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Investigating The Structural Basis For Human Disease: Apobec3a And Profilin, Tania V. Silvas Jan 2018

Investigating The Structural Basis For Human Disease: Apobec3a And Profilin, Tania V. Silvas

GSBS Dissertations and Theses

Analyzing protein tertiary structure is an effective method to understanding protein function. In my thesis study, I aimed to understand how surface features of protein can affect the stability and specificity of enzymes. I focus on 2 proteins that are involved in human disease, Profilin (PFN1) and APOBEC3A (A3A). When these proteins are functioning correctly, PFN1 modulates actin dynamics and A3A inhibits retroviral replication. However, mutations in PFN1 are associated with amyotrophic lateral sclerosis (ALS) while the over expression of A3A are associated with the development of cancer. Currently, the pathological mechanism of PFN1 in this fatal disease is unknown ...


Overcoming Toxicity From Transgene Overexpression Through Vector Design In Aav Gene Therapy For Gm2 Gangliosidoses, Diane L. Golebiowski Sep 2016

Overcoming Toxicity From Transgene Overexpression Through Vector Design In Aav Gene Therapy For Gm2 Gangliosidoses, Diane L. Golebiowski

GSBS Dissertations and Theses

GM2 gangliosidoses are a family of lysosomal storage disorders that include both Tay-Sachs and Sandhoff diseases. These disorders result from deficiencies in the lysosomal enzyme β-N-acetylhexosaminidase (HexA). Impairment of HexA leads to accumulation of its substrate, GM2 ganglioside, in cells resulting in cellular dysfunction and death. There is currently no treatment for GM2 gangliosidoses. Patients primarily present with neurological dysfunction and degeneration. Here we developed a central nervous system gene therapy through direct injection that leads to long-term survival in the Sandhoff disease mouse model. We deliver an equal mixture of AAVrh8 vectors that encode for the two subunits (α ...


Viral Proteases As Drug Targets And The Mechanisms Of Drug Resistance: A Dissertation, Kuan-Hung Lin Sep 2016

Viral Proteases As Drug Targets And The Mechanisms Of Drug Resistance: A Dissertation, Kuan-Hung Lin

GSBS Dissertations and Theses

Viral proteases have been shown to be effective targets of anti-viral therapies for human immunodeficiency virus (HIV) and hepatitis C virus (HCV). However, under the pressure of therapy including protease inhibitors, the virus evolves to select drug resistance mutations both in the protease and substrates. In my thesis study, I aimed to understand the mechanisms of how this protease−substrate co-evolution contributes to drug resistance. Currently, there are no approved drugs against dengue virus (DENV); I investigated substrate recognition by DENV protease and designed cyclic peptides as inhibitors targeting the prime site of dengue protease.

First, I used X-ray crystallography ...


Roles Of Protein Arginine Methyltransferase 7 And Jumonji Domain-Containing Protein 6 In Adipocyte Differentiation: A Dissertation, Yu-Jie Hu Oct 2015

Roles Of Protein Arginine Methyltransferase 7 And Jumonji Domain-Containing Protein 6 In Adipocyte Differentiation: A Dissertation, Yu-Jie Hu

GSBS Dissertations and Theses

Regulation of gene expression comprises a wide range of mechanisms that control the abundance of gene products in response to environmental and developmental changes. These biological processes can be modulated by posttranslational modifications including arginine methylation. Among the enzymes that catalyze the methylation, protein arginine methyltransferase 7 (PRMT7) is known to modify histones to repress gene expression. Jumonji domain-containing protein 6 (JMJD6) is a putative arginine demethylase that potentially antagonize PRMT7. However, the biological significance of these enzymes is not well understood. This thesis summarizes the investigation of both PRMT7 and JMJD6 in cell culture models for adipocyte differentiation. The ...


