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Articles 1 - 30 of 489

Full-Text Articles in Cell Biology

The Central Role Of The Tail In Switching Off 10s Myosin Ii Activity, Shixin Yang, Kyounghwan Lee, John L. Woodhead, Osamu Sato, Mitsuo Ikebe, Roger Craig Sep 2019

The Central Role Of The Tail In Switching Off 10s Myosin Ii Activity, Shixin Yang, Kyounghwan Lee, John L. Woodhead, Osamu Sato, Mitsuo Ikebe, Roger Craig

Radiology Publications and Presentations

Myosin II is a motor protein with two heads and an extended tail that plays an essential role in cell motility. Its active form is a polymer (myosin filament) that pulls on actin to generate motion. Its inactive form is a monomer with a compact structure (10S sedimentation coefficient), in which the tail is folded and the two heads interact with each other, inhibiting activity. This conformation is thought to function in cells as an energy-conserving form of the molecule suitable for storage as well as transport to sites of filament assembly. The mechanism of inhibition of the compact molecule ...


Promotion Of Adipogenesis By Jmjd6 Requires The At Hook-Like Domain And Is Independent Of Its Catalytic Function, Pablo Reyes-Gutierrez, Jake W. Carrasquillo-Rodriguez, Anthony N. Imbalzano Aug 2019

Promotion Of Adipogenesis By Jmjd6 Requires The At Hook-Like Domain And Is Independent Of Its Catalytic Function, Pablo Reyes-Gutierrez, Jake W. Carrasquillo-Rodriguez, Anthony N. Imbalzano

Open Access Articles

JMJD6 is a member of the Jumonji C domain containing enzymes that demethylate and/or hydroxylate substrate proteins. It is a multi-functional protein that has been implicated in disparate aspects of transcriptional and post-transcriptional control of gene expression, including but not limited to enhancer and promoter binding, release of paused RNA polymerase II, control of splicing, and interaction with the translation machinery. JMJD6 contributes to multiple aspects of animal development, including adipogenesis modeled in culture. We mutated proposed or characterized domains in the JMJD6 protein to better understand the requirement for JMJD6 in adipogenic differentiation. Mutation of JMJD6 amino acids ...


Calcineurin Broadly Regulates The Initiation Of Skeletal Muscle-Specific Gene Expression By Binding Target Promoters And Facilitating The Interaction Of The Swi/Snf Chromatin Remodeling Enzyme, Hanna Witwicka, Jumpei Nogami, Sabriya A. Syed, Kazumitsu Maehara, Teresita Padilla-Benavides, Yasuyuki Ohkawa, Anthony N. Imbalzano Jul 2019

Calcineurin Broadly Regulates The Initiation Of Skeletal Muscle-Specific Gene Expression By Binding Target Promoters And Facilitating The Interaction Of The Swi/Snf Chromatin Remodeling Enzyme, Hanna Witwicka, Jumpei Nogami, Sabriya A. Syed, Kazumitsu Maehara, Teresita Padilla-Benavides, Yasuyuki Ohkawa, Anthony N. Imbalzano

Open Access Articles

Calcineurin (Cn) is a calcium-activated serine/threonine protein phosphatase that is broadly implicated in diverse cellular processes, including the regulation of gene expression. During skeletal muscle differentiation, Cn activates the NFAT transcription factor but also promotes differentiation by counteracting the negative influences of protein kinase C beta (PKCbeta) via dephosphorylation and activation of BRG1, an enzymatic subunit of the mammalian SWI/SNF ATP-dependent chromatin remodeling enzyme. Here we identified four major temporal patterns of Cn-dependent gene expression in differentiating myoblasts and determined that Cn is broadly required for the activation of the myogenic gene expression program. Mechanistically, Cn promotes gene ...


