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Full-Text Articles in Molecular Biology

Phosphorylation And Ubiquitination Events In The Regulation Of Gap Junction Protein Connexin 43, Rachel Margraf May 2018

Phosphorylation And Ubiquitination Events In The Regulation Of Gap Junction Protein Connexin 43, Rachel Margraf

Eckardt Scholars Projects

Connexin 43 (Cx43) accrual and removal from gap junctions is a complex progress regulated by specific phosphorylations, ubiquitinations and binding and release of regulatory proteins on the C- terminal tail of Cx43. In Thévenin & Margraf et al., 2017, our lab showed that specific phosphorylations on the C-terminal tail of Cx43 occur before and after the binding and release of the scaffold protein Zona Occludens-1 (ZO-1). In Kells-Andrews & Margraf et al., 2018 we show that K63-poly-ubiquitination occurs on residues K264 and K303 of the Cx43 C-terminal tail. This undergraduate thesis summarizes the immunofluorescence imaging and quantification I have contributed to ...


Cell-Bioactive Glass Scaffold Interactions: Biological Response To Chemistry And Topology, Tia Kowal Jan 2017

Cell-Bioactive Glass Scaffold Interactions: Biological Response To Chemistry And Topology, Tia Kowal

Theses and Dissertations

The medical community is transitioning from replacement to regeneration with the advent of tissue engineering; yet, it is not well understood how cells of the body can interact with the biologically active scaffolds used to guide tissue regeneration. In order to design the ideal material for the regeneration of different tissues, we must first have a comprehensive understanding of the fundamental mechanisms that allow cells to not only attach to these bioscaffold materials, but to also take cues from them as to what tissue should be regenerated. The Jain lab in Lehigh University’s Material Science and Engineering department developed ...


Regulation Of Gap Junction Internalization And Degradation, Rachael Kells Andrews Jan 2017

Regulation Of Gap Junction Internalization And Degradation, Rachael Kells Andrews

Theses and Dissertations

Gap junctions (GJs) are channels that traverse the plasma membrane of neighboring cells and provide direct intercellular communication (GJIC) in multi-cellular organisms. GJIC is a prerequisite for coordinated development, differentiation and tissue function; disruption of which can cause disease. Post-translational modification is essential for regulation of GJ trafficking, gating, internalization, and degradation. In the dissertation work presented here (1) I show the role of clathrin-mediated endocytosis (CME) on acute Cx43 (a GJ protein) GJ internalization. I treated primary pulmonary artery endothelial cells (pPAECs) with CME inhibitors after vascular endothelial growth factor (VEGF) stimulation and analyzed internalization patterns of GJs. VEGF ...


The Regenerating Fin As A Model To Examine The Skeletal Defects Of Roberts Syndrome, Rajeswari Banerji Jan 2017

The Regenerating Fin As A Model To Examine The Skeletal Defects Of Roberts Syndrome, Rajeswari Banerji

Theses and Dissertations

Roberts Syndrome (RBS) is a human developmental disorder characterized by craniofacial abnormalities, limb malformation and often severe mental retardation. RBS arises from mutations in the cohesin auxiliary factor ESCO2 that targets the SMC3 subunit of the cohesin complex. Mutations in cohesin subunits and a subset of cohesin auxiliary factors gives rise to a related developmental malady termed Cornelia de Lange Syndrome (CdLS). They are collectively termed cohesinopathies since both disorders comprise overlapping phenotypes and the causative genes for both syndromes perform common activities. The underlying cause of CdLS is largely modeled as occurring through transcriptional deregulation. Whereas, the mechanism that ...