Rna Interference By The Numbers: Explaining Biology Through Enzymology: A Dissertation, Liang Meng Wee Jun 2013

Rna Interference By The Numbers: Explaining Biology Through Enzymology: A Dissertation, Liang Meng Wee

GSBS Dissertations and Theses

Small silencing RNAs function in almost every aspect of cellular biology. Argonaute proteins bind small RNA and execute gene silencing. The number of Argonaute paralogs range from 5 in Drosophila melanogaster , 8 in Homo sapiens to an astounding 27 in Caenorhabditis elegans. This begs several questions: Do Argonaute proteins have different small RNA repertoires? Do Argonaute proteins behave differently? And if so, how are they functionally and mechanistically distinct?

To address these questions, we examined the thermodynamic, kinetic and functional properties of fly Argonaute1 (dAgo1), fly Argonaute2 (dAgo2) and mouse Argonaute2 (mAGO2). Our studies reveal that in fly, small RNA ...


Investigating The Roles Of Nedd4.2s And Nef In The Release And Replication Of Hiv-1: A Dissertation, Eric R. Weiss Sep 2012

Investigating The Roles Of Nedd4.2s And Nef In The Release And Replication Of Hiv-1: A Dissertation, Eric R. Weiss

GSBS Dissertations and Theses

Replication of HIV-1 requires the assembly and release of mature and infectious viral particles. In order to accomplish this goal, HIV-1 has evolved multiple methods to interact with the host cell. HIV-1 recruits the host cell ESCRT machinery to facilitate the release of nascent viral particles from the host cell membrane. Recruitment of these cellular factors is dependent on the presence of short motifs in Gag referred to as Late-domains. Deletion or mutation of these domains results in substantial decrease in the release of infectious virions. However, previously published work has indicated that over-expression of the E3 ubiquitin ligase, NEDD4 ...


Hepatitis C Virus Non-Structural Protein 3/4a: A Tale Of Two Domains: A Dissertation, Cihan Aydin Aug 2012

Hepatitis C Virus Non-Structural Protein 3/4a: A Tale Of Two Domains: A Dissertation, Cihan Aydin

GSBS Dissertations and Theses

Two decades after the discovery of the Hepatitis C Virus (HCV), Hepatitis C infection still persists to be a global health problem. With the recent approval of the first set of directly acting antivirals (DAAs), the rate of sustained viral response for HCV-infected patients increased significantly. However, a complete cure has not been found yet. Drug development efforts primarily target NS3/4A protease, bifunctional serine protease-RNA helicase of HCV. HCV NS3/4A is critical in viral function; protease domain processes the viral polyprotein and helicase domain aids replication of HCV genome by unwinding double stranded RNA transcripts produced by NS5B ...


The Role Of Itk In The Development Of Gamma Delta Nkt Cells: A Dissertation, Catherine C. Yin Aug 2012

The Role Of Itk In The Development Of Gamma Delta Nkt Cells: A Dissertation, Catherine C. Yin

GSBS Dissertations and Theses

The immune system is a complex network of interacting cells and tissues that is designed to protect the body from pathogens and other foreign substances. T cells are a major component of the immune system and consist of two distinct lineages distinguished by the expression of αβ or γδ T cell receptors (TCR). The Tec family kinase, Itk is an important mediator of signaling downstream of the TCR. Past studies on Itk has focused on how Itk regulates development, activation and differentiation of conventional αβ T cells and more recently how Itk regulates the development of innate-like αβ T cells ...


Studies On Cellular Host Factors Involved In The Hiv-1 Life Cycle: A Dissertation, Anna Kristina Serquiña Aug 2012

Studies On Cellular Host Factors Involved In The Hiv-1 Life Cycle: A Dissertation, Anna Kristina Serquiña

GSBS Dissertations and Theses

Human Immunodeficiency Virus Type 1 (HIV-1) is the causative agent of Acquired Immunodeficiency Syndrome (AIDS), currently the leading cause of death from infectious diseases. Since HIV-1 co-opts the host cellular machinery, the study of cellular factors involved is a rational approach in discovering novel therapeutic targets for AIDS drug development. In this thesis, we present studies on two such proteins. APOBEC3G is from the family of cytidine deaminases known to keep endogenous retroviruses and retrotransposons at bay to maintain stability of the human genome. APOBEC3G targets Vif-deficient HIV-1 particles and renders them noninfectious, partially through deaminase-dependent hypermutation of the provirus ...


