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2010

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Articles 1 - 30 of 103

Full-Text Articles in Cell Biology

Biphasic Targeting And Cleavage Furrow Ingression Directed By The Tail Of A Myosin Ii, X. Fang, J. Y. Luo, R. Nishihama, C. Wloka, C. Dravis, M. Travaglia, M. Iwase, Elizabeth Ann Vallen, E. Bi Dec 2010

Biphasic Targeting And Cleavage Furrow Ingression Directed By The Tail Of A Myosin Ii, X. Fang, J. Y. Luo, R. Nishihama, C. Wloka, C. Dravis, M. Travaglia, M. Iwase, Elizabeth Ann Vallen, E. Bi

Biology Faculty Works

Cytokinesis in animal and fungal cells utilizes a contractile actomyosin ring (AMR). However, how myosin II is targeted to the division site and promotes AMR assembly, and how the AMR coordinates with membrane trafficking during cytokinesis, remains poorly understood. Here we show that Myo1 is a two-headed myosin II in Saccharomyces cerevisiae, and that Myo1 localizes to the division site via two distinct targeting signals in its tail that act sequentially during the cell cycle. Before cytokinesis, Myo1 localization depends on the septin-binding protein Bni5. During cytokinesis, Myo1 localization depends on the IQGAP Iqg1. We also show that the Myo1 ...


The Roles Of Elevated Bcl-2 In Ovarian Cancer, Nicole Shree Anderson Dec 2010

The Roles Of Elevated Bcl-2 In Ovarian Cancer, Nicole Shree Anderson

Graduate Theses and Dissertations

Ovarian cancer (OC) is the second most common gynecologic cancer; however it is responsible for the most gynecologic cancer-related deaths. Apoptosis evasion is an important mechanism in OC tumorigenesis, and the prototypic anti-apoptotic protein, B-cell lymphoma 2 (Bcl-2), is often overexpressed in OC tumors. Gaining a better understanding of the mechanism(s) behind Bcl-2 overexpression and potential extra-anti-apoptotic functions of Bcl-2 could elucidate the importance of elevated Bcl-2 in OC. In the current study, I show through immunohistochemical analysis of normal, benign, and OC tissue sections, that both epithelial and stromal Bcl-2 expression decreases with OC progression. However, the number ...


Novel Constitutively Active Point Mutations In The Nh2 Domain Of Cxcr2 Capture The Receptor In Different Activation States, Giljun Park Dec 2010

Novel Constitutively Active Point Mutations In The Nh2 Domain Of Cxcr2 Capture The Receptor In Different Activation States, Giljun Park

Doctoral Dissertations

Chemokines are structurally and functionally related 8-10 kDa proteins defined by four conserved cysteine residues. They consist of a superfamily of proinflammatory mediators that promote the recruitment of various kinds of leukocytes and other cell types through binding to their respective chemokine receptor, a member of the GPCR family. Abnormal control of this system results in various diseases including tumorigenesis and cancer metastasis. Deregulation can occur when constitutively active mutant (CAM) chemokine receptors are locked in the “on” position. This can lead to cellular transformation/tumorigenesis. A viral CAM receptor, ORF74, that can cause tumors in humans, also has homology ...


Role Of Emerin And Protein Kinase C In Herpes Simplex Nuclear Egress, Natalie Leach Dec 2010

Role Of Emerin And Protein Kinase C In Herpes Simplex Nuclear Egress, Natalie Leach

Theses and Dissertations

The nuclear lamina consists of a mesh-like network of lamin proteins anchored to the inner nuclear membrane by interactions with integral membrane proteins such as emerin. Emerin binding to lamin A/C is one of the interactions that connect the inner nuclear membrane to the lamina. Infection by herpesviruses results in changes in the organization of the nuclear lamina, perhaps in order to facilitate envelopment of capsids at the inner nuclear membrane. In HSV-1 infected cells, alterations to the lamin proteins have been shown to involve pUL34, pUL31, and pUS3 proteins, which are also required for normal nuclear envelopment. We ...