Smooth Muscle Cell-Specific Tmem16a Deletion Does Not Alter Ca2+ Signaling, Uterine Contraction, Gestation Length Or Litter Size In Micedagger, Mingzi Qu, Ping Lu, Karl D. Bellve, Kevin E. Fogarty, Lawrence M. Lifshitz, Fangxiong Shi, Ronghua Zhuge Jun 2019

Smooth Muscle Cell-Specific Tmem16a Deletion Does Not Alter Ca2+ Signaling, Uterine Contraction, Gestation Length Or Litter Size In Micedagger, Mingzi Qu, Ping Lu, Karl D. Bellve, Kevin E. Fogarty, Lawrence M. Lifshitz, Fangxiong Shi, Ronghua Zhuge

Program in Molecular Medicine Publications and Presentations

Ion channels in myometrial cells play critical roles in spontaneous and agonist-induced uterine contraction during the menstrual cycle, pregnancy maintenance and parturition; thus identifying the genes of ion channels in these cells and determining their roles are essential to understanding the biology of reproduction. Previous studies with in vitro functional and pharmacological approaches have produced controversial results regarding the presence and role of TMEM16A Ca2+-activated Cl- channels in myometrial cells. To unambiguously determine the function of this channel in these cells, we employed a genetic approach by using smooth muscle cell-specific TMEM16A deletion (i.e. TMEM16ASMKO) mice. We found ...


Serum Deprivation Of Mesenchymal Stem Cells Improves Exosome Activity And Alters Lipid And Protein Composition, Reka A. Haraszti, Rachael Miller, Michelle L. Dubuke, Andrew H. Coles, Marie C. Didiot, Dimas Echeverria, Matteo Stoppato, Yves Y. Sere, John D. Leszyk, Julia F. Alterman, Bruno M. D. C. Godinho, Matthew R. Hassler, Rachel Wollacott, Yan Wang, Scott A. Shaffer, Neil Aronin, Anastasia Khvorova May 2019

Serum Deprivation Of Mesenchymal Stem Cells Improves Exosome Activity And Alters Lipid And Protein Composition, Reka A. Haraszti, Rachael Miller, Michelle L. Dubuke, Andrew H. Coles, Marie C. Didiot, Dimas Echeverria, Matteo Stoppato, Yves Y. Sere, John D. Leszyk, Julia F. Alterman, Bruno M. D. C. Godinho, Matthew R. Hassler, Rachel Wollacott, Yan Wang, Scott A. Shaffer, Neil Aronin, Anastasia Khvorova

Open Access Articles

Exosomes can serve as delivery vehicles for advanced therapeutics. The components necessary and sufficient to support exosomal delivery have not been established. Here we connect biochemical composition and activity of exosomes to optimize exosome-mediated delivery of small interfering RNAs (siRNAs). This information is used to create effective artificial exosomes. We show that serum-deprived mesenchymal stem cells produce exosomes up to 22-fold more effective at delivering siRNAs to neurons than exosomes derived from control cells. Proteinase treatment of exosomes stops siRNA transfer, indicating that surface proteins on exosomes are involved in trafficking. Proteomic and lipidomic analyses show that exosomes derived in ...


Extraction, Purification And Evaluation Of Prmt5-Inhibitory Phytochemical Compounds For The Treatment Of Prostate Adenocarcinoma, Oliver H. Richmond Iii May 2019

Extraction, Purification And Evaluation Of Prmt5-Inhibitory Phytochemical Compounds For The Treatment Of Prostate Adenocarcinoma, Oliver H. Richmond Iii

Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University

The development and advancement of prostate cancer is supported by a plethora of genetic and proteomic abnormalities, including events of post-translational modifications. The protein arginine methyltransferase 5 (PRMT5) enzyme regulates epigenetic events of histone modifications and protein post-translational modifications within protein signaling pathways. PRMT5 functions by catalyzing the symmetric dimethylation of terminal arginine residues on target protein substrates. Under abnormal conditions of overexpression and upregulation, PRMT5 methyltransferase activity constitutively drives the growth and proliferation of dysregulated cells. Overexpression or upregulation of PRMT5 correlates with disease progression as observed among numerous cancer types, including breast, colorectal, leukemia, lung, melanoma and prostate ...