Understanding Small Rna Formation In Drosophila Melanogaster: A Dissertation, Elif Sarinay Cenik Jul 2012

Understanding Small Rna Formation In Drosophila Melanogaster: A Dissertation, Elif Sarinay Cenik

GSBS Dissertations and Theses

Drosophila Dicer-2 generates small interfering RNAs (siRNAs) from long double-stranded RNA (dsRNA), whereas Dicer-1 produces microRNAs from premicroRNA. My thesis focuses on the functional characteristics of two Drosophila Dicers that makes them specific for their biological substrates. We found that RNA binding protein partners of Dicers and two small molecules, ATP and phosphate are key in regulating Drosophila Dicers’ specificity. Without any additional factor, recombinant Dicer-2 cleaves pre-miRNA, but its product is shorter than the authentic miRNA. However, the protein R2D2 and inorganic phosphate block pre-miRNA processing by Dicer-2. In contrast, Dicer-1 is inherently capable of processing the substrates of ...


A Role For C-Jun Kinase (Jnk) Signaling In Glial Engulfment Of Degenerating Axons: A Dissertation, Jennifer M. Macdonald Jun 2012

A Role For C-Jun Kinase (Jnk) Signaling In Glial Engulfment Of Degenerating Axons: A Dissertation, Jennifer M. Macdonald

GSBS Dissertations and Theses

The central nervous system (CNS) is composed of two types of cells: neurons that send electrical signals to transmit information throughout the animal and glial cells. Glial cells were long thought to be merely support cells for the neurons; however, recent work has identified many critical roles for these cells during development and in the mature animal. In the CNS, glial cells act as the resident immune cell and they are responsible for the clearance of dead or dying material. After neuronal injury or death, glial cells become reactive, exhibiting dramatic changes in morphology and patterns of gene expression and ...


Antagonistic Pleiotropy: The Role Of Smurf2 In Cancer And Aging: A Dissertation, Charusheila Ramkumar Jun 2012

Antagonistic Pleiotropy: The Role Of Smurf2 In Cancer And Aging: A Dissertation, Charusheila Ramkumar

GSBS Dissertations and Theses

In response to telomere shortening, oxidative stress, DNA damage or aberrant activation of oncogenes, normal somatic cells exit the cell cycle and enter an irreversible growth arrest termed senescence. The limited proliferative capacity imposed by senescence on cells impedes the accumulation of mutations necessary for tumorigenesis and prevents proliferation of cells at risk of neoplastic transformation. Opposite to the tumor suppressor function, accumulation of senescent cells in adult organisms is thought to contribute to aging by depleting the renewal capacity of tissues and stem/progenitor cells, and by interfering with tissue homeostasis and functions. The Antagonistic Pleiotropy Theory of senescence ...


The Molecular Mechanisms For Maintenance Of Cancer Stem Cells In Chronic Myeloid Leukemia: A Dissertation, Haojian Zhang May 2012

The Molecular Mechanisms For Maintenance Of Cancer Stem Cells In Chronic Myeloid Leukemia: A Dissertation, Haojian Zhang

GSBS Dissertations and Theses

Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder associated with the Philadelphia chromosome (Ph) that arises from a reciprocal translocation between chromosomes 9 and 22, thereby resulting in the formation of the chimeric BCR-ABL oncogene encoding a constitutively activated tyrosine kinase. BCR-ABL tyrosine kinase inhibitors (TKIs) induce a complete hematologic and cytogenetic response in the majority of chronic phrase CML patients. However, TKIs cannot efficiently eradicate leukemia stem cells (LSCs) because of the insensitivity of LSCs to TKIs. Therefore, developing new strategies to target LSCs is necessary and critical for curing CML, and success of this approach ...