Control Of The Protein And Lipid Content Of The Plasma Membrane By Atp-Binding Cassette Transporter Proteins In S. Cerevisiae, Soraya Sarah Johnson Dec 2010

Control Of The Protein And Lipid Content Of The Plasma Membrane By Atp-Binding Cassette Transporter Proteins In S. Cerevisiae, Soraya Sarah Johnson

Theses and Dissertations

Pdr5 and Yor1 are two ATP-binding cassette transporters regulated by the pleiotropic drug resistance (PDR) network in the yeast Saccharomyces cerevisiae. Recent work from another group demonstrated that a pdr5Δ yor1 strain confers remarkable resistance to a sphingolipid intermediate, phytosphingosine (PHS), which was surprising as loss of these transporters normally leads to elevated drug sensitivity.

PHS is toxic to the cell at high levels due to mislocalization of nutrient permeases, such as the high affinity tryptophan transporter, Tat2. Although the above study suggested that this resistance was due to increased expression of Rsb1, a known mediator of PHS tolerance, this ...


Production, Purification And Crystallization Of Membrane Integrated Multimeric Bax, Adelbert Mark Villoso Dec 2010

Production, Purification And Crystallization Of Membrane Integrated Multimeric Bax, Adelbert Mark Villoso

UNLV Theses, Dissertations, Professional Papers, and Capstones

Apoptosis, or programmed cell death, is a vital process intimately involved in the embryonic development and homeostatic maintenance of all multicellular organisms. The committing step to apoptosis is regulated by a key protein, Bax, and its ability to integrate and form a pore structure at the outer mitochondrial membrane.


Unfortunately, the molecular details of apoptosis remain largely unclear due to the lack of structural data of integral membrane (IM) Bax. Experimental limitations of membrane protein production have slowed the pursuit of an IM-Bax structure simply because standard protocols for producing recombinant IM-Bax are inefficient in producing adequate quantities of IM-Bax ...


Dynamic Remodeling Of The Stressed Heart: Role Of Protein Degradation Pathways, Deborah Vela Dec 2010

Dynamic Remodeling Of The Stressed Heart: Role Of Protein Degradation Pathways, Deborah Vela

UT GSBS Dissertations and Theses (Open Access)

The heart is a remarkable organ. In order to maintain its function, it remodels in response to a variety of environmental stresses, including pressure overload, volume overload, mechanical or pharmacological unloading and hormonal or metabolic disturbances. All these responses are linked to the inherent capacity of the heart to rebuild itself. Particularly, cardiac pressure overload activates signaling pathways of both protein synthesis and degradation. While much is known about regulators of protein synthesis, little is known about regulators of protein degradation in hypertrophy. The ubiquitin-proteasome system (UPS) selectively degrades unused and abnormal intracellular proteins. I speculated that the UPS may ...


Identifying Mechanisms Associated With Innate Immunity In Cows Genetically Susceptible To Mastitis, Alexandra Alida Elliott Dec 2010

Identifying Mechanisms Associated With Innate Immunity In Cows Genetically Susceptible To Mastitis, Alexandra Alida Elliott

Doctoral Dissertations

Mastitis, or mammary gland inflammation, causes the greatest loss in profit for dairy producers. Mastitis susceptibility differs among cows due to environmental, physiological, and genetic factors. Prior research identified a genetic marker in a chemokine receptor, CXCR1, associated with mastitis susceptibility and decreased neutrophil migration. Current research seeks to identify reasons behind mastitis susceptibility by validating this model through in vivo challenge with Streptococcus uberis and studying specific mechanisms causing impaired neutrophil migration. Holstein cows with GG (n=19), GC (n=28), and CC (n=20) genotypes at CXCR1+777 were challenged intramammarily with S. uberis strain UT888. After challenge ...