Arf Gtpases And Their Gefs And Gaps: Concepts And Challenges, Elizabeth Sztul, Pei-Wen Chen, James E. Casanova, Jacqueline Cherfils, Joel B. Dacks, David G. Lambright, Fang-Jen S. Lee, Paul A. Randazzo, Lorraine C. Santy, Annette Schurmann, Ilka Wilhelmi, Marielle E. Yohe, Richard A. Kahn May 2019

Arf Gtpases And Their Gefs And Gaps: Concepts And Challenges, Elizabeth Sztul, Pei-Wen Chen, James E. Casanova, Jacqueline Cherfils, Joel B. Dacks, David G. Lambright, Fang-Jen S. Lee, Paul A. Randazzo, Lorraine C. Santy, Annette Schurmann, Ilka Wilhelmi, Marielle E. Yohe, Richard A. Kahn

Program in Molecular Medicine Publications and Presentations

Detailed structural, biochemical, cell biological, and genetic studies of any gene/protein are required to develop models of its actions in cells. Studying a protein family in the aggregate yields additional information, as one can include analyses of their coevolution, acquisition or loss of functionalities, structural pliability, and the emergence of shared or variations in molecular mechanisms. An even richer understanding of cell biology can be achieved through evaluating functionally linked protein families. In this review, we summarize current knowledge of three protein families: the ARF GTPases, the guanine nucleotide exchange factors (ARF GEFs) that activate them, and the GTPase-activating ...


Targeting Sec61Α By Ipomoeassin F Leads To Highly Cytotoxic Effect, Zhijian Hu May 2019

Targeting Sec61Α By Ipomoeassin F Leads To Highly Cytotoxic Effect, Zhijian Hu

Theses and Dissertations

Ipomoeassin F is a flagship congener of a resin glycoside family that inhibits growth of many tumor cell lines with only single-digital nanomolar IC50 values. However, biological and pharmacological mechanisms of ipomoeassin F have been undefined. To facilitate exploration of the biological and pharmacological properties, we performed sophisticate SAR (Structure–activity relationship) studies of ipomoeassin F to understand its pharmacophore and structure properties so that we can design favorable probes for further biological investigation. By applying appropriate deviates that possess fluorescent groups and similar bio-activity, the target protein was found to be localized in endoplasmic reticulum (ER). Through biotin affinity ...


Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey Apr 2019

Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey

Biology ETDs

Properly executed cell division is crucial to development, maintenance, and longevity of multicellular organisms. Defects in both symmetric and asymmetric divisions can lead to improper developmental patterning, as well as genomic instability, disruption of tissue homeostasis, and cancer. Our research focuses on how regulators orchestrate proper cell divisions. Mushroom Body Defect (Mud) is one such regulator, and here we describe how Mud is regulated via the Hippo signaling pathway kinase Warts (Wts), showing Wts phosphorylates Mud to enhance interaction with the polarity protein Partner of Inscuteable, promoting spindle orientation activity. We next focus on another regulator, Shortstop (Shot), describing a ...


Endosome To Golgi Retrieval Of The Vacuolar Protein Sorting Receptor, Vps10p, Requires The Function Of The Vps29, Vps30, And Vps35 Gene Products, Matthew N. J. Seaman, Eric G. Marcusson, Joan Lin-Cereghino, Scott D. Emr Mar 2019

Endosome To Golgi Retrieval Of The Vacuolar Protein Sorting Receptor, Vps10p, Requires The Function Of The Vps29, Vps30, And Vps35 Gene Products, Matthew N. J. Seaman, Eric G. Marcusson, Joan Lin-Cereghino, Scott D. Emr

Joan Lin-Cereghino

Mutations in the S. cerevisiae VPS29 and VPS30 genes lead to a selective protein sorting defect in which the vacuolar protein carboxypeptidase Y (CPY) is missorted and secreted from the cell, while other soluble vacuolar hydrolases like proteinase A (PrA) are delivered to the vacuole. This phenotype is similar to that seen in cells with mutations in the previously characterized VPS10 and VPS35 genes. Vps10p is a late Golgi transmembrane protein that acts as the sorting receptor for soluble vacuolar hydrolases like CPY and PrA, while Vps35p is a peripheral membrane protein which cofractionates with membranes enriched in Vps10p. The ...


