Life Sciences Commons^™

Small Heat Shock Protein 27 And Its Role In Human Disease, Bianka Andrea Holguin

Open Access Theses & Dissertations

Small heat shock protein 27 (Hsp27) is a ubiquitously expressed molecular chaperone with roles in many physiological processes. As an ATP-independent molecular chaperone, Hsp27 protects substrates from irreversible aggregation and holds them in a folding competent state for later recycling into the proteome. Hsp27 proteins form dimers that are assembled into large oligomeric complexes. Phosphorylation of Hsp27 dissembles the oligomers into chaperone active dimers. Several missense mutations of Hsp27 are causative for the neurodegenerative disorders Charcot-Marie-Tooth disease 2F and distal Hereditary Motor Neuropathy IIB. Here I show that the oligomerization and chaperoning ability of Hsp27 are altered by the Hsp27 …

Simulation Of The Interaction Between Striated Muscle Unc-45 And Transcription Factor Gata-4, Drake Alexander Duncan

Electronic Theses and Dissertations

Striated Muscle UNC-45, also known as UNC-45b, is an important protein that acts as a chaperone for myosin in cardiac and skeletal muscles, binding to myosin at its C-terminal UCS domain and regulating its assembly into thick filaments and sarcomeric structures. The UCS domain contains a large loop that is believed to be the first point of interaction between myosin and UNC-45b. GATA-4 is an essential transcription factor that facilitates transcription of several genes in cardiac development, particularly alpha-heavy chain myosin in heart tissue. Recently, studies have shown that there is interaction of GATA-4 with UNC-45b and that GATA-4 binds …

Substrate Trafficking Within The Type Vii Secretion Systems Of Pathogenic Mycobacteria, Zachary A. Williamson

Theses and Dissertations--Molecular and Cellular Biochemistry

Tuberculosis (TB), primarily caused by infection of Mycobacterium tuberculosis (Mtb) in the lungs, is the deadliest infectious bacterial disease killing 1.5 million people annually. A major determinant of virulence is active secretion through three specialized type VII secretion (ESX) systems; ESX-1, ESX-3, and ESX-5. A large group of substrates exported by the ESX systems is the PE (Proline-Glutamine) and PPE (Proline-Proline-Glutamate) families of proteins, which are highly expanded in the pathogenic species of Mycobacteria and encompass over 7% of Mtb’s genome coding capacity. PE and PPE proteins interact together to form PE-PPE heterodimers, and are secreted through …

Generation Of Full-Length Wild-Type Gata4 Protein And Characterization Of Its Binding To Unc-45 Domains, Morgan Anderson

Electronic Theses and Dissertations

Striated muscle UNC-45 (SM UNC-45) protein acts as a chaperone for cardiac and skeletal muscle myosins; regulating their folding, assembly into thick filaments, interaction with other sarcomeric proteins, and degradation. GATA4 is an important transcription factor that regulates the expression of several cardiac muscle proteins, including myosin. A previous study demonstrated for the first time that SM UNC-45 (also known as UNC-45B) physically interacted with GATA4. The major revelation from this study is that SM UNC-45 has the potential to exert both short-term (protein level) and long-term (gene level) controls over myosin and therefore muscle structure and function. The aim …

Thiol-Based Misfolding: Linking Redox Balance To Cytosolic Proteostasis, Ford Amy

Dissertations & Theses (Open Access)

The eukaryotic cytosolic proteome is vulnerable to changes in proteostatic and redox balance caused by temperature, pH, oxidants and xenobiotics. Cysteine-containing proteins are especially at risk as the thiol side chain is subject to oxidation, adduction and chelation by thiol-reactive compounds. All of these thiol-modifiers have been demonstrated to induce the heat shock response and recruit protein chaperones to sites of presumed protein aggregation in the budding yeast Saccharomyces cerevisiae. However, endogenous targets of thiol stress toxicity responsible for these outcomes are largely unknown. Furthermore, I hypothesize proteins identified as redox-active are prone to misfolding and aggregation by thiol-specific …

Identification And Characterization Of Small Molecules Targeting Fkbp52 As A Novel Treatment For Prostate Cancer, Naihsuan C. Guy

Open Access Theses & Dissertations

Prostate cancer (PCa) is one of the most commonly diagnosed diseases and the second leading cause of cancer deaths among men worldwide. Its growth is dependent upon androgen receptor (AR) signaling and the mainstay for treatment is hormone-ablation therapy using antiandrogens and/or androgen-deprivation therapies (ADT). Treatment of PCa with antiandrogens and/or ADT are initially effective; they act to repress the AR by directly competing with androgens for the ligand binding domain (LBD) and prevent activation of the receptor resulting in tumor regression. Unfortunately, the resistance to these treatments invariably emerges and results in a much more aggressive form of tumor …