Virulence Of An Emerging Respiratory Pathogen, Genus Pandoraea, In Vivo And Its Interactions With Lung Epithelial Cells, Gillian Herbert, Anne Costello, Lydia Fabunmi, Kirsten Schaffer, Kevin Kavanagh, Emma M. Caraher, Máire Callaghan, Siobhan Mcclean Nov 2010

Virulence Of An Emerging Respiratory Pathogen, Genus Pandoraea, In Vivo And Its Interactions With Lung Epithelial Cells, Gillian Herbert, Anne Costello, Lydia Fabunmi, Kirsten Schaffer, Kevin Kavanagh, Emma M. Caraher, Máire Callaghan, Siobhan Mcclean

Articles

Pandoraea species have emerged as opportunistic pathogens among cystic fibrosis (CF) and non-CF patients. Pandoraea pulmonicola is the predominant Pandoraea species among Irish CF patients. The objective of this study was to investigate the pathogenicity and potential mechanisms of virulence of Irish P. pulmonicola isolates and strains from other Pandoraea species. Three patients from whom the P. pulmonicola isolates were isolated have since died. The in vivo virulence of these and other Pandoraea strains was examined by determining the ability to kill Galleria mellonella larvae. The P. pulmonicola strains generally were the most virulent of the species tested, with three ...


Cancer-Related Ectopic Expression Of The Bone-Related Transcription Factor Runx2 In Non-Osseous Metastatic Tumor Cells Is Linked To Cell Proliferation And Motility, David T. Leong, Jitesh Pratap, Barry P. Pereira, Saminathan S. Nathan, Jason R. Dobson, Jane B. Lian, Yoshiaki Ito, Gary S. Stein, Manuel Salto-Tellez, Simon M. Cool, Andre J. Van Wijnen, Joleen Lim, Xuewei Goh, Hui S. Kwok, P. Mathijs Voorhoeve Oct 2010

Cancer-Related Ectopic Expression Of The Bone-Related Transcription Factor Runx2 In Non-Osseous Metastatic Tumor Cells Is Linked To Cell Proliferation And Motility, David T. Leong, Jitesh Pratap, Barry P. Pereira, Saminathan S. Nathan, Jason R. Dobson, Jane B. Lian, Yoshiaki Ito, Gary S. Stein, Manuel Salto-Tellez, Simon M. Cool, Andre J. Van Wijnen, Joleen Lim, Xuewei Goh, Hui S. Kwok, P. Mathijs Voorhoeve

Stein, Stein, Lian, vanWijnen Lab Publications

INTRODUCTION: Metastatic breast cancer cells frequently and ectopically express the transcription factor RUNX2, which normally attenuates proliferation and promotes maturation of osteoblasts. RUNX2 expression is inversely regulated with respect to cell growth in osteoblasts and deregulated in osteosarcoma cells.

METHODS: Here, we addressed whether the functional relationship between cell growth and RUNX2 gene expression is maintained in breast cancer cells. We also investigated whether the aberrant expression of RUNX2 is linked to phenotypic parameters that could provide a selective advantage to cells during breast cancer progression.

RESULTS: We find that, similar to its regulation in osteoblasts, RUNX2 expression in MDA-MB-231 ...


Detection Of Flaviviruses And Orthobunyaviruses In Mosquitoes In The Yucatan Peninsula Of Mexico In 2008, Jose A. Farfan-Ale, Maria A. Loroño-Pino, Julian E. Garcia-Rejon, Victor Soto, Ming Lin, Molly Staley, Karin S. Dorman, Lyric C. Bartholomay, Einat Hovav, Bradley J. Blitvich Oct 2010

Detection Of Flaviviruses And Orthobunyaviruses In Mosquitoes In The Yucatan Peninsula Of Mexico In 2008, Jose A. Farfan-Ale, Maria A. Loroño-Pino, Julian E. Garcia-Rejon, Victor Soto, Ming Lin, Molly Staley, Karin S. Dorman, Lyric C. Bartholomay, Einat Hovav, Bradley J. Blitvich

Entomology Publications

A total of 191,244 mosquitoes from 24 species were collected in the Yucatan Peninsula of Mexico from January to December 2008, and tested for the presence of cytopathic virus by virus isolation in Vero cells. Eighteen virus isolates were obtained, all of which were orthobunyaviruses. These were identified by reverse transcription-polymerase chain reaction (RT-PCR) and nucleotide sequencing as Cache Valley virus (n = 17) and South River virus (n = 1). A subset (n = 20,124) of Culex quinquefasciatus collected throughout the year was further tested by RT-PCR using flavivirus-specific primers. Flavivirus RNA was present in this mosquito species year-round. The ...