Unified Methods For Feature Selection In Large-Scale Genomic Studies With Censored Survival Outcomes, Lauren Spirko-Burns, Karthik Devarajan Mar 2019

Unified Methods For Feature Selection In Large-Scale Genomic Studies With Censored Survival Outcomes, Lauren Spirko-Burns, Karthik Devarajan

COBRA Preprint Series

One of the major goals in large-scale genomic studies is to identify genes with a prognostic impact on time-to-event outcomes which provide insight into the disease's process. With rapid developments in high-throughput genomic technologies in the past two decades, the scientific community is able to monitor the expression levels of tens of thousands of genes and proteins resulting in enormous data sets where the number of genomic features is far greater than the number of subjects. Methods based on univariate Cox regression are often used to select genomic features related to survival outcome; however, the Cox model assumes proportional ...


Regorafenib Enhances Lethality Of Sildenafil And Curcumin In Colorectal Cancer Cells, Kervin Benjamin Owusu Jan 2019

Regorafenib Enhances Lethality Of Sildenafil And Curcumin In Colorectal Cancer Cells, Kervin Benjamin Owusu

Theses and Dissertations

In the United States, more than 130,000 people will be diagnosed with colorectal cancer (CRC) each year and an estimated 50,000 people will die from the disease. Standard of care (SOC) therapies for CRC combine multiple cytotoxic chemotherapeutic drugs. These combinations have varying degrees of effectiveness and can often result in significant patient morbidity. For second recurrence patients, the multi-kinase inhibitor, regorafenib, is an approved agent, but is often poorly tolerated at current doses. In the current study, we propose to develop therapeutic regime of combining agents with modest toxicity profiles: curcumin and sildenafil with regorafenib. Using clinically ...


Principles And Properties Of Rna Self-Assembly, Gabriel Tauber Jan 2019

Principles And Properties Of Rna Self-Assembly, Gabriel Tauber

Undergraduate Honors Theses

Ribonucleoprotein (RNP) granules are membraneless assemblies of condensed RNA and protein that form through multivalent interactions between the constituent components. Recently, RNA self-assembly has been shown to contribute to the formation of stress granules, which are RNP granules associated with the stress response and neurodegeneration. However, little is understood about the properties of self-assembled RNA. Here, I show that different RNA sequences can self- assemble into condensates with distinct material properties and partitioning preferences in vitro. Due to interactions that minimize surface free energy, RNA self-assembly can generate the spontaneous self-patterning of RNA assemblies. By reducing surface free energy, thereby ...


The Regulation Of Egfr Signaling And Kras Tumorigenesis By Receptor Palmitoylation, Akriti Kharbanda Jan 2019

The Regulation Of Egfr Signaling And Kras Tumorigenesis By Receptor Palmitoylation, Akriti Kharbanda

Publicly Accessible Penn Dissertations

Non-Small Cell Lung Cancer (NSCLC) is often characterized by mutually exclusive mutations in epidermal growth factor receptor (EGFR) or KRAS. The mutual exclusivity of these mutations is due to synthetic lethality, revealing a potential therapeutic vulnerability if possible to selectively activate EGFR in KRAS mutant cells. This thesis work demonstrates a previously unidentified mechanism of EGFR signal regulation through palmitoylation, the addition of the 16-carbon palmitate. The palmitoyltransferase, DHHC20, catalyzes this palmitoylation to Cys1025, Cys1122 and Cys1034 on the C-terminal tail of EGFR. Loss of EGFR palmitoylation leads to hyperactivation of the receptor, but decreased cell growth of KRAS mutant ...


Hla-Do Modulates The Diversity Of The Mhc-Ii Self-Peptidome, Padma P. Nanaware, Mollie M. Jurewicz, John D. Leszyk, Scott A. Shaffer, Lawrence J. Stern Dec 2018

Hla-Do Modulates The Diversity Of The Mhc-Ii Self-Peptidome, Padma P. Nanaware, Mollie M. Jurewicz, John D. Leszyk, Scott A. Shaffer, Lawrence J. Stern

Open Access Articles

Presentation of antigenic peptides on MHC-II molecules is essential for tolerance to self and for initiation of immune responses against foreign antigens. DO (HLA-DO in humans, H2-O in mice) is a non-classical MHC-II protein that has been implicated in control of autoimmunity and regulation of neutralizing antibody responses to viruses. These effects likely are related to a role of DO in selecting MHC-II epitopes, but previous studies examining the effect of DO on presentation of selected CD4 T cell epitopes have been contradictory. To understand how DO modulates MHC-II antigen presentation, we characterized the full spectrum of peptides presented by ...


