Medical Molecular Biology Commons^™

Effects Of Maackia Amurensis Seed Lectin (Masl) On Oscc Cell Morphology, Pdpn Expression, Growth, And Motility In A Phase 1 Clinical Trial, Ariel C Yin, Cayla J Holdcraft, Tyler J Hellmig, Eamonn J Brace, David I Suster, Alan J Shienbaum, Dylan Roden, Evelyne Kalyoussef, Ghayoour Mir, Eugenio Capitle, Soly Baredes, Rabie M Shanti, Mika K Kaneko, Yukinari Kato, Hisataka Kobayashi, Aki Furusawa, Mahnaz Fatahzadeh, Gary S Goldberg

Rowan-Virtua School of Osteopathic Medicine Departmental Research

BACKGROUND: Podoplanin (PDPN) has emerged as a functionally relevant biomarker and chemotherapeutic target expressed by OSCC cells. PDPN signaling can directly increase tumor cell invasion and metastasis, and also inhibit host lymphocyte activation and immune response. Accordingly, antibodies and Maackia amurensis seed lectin (MASL) can target the PDPN receptor to inhibit OSCC cell migration and viability. However, the effects of MASL on OSCC cells in oral cancer patients has not yet been reported.

METHODS: We conducted a Phase 1 human clinical trial to examine the effects of a single 100 mg oral dose of MASL on OSCC cell morphology, PDPN …

Mechanisms Of Extracellular Vesicle Uptake And Implications For The Design Of Cancer Therapeutics, Stephanie R Jackson Cullison, Joseph P Flemming, Kubra Karagoz, Peter J Wermuth, Mỹ G Mahoney

Rowan-Virtua School of Osteopathic Medicine Departmental Research

The translation of pre-clinical anti-cancer therapies to regulatory approval has been promising, but slower than hoped. While innovative and effective treatments continue to achieve or seek approval, setbacks are often attributed to a lack of efficacy, failure to achieve clinical endpoints, and dose-limiting toxicities. Successful efforts have been characterized by the development of therapeutics designed to specifically deliver optimal and effective dosing to tumour cells while minimizing off-target toxicity. Much effort has been devoted to the rational design and application of synthetic nanoparticles to serve as targeted therapeutic delivery vehicles. Several challenges to the successful application of this modality as …

Effects Of Cadherin Mediated Contact Normalization On Oncogenic Src Kinase Mediated Gene Expression And Protein Phosphorylation, Rachel E Nicoletto, Cayla J Holdcraft, Ariel C Yin, Edward P Retzbach, Stephanie A Sheehan, Amanda A Greenspan, Christopher M Laugier, Jason Trama, Caifeng Zhao, Haiyan Zheng, Gary S Goldberg

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Nontransformed cells form heterotypic cadherin junctions with adjacent transformed cells to inhibit tumor cell growth and motility. Transformed cells must override this form of growth control, called "contact normalization", to invade and metastasize during cancer progression. Heterocellular cadherin junctions between transformed and nontransformed cells are needed for this process. However, specific mechanisms downstream of cadherin signaling have not been clearly elucidated. Here, we utilized a β-catenin reporter construct to determine if contact normalization affects Wnt signaling in transformed cells. β-catenin driven GFP expression in Src transformed mouse embryonic cells was decreased when cultured with cadherin competent nontransformed cells compared to …

A Homogeneous Time-Resolved Fluorescence Screen To Identify Sirt2 Deacetylase And Defatty-Acylase Inhibitors, Jie Yang, Joel Cassel, Brian C Boyle, Daniel Oppong, Young-Hoon Ahn, Brian P Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Human sirtuin-2 (SIRT2) has emerged as an attractive drug target for a variety of diseases. The enzyme is a deacylase that can remove chemically different acyl modifications from protein lysine residues. Here, we developed a high-throughput screen based on a homogeneous time-resolved fluorescence (HTRF) binding assay to identify inhibitors of SIRT2's demyristoylase activity, which is uncommon among many ligands that only affect its deacetylase activity. From a test screen of 9600 compounds, we identified a small molecule that inhibited SIRT2's deacetylase activity (IC50 = 7 μM) as well as its demyristoylase activity (IC50 = 37 μM). The inhibitor was composed …