Quantitative Trait Loci Mapping Reveals Candidate Pathways Regulating Cell Cycle Duration In Plasmodium Falciparum, Heather B. Reilly Ayala, Mark A. Wacker, Geoffrey Siwo, Michael T. Ferdig Oct 2010

Quantitative Trait Loci Mapping Reveals Candidate Pathways Regulating Cell Cycle Duration In Plasmodium Falciparum, Heather B. Reilly Ayala, Mark A. Wacker, Geoffrey Siwo, Michael T. Ferdig

Faculty Publications - Department of Biology and Chemistry

Background: Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results: Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect ...


Molecular Mechanism Of Agc Kinases In Human Malignant, Shaokun Shu Oct 2010

Molecular Mechanism Of Agc Kinases In Human Malignant, Shaokun Shu

Graduate Theses and Dissertations

The maintenance of normal cell function and tissue homeostasis is dependent on the precise regulation of multiple signaling pathways that control cellular decisions to either proliferate, differentiate, arrest cell growth, or initiate programmed cell death (apoptosis). Cancer arises when clones of mutated cells escape this balance and proliferate inappropriately without compensatory apoptosis. Deregulated cell growth occurs as a result of perturbed signal transduction that modulates or alters cellular behavior or function to keep the critical balance between the rate of cell-cycle progression (cell division) and cell growth (cell mass) on one hand, and programmed cell death (apoptosis, autophagy) on the ...


Hippocampal C-Jun-N-Terminal Kinases Serve As Negative Regulators Of Associative Learning, Tessi Sherrin, Thomas Blank, Cathrin Hippel, Martin Rayner, Roger J. Davis, Cedomir Todorovic Oct 2010

Hippocampal C-Jun-N-Terminal Kinases Serve As Negative Regulators Of Associative Learning, Tessi Sherrin, Thomas Blank, Cathrin Hippel, Martin Rayner, Roger J. Davis, Cedomir Todorovic

Davis Lab Publications

In the adult mouse, signaling through c-Jun N-terminal kinases (JNKs) links exposure to acute stress to various physiological responses. Inflammatory cytokines, brain injury and ischemic insult, or exposure to psychological acute stressors induce activation of hippocampal JNKs. Here we report that exposure to acute stress caused activation of JNKs in the hippocampal CA1 and CA3 subfields, and impaired contextual fear conditioning. Conversely, intrahippocampal injection of JNKs inhibitors sp600125 (30 mum) or D-JNKI1 (8 mum) reduced activity of hippocampal JNKs and rescued stress-induced deficits in contextual fear. In addition, intrahippocampal administration of anisomycin (100 mug/mul), a potent JNKs activator, mimicked ...


The Human In 3d: Advanced Morphometric Analysis Of High-Resolution Anatomically Accurate Computed Models, Summer J. Decker Oct 2010

The Human In 3d: Advanced Morphometric Analysis Of High-Resolution Anatomically Accurate Computed Models, Summer J. Decker

Graduate Theses and Dissertations

Computed virtual models of anatomical structures are proving to be of increasing value in clinical medicine, education and research. With a variety of fields focused on craniofacial and pelvic anatomy there is a need for accurate anatomical models. Recent technological advancements in computer and medical imaging technologies have provided the tools necessary to develop three-dimensional (3D) functional models of human anatomy for use in medicine (surgical planning and education), forensics and engineering (computer-aided design (CAD) and finite element analysis).

Traditionally caliper methodologies are used in the quantitative analysis of human anatomy. In order for experts in anatomy and morphometrics to ...