Data On Spectrum-Based Fluorescence Resonance Energy Transfer Measurement Of E. Coli Multidrug Transporter Acrb, Yuguang Cai, Thomas E. Wilkop, Yinan Wei Dec 2018

Data On Spectrum-Based Fluorescence Resonance Energy Transfer Measurement Of E. Coli Multidrug Transporter Acrb, Yuguang Cai, Thomas E. Wilkop, Yinan Wei

Chemistry Faculty Publications

This paper presented the dataset of correction parameters used in the determination of the energy transfer efficiencies from the spectrum-based fluorescence resonance energy transfer (FRET) measurement in a trimeric membrane protein AcrB. The cyan fluorescent protein (CFP) and yellow fluorescent protein (YPet) were used as the donor and acceptor, respectively. Two AcrB fusion proteins were constructed, AcrB-CFP and AcrB-YPet. The proteins were co-expressed in Escherichia coli cells, and energy transfer efficiency were determined in live cells. To obtain reliable energy transfer data, a complete set of correction parameters need to be first determined to accommodate for factors such as background ...


Fatty Acid Amides And Their Biosynthetic Enzymes Found In Insect Model Systems, Ryan L. Anderson Nov 2018

Fatty Acid Amides And Their Biosynthetic Enzymes Found In Insect Model Systems, Ryan L. Anderson

Graduate Theses and Dissertations

A fatty acid amide is precisely as the name suggests: A fatty acid (CHn-COOH), in which the hydroxyl group of the carboxylic acid is displaced by an amine functional group from a biogenic amine (R-NH2), ultimately forming an amide bond. Furthermore, these fatty acid amides can be composed of a variety of different acyl chain lengths donated by the fatty acid and a myriad of different biogenic amines. Thus, these molecules can be subdivided in a number of different ways including the separation of short chain (acetyl to heptanoyl) and long chain (palmitoyl to arachidonoyl) and also based off the ...


Colorectal Cancer Liver Metastatic Growth Depends On Pad4-Driven Citrullination Of The Extracellular Matrix, A. E. Yuzhalin, A. N. Gordon-Weeks, M. L. Tognoli, K. Jones, B. Markelc, R. Konietzny, R. Fischer, Aaron Muth, E. O'Neill, Paul R. Thompson, P. J. Venables, B. M. Kessler, S. Y. Lim, R. J. Muschel Nov 2018

Colorectal Cancer Liver Metastatic Growth Depends On Pad4-Driven Citrullination Of The Extracellular Matrix, A. E. Yuzhalin, A. N. Gordon-Weeks, M. L. Tognoli, K. Jones, B. Markelc, R. Konietzny, R. Fischer, Aaron Muth, E. O'Neill, Paul R. Thompson, P. J. Venables, B. M. Kessler, S. Y. Lim, R. J. Muschel

Open Access Articles

Citrullination of proteins, a post-translational conversion of arginine residues to citrulline, is recognized in rheumatoid arthritis, but largely undocumented in cancer. Here we show that citrullination of the extracellular matrix by cancer cell derived peptidylarginine deiminase 4 (PAD4) is essential for the growth of liver metastases from colorectal cancer (CRC). Using proteomics, we demonstrate that liver metastases exhibit higher levels of citrullination and PAD4 than unaffected liver, primary CRC or adjacent colonic mucosa. Functional significance for citrullination in metastatic growth is evident in murine models where inhibition of citrullination substantially reduces liver metastatic burden. Additionally, citrullination of a key matrix ...


