Dopamine Regulation Of Cone-Cone Gap Junctions In Ground Squirrel Retina,
2011
Illinois Mathematics and Science Academy
Dopamine Regulation Of Cone-Cone Gap Junctions In Ground Squirrel Retina, Xiaoyu Li '12, Steven Devries
Student Publications & Research
Cone photoreceptors are electrically coupled such that when the electrical potential in one cell changes, it also changes in adjacent, coupled cells. Phosphorylation of the cone gap junction protein, connexin 36 (Cx36), determines whether a coupling channel is “open” or “closed”. Cx36- containing gap junctions are phosphorylated in the open state and dephosphorylated in the closed state. Cone-cone gap junction modulation has not been extensively studied, however, the presence of rod-cone gap junction modulation raises the possibility that the same is true for cone pairs. Pieces of thirteen-lined ground squirrel retina were removed from the eye and the tissue was …
The Pcdp1 Complex Coordinates The Activity Of Dynein Isoforms To Produce Wild-Type Ciliary Motility,
2011
Dartmouth College
The Pcdp1 Complex Coordinates The Activity Of Dynein Isoforms To Produce Wild-Type Ciliary Motility, Christen G. Dipetrillo, Elizabeth F. Smith
Dartmouth Scholarship
Generating the complex waveforms characteristic of beating cilia requires the coordinated activity of multiple dynein isoforms anchored to the axoneme. We previously identified a complex associated with the C1d projection of the central apparatus that includes primary ciliary dyskinesia protein 1 (Pcdp1). Reduced expression of complex members results in severe motility defects, indicating that C1d is essential for wild-type ciliary beating. To define a mechanism for Pcdp1/C1d regulation of motility, we took a functional and structural approach combined with mutants lacking C1d and distinct subsets of dynein arms. Unlike mutants completely lacking the central apparatus, dynein-driven microtubule sliding velocities are …
Differential Interactions Of The Formins Inf2, Mdia1, And Mdia2 With Microtubules,
2011
University Joseph Fourier
Differential Interactions Of The Formins Inf2, Mdia1, And Mdia2 With Microtubules, Jeremie Gaillard, Bvinay Ramabhadran, Emmanuelle Neumanne, Pinar Gurel, Laurent Blanchoin, Marylin Vantard, Henry N. Higgs
Dartmouth Scholarship
A number of cellular processes use both microtubules and actin filaments, but the molecular machinery linking these two cytoskeletal elements remains to be elucidated in detail. Formins are actin-binding proteins that have multiple effects on actin dynamics, and one formin, mDia2, has been shown to bind and stabilize microtubules through its formin homology 2 (FH2) domain. Here we show that three formins, INF2, mDia1, and mDia2, display important differences in their interactions with microtubules and actin. Constructs containing FH1, FH2, and C-terminal domains of all three formins bind microtubules with high affinity (K(d) < 100 nM). However, only mDia2 binds microtubules at 1:1 stoichiometry, with INF2 and mDia1 showing saturating binding at approximately 1:3 (formin dimer:tubulin dimer). INF2-FH1FH2C is a potent microtubule-bundling protein, an effect that results in a large reduction in catastrophe rate. In contrast, neither mDia1 nor mDia2 is a potent microtubule bundler. The C-termini of mDia2 and INF2 have different functions in microtubule interaction, with mDia2's C-terminus required for high-affinity binding and INF2's C-terminus required for bundling. mDia2's C-terminus directly binds microtubules with submicromolar affinity. These formins also differ in their abilities to bind actin and microtubules simultaneously. Microtubules strongly inhibit actin polymerization by mDia2, whereas they moderately inhibit mDia1 and have no effect on INF2. Conversely, actin monomers inhibit microtubule binding/bundling by INF2 but do not affect mDia1 or mDia2. These differences in interactions with microtubules and actin suggest differential function in cellular processes requiring both cytoskeletal elements.