Characterization Of Metastasis-Associated Cell Surface Glycoproteins In Prostate Cancer, Lifang Yang Oct 2010

Characterization Of Metastasis-Associated Cell Surface Glycoproteins In Prostate Cancer, Lifang Yang

Theses and Dissertations in Biomedical Sciences

Prostate cancer (PCa) is a major health problem in males in the United States. Its lethality is mostly attributed to the primary tumor metastasizing to distant sites that are highly resistant to conventional therapies. Serum Prostate Specific Antigen (PSA) is the only protein biomarker used in clinic for prediction of prostate cancer recurrence following local therapies. Nonetheless, PSA lacks the ability to predict the behavior of an individual tumor in an individual patient. Therefore, development of reliable biomarkers for detection of metastatic potential in primary tumors, as well as discovery of new therapeutic targets, is in a great need for ...


Requirement Of Jip1-Mediated C-Jun N-Terminal Kinase Activation For Obesity-Induced Insulin Resistance, Caroline Morel, Claire L. Standen, Dae Young Jung, Susan Gray, Helena Ong, Richard A. Flavell, Jason K. Kim, Roger J. Davis Oct 2010

Requirement Of Jip1-Mediated C-Jun N-Terminal Kinase Activation For Obesity-Induced Insulin Resistance, Caroline Morel, Claire L. Standen, Dae Young Jung, Susan Gray, Helena Ong, Richard A. Flavell, Jason K. Kim, Roger J. Davis

Davis Lab Publications

The c-Jun NH(2)-terminal kinase (JNK) interacting protein 1 (JIP1) has been proposed to act as a scaffold protein that mediates JNK activation. However, recent studies have implicated JIP1 in multiple biochemical processes. Physiological roles of JIP1 that are related to the JNK scaffold function of JIP1 are therefore unclear. To test the role of JIP1 in JNK activation, we created mice with a germ line point mutation in the Jip1 gene (Thr(103) replaced with Ala) that selectively blocks JIP1-mediated JNK activation. These mutant mice exhibit a severe defect in JNK activation caused by feeding of a high-fat ...


The Biogeochemistry Of Submerged Coastal Karst Features In West Central Florida, Keith Michael Garman Sep 2010

The Biogeochemistry Of Submerged Coastal Karst Features In West Central Florida, Keith Michael Garman

Graduate Theses and Dissertations

West Central Florida is a complex karst environment with numerous sinkholes, springs, and submerged cave systems. Many of these karst features are anchialine, located within the subterranean estuary where freshwater and saltwater mix. Water quality data and/or fauna data were obtained from twenty-one karst features and their associated cave systems. The anchialine karst environment of the study area has a wide range of habitats with measured salinities ranging from freshwater at <0.2 ppt to sulfidic, hypersaline water at 38.5 ppt and measured pH readings ranging from 6.39 in water impacted by sulfur oxidizing bacteria to 10.3 in an isolated room of a cave. Stygobitic crustaceans were identified in conduits extending beneath the Gulf of Mexico supporting the hypotheses that freshwater crustaceans could survive higher sea levels in freshwater conduits beneath saltwater. The fauna associated with the anchialine cave systems included Sabellidae and Polychaeta worms, hydroids, cnidarians and hydrobiid snails. Jewfish Sink, like other anaerobic marine basins that were submarine springs, has four zones: oxic zone, transition zone, upper anoxic zone and anoxic bottom water. The upper zones have seasonal water quality variations from winter cooling and sinking of surface water and changes in the microbial communities. Activity of sulfate reducing bacteria is carbon limited in the anoxic zones, where sulfate reduction is the major metabolic process, and primary production is phosphate limited in the oxic zones. Organic input from the Gulf of Mexico drives the bacterial anaerobic ecosystem, resulting in a “sulfide pump”, in which sulfide percolates upward removing oxygen from the overlying sediment.