Investigating The Roles Of Fucosylation And Calcium Signaling In Melanoma Invasion, Tyler S. Keeley Nov 2018

Investigating The Roles Of Fucosylation And Calcium Signaling In Melanoma Invasion, Tyler S. Keeley

Graduate Theses and Dissertations

Melanoma is the deadliest form of skin cancer. Prognosis for early stage melanoma patients is excellent, and surgery is often curative for these patients. However, once patients have presented with invasive disease, the average 5-year survival rate drops significantly from over 90% to between 10 and 15%. Several therapies have been developed to target a commonly mutated oncogene BRAF, or its downstream effectors. Unfortunately, while these treatments show robust initial response, most patients relapse within a year. Moreover, therapy-resistant tumors are often more invasive and metastatic. Therefore, it is important to investigate the molecular mechanisms underlying melanoma invasion and metastasis ...


Angiomotins Stimulate Lats Kinase Autophosphorylation And Act As Scaffolds That Promote Hippo Signaling, Sebastian Mana-Capelli, Dannel Mccollum Sep 2018

Angiomotins Stimulate Lats Kinase Autophosphorylation And Act As Scaffolds That Promote Hippo Signaling, Sebastian Mana-Capelli, Dannel Mccollum

Open Access Articles

The Hippo pathway controls cell proliferation, differentiation, and survival by regulating the YAP transcriptional coactivator in response to various stimuli, including the mechanical environment. The major YAP regulators are the LATS1/2 kinases, which phosphorylate and inhibit YAP. LATS1/2 are activated by phosphorylation on a hydrophobic motif (HM) outside the kinase domain by MST1/2 and other kinases. Phosphorylation of the HM motif then triggers autophosphorylation of the kinase in the activation loop (AL) to fully activate the kinase, a process facilitated by MOB1. The angiomotin family of proteins (AMOT, AMOTL1, and AMOTL2) bind LATS1/2 and promote its ...


Histone Citrullination Represses Mirna Expression Resulting In Increased Oncogene Mrnas In Somatolactotrope Cells., Stanley B Devore, Coleman H. Young, Guangyuan Li, Anitha Sundararajan, Thiruvarangan Ramaraj, Joann Mudge, Faye Schilkey, Aaron Muth, Paul R. Thompson, Brian D. Cherrington Sep 2018

Histone Citrullination Represses Mirna Expression Resulting In Increased Oncogene Mrnas In Somatolactotrope Cells., Stanley B Devore, Coleman H. Young, Guangyuan Li, Anitha Sundararajan, Thiruvarangan Ramaraj, Joann Mudge, Faye Schilkey, Aaron Muth, Paul R. Thompson, Brian D. Cherrington

University of Massachusetts Medical School Publications

Peptidylarginine deiminase (PAD) enzymes convert histone arginine residues into citrulline to modulate chromatin organization and gene expression. Although PADs are expressed in anterior pituitary gland cells, their functional role and expression in pituitary adenomas is unknown. To begin to address these questions, we first examined normal human pituitaries and pituitary adenomas and found that PAD2, PAD4 and citrullinated histones are highest in prolactinomas and somatoprolactinomas. In the somatoprolactinoma-derived GH3 cell line, PADs citrullinate histone H3, which is attenuated by a pan-PAD inhibitor. RNA-sequencing and ChIP studies show that the expression of microRNAs let-7c-2, miR-23b and miR-29c is suppressed by histone ...


Renal Risk Variants Of Apolipoprotein L-1 Form Channels At The Plasma Membrane That Lead To A Cytotoxic Influx Of Calcium, Joseph A. Giovinazzo Sep 2018

Renal Risk Variants Of Apolipoprotein L-1 Form Channels At The Plasma Membrane That Lead To A Cytotoxic Influx Of Calcium, Joseph A. Giovinazzo

All Dissertations, Theses, and Capstone Projects

Apolipoprotein L-1 (APOL1) is a secreted protein that provides protection against several protozoan parasites due to its channel forming properties. Recently evolved variants, G1 and G2, increase kidney disease risk when present in two copies. In mammalian cells, overexpression of G1 and G2, but not wild-type G0, leads to swelling and eventual lysis. However, the mechanism of cell death remains elusive with multiple pathways being invoked, such as autophagic cell death mediated by a BH3 domain in APOL1, which we evaluated in this study. We hypothesized that the common trigger for these pathways is the APOL1 cation channel, which is ...