Catalytic Mechanisms In Sec7 And Vps9 Domain Exchange Factors For Arf And Rab Gtpases: A Dissertation, Meng-Tse Lee May 2012

Catalytic Mechanisms In Sec7 And Vps9 Domain Exchange Factors For Arf And Rab Gtpases: A Dissertation, Meng-Tse Lee

GSBS Dissertations and Theses

Vesicle budding, membrane trafficking, and lipid metabolism depend on the switching of Arf and Rab GTPases from the inactive GDP bound state to the active GTP bound state. However, Arf and Rab GTPases have intrinsic rates of GDP to GTP exchange that are much slower (hours to days) than the time scale of the relevant trafficking processes (seconds or less). In cells, the activation of Arf and Rab GTPases is tightly regulated by guanine nucleotide exchange factors (GEFs) with Sec7 or Vps9 domains, respectively.

Full length Cytohesins, which have a domain architecture consisting of heptad repeats, a Sec7 domain, a ...


Targeting The Histone Acetyl-Transferase, Rtt109, For Novel Anti-Fungal Drug Development: A Dissertation, Jessica Lopes Da Rosa-Spiegler May 2012

Targeting The Histone Acetyl-Transferase, Rtt109, For Novel Anti-Fungal Drug Development: A Dissertation, Jessica Lopes Da Rosa-Spiegler

GSBS Dissertations and Theses

Discovery of new antifungal chemo-therapeutics for humans is limited by the large degree of conservation among eukaryotic organisms. In recent years, the histone acetyl-transferase Rtt109 was identified as the sole enzyme responsible for an abundant and important histone modification, histone H3 lysine 56 (H3K56) acetylation. In the absence of Rtt109, the lack of acetylated H3K56 renders yeast cells extremely sensitive to genotoxic agents. Consequently, the ability to sustain genotoxic stress from the host immune system is crucial for pathogens to perpetuate an infection. Because Rtt109 is conserved only within the fungal kingdom, I reasoned that Rtt109 could be a novel ...


Gene Therapy For Very Long Chain Acyl-Coa Dehydrogenase Deficiency Using Adeno-Associated Virus Vectors: A Dissertation, Allison M. Keeler Apr 2012

Gene Therapy For Very Long Chain Acyl-Coa Dehydrogenase Deficiency Using Adeno-Associated Virus Vectors: A Dissertation, Allison M. Keeler

GSBS Dissertations and Theses

Very long chain acyl-coA dehydrogenase (VLCAD) is the rate-limiting step in mitochondrial fatty acid oxidation. VLCAD deficient mice and patients’ clinical symptoms stem from not only an energy deficiency but also long-chain metabolite accumulations. VLCAD deficient mice were treated systemically with 1x10 12 vector genomes of rAAV9-VLCAD. Expression was detected in the liver, heart and muscle. Also substantial expression of VLCAD was noted in the brain, where it was expressed across different sections of the brain and in different cell types with different morphologies. Biochemical correction was observed in vector-treated mice beginning two weeks post-injection, as characterized by a significant ...


A New Murine Model For Enterohemorrhagic Escherichia Coli Infection Reveals That Actin Pedestal Formation Facilitates Mucosal Colonization And Lethal Disease: A Dissertation, Emily M. Mallick Mar 2012

A New Murine Model For Enterohemorrhagic Escherichia Coli Infection Reveals That Actin Pedestal Formation Facilitates Mucosal Colonization And Lethal Disease: A Dissertation, Emily M. Mallick

GSBS Dissertations and Theses

Enterohemorrhagic Escherichia coli (EHEC) colonizes the intestine and produces the phage-encoded Shiga toxin (Stx) which is absorbed systemically and can lead to hemolytic uremic syndrome (HUS) characterized by hemolytic anemia, thrombocytopenia, and renal failure. EHEC, and two related pathogens, Enteropathogenic E. coli (EPEC), and the murine pathogen, Citrobacter rodentium, are attaching and effacing (AE) pathogens that intimately adhere to enterocytes and form actin “pedestals” beneath bound bacteria. The actin pedestal, because it is a unique characteristic of AE pathogens, has been the subject of intense study for over 20 years. Investigations into the mechanism of pedestal formation have revealed that ...