Identification Of An Archaeal Presenilin-Like Intramembrane Protease, Celia Torres-Arancivia, Carolyn M. Ross, Jose Chavez, Zahra Assur, Georgia Dolios, Filippo Mancia, Iban Ubarretxena-Belandia Sep 2010

Identification Of An Archaeal Presenilin-Like Intramembrane Protease, Celia Torres-Arancivia, Carolyn M. Ross, Jose Chavez, Zahra Assur, Georgia Dolios, Filippo Mancia, Iban Ubarretxena-Belandia

Publications and Research

Background: The GXGD-type diaspartyl intramembrane protease, presenilin, constitutes the catalytic core of the c-secretase multi-protein complex responsible for activating critical signaling cascades during development and for the production of b-amyloid peptides (Ab) implicated in Alzheimer’s disease. The only other known GXGD-type diaspartyl intramembrane proteases are the eukaryotic signal peptide peptidases (SPPs). The presence of presenilin-like enzymes outside eukaryots has not been demonstrated. Here we report the existence of presenilin-like GXGD-type diaspartyl intramembrane proteases in archaea.

Methodology and Principal Findings: We have employed in vitro activity assays to show that MCMJR1, a polytopic membrane protein from the archaeon Methanoculleus marisnigri ...


The Roles Of Nitric Oxide Synthases (Nos) In Endochondral Bone Formation, Qian Yan Sep 2010

The Roles Of Nitric Oxide Synthases (Nos) In Endochondral Bone Formation, Qian Yan

Electronic Thesis and Dissertation Repository

Longitudinal growth of endochondral bones is controlled by the cartilage growth plate. Chondrocyte proliferation and hypertrophy, vascular invasion, formation of ossification centers and cartilage replacement by bone tissue are all important processes required for normal growth. These biological processes have to be tightly regulated or disturbances will lead to skeletal diseases. A large number of genes, growth factors and hormones have been implicated in the regulation of growth plate biology, however, less is known about the intracellular signaling pathways involved. Nitric oxide (NO) has been identified as a regulator of cellular proliferation, differentiation, migration, survival and metabolism in multiple cell ...


Mitochondrial Dysfunction And Akt Isoform-Specific Regulation In 3t3-L1 Adipocytes: A Dissertation, Xiarong Shi Sep 2010

Mitochondrial Dysfunction And Akt Isoform-Specific Regulation In 3t3-L1 Adipocytes: A Dissertation, Xiarong Shi

GSBS Dissertations and Theses

Excess food consumption and/or lack of exercise have dramatically contributed to the prevalence of overweight (BMI≥25) and obesity (BMI≥30) in modern society. The obesity epidemic has been linked to the rise in type 2 diabetes. In recent years, evidence has pointed to a close association between mitochondrial dysfunction in white adipose tissue (WAT) and insulin resistance, a key feature of type 2 diabetes. In order to dissect the cause and effect relationship between WAT mitochondrial dysfunction and insulin resistance, we established an in vitro cell line system to investigate this issue. We artificially introduced mitochondrial dysfunction in ...


Cep290 Tethers Flagellar Transition Zone Microtubules To The Membrane And Regulates Flagellar Protein Content, Branch Craige, Che-Chia Tsao, Dennis R. Diener, Yuqing Hou, Karl-Ferdinand Lechtreck, Joel L. Rosenbaum, George B. Witman Sep 2010

Cep290 Tethers Flagellar Transition Zone Microtubules To The Membrane And Regulates Flagellar Protein Content, Branch Craige, Che-Chia Tsao, Dennis R. Diener, Yuqing Hou, Karl-Ferdinand Lechtreck, Joel L. Rosenbaum, George B. Witman

Witman Lab Publications

Mutations in human CEP290 cause cilia-related disorders that range in severity from isolated blindness to perinatal lethality. Here, we describe a Chlamydomonas reinhardtii mutant in which most of the CEP290 gene is deleted. Immunoelectron microscopy indicated that CEP290 is located in the flagellar transition zone in close association with the prominent microtubule-membrane links there. Ultrastructural analysis revealed defects in these microtubule-membrane connectors, resulting in loss of attachment of the flagellar membrane to the transition zone microtubules. Biochemical analysis of isolated flagella revealed that the mutant flagella have abnormal protein content, including abnormal levels of intraflagellar transport proteins and proteins associated ...