Beta-Lysine Discrimination By Lysyl-Trna Synthetase,
2011
The Ohio State University
Beta-Lysine Discrimination By Lysyl-Trna Synthetase, Marla S. Gilreath, Hervé Roy, Tammy J. Bullwinkle, Assaf Katz, Michael Ibba, William Wiley Navarre
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Elongation factor P is modified with (R)‐β‐lysine by the lysyl‐tRNA synthetase (LysRS) paralog PoxA. PoxA specificity is orthogonal to LysRS, despite their high similarity. To investigate α‐ and β‐lysine recognition by LysRS and PoxA, amino acid replacements were made in the LysRS active site guided by the PoxA structure. A233S LysRS behaved as wild type with α‐lysine, while the G469A and A233S/G469A variants decreased stable α‐lysyl‐adenylate formation. A233S LysRS recognized β‐lysine better than wildtype, suggesting a role for this residue in discriminating α‐ and β‐amino acids. Both enantiomers of β‐lysine were substrates for tRNA aminoacylation by LysRS, which, together with …
Expression Of Hyp-O-Glycan Modified Protein In Plant Using Transient And Cell Culture Platforms,
2011
Arkansas State University
Expression Of Hyp-O-Glycan Modified Protein In Plant Using Transient And Cell Culture Platforms, Di Wu
Student Theses and Dissertations
Plants have emerged as cost-effective, efficient factories to produce foreign proteins of pharmaceutical importance. Agrobacterium-mediated transient expression provides a rapid and simple plant system for production but is often linked with low protein recovery. Plant-specific hydroxyproline (Hyp)-O-glycosylation has been demonstrated to increase protein stability and solubility (termed Hyp-Glyco technology). To test if Hyp-glycans attached to a target protein can improve overall transiently expressed protein yields, EGFP reporter protein was expressed as fusion with a 5 or 32 repeats of Ser-Pro motif ((SP)5 or (SP)32 ) that directs extensive Hyp-O-glycosylation. My thesis project has provided the first demonstration that the Hyp-O-glcosylation …
The Filament-Forming Protein Pil1 Assembles Linear Eisosomes In Fission Yeast,
2011
Dartmouth College
The Filament-Forming Protein Pil1 Assembles Linear Eisosomes In Fission Yeast, Ruth Kabeche, Suzanne Baldissard, John Hammond, Louisa Howard, James B. Moseley
Dartmouth Scholarship
The cortical cytoskeleton mediates a range of cellular activities such as endocytosis, cell motility, and the maintenance of cell rigidity. Traditional polymers, including actin, microtubules, and septins, contribute to the cortical cytoskeleton, but additional filament systems may also exist. In yeast cells, cortical structures called eisosomes generate specialized domains termed MCCs to cluster specific proteins at sites of membrane invaginations. Here we show that the core eisosome protein Pil1 forms linear cortical filaments in fission yeast cells and that purified Pil1 assembles into filaments in vitro. In cells, Pil1 cortical filaments are excluded from regions of cell growth and are …
The Trna Synthetase Paralog Poxa Modifies Elongation Factor-P With (R)-Β-Lysine,
2011
The Ohio State University
The Trna Synthetase Paralog Poxa Modifies Elongation Factor-P With (R)-Β-Lysine, Hervé Roy, S. Betty Zou, Tammy J. Bullwinkle, Benjamin S. Wolfe, Marla S. Gilreath, Craig J. Forsyth, William Wiley Navarre, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The lysyl-tRNA synthetase paralog PoxA modifies elongation factor P (EF-P) with α-lysine at low efficiency. Cell-free extracts containing non–α-lysine substrates of PoxA modified EF-P with a change in mass consistent with addition of β-lysine, a substrate also predicted by genomic analyses. EF-P was efficiently functionally modified with (R)-β-lysine but not (S)-β-lysine or genetically encoded α-amino acids, indicating that PoxA has evolved an activity orthogonal to that of the canonical aminoacyl-tRNA synthetases.