Dissecting Somatic Cell Reprogramming By Micrornas And Small Molecules: A Dissertation, Zhonghan Li Mar 2012

Dissecting Somatic Cell Reprogramming By Micrornas And Small Molecules: A Dissertation, Zhonghan Li

GSBS Dissertations and Theses

Somatic cells could be reprogrammed into an ES-like state called induced pluripotent stem cells (iPSCs) by expression of four transcriptional factors: Oct4, Sox2, Klf4 and cMyc. iPSCs have full potentials to generate cells of all lineages and have become a valuable tool to understand human development and disease pathogenesis. However, reprogramming process suffers from extremely low efficiency and the molecular mechanism remains poorly understood.

This dissertation is focused on studying the role of small non-coding RNAs (microRNAs) and kinases during the reprogramming process in order to understand how it is regulated and why only a small percentage of cells could ...


Support Of Mitochondrial Dna Replication By Human Rad51: A Dissertation, Jay M. Sage Dec 2011

Support Of Mitochondrial Dna Replication By Human Rad51: A Dissertation, Jay M. Sage

GSBS Dissertations and Theses

The function of homologous DNA recombination in human mitochondria has been a topic of ongoing debate for many years, with implications for fields ranging from DNA repair and mitochondrial disease to population genetics. While genetic and biochemical evidence supports the presence of a mitochondrial recombination activity, the purpose for this activity and the proteins involved have remained elusive. The work presented in this thesis was designed to evaluate the mitochondrial localization of the major recombinase protein in human cells, Rad51, as well as determine what function it plays in the maintenance of mitochondrial DNA (mtDNA) copy number that is critical ...


Treating Gm1 Gangliosidosis With Ex Vivo Hematopoietic Stem Cell Gene Therapy Without Using Total Body Irradiation: A Masters Thesis, Michael Whalen Aug 2011

Treating Gm1 Gangliosidosis With Ex Vivo Hematopoietic Stem Cell Gene Therapy Without Using Total Body Irradiation: A Masters Thesis, Michael Whalen

GSBS Dissertations and Theses

GM1 gangliosidosis is an autosomal recessive lysosomal storage disease, caused by a deficiency in the enzyme β-galactosidase. The disease affects the CNS, liver, kidney, heart and skeletal system, leading to severe neurodegeneration and death. We propose to treat this disorder using ex vivo hematopoietic stem cell therapy. The effectiveness of this therapy requires the recruitment of transduced donor cells to the CNS. This is only found to occur after mice are conditioned with total body irradiation, due to the increase in CNS cytokine production and blood brain barrier permeability that occurs. As the use of total body irradiation in pediatric ...


Role Of Protein Flexibility In Function, Resistance Pathways And Substrate Recognition Specificity In Hiv-1 Protease: A Dissertation, Seema Mittal Aug 2011

Role Of Protein Flexibility In Function, Resistance Pathways And Substrate Recognition Specificity In Hiv-1 Protease: A Dissertation, Seema Mittal

GSBS Dissertations and Theses

In the 30 years since the Center for Disease Control's Morbidity and Mortality Weekly Report published the first mention of what later was determined to be AIDS (Acquired immunodeficiency syndrome) and HIV (Human immunodeficiency virus) recognized as the causative pathogen, much has been done to understand this disease’s pathogenesis, development of drugs and emergence of drug resistance under selective drug therapy. Highly Active Antiretroviral Therapy (HAART), a combination of drugs that includes HIV-1 reverse transcriptase, protease, and more recently, integrase and entry inhibitors, have helped stabilize the HIV prevalence at extraordinarily high levels. Despite the recent stabilization of ...