The Mitosis-To-Interphase Transition Is Coordinated By Cross Talk Between The Sin And Mor Pathways In Schizosaccharomyces Pombe, Samriddha Ray, Kazunori Kume, Sneha Gupta, Wanzhong Ge, Mohan Balasubramanian, Dai Hirata, Dannel Mccollum Sep 2010

The Mitosis-To-Interphase Transition Is Coordinated By Cross Talk Between The Sin And Mor Pathways In Schizosaccharomyces Pombe, Samriddha Ray, Kazunori Kume, Sneha Gupta, Wanzhong Ge, Mohan Balasubramanian, Dai Hirata, Dannel Mccollum

GSBS Student Publications

The mechanisms that regulate cytoskeletal remodeling during the transition between mitosis and interphase are poorly understood. In fission yeast the MOR pathway promotes actin polarization to cell tips in interphase, whereas the SIN signaling pathway drives actomyosin ring assembly and cytokinesis. We show that the SIN inhibits MOR signaling in mitosis by interfering with Nak1 kinase-mediated activation of the most downstream MOR component, the NDR family kinase Orb6. Inactivation of the MOR may be a key function of the SIN because attenuation of MOR signaling rescued the cytokinetic defects of SIN mutants and allowed weak SIN signaling to trigger ectopic ...


Endothelial Cell Cortactin Phosphorylation By Src Contributes To Polymorphonuclear Leukocyte Transmigration In Vitro, L. Yang, Jennifer R. Kowalski, X. Zhan, S. M. Thomas, F. W. Luscinskas Sep 2010

Endothelial Cell Cortactin Phosphorylation By Src Contributes To Polymorphonuclear Leukocyte Transmigration In Vitro, L. Yang, Jennifer R. Kowalski, X. Zhan, S. M. Thomas, F. W. Luscinskas

Jennifer Kowalski

The underlying mechanisms that regulate leukocyte transendothelial migration through the vascular endothelium remain unclear. Cortactin is a substrate of Src tyrosine kinases and a regulator of cytoskeletal dynamics. Previous studies demonstrated a role for Src phosphorylation of cortactin in clustering of E-selectin and intercellular cell adhesion molecule-1 around adherent leukocytes. In the current study, we used an in vitro flow model to investigate the role of Src-induced cortactin phosphorylation in endothelium during polymorphonuclear leukocyte (PMN) transmigration through human umbilical vein endothelium (HUVEC) monolayers preactivated with tumor necrosis factor-{alpha}. Inhibition of Src in HUVEC using Src kinase inhibitors PP2 and ...


Cortactin Regulates Cell Migration Via Activation Of N-Wasp, Jennifer Kowalski, C. Egile, S. Gil, S. Snapper, R. Li, S. Thomas Sep 2010

Cortactin Regulates Cell Migration Via Activation Of N-Wasp, Jennifer Kowalski, C. Egile, S. Gil, S. Snapper, R. Li, S. Thomas

Jennifer Kowalski

Cortactin is an actin-associated scaffolding protein that regulates cell migration. Amplification of the human gene, EMS1, has been detected in breast, head and neck tumors, where it correlates with increased invasiveness. Cortactin can regulate actin dynamics directly via its N-terminal half, which can bind and activate the Arp2/3 complex. The C-terminal portion of cortactin, however, is thought to have limited function in its regulation of the actin polymerization machinery. In this report, we identify a role for the cortactin C-terminus in regulating cell migration and, more specifically, actin dynamics. Overexpression of either full-length cortactin or cortactin C-terminus is sufficient ...


Distinct Macrophage Subpopulations Regulate Viral Encephalitis But Not Viral Clearance In The Cns, Christina D. Steel, Woong-Ki Kim, Larry Sanford, Laurie Wellman, Sandra Burnett, Nico Van Rooijen, Rochard P. Ciavarra Sep 2010

Distinct Macrophage Subpopulations Regulate Viral Encephalitis But Not Viral Clearance In The Cns, Christina D. Steel, Woong-Ki Kim, Larry Sanford, Laurie Wellman, Sandra Burnett, Nico Van Rooijen, Rochard P. Ciavarra

Biological Sciences Faculty Publications

Intranasal application of vesicular stomatitis virus (VSV) induces acute encephalitis characterized by a pronounced myeloid and T cell infiltrate. The role of distinct phagocytic populations on VSV encephalitis was therefore examined in this study. Ablation of peripheral macrophages did not impair VSV encephalitis or viral clearance from the brain, whereas, depletion of splenic marginal dendritic cells impaired this response and enhanced morbidity/mortality. Selective depletion of brain perivascular macrophages also suppressed this response without altering viral clearance. Thus, two anatomically distinct phagocytic populations regulate VSV encephalitis in a non-redundant fashion although neither population is essential for viral clearance in the ...