Serum- And Glucocorticoid-Induced Kinase 3 In Recycling Endosomes Mediates Acute Activation Of Na+/H+ Exchanger Nhe3 By Glucocorticoids,
2011
Emory University
Serum- And Glucocorticoid-Induced Kinase 3 In Recycling Endosomes Mediates Acute Activation Of Na+/H+ Exchanger Nhe3 By Glucocorticoids, Peijian He, Sei-Jung Lee, Songbai Lin, Ursula Seidler, Florian Lang, Geza Fejes-Toth, Aniko Naray-Fejes-Toth, C. Chris Yun
Dartmouth Scholarship
Na(+)/H(+) exchanger 3 (NHE3) is the major Na(+) transporter in the intestine. Serum- and glucocorticoid-induced kinase (SGK) 1 interacts with NHE regulatory factor 2 (NHERF2) and mediates activation of NHE3 by dexamethasone (Dex) in cultured epithelial cells. In this study, we compared short-term regulation of NHE3 by Dex in SGK1-null and NHERF2-null mice. In comparison to wild-type mice, loss of SGK1 or NHERF2 significantly attenuated regulation of NHE3 by Dex but did not completely obliterate the effect. We show that transfection of SGK2 or SGK3 in PS120 cells resulted in robust activation of NHE3 by Dex. However, unlike SGK1 or …
Identification Of Nitrifying Bacteria Contained In A Commercial Inoculant Using Molecular Biology Techniques,
2011
University of Nevada, Las Vegas
Identification Of Nitrifying Bacteria Contained In A Commercial Inoculant Using Molecular Biology Techniques, Anthony Harrington, John Perry, Penny S. Amy
Undergraduate Research Opportunities Program (UROP)
Nitrifying bacteria play an important role in aquatic and terrestrial environments through the nitrogen cycle. Nitrification, one of the processes of the nitrogen cycle, refers to the oxidation of ammonia to nitrate. This process requires two types of chemoautotrophic bacteria, ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB). These bacteria are essential in maintaining an optimal environment for plants and aquatic organisms, such as fish. Current applications of nitrifiers include: inoculants for aquariums, biofertilizers, and nitrogen removal in wastewater treatment plants. This study wants to identify a consortium of nitrifers that can be used to produce sufficient nitrate for plants in …
Inactivation Of Spo0a Gene Increases Stationary Phase Mutagenesis In Bacillus Subtilis,
2011
California State University - San Marcos
Inactivation Of Spo0a Gene Increases Stationary Phase Mutagenesis In Bacillus Subtilis, Denisse Reyes, Amanda Prisbrey, Holly Martin, Eduardo Robleto
Undergraduate Research Opportunities Program (UROP)
Stationary phase mutagenesis occurs when a population of cells acquires mutations conferring escape from nongrowing or stress conditions. This type of mutations is observed in nutritionally starved cells. Because the mutations occur after the onset of stress and in cells that are in non-replicative conditions, elucidating the underlying mechanisms contributes novel views to the process of evolution and apply to the formation of cancer in human cells and antibiotic resistance in microbial pathogens. Studies have shown that in Bacillus subtilis, the Mfd protein which is a transcription repair coupling factor is necessary for this phenomenon to occur. Here, we investigate …
Synthesis Of Chimeric Receptors Essential For Spore Germination,
2011
Juniata College
Synthesis Of Chimeric Receptors Essential For Spore Germination, Christopher Yip, Christian Ross, Eduardo Robleto, Ernesto Abel-Santos
Undergraduate Research Opportunities Program (UROP)
Various species of bacteria have been reported to form an endospore, a metabolically dormant cell, during times of nutrient deficiencies and extreme stress. These said structures are outstandingly resistant to harsh chemicals, extreme temperatures, and can revert back to a metabolically active cell, through a process known as germination, when the necessary conditions are met. The rigid membrane of the endospore contains various germination (Ger) receptors which sense the external environment for necessary metabolites and germinants. Ger receptors are encoded by tricistronic operons that produce three distinct membrane proteins, the A, B, and C subunits. Although the function of the …
Investigating The Origin Of Coprolites From Three Great Basin Caves,
2011
University of Minnesota
Investigating The Origin Of Coprolites From Three Great Basin Caves, Chelsey Vandrisse, Duane P. Moser, David Rhode
Undergraduate Research Opportunities Program (UROP)
The study of coprolites (mummified feces) is a relatively new endeavor, which enables investigations of the health and diet of ancient people and provides some of the oldest evidence to date for the human habitation in North America (2). In this project, 18 coprolites were examined from archeological digs at three Great Basin caves: the Bonneville Estates Rockshelter (UT), Hidden Cave (NV), and Top of the Terrace Rockshelter (UT). The main objectives were: 1) to verify human origin through the presence of mitochondrial DNA (mtDNA) and 2) assuming human origin, characterize intestinal microflora of Native Americans prior to European contact. …
The Role Of An Abc Transporter As A Steroid Antagonist In Drosophila,
2011
University of Nevada, Las Vegas
The Role Of An Abc Transporter As A Steroid Antagonist In Drosophila, Gregory King, Andrew Andres
Undergraduate Research Opportunities Program (UROP)
Drosophila melanogaster are holometabolous insects that have several distinct life stages including larvae and a winged adult. The larval stage is mainly a time of feeding and growth, while the adult stage is optimized for sexual reproduction and dissemination. The larval stage can itself be divided into three time periods, or instars: 1st (L1), 2nd (L2), and 3rd (L3) (Figure 1). Larval growth – both between instars and beyond – depends on specific signaling pathways controlled by a cholesterol derived steroid, 20-hydroxyecdysone (20E). Although 20E is a systemic developmental signal, little is known about the molecular details of how different …
Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells,
2011
University of Nevada, Las Vegas
Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Holly Martin, Christian Ross, Ronald Yasbin, Eduardo Robleto
Undergraduate Research Opportunities Program (UROP)
It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known as stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It has been proposed that in non~growing cells, the process of transcription plays an important role in mutagenesis. We test the hypothesis that DNA secondary structures, formed during transcription, promote mutagenesis. The transcription-generated structures are speculated to be prone to mutations by …
Regulation Of The Shigella Flexneri Icsp Gene And H-Ns Dependent Repression,
2011
University of Nevada, Las Vegas
Regulation Of The Shigella Flexneri Icsp Gene And H-Ns Dependent Repression, Rosa Ojeda, Amanda Wigley, Dustin Harrison, Helen Wing
Undergraduate Research Opportunities Program (UROP)
The gram negative bacterium Shigella flexneri is known to cause dysentery in humans and primates. In order to help prevent the spread of shigellosis, gene regulation must be understood. Studies show that the virulence genes in S .flexneri are thermo regulated. At 30°C histone-like nucleoid structuring protein (H-NS) represses transcription of virulence genes and at 37°C VirB derepresses virulence genes. One of the genes that contribute to the virulence of S. flexneri is icsP. My project focuses on the regulation of the S. flexneri icsP gene and has two main goals. The first is to identify the sequence of H-NS …
Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead,
2011
Western Washington University
Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley
STAR Program Research Presentations
Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head …
Computational Identification Of Protein Catalytic Sites: Tests, Validation,
2011
California State University - East Bay
Computational Identification Of Protein Catalytic Sites: Tests, Validation, Dan Kirshner, Jerome Nilmeier, Felice Lightstone
STAR Program Research Presentations
This project is one element of the analysis “pipeline” to characterize an organism that previously has not been well-studied. Once a protein of unknown structure has been computationally modeled (based on its sequence similarity to proteins with solved structures), then catalytic sites are identified on the model by comparison to a library of known sites. This work tested the identification algorithms with a set of proteins that have known structures and catalytic sites.
Stimulator Of Neurotropic Effects Determining The Mechanism Of Action Of The Ms-818 Compound Through Protein Identification By Affinity Chromatography And Sds-Page,
2011
University of Central Florida
Stimulator Of Neurotropic Effects Determining The Mechanism Of Action Of The Ms-818 Compound Through Protein Identification By Affinity Chromatography And Sds-Page, Charlene Seraphina Dass
HIM 1990-2015
The MS-818 compound is used in the proliferation process of neuronal cells and many biological activities that accompany this process such as astrocyte differentiation, inhibition of neuronal apoptosis, and fraction repairs. We do know the effects of this compound, but the mechanism of action remained uncertain until now. To determine the pathway of this compound, NT2 cells were cultured and lysed to isolate the proteins. Affinity Chromatography was performed in order to immobilize the MS-818 compound to a Hi-Trap NHS column. The NT2 protein sample was injected through the column and eluted with a MS-818 concentrated, high salt content elution …
Changes In Expression Of Akt Pathway Proteins Following Treatment With Rg3 In Vitro,
2011
Clemson University
Changes In Expression Of Akt Pathway Proteins Following Treatment With Rg3 In Vitro, Kathryn Schalkoff
All Theses
To assess changes in AKT pathway signaling, a recombinant protein of the G3 domain of rat laminin-5 (rG3) that specifically binds the alpha subunit of integrins α6β1 and α6β4 expressed on cancer cells (e.g., MDA-MB-231) was produced. This recombinant protein is believed to interrupt the intracellular signaling events of the AKT pathway, causing a decrease in proliferation and survival of cells after treatment. Viability assays confirmed an apoptotic effect of rG3 on cells in a dose-dependent manner. However, data from gene expression studies of Caspase-9, GRB10, and CDKNIB proved non-conclusive that rG3 is acting upon gene expression, leading to the …
Developmental Deregulation And Tumorigenesis Inhibition In 14-3-3zeta Knockout Mouse,
2011
The University of Texas Graduate School of Biomedical Sciences at Houston
Developmental Deregulation And Tumorigenesis Inhibition In 14-3-3zeta Knockout Mouse, Jun Yang
Dissertations and Theses (Open Access)
Cancer is second leading cause of death in the United States. Improving cancer care through patient care, research, education and prevention not only saves lives, but reduces health care cost as well. Breast cancer is the most leading cause of cancer incidence and cancer related death in women of the United States. 14-3-3s are a family of conserved proteins ubiquitously expressed in all eukaryotic organisms. They form complexes with hundreds of proteins by binding to specific phospho-serine/threonine containing motifs. In this way they regulate a variety of cellular processes and are involved in many human diseases especially cancer to our …