Structural Studies Of The Anti-Hiv Human Protein Apobec3g Catalytic Domain: A Dissertation, Shivender Shandilya Aug 2011

Structural Studies Of The Anti-Hiv Human Protein Apobec3g Catalytic Domain: A Dissertation, Shivender Shandilya

GSBS Dissertations and Theses

HIV/AIDS is a disease of grave global importance with over 33 million people infected world-wide and nearly 2 million deaths each year. The rapid emergence of drug resistance, due to viral mutation, renders anti-retroviral drug candidates ineffective with alarming speed and regularity. Instead of targeting mutation prone viral proteins, an alternative approach is to target host proteins that interact with viral proteins and are critical for the HIV life-cycle. APOBEC3G is a host anti-HIV restriction factor that can exert tremendous negative pressure by hypermutating the viral genome and has the potential to be a promising candidate for anti-retroviral therapeutic ...


Dissection Of Α6Β4 Integrin-Dependent Signaling And Breast Carcinoma Invasion: A Dissertation, Xiaoqing Yang Jul 2011

Dissection Of Α6Β4 Integrin-Dependent Signaling And Breast Carcinoma Invasion: A Dissertation, Xiaoqing Yang

GSBS Dissertations and Theses

Breast cancer is one of the most prevalent cancers in the world. Each year, over 400,000 women die from breast cancer world wide and metastasis is the main cause of their mortality. Tumor cell invasion into the adjacent tissue is the first step in the multistep process of cancer metastasis and it involves multiple protein changes. The α6β4 integrin, a transmembrane heterodimeric laminin receptor is associated with poor prognosis in many tumor types, including breast cancer. Src family kinase (SFK) activity is elevated in many cancers and this activity also correlates with invasive tumor behavior. The α6β4 integrin can ...


The Role Of Pc4 In Oxidative Stress: A Dissertation, Lijian Yu Jun 2011

The Role Of Pc4 In Oxidative Stress: A Dissertation, Lijian Yu

GSBS Dissertations and Theses

Oxidative stress is a cellular condition where cells are challenged by elevated levels of reactive oxygen species (ROS) that are produced endogenously or exogenously. ROS can damage vital cellular components, including lipid, protein, DNA and RNA. Oxidative damage to DNA often leads to cell death or mutagenesis, the underlying cause of various human disease states. Previously our laboratory discovered that human PC4 gene can prevent oxidative mutagenesis in the bacterium Escherichia coli and that the yeast homolog SUB1 has a conserved function in oxidation protection. In this thesis I examined the underlying mechanisms of PC4’s oxidation protection function. My ...


Quantitative Analysis Of Novel Chemical And Shrna Based Methods To Increase Survival Of Motor Neuron Protein Levels, Matthew C. Evans Jun 2011

Quantitative Analysis Of Novel Chemical And Shrna Based Methods To Increase Survival Of Motor Neuron Protein Levels, Matthew C. Evans

GSBS Dissertations and Theses

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder that is the leading genetic cause of infantile death. SMA is caused by homozygous deletion or mutation of the survival of motor neuron 1 gene (SMN1). The SMN2 gene is nearly identical to SMN1, however is alternatively spliced. The close relationship to SMN1 results in SMN2 being a very power genetic modifier of SMA disease severity and a target for therapies. In this study we attempt to characterize novel chemical compounds identified as potential activators of the SMN2 gene. Additionally, we sought to determine the regulatory role individual HDAC proteins ...