Rna Aptamers For Molecular Chaperones Hsp27 And Hsp90, Sathishkumar Kumar Munusamy

Legacy Theses & Dissertations (2009 - 2024)

Hsp90 and Hsp27 are members of the heat shock protein family of chaperones that perform multiple roles in cellular maintenance through protein folding and inhibition of apoptosis. They are abundantly expressed in cells and are over-expressed during conditions of stress. Hsp90 requires ATP for its chaperone function while Hsp27 self-associates into higher order oligomers enclosing its substrate. Their ability to interact with other proteins or with themselves lies at the heart of their mechanisms. The specific consequences of each of their interactions on global cellular health have not yet been fully discovered. The sheer diversity of proteins that interact with …

Rna Aptamer Mediated Manipulation Of The 70 Kilodalton Heat Shock Protein Chaperone Machinery, Deepak Thirunavukarasu

Legacy Theses & Dissertations (2009 - 2024)

Protein quality control involves refolding of damaged proteins and facilitating degradation of irreparable proteins. Understanding the protein quality control mechanism is critical, since defects in it has been implicated in a number of age-related diseases like neurodegenerative diseases and also in cancer. A vast network of molecular chaperones and proteolytic systems collaborate to maintain protein quality control. The 70 kilodalton Heat shock protein (Hsp70) is a highly conserved and ubiquitous chaperone, which interacts with a variety of protein substrates including newly synthesized polypeptides, unfolded, partially misfolded and native proteins to maintain protein quality control. Hsp70 chaperone function is coupled to …

Chaperone-Mediated Folding And Assembly Of Β-Propeller Proteins Into Cellular Signaling Complexes, Rebecca L. Plimpton

Theses and Dissertations

G protein signaling depends on the ability of the individual subunits of the G protein heterotrimer to assemble into a functional complex. Formation of the G protein βγ (Gβγ) dimer is particularly challenging because it is an obligate dimer in which the individual subunits are unstable on their own. Recent studies have revealed an intricate chaperone system that brings the Gβ and Gγ subunits together. This system includes the cytosolic chaperonin containing TCP-1 (CCT) and a co-chaperone phosducin-like protein 1 (PhLP1). Two key intermediates in the Gβγ assembly process, the Gβ-CCT and the PhLP1-Gβ-CCT complexes, were isolated and their structures …

Molecular Chaperone Tools For Use Against Neurodegenerative Diseases, Matthew Tinkham

Senior Honors Projects

A noted characteristic found in several neurodegenerative disorders, including Alzheimer’s Disease, Parkinson’s Disease, Huntington’s Disease and bovine spongiform encephalopathy, is the accumulation of amyloid plaques in the brain. Amyloid plaques contain deposits of fibrillar aggregates of misfolded proteins that disrupt normal functionality in neurons. Certain variants of these misfolded proteins are self-replicating; these self-replicating amyloids are termed prions (for infectious protein). We are interested in how protein misfolding contributes to amyloid formation and how molecular chaperone proteins can change the formation of amyloid deposits. Chaperone proteins function by catalyzing the proper folding of other proteins, the refolding of misfolded proteins, …

Understanding Multidrug Resistance In Gram-Negative Bacteria -- A Study Of A Drug Efflux Pump Acrb And A Periplasmic Chaperone Sura, Meng Zhong

Theses and Dissertations--Chemistry

Multiple drug resistance (MDR) has been a severe issue in treatment and recovery from infection.Gram-negative bacteria intrinsically exhibit higher drug tolerance than Gram-positive microbes. In this thesis, two proteins involved in Gram-negative bacterial MDR were studied, AcrB and SurA.

Resistance-nodulation-cell division pump AcrAB-TolC is the major MDR efflux system in Gram-negative bacteria and efficiently extrudes a broad range of substances from the cells. To study subtle conformational changes of AcrB in vivo, a reporter platform was designed. Cysteine pairs were introduced into different regions in the periplasmic domain of the protein, and the extents of disulfide bond formation were …

Structural Basis For Ternary Complex Formation Between Tau, Hsp90, And Fkbp51, Alexander Steven Barrett

USF Tampa Graduate Theses and Dissertations

The accumulation of the microtubule associated protein tau has been implicated in several neurological disorders; however, its interaction with chaperones along its normal degradation pathway remains largely uncharacterized at single residue resolution. In this study, nuclear magnetic resonance (NMR) spectroscopy was used to probe the interaction between tau, the molecular chaperone Hsp90, and the immunophilin FKBP51. Resonance intensity changes were observed for specific residues in the heteronuclear single quantum coherence (HSQC) spectra of 15N-labeled tau in the presence of Hsp90 and/or FKBP51. Analysis of the HSQC spectra identified the two hydrophobic hexapeptide motifs located at residues V275 - K280 and …