Hapln1a-Ecm Mediates Cx43 Dependent Skeletal Phenotypes During Zebrafish Fin Regeneration, Jayalakshmi Govindan Jan 2016

Hapln1a-Ecm Mediates Cx43 Dependent Skeletal Phenotypes During Zebrafish Fin Regeneration, Jayalakshmi Govindan

Theses and Dissertations

Skeletal development is a tightly regulated process and requires proper communication between the cells for efficient exchange of information. Cell–cell communication, facilitating the exchange of small metabolites, ions and second messengers, takes place via aqueous proteinaceous channels called gap junctions. Connexins (Cx) are the subunits of a gap junction channel, and Cx43 is the major Cx expressed in bone cells. Mutations in human and mouse Cx43 result in a severe skeletal disorder called oculodentaldigital dysplasia (ODDD) characterized by craniofacial abnormalities and limb deformities. Mutations in zebrafish cx43 produces the short fin (sof b123) phenotype and is characterized by short ...


Understanding Connexin43 Dependent Skeletal Morphogenesis - Progress Made And Promises Ahead, Joyita Bhadra Jan 2016

Understanding Connexin43 Dependent Skeletal Morphogenesis - Progress Made And Promises Ahead, Joyita Bhadra

Theses and Dissertations

Skeletal morphogenesis is a complex process through which bones grow to their correct size and shape and find their location in the body. A number of signaling pathways are involved in proper regulation of this process. Among them, Gap Junctional Intercellular Communication (GJIC) is important for proper bone growth and patterning. In our lab, we use regenerating caudal fin of a zebrafish to study skeletal morphogenesis. Our examination of a fin length mutant sofb123 has identified a gap junction protein called Connexin43 (Cx43). Cx43 regulates growth and patterning during regeneration by promoting cell proliferation and suppressing joint formation, respectively. The ...


Separation Of Cohesin-Dependent Pathways In Saccharomyces Cerevisiae, Kevin Tong Jan 2015

Separation Of Cohesin-Dependent Pathways In Saccharomyces Cerevisiae, Kevin Tong

Theses and Dissertations

All living organisms consist of cells that undergo a cell cycle to grow and divide so that the resulting daughter cells are exact replicas of the parent cell. To achieve this feat, a parent cell will first replicate its DNA into two identical copies during S phase of the cell cycle, and then segregate those copies into two daughter cells during anaphase of mitosis. Ensuring that daughter cells receive identical sets of chromosomes requires mechanisms that check for accurate DNA replication, compaction of replicated sister chromatids, and proper segregation of chromosomes. The protein complex termed cohesins identify replicated sister chromatids ...


From Computer To Bench Work: Is There Evidence For A Gene Product Upstream Of Gene Product 1 In Mycobacteriophage Euphoria?, Lauren Kraft May 2014

From Computer To Bench Work: Is There Evidence For A Gene Product Upstream Of Gene Product 1 In Mycobacteriophage Euphoria?, Lauren Kraft

Eckardt Scholars Projects

No abstract provided.


Signals And Molecular Mechanisms Involved In Gap Junction Internalization, John Fong Jan 2014

Signals And Molecular Mechanisms Involved In Gap Junction Internalization, John Fong

Theses and Dissertations

A gap junction (GJ) is formed when two hemi-channels from two apposed cells dock in the extracellular space. GJs mediate cell-cell communication by allowing direct transfer of molecules (<1.5 kDa) from one cell to the other through these channels. Direct intercellular communication mediated by gap junction channels is a hallmark of normal cell and tissue physiology. In addition, GJs are likely to significantly contribute to physical cell-cell coupling. Clearly, these cellular functions require precise modulation. Defects in GJ intercellular communication lead to serious illnesses. Interestingly, docked GJ channels cannot be separated under physiological conditions. We previously described that cells efficiently internalize their GJs in a clathrin-mediated endocytic process to form double-membrane vesicles termed annular gap junctions (AGJs) or connexosomes (Baker et al., 2008; Gumpert et al., 2008; Piehl et al., 2007). How this complex process is achieved mechanistically in a cell is still unclear. In this dissertation, (1) I elucidate the signals and molecular mechanisms that are involved in GJ internalization. By mutagenesis, I identified two functional tyrosine-based sorting signals (YXX) in the Cx43 (a GJ protein) C-terminal domain that interact with the classical clathrin adaptor protein, adaptor protein complex-2 (AP-2), to recruit clathrin to the plasma membrane (PM), followed by GJ endocytosis. Mutating these two YXX sorting motifs results in inhibition of AP-2 binding, increased accumulation of GJ channels in the PM, impairment of GJ internalization, and increased Cx43 protein half-life. (2) In order to understand the Cx43 protein modifications that initiate GJ endocytosis, I treated mouse embryonic stem cells (mES) with epidermal growth factor (EGF) and analyzed Cx43 phosphorylation. I found that EGF activates MAPK and PKC to phosphorylate Cx43 at Ser262, Ser279/282, and Ser368. These phosphorylation events induce inhibition of GJIC and trigger GJ internalization. Pharmacological inhibition of MAPK counteracts with EGF to maintain GJIC and to inhibit EGF-induced GJ internalization. Work conducted during my PhD contributed to three primary research papers (two published, one submitted) and three review articles.