Regulation Of Humoral Immunity By Pim Kinases: A Dissertation, Kristen N. Willems Jun 2011

Regulation Of Humoral Immunity By Pim Kinases: A Dissertation, Kristen N. Willems

GSBS Dissertations and Theses

Pim (Provirus Integration site for Moloney murine leukemia virus) kinases are a family of three serine/threonine kinases involved in cell cycle, survival and metabolism. These kinases were first identified in malignant cells and are most often associated with their role in cancer. Their role in immunity and lymphocytes is less well known. To date, it has been shown that Pim 1 and/or Pim 2 are important for T lymphocyte survival and activation when the Akt signaling pathway is inhibited by rapamycin. In addition, our laboratory has shown that Pim 2 is critical for BLyS-mediated naive B lymphocyte survival ...


The Importance Of The Centrosomal Localization Sequence Of Cyclin E For Promoting Centrosome Duplication: A Dissertation, Joshua J. Nordberg May 2011

The Importance Of The Centrosomal Localization Sequence Of Cyclin E For Promoting Centrosome Duplication: A Dissertation, Joshua J. Nordberg

GSBS Dissertations and Theses

This thesis comprises three separate studies that investigate the consequences of supernumary centrosomes, the effect of centrosome loss, and a control mechanism for regulating CDK2/cyclin E activity in centrosome duplication.

The centrosome is the major microtubule-organizing center of the cell. When the cell enters mitosis, it is of critical importance that the cell has exactly two centrosomes in order to properly segregate the chromosomes to two daughter cells. Supernumary centrosomes are a problem for the cell in that they increase the incidence of chromosomal instability. Aberrant centrosome numbers are seen in a number of cancers, and there has been ...


Critical And Independent Roles Of The P/Caf Acetyltransferase In Arf-P53 Signaling: A Dissertation, Ian M. Love May 2011

Critical And Independent Roles Of The P/Caf Acetyltransferase In Arf-P53 Signaling: A Dissertation, Ian M. Love

GSBS Dissertations and Theses

For 30 years, the tumor suppressor p53 has been a subject of intense research in nearly every discipline of scientific inquiry. While numerous surprising roles for p53 in health and disease are uncovered each year, the central role of its activation in preventing neoplastic transformation has been and will remain at the forefront of p53 research as investigators work to address an unexpectedly complex question—precisely how does p53 integrate upstream stress signals to coordinate activation of its target genes in response to stress?

One manner in which to address this question is at the level of transcription initiation—after ...


Hsp90-Mediated Maturation Of Kinases And Nuclear Steroid Hormone Receptors: A Dissertation, Natalie W. Pursell Apr 2011

Hsp90-Mediated Maturation Of Kinases And Nuclear Steroid Hormone Receptors: A Dissertation, Natalie W. Pursell

GSBS Dissertations and Theses

Among heat shock proteins, Hsp90 is unusual because it is not required for the proper folding of most cellular proteins but rather is disproportionally linked to the activation of signal transduction proteins including over forty kinases and many steroid hormone receptors. Mutated forms of many Hsp90 clients are causative agents in cancer, making Hsp90 a promising pharmacological target. Many small molecular inhibitors have been identified that competitively bind to the ATP binding site of Hsp90, some of which are in clinical trials as anticancer agents. Although the activation of kinase and hormone receptor clients by Hsp90 and its co-chaperones has ...


Dissecting Signaling Pathways That Regulate Axonal Guidance Effects Of Sonic Hedgehog: A Dissertation, Daorong Guo Mar 2011

Dissecting Signaling Pathways That Regulate Axonal Guidance Effects Of Sonic Hedgehog: A Dissertation, Daorong Guo

GSBS Dissertations and Theses

During development, axons respond to a variety of guidance cues in the environment to navigate to the proper targets. Sonic hedgehog (Shh), a classical morphogen, has been shown to function as a guidance factor that directly acts on the growth cones of various types of axons. We previously found that Shh affects retinal ganglion cell (RGC) axonal growth and navigation in a concentration-dependent manner. However, the signaling pathways that mediate such events are still unclear.

In this thesis, we show that high concentrations of Shh induce growth cone collapse and repulsive turning of the chick RGC through rapid increase of ...