Small Heat Shock Protein Activity Is Regulated By Variable Oligomeric Substructure, J. L. Benesch, M. Ayoub, C. V. Robinson, J. A. Aquilina

J. A. Aquilina

The alpha-crystallins are members of the small heat shock protein (sHSP) family of molecular chaperones which have evolved to minimize intracellular protein aggregation, however they are also implicated in a number of protein deposition diseases. In this study we have employed novel mass spectrometry techniques to investigate the changes in quaternary structure associated with this switch from chaperone to adjuvant of aggregation. We have replicated the oligomeric rearrangements observed for in vivo disease-related modifications, without altering the protein sequence, by refolding the alpha-crystallins in vitro. This refolding results in a loss of dimeric substructure concomitant with an augmentation of substrate …

Novel Phosducin-Like Protein Binding Partners: Exploring Chaperone And Tumor Suppressor Protein Interactions, Amy Jetaun Gray

Theses and Dissertations

Many proteins cannot fold into their native state without the assistance of one or more molecular chaperones. Chaperonins are an essential class of chaperones that provide an isolated chamber for proteins to fold. CCT, a group II chaperonin found in eukaryotes assists in the folding of actins, tubulins, and many other cellular proteins. PhLP1 is a member of the phosducin protein family that assists CCT in the folding of Gβ and its subsequent assembly with Gγ. However, previous studies have not addressed the scope of PhLP1 and CCT-mediated Gβγ; assembly. The data presented in Chapter 2 shows that PhLP1 plays …

Physical Models Of Amyloid Fibril Assembly, Shannon Elizabeth Hill

USF Tampa Graduate Theses and Dissertations

Formation of large fibers and plaques by amyloid proteins is recognized as the molecular hallmark of an increasing number of human disorders, including Parkinson's disease, Alzheimer's disease and even type II diabetes. The broader objective of my research is to unravel the basic mechanisms that initiate and regulate fibril formation by amyloidogenic proteins. This objective is significant because even basic aspects of how fibril formation proceeds from a soluble, monomeric protein to an insoluble amyloid fibril remain much debated. Furthermore, there is increasingly strong evidence suggesting that intermediates of the aggregation process, with properties distinct from those of mature fibrils, …

Role Of Molecular Chaperones In G Protein B5-Regulator Of G Protein Signaling Dimer Assembly And G Protein By Dimer Specificity, Alyson Cerny Howlett

Theses and Dissertations

In order for G protein signaling to occur, the G protein heterotrimer must be assembled from its nascent polypeptides. The most difficult step in this process is the formation of the Gβγ dimer from the free subunits since both are unstable in the absence of the other. Recent studies have shown that phosducin-like protein (PhLP1) works as a co-chaperone with the cytosolic chaperonin complex (CCT) to fold Gβ and mediate its interaction with Gγ. However, these studies did not address questions concerning the scope of PhLP1 and CCT-mediated Gβγ assembly, which are important questions given that there are four Gβs …

Small Heat Shock Protein Activity Is Regulated By Variable Oligomeric Substructure, J. L. Benesch, M. Ayoub, C. V. Robinson, J. A. Aquilina

Faculty of Science - Papers (Archive)

The alpha-crystallins are members of the small heat shock protein (sHSP) family of molecular chaperones which have evolved to minimize intracellular protein aggregation, however they are also implicated in a number of protein deposition diseases. In this study we have employed novel mass spectrometry techniques to investigate the changes in quaternary structure associated with this switch from chaperone to adjuvant of aggregation. We have replicated the oligomeric rearrangements observed for in vivo disease-related modifications, without altering the protein sequence, by refolding the alpha-crystallins in vitro. This refolding results in a loss of dimeric substructure concomitant with an augmentation of substrate …

Characterization Of Heat Shock Protein A12b As A Novel Angiogenesis Regulator., Rebecca J. Steagall

Electronic Theses and Dissertations

Previously, we cloned Heat shock protein A12B (HspA12B), the newest member of a recently defined subfamily of proteins distantly related to the Hsp70 family that are enriched in atherosclerotic lesions. We have found that HspA12B is predominantly expressed in vascular endothelium, and that it is involved in angiogenesis which we probed by in vitro angiogenesis assays (Matrigel), migration assays and Directed In Vivo Angiogenesis Assay (DIVAA). Hsp70s are molecular chaperones that are inducible by stress and have been found to be anti-apoptotic (Li et al. 2000; Nylandsted et al. 2000; Garrido et al. 2001). Because of its homology to Hsp70, …