The Role Of Chl1 Dna Helicase In Cohesion Deposition And Establishment, Soumya Rudra Jan 2014

The Role Of Chl1 Dna Helicase In Cohesion Deposition And Establishment, Soumya Rudra

Theses and Dissertations

Sister chromatid cohesion is crucial for the accurate transmission of genetic material during cell division. The conserved family of cohesin proteins that mediate sister chromatid tethering reactions require Scc2, Scc4 for chromatin association and Eco1 for conversion to a tethering competent state. The mechanism by which cohesin proteins mediate cohesion establishment between newly replicated sister chromatids remains elusive. Popular models posit that cohesins loaded in front of the replication fork is modified by Eco1 and conformational changes in the cohesin complex allows the replication fork to pass through cohesin barriers thereby converting cohesins into a cohesion competent state to enable ...


Elucidating The Anti-Inflammatory Roles Of Heparin And Shear Stress In Atherosclerosis, Joshua B. Slee Jan 2014

Elucidating The Anti-Inflammatory Roles Of Heparin And Shear Stress In Atherosclerosis, Joshua B. Slee

Theses and Dissertations

Atherosclerosis, an inflammatory disease characterized by the hardening of the arteries and often attributed to poor life style choices, is the leading cause of death in the United States, Europe, and most of Asia. This disease is caused by injury to the arterial wall, causing an inflammatory response which can become misregulated, and over the lifetime of an individual can lead to plaque formation. Hallmarks of atherosclerotic plaque formation include the proliferation and migration of vascular smooth muscle cells (VSMCs) to the injured site in the arterial wall and endothelial cell dysfunction, both of which contribute to plaque formation. In ...


Determining How Defects In Connexin 43 Cause Skeletal Diseases, Quynh V. Ton Jan 2014

Determining How Defects In Connexin 43 Cause Skeletal Diseases, Quynh V. Ton

Theses and Dissertations

The zebrafish fin is composed of multiple bony fin rays. Each fin ray is comprised of multiple segments separated by joints. Regulatory mechanisms that control joint morphogenesis and ray segment length in zebrafish fins are not fully understood. We utilize the fin length mutants short fin (sof b123) and another long fin (alf dty86) to provide insight into these processes. The sof b123 mutant has short fins and short segments due to a mutation in the gap junction protein gene connexin43 (cx43). In contrast, the alf dty86 mutant has long fins, long segments, and over-expression of cx43. Thus, the two ...


Linking Cell Cycle Delays To Apoptosis In Cancer Cells, Victoria Caruso Silva Jan 2014

Linking Cell Cycle Delays To Apoptosis In Cancer Cells, Victoria Caruso Silva

Theses and Dissertations

For any cell within a multicellular organism, a multitude of environmental signals influence cell fate. The context and timing of these often redundant and overlapping signaling cascades govern whether a cell will differentiate, reproduce or die. Some of these signaling networks form checkpoints that sense and respond to the needs of the individual cell. In cancer, often one or more of these signals is missing or mutated which results in uncontrolled cell growth, usually to the detriment of the organism. Understanding the signaling events that normally control cell proliferation and death is important for controlling and eliminating cancerous cells. Microtubule ...