Münch, Morphology, Microfluidics – Our Structural Problem With The Phloem [Review Article], Michael Knoblauch, Winfried S. Peters Aug 2010

Münch, Morphology, Microfluidics – Our Structural Problem With The Phloem [Review Article], Michael Knoblauch, Winfried S. Peters

Winfried S. Peters

The sieve tubes of the phloem are enigmatic structures. Their role as channels for the distribution of assimilates was established in the 19th century, but their sensitivity to disturbations has hampered the elucidation of their transport mechanisms and its regulation ever since. Ernst Münch's classical monograph of 1930 is generally regarded as the first coherent theory of phloem transport, but the ‘Münchian’ pressure flow mechanism had been discussed already before the turn of the century. Münch's impact rather rested on his simple physical models of the phloem that visualized pressure flow in an intuitive way, and we argue ...


The Role Of The Exocyst In Exocytosis And Cell Migration, Jianglan Liu Aug 2010

The Role Of The Exocyst In Exocytosis And Cell Migration, Jianglan Liu

Publicly Accessible Penn Dissertations

The exocyst, an evolutionarily conserved octameric protein complex, plays a crucial role in the tethering of post-Golgi secretory vesicles to the plasma membrane for exocytosis and cell migration. How the exocyst is targeted to sites of exocytosis and how this complex regulates cell migration are poorly understood. I have carried out experiments to characterize Exo70, a component of the exocyst complex. Firstly, I found that Exo70 directly interacts with phosphatidylinositol 4,5-bisphosphate through positively charged residues at its C-terminus, and this interaction is critical for the plasma membrane targeting of Exo70. Using the ts045 vesicular stomatitis virus glycoprotein trafficking assay ...


Defining The Role Of Il-15 Trans-Presentation By Distinct Cell-Types During The Development And Homeostasis Of Natural Killer And Invariant Natural Killer T Cells, Eliseo F. Castillo Aug 2010

Defining The Role Of Il-15 Trans-Presentation By Distinct Cell-Types During The Development And Homeostasis Of Natural Killer And Invariant Natural Killer T Cells, Eliseo F. Castillo

UT GSBS Dissertations and Theses (Open Access)

The immuno-regulatory functions displayed by NK and iNKT cells have highlighted their importance as key lymphocytes involved in innate and adaptive immunity. Therefore, understanding the dynamics influencing the generation of NK and iNKT cells is extremely important. IL-15 has been shown to provide a critical signal throughout the development and homeostasis of NK and iNKT cells; however, the cellular source of IL-15 has remained unclear. In this investigation, I provide evidence that the cell-type providing IL-15 to NK and iNKT cells via trans-presentation is determined by the tissue site and the maturation status of NK and iNKT cells. For NK ...


The Role Of Tyrosine Phosphorylation In The Functions Of The Tumor Suppressor Gprc5a, Xiaofeng Lin Aug 2010

The Role Of Tyrosine Phosphorylation In The Functions Of The Tumor Suppressor Gprc5a, Xiaofeng Lin

UT GSBS Dissertations and Theses (Open Access)

The retinoic acid inducible G protein coupled receptor family C group 5 type A (GPRC5A) is expressed preferentially in normal lung tissue but its expression is suppressed in the majority of human non-small cell lung cancer cell lines and tissues. This differential expression has led to the idea that GPRC5A is a potential tumor suppressor. This notion was supported by the finding that mice with a deletion of the Gprc5a gene develop spontaneous lung tumors. However, there are various tumor cell lines and tissue samples, including lung, that exhibit higher GPRC5A expression than normal tissues and some reports by other ...