Tumor-Stroma Interactions Differentially Alter Drug Sensitivity Based On The Origin Of Stromal Cells, Benjamin D. Landry, Thomas Leete, Ryan Richards, Peter Cruz-Gordillo, Hannah R. Schwartz, Megan E. Honeywell, Gary Ren, Alyssa D. Schwartz, Shelly R. Peyton, Michael J. Lee Aug 2018

Tumor-Stroma Interactions Differentially Alter Drug Sensitivity Based On The Origin Of Stromal Cells, Benjamin D. Landry, Thomas Leete, Ryan Richards, Peter Cruz-Gordillo, Hannah R. Schwartz, Megan E. Honeywell, Gary Ren, Alyssa D. Schwartz, Shelly R. Peyton, Michael J. Lee

Program in Systems Biology Publications and Presentations

Due to tumor heterogeneity, most believe that effective treatments should be tailored to the features of an individual tumor or tumor subclass. It is still unclear, however, what information should be considered for optimal disease stratification, and most prior work focuses on tumor genomics. Here, we focus on the tumor microenvironment. Using a large-scale coculture assay optimized to measure drug-induced cell death, we identify tumor-stroma interactions that modulate drug sensitivity. Our data show that the chemo-insensitivity typically associated with aggressive subtypes of breast cancer is not observed if these cells are grown in 2D or 3D monoculture, but is manifested ...


Characterization Of A Variant Of Tuberous Sclerosis Complex 2 And Its Interaction With Rheb, Sowmya Sivakumar Aug 2018

Characterization Of A Variant Of Tuberous Sclerosis Complex 2 And Its Interaction With Rheb, Sowmya Sivakumar

Theses and Dissertations

Protein-protein interactions are vital in maintaining proper function and homeostasis in cells. Some signaling pathways are regulated by G-proteins that work like switches to activate and deactivate pathways. Mutations in these proteins, their effectors or the interaction between proteins may cause dysregulation of signals that can lead to many diseases.

Rheb, Ras homology enriched in brain, is a Ras family GTPase that is vital in regulation of the mTOR (mammalian target of rapamycin) pathway that signals cell proliferation and growth. Due to the low intrinsic GTPase activity of Rheb, a GTPase activating protein (GAP), Tuberous Sclerosis Complex 2 (TSC2) down ...


Egfr Signaling From The Early Endosome., Julie A. Gosney Aug 2018

Egfr Signaling From The Early Endosome., Julie A. Gosney

Electronic Theses and Dissertations

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is an integral component of proliferative signaling. When activated by a ligand at the plasma membrane, EGFR dimerizes with another ErbB family receptor, leading to kinase domain activation and transphosphorylation of C-terminus tyrosine residues. These phosphotyrosines act as crucial regulators of EGFR signaling as effector proteins dock to the receptor at these sites. The receptor undergoes clathrin-mediated endocytosis into early endosomes, where it can then be trafficked to a lysosome for degradation. However, the kinase domain of EGFR retains its activity during trafficking, suggesting that EGFR can continue ...


Pias-Family Proteins Negatively Regulate Glis3 Transactivation Function Through Sumo Modification In Pancreatic Β Cells, Tyler M. Hoard, Xiaoping Yang, Anton M. Jetten, Gary T. Zeruth Dr. Jul 2018

Pias-Family Proteins Negatively Regulate Glis3 Transactivation Function Through Sumo Modification In Pancreatic Β Cells, Tyler M. Hoard, Xiaoping Yang, Anton M. Jetten, Gary T. Zeruth Dr.

Faculty & Staff Research and Creative Activity

Gli-similar 3 (Glis3) is Krüppel-like transcription factor associated with the transcriptional regulation of insulin. Mutations within the Glis3 locus have been implicated in a number of pathologies including diabetes mellitus and hypothyroidism. Despite its clinical significance, little is known about the proteins and posttranslational modifications that regulate Glis3 transcriptional activity. In this report, we demonstrate that the SUMO-pathway associated proteins, PIASy and Ubc9 are capable of regulating Glis3 transactivation function through a SUMO-dependent mechanism. We present evidence that SUMOylation of Glis3 by PIAS-family proteins occurs at two conserved lysine residues within the Glis3 N-terminus and modification of Glis3 by SUMO ...


Effect Of Egta On Sit1 Scramblase Gene Expression And Cell Growth In Tetrahymena Thermophila, Emma Esposito, Theda Knauth, Amelia Ohnstad, Stefanie Otto-Hitt Jul 2018

Effect Of Egta On Sit1 Scramblase Gene Expression And Cell Growth In Tetrahymena Thermophila, Emma Esposito, Theda Knauth, Amelia Ohnstad, Stefanie Otto-Hitt

Life and Environmental Sciences Course-based Research Projects

Scramblase is an enzyme that facilitates the movement of newly synthesized phospholipids from the cytosolic side to the extracellular side of the lipid bilayer. This process is vital for cell membrane repair and growth. In Tetrahymena thermophila, the gene SIT1 encodes for the Scramblase protein, whose functionality is Ca2+-dependent. In this experiment, the concentration of accessible Ca2+ ions was decreased in order to observe whether the change had an aect on the expression of SIT1 and cell growth. It was hypothesized that expression of the SIT1 gene would increase, while cell growth would decrease. To carry out the experiment ...


Dynamics And Interactions Of Membrane Proteins, Azamat Galiakhmetov Jul 2018

Dynamics And Interactions Of Membrane Proteins, Azamat Galiakhmetov

Dissertations (2009 -)

Membrane proteins are members of the class of proteins that perform their functions while being associated with a lipid bilayer. In the cell, they serve as transporters, receptors, anchors and enzymes. The domain organisation of these proteins suggests importance of lipid membrane and protein-lipid interactions for protein function. The requirement of a membrane mimic and the level of its resemblance to a native one for protein investigation makes the studies of membrane proteins a challenging project. My research work is focusing on the biophysical and biochemical studies of membrane proteins. This dissertation outlines two separate projects, each with their own ...


Role Of The Mapk/Cjun Nh2-Terminal Kinase Signaling Pathway In Starvation-Induced Autophagy, Seda Barutcu, Nomeda Girnius, Santiago Vernia, Roger J. Davis Jun 2018

Role Of The Mapk/Cjun Nh2-Terminal Kinase Signaling Pathway In Starvation-Induced Autophagy, Seda Barutcu, Nomeda Girnius, Santiago Vernia, Roger J. Davis

Davis Lab Publications

Autophagy is required for cellular homeostasis and can determine cell viability in response to stress. It is established that MTOR is a master regulator of starvation-induced macroautophagy/autophagy, but recent studies have also implicated an essential role for the MAPK8/cJun NH2-terminal kinase 1 signal transduction pathway. We found that MAPK8/JNK1 and MAPK9/JNK2 were not required for autophagy caused by starvation or MTOR inhibition in murine fibroblasts and epithelial cells. These data demonstrate that MAPK8/9 has no required role in starvation-induced autophagy. We conclude that the role of MAPK8/9 in autophagy may be context-dependent and more ...


Cell Clustering Mediated By The Adhesion Protein Pvrl4 Is Necessary For Alpha6beta4 Integrin-Promoted Ferroptosis Resistance In Matrix-Detached Cells, Caitlin W. Brown, John J. Amante, Arthur M. Mercurio Jun 2018

Cell Clustering Mediated By The Adhesion Protein Pvrl4 Is Necessary For Alpha6beta4 Integrin-Promoted Ferroptosis Resistance In Matrix-Detached Cells, Caitlin W. Brown, John J. Amante, Arthur M. Mercurio

University of Massachusetts Medical School Faculty Publications

Ferroptosis is an iron-dependent form of programmed cell death characterized by the accumulation of lipid-targeting reactive oxygen species that kill cells by damaging their plasma membrane. The lipid-repair enzyme glutathione peroxidase 4 (GPX4) protects against this oxidative damage and enables cells to resist ferroptosis. Recent work has revealed that matrix-detached carcinoma cells can be susceptible to ferroptosis and that they can evade this fate through the signaling properties of the alpha6beta4 integrin, which sustains GPX4 expression. Although these findings on ferroptosis are provocative, they differ from those in previous studies indicating that matrix-detached cells are prone to apoptosis, via a ...