Applying Automated Tracking Of Microtubules By Plustiptracker, Cody Andrew Molnar Jan 2014

Applying Automated Tracking Of Microtubules By Plustiptracker, Cody Andrew Molnar

Theses and Dissertations

Automated microtubule tracking programs have potential as a powerful tool for analyzing a variety of experimental conditions. Here, we apply one such program, plusTipTracker, developed by the Danuser lab, to investigate the effects of stathmin and p27 depletion on microtubule dynamics. We also apply plusTipTracker to analyze the relationship between p53 and taxol on microtubule dynamics. By developing a standardized procedure, we were able to streamline the detection and analysis of these conditions much faster than is possible by hand. We found that both p27 and stathmin depletion alter microtubule dynamics. This is proposed to be a result of p27 ...


Signaling Networks That Induce Melanomagenesis And Metastasis That Can Be Exploited For Therapeutic Benefit, Eden Elizabeth Tanzosh Jan 2013

Signaling Networks That Induce Melanomagenesis And Metastasis That Can Be Exploited For Therapeutic Benefit, Eden Elizabeth Tanzosh

Theses and Dissertations

Melanoma is the most lethal type of skin cancer and originates in melanocytes, cells that produce the pigment melanin. Five year survival rates are particularly high for this type of cancer if the tumor is diagnosed and treated early. However, survival rates decline significantly if the tumor is allowed to metastasize. Frequency of melanoma has risen over recent years, especially in young people. Much progress has been made in treating melanoma; however, tumor recurrence is frequently seen in patients after treatment has concluded. The leading genes that are found to be mutated in melanoma are v-Raf murine sarcoma viral oncogene ...


Characterization Of The Ribosomal Protein L22e Family In Drosophila Melanogaster: Evidence For Functional Diversification Of Duplicated Ribosomal Protein Genes, Michael G. Kearse Jan 2013

Characterization Of The Ribosomal Protein L22e Family In Drosophila Melanogaster: Evidence For Functional Diversification Of Duplicated Ribosomal Protein Genes, Michael G. Kearse

Theses and Dissertations

Gene duplication is a contributing factor to genome evolution in eukaryotes. With an additional copy, selective pressure is relieved, allowing for accumulation of genetic variation and possible development of new or altered functions. Ribosomal protein (Rp) genes are a common class of duplicated genes found throughout eukaryotes. Typically encoding highly similar or identical proteins at separate loci, duplicated Rps were originally thought to be redundant and to relieve the high demand for translation. However, recent reports in yeast have shown phenotypic differences between Rp paralogue knockouts, suggesting functional non-redundancy. Little effort has been devoted toward elucidating the function of Rp ...


The Sperm Equatorial Segment: An Organizing Center For Sperm Protein Relocalization And Facilitation Of Fertilization, Wutigri Nimlamool Jan 2013

The Sperm Equatorial Segment: An Organizing Center For Sperm Protein Relocalization And Facilitation Of Fertilization, Wutigri Nimlamool

Theses and Dissertations

The equatorial segment (the EqS) of mammalian sperm has been reported to be a site for sperm-egg fusion initiation. The subdomain, called the equatorial subsegment (the EqSS), within the EqS has been identified in sperm of many species; however, there is no clear report showing the existence of this subdoman in human sperm. The EqS has been hypothesized to be an organizing center for assembly of molecular complexes required for gamete interaction and fusion. Several sperm proteins have been reported to relocate to the EqS to make this region fusion competent. However, molecular mechanisms that regulate relocalization of sperm proteins ...


One Gene, Two Products: An Investigation Of The Alternative Spliced Variant Rpl22-Like Short In Drosophila Melanogaster, Alex S. Chen May 2012

One Gene, Two Products: An Investigation Of The Alternative Spliced Variant Rpl22-Like Short In Drosophila Melanogaster, Alex S. Chen

Eckardt Scholars Projects

No abstract provided.


