In these studies, we sought to characterize the cellu-lar expression pattern, binding partner, and function of a recently identified FCRL family member, human FCRL6. By developing specific monoclonal antibodies (mAbs) we determined that FCRL6 is dis-tinctly expressed by cytotoxic lymphocytes, namely NK cells, CD8+ T cells, …
Regulation Of Tissue Remodeling Through The Calreticulin Binding Domain Of Thrombospondin-1, Mariya Ts'ana Sweetwyne
Regulation Of Tissue Remodeling Through The Calreticulin Binding Domain Of Thrombospondin-1, Mariya Ts'ana Sweetwyne
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Thrombospondin-1 (TSP1) is a multifunctional matricellular protein released by platelets in response to injury and secreted by cells under stress. TSP1 is cleaved into functional N- and C-terminal domain fragments, which have paradoxical actions with respect to angiogenesis, cell survival, and cell adhesion. Wound healing studies by others demonstrated that TSP1 knockout mice have delayed rates of wound closure, which was attributed to actions of the C-terminal domain. We wished to investigate the specific role of the N-terminal domain in tissue remodeling. Previously, we established that a sequence (aa 17-35) in the N-terminal domain of TSP1 induces focal adhesion disassembly, …
Characterization Of The Induction And Regulation Of Early B Cell Development, Melissa Ann Thal
Characterization Of The Induction And Regulation Of Early B Cell Development, Melissa Ann Thal
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Hematopoiesis is a highly regulated process directed by the microenvironment or niche in the bone marrow and the transcription factors those signals activate. Gene knockout experiments have identified critical cytokine signals and transcription factors required for promoting the differentiation of a hematopoietic stem cell to a B cell, but the regulatory mechanisms have yet to be fully elucidated. In early B cell development, a transcriptional hierarchy exists wherein E2A proteins activate early B-cell factor (Ebf1), which in turn activates expression of the B cell commitment factor, Pax5. In our studies, we use IL-7 receptor alpha chain (IL-7Rα) knockout animals that …
The Role Of Mitochondria And Plasma Membrane Ca2+ Transport Systems In Ca2+-Dependent Glutamate Release From Rat Cortical Astrocytes, Reno Cervo Reyes
The Role Of Mitochondria And Plasma Membrane Ca2+ Transport Systems In Ca2+-Dependent Glutamate Release From Rat Cortical Astrocytes, Reno Cervo Reyes
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Astrocytes, a type of glial cell in the central nervous system, are recognized for their support roles to neurons. They supply neurons with metabolites, maintain ion homeostasis and clear the synaptic space of neurotransmitters. However, it has been found that some astrocytes have receptors for neurotransmitter and neuroligands, exhibit Ca2+ excitability when stimulated via these receptors, and secrete gliotransmitters as an output of this Ca2+ excitability. In the Ca2+-dependent release of glutamate, it has been shown that the endoplasmic reticulum is the predominant source and the extracellular space is the auxiliary source of free Ca2+ necessary for triggering exocytosis. Because …
Identification And Characterization Of Virulence Factors Of Mycoplasmas, Wenyi Luo
Identification And Characterization Of Virulence Factors Of Mycoplasmas, Wenyi Luo
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Mycoplasmas cause a group of diseases that are characterized by their chronicity and resistance to treatment. Diseases caused by the murine pathogens Mycoplasma pulmonis and Mycoplasma arthritidis are often studied as models of human diseases caused by a variety of chronic pathogens that induce a similar pathology. Among several candidate pathogenic factors, superantigens and degradative enzymes such as glycosidases are potentially important but not well characterized. The M. arthritidis mitogen (MAM) is a superantigen secreted by M. arthritidis. Its role with respect to arthritogenicity and toxicity is unclear. To improve the efficiency of transformation and hence enhance efforts to generate …
The Essential Role Of Macrophages And Tlr Signaling In The Host Response To Mycoplasma Pneumoniae, Jen-Feng Lai
The Essential Role Of Macrophages And Tlr Signaling In The Host Response To Mycoplasma Pneumoniae, Jen-Feng Lai
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Several reports have suggested that Mycoplasma pneumoniae (Mp) can contribute importantly to the expression of symptoms in asthmatic human subjects. As a foundation for understanding the interactions between Mp and asthma susceptibility, we first studied the mechanisms by which the host normally eliminated Mp. Mice were inoculated with 4x106 Mp intranasally. Twenty-four hours after inoculation with Mp, subpopulations of CD11b+ macrophages/monocytes had been recruited into the lungs. The clearance of Mp was impaired both in macrophage-depleted and in macrophage-deficient mice. Furthermore, mice deficient in MyD88, a major adaptor for TLR signaling, showed dramatically defective clearance of Mp, associated with reduced …
Regulation Of B Cell Biology By Fcγ Receptors, Xinrui Li
Regulation Of B Cell Biology By Fcγ Receptors, Xinrui Li
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B cell development, maturation and proliferation are all strictly regulated processes. Disruption of the regulatory network at any step would lead to immune disorders. The regulatory system of B cells can be considered as two layers: a general homeostasis regulation system and a specificity-based control system. General regulation of B cell homeostasis is mastered by BLyS (B Lymphocyte Stimulator) and several other BLyS family cytokines, which serve as a crucial survival factor for which transitional and mature B cells compete. Specificity-based control is achieved via B cell antigen receptors (BCRs), which serve as a determinant of whether an antigen-specific B …
Structural And Functional Studies On Heat Shock Protein Hsp40-Hdj1 And Golgi Er Trafficking Protein Get3, Junbin Hu
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Molecular chaperones are a large group of proteins that bind and stabilize nascent polypeptides and facilitate protein folding. One major function of chaperones is to bind hydrophobic segments of nascent polypeptides to prevent them from aggregating. How chaperone Hsp40 recognizes and interacts with polypeptides and cooperates with chaperone Hsp70 is a fundamental question. The crystal structure of the putative peptide-binding fragment of Hdj1, a human member of the type II Hsp40 family was determined, suggesting the domain I of Hsp40 may possess significant flexibility which is important for Hsp40 to regulate the size of the cleft. The flexibility may be …
Understanding The Regulatory Mechanisms Of Ubp-M And H2a Deubiquitination In Chromatin And Cellular Functions, Heui Yun Joo
Understanding The Regulatory Mechanisms Of Ubp-M And H2a Deubiquitination In Chromatin And Cellular Functions, Heui Yun Joo
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Posttranslational modifications of histones regulate important chromatin and cellular functions. Among them, ubiquitination of histone H2A is correlated to transcriptional repression, such as HOX gene silencing and X chromosome inactiviation. Little was known about the removal of ubiquitin from histones, the enzyme(s) involved and its function in chromatin dynamics. We have identified the protein Ubp-M (USP16) to be the H2A- and nucleosome-specific deubiquitinase. We also demonstrated that Ubp-M-mediated H2A deubiquitination is involved in cell cycle progression to M-phase, HOX gene expression, and posterior development in Xenopus laevis. Furthermore, we have also purified USP12 and USP46 which contain an Ubp-M independent …