Distinct Expression Patterns Of Hedgehog Signaling Components In Mouse Gustatory System During Postnatal Tongue Development And Adult Homeostasis, Archana Kumari, Nicole E Franks, Libo Li, Gabrielle Audu, Sarah Liskowicz, John D Johnson, Charlotte M Mistretta, Benjamin L Allen

Rowan-Virtua School of Osteopathic Medicine Departmental Research

The Hedgehog (HH) pathway regulates embryonic development of anterior tongue taste fungiform papilla (FP) and the posterior circumvallate (CVP) and foliate (FOP) taste papillae. HH signaling also mediates taste organ maintenance and regeneration in adults. However, there are knowledge gaps in HH pathway component expression during postnatal taste organ differentiation and maturation. Importantly, the HH transcriptional effectors GLI1, GLI2 and GLI3 have not been investigated in early postnatal stages; the HH receptors PTCH1, GAS1, CDON and HHIP, required to either drive HH pathway activation or antagonism, also remain unexplored. Using lacZ reporter mouse models, we mapped expression of the HH …

Rewiring The Sex-Determination Pathway During The Evolution Of Self-Fertility., Yongquan Shen, Shin-Yi Lin, Jonathan Harbin, Richa Amin, Allison Vassalotti, Joseph Romanowski, Emily Schmidt, Alexis Tierney, Ronald E Ellis

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Although evolution is driven by changes in how regulatory pathways control development, we know little about the molecular details underlying these transitions. The TRA-2 domain that mediates contact with TRA-1 is conserved in Caenorhabditis. By comparing the interaction of these proteins in two species, we identified a striking change in how sexual development is controlled. Identical mutations in this domain promote oogenesis in Caenorhabditis elegans but promote spermatogenesis in Caenorhabditis briggsae. Furthermore, the effects of these mutations involve the male-promoting gene fem-3 in C. elegans but are independent of fem-3 in C. briggsae. Finally, reciprocal mutations in these genes show …

Maackia Amurensis Seed Lectin (Masl) And Soluble Human Podoplanin (Shpdpn) Sequence Analysis And Effects On Human Oral Squamous Cell Carcinoma (Oscc) Cell Migration And Viability, Ariel C Yin, Cayla J Holdcraft, Eamonn J Brace, Tyler J Hellmig, Sayan Basu, Saumil Parikh, Katarzyna Jachimowska, Evelyne Kalyoussef, Dylan Roden, Soly Baredes, Eugenio M Capitle, David I Suster, Alan J Shienbaum, Caifeng Zhao, Haiyan Zheng, Kevin Balcaen, Simon Devos, Jurgen Haustraete, Mahnaz Fatahzadeh, Gary S Goldberg

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Maackia amurensis lectins serve as research and botanical agents that bind to sialic residues on proteins. For example, M. amurensis seed lectin (MASL) targets the sialic acid modified podoplanin (PDPN) receptor to suppress arthritic chondrocyte inflammation, and inhibit tumor cell growth and motility. However, M. amurensis lectin nomenclature and composition are not clearly defined. Here, we sought to definitively characterize MASL and its effects on tumor cell behavior. We utilized SDS-PAGE and LC-MS/MS to find that M. amurensis lectins can be divided into two groups. MASL is a member of one group which is composed of subunits that form dimers, …

The Role Of Med13 In Proteaphagy, John Sauer, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

Regulation of proteasomes is important for adaptation to cellular stress. Previous studies have shown that following starvation stress, proteasomes are targeted for destruction by autophagy. However, how cells control proteasomes in response to nitrogen starvation remains unclear. This study delves into the intricate interplay between Med13, proteaphagy, and stress response regulation, aiming to elucidate their roles in cellular survival mechanisms. It focused on the highly conserved Cdk8 kinase module (CKM) of the Mediator complex a that plays a pivotal involvement in cellular signaling and gene regulation under stress conditions. During the investigation, we asked if the degradation of specific proteasome …

Trna Anticodon Cleavage By Target-Activated Crispr-Cas13a Effector, Ishita Jain, Matvey Kolesnik, Konstantin Kuznedelov, Leonid Minakhin, Natalia Morozova, Anna Shiriaeva, Alexandr Kirillov, Sofia Medvedeva, Alexei Livenskyi, Laura Kazieva, Kira S Makarova, Eugene V Koonin, Sergei Borukhov, Konstantin Severinov, Ekaterina Semenova

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Type VI CRISPR-Cas systems are among the few CRISPR varieties that target exclusively RNA. The CRISPR RNA–guided, sequence-specific binding of target RNAs, such as phage transcripts, activates the type VI effector, Cas13. Once activated, Cas13 causes collateral RNA cleavage, which induces bacterial cell dormancy, thus protecting the host population from the phage spread. We show here that the principal form of collateral RNA degradation elicited by Leptotrichia shahii Cas13a expressed in Escherichia coli cells is the cleavage of anticodons in a subset of transfer RNAs (tRNAs) with uridine-rich anticodons. This tRNA cleavage is accompanied by inhibition of protein synthesis, thus …

Ksp1 Is An Autophagic Receptor Protein For The Snx4-Assisted Autophagy Of Ssn2/Med13, Sara E Hanley, Stephen D Willis, Steven J Doyle, Randy Strich, Katrina F Cooper

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Ksp1 is a casein II-like kinase whose activity prevents aberrant macroautophagy/autophagy induction in nutrient-rich conditions in yeast. Here, we describe a kinase-independent role of Ksp1 as a novel autophagic receptor protein for Ssn2/Med13, a known cargo of Snx4-assisted autophagy of transcription factors. In this pathway, a subset of conserved transcriptional regulators, Ssn2/Med13, Rim15, and Msn2, are selectively targeted for vacuolar proteolysis following nitrogen starvation, assisted by the sorting nexin heterodimer Snx4-Atg20. Here we show that phagophores also engulf Ksp1 alongside its cargo for vacuolar proteolysis. Ksp1 directly associates with Atg8 following nitrogen starvation at the interface of an Atg8-family interacting …

The Involvement Of Ubiquitin In Med13 Cyclin C Degradation Following Cellular Stress, Ayesha Gurnani, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

The Cdk8 Kinase Module is a dissociable regulator of cellular stress response genes, with degradation of its components Med13 and cyclin C eventually determining cell fate decisions such as engaging cell survival or cell death mechanisms. We aimed to explore the roles of ubiquitin in degradation of the Cdk8 Kinase Module following nitrogen starvation, with respect to the potential involvement of deubiquitinating enzyme Doa4, lysine linkage at position K63, and E2 ubiquitin conjugating enzymes Ubc4 and Ubc5. We utilized Western blot analysis to observe nitrogen starvation-induced degradation of Med13-HA in wild-type, doa4 mutant, and K63R yeast strains; degradation of cyclin …

Identifying Co-Factors That Drive Tra-1 Activator Function, Jibran Imtiaz, Yongquan Shen, Ronald Ellis

Rowan-Virtua Research Day

Gli proteins are involved in cell fate determination, proliferation, and patterning in many species and are major effectors of Hedgehog (Hh) signaling. There are three Gli proteins in humans, and mutations or errors in their regulation lead to a variety of developmental disorders or cancer. However, the mechanisms by which they interact with co-factors are poorly understood. We are analyzing co-factors of Gli proteins using TRA-1 in Caenorhabditis nematodes. The TRA-1 zinc fingers are structurally like those of other Gli proteins, and TRA-1 can be cleaved like other Gli proteins to form a repressor. However, its function has changed during …

Immunomodulatory Effects Of Resolvin D2 In A Model Of Infection, Prem Yugandhar Kadiyam Sundarasivarao

Graduate School of Biomedical Sciences Theses and Dissertations

Dysregulated hyperinflammatory host immune response to underlying bacterial infections is a characteristic of sepsis. In sepsis, bacteria often trigger abnormal hyperinflammatory responses which can cause multiple organ failure and if sustained can lead to an immunosuppressive phase where the host is susceptible to secondary infections caused by opportunistic bacteria like Pseudomonas aeruginosa (P. aeruginosa