Identification And Characterization Of Site-Directed A-To-I Rna Editing Targets, Christina Priska Godfried Sie Jan 2012

Identification And Characterization Of Site-Directed A-To-I Rna Editing Targets, Christina Priska Godfried Sie

Theses and Dissertations

No abstract provided.


Integration Of Transcriptomic And Metabolomic Profiling To Identify Mechanisms And Biomarkers Of Statin-Induced Myopathy, Jeffrey David Vassallo Jan 2012

Integration Of Transcriptomic And Metabolomic Profiling To Identify Mechanisms And Biomarkers Of Statin-Induced Myopathy, Jeffrey David Vassallo

Theses and Dissertations

No abstract provided.


Alu Repetitive Elements Transcribed By Rna Polymerase Iii Are A-To-I Rna Editing Targets, Dylan Edward Dupuis Jan 2012

Alu Repetitive Elements Transcribed By Rna Polymerase Iii Are A-To-I Rna Editing Targets, Dylan Edward Dupuis

Theses and Dissertations

No abstract provided.


Role(S) Of Sperm Membrane Associated ¥Á-L-Fucosidase In Fertilization, Kamonrat Phopin Jan 2012

Role(S) Of Sperm Membrane Associated ¥Á-L-Fucosidase In Fertilization, Kamonrat Phopin

Theses and Dissertations

No abstract provided.


Stathmin Depletion From Cells Lacking P53 Leads To Delayed Cell Cycle Progression And Apoptosis Due To Increased Microtubule Stability, Bruce Knighton Carney Jan 2011

Stathmin Depletion From Cells Lacking P53 Leads To Delayed Cell Cycle Progression And Apoptosis Due To Increased Microtubule Stability, Bruce Knighton Carney

Theses and Dissertations

No abstract provided.


Strategies For Modifying The Genomes Of Alternate Adenoviral Serotypes To Allow Growth In Per.C6[Superscript Tm] Cells, Nancy M. Dougherty Jan 2004

Strategies For Modifying The Genomes Of Alternate Adenoviral Serotypes To Allow Growth In Per.C6[Superscript Tm] Cells, Nancy M. Dougherty

Theses and Dissertations

No abstract provided.


Development Of A Novel Assay For The Detection Of Viral Stability In Lyophilized Vaccines, Jeffrey Thomas Blue Jan 1999

Development Of A Novel Assay For The Detection Of Viral Stability In Lyophilized Vaccines, Jeffrey Thomas Blue

Theses and Dissertations

No abstract provided.


Studies To Identify Factors Involved In Processing Of 28s Rrna In The Gap Region, Lynn Roginsky Jan 1999

Studies To Identify Factors Involved In Processing Of 28s Rrna In The Gap Region, Lynn Roginsky

Theses and Dissertations

No abstract provided.


Identification Of Tissue Specific Expression And Polymorphic Differences In Neuropeptide Y Receptors Y1 And Y5, Avery R. Soderman Jan 1999

Identification Of Tissue Specific Expression And Polymorphic Differences In Neuropeptide Y Receptors Y1 And Y5, Avery R. Soderman

Theses and Dissertations

No abstract provided.


Evidence That Heparin Affects Protein Levels Of Three Extracellular Matrix Glycoproteins, Kimberly J. Sebo Jan 1996

Evidence That Heparin Affects Protein Levels Of Three Extracellular Matrix Glycoproteins, Kimberly J. Sebo

Theses and Dissertations

No abstract provided.


The Use Of Random Peptide Libraries To Define The Epitopes Of Two Hiv Gp41 Monoclonal Antibodies, Beth Arnold Jan 1996

The Use Of Random Peptide Libraries To Define The Epitopes Of Two Hiv Gp41 Monoclonal Antibodies, Beth Arnold

Theses and Dissertations

No abstract provided.


Effects Of Temperature And Ethanol On Maturation And Germination Of Trichoderma Reesei, Kum Kum Sharma Jan 1992

Effects Of Temperature And Ethanol On Maturation And Germination Of Trichoderma Reesei, Kum Kum Sharma

Theses and Dissertations

No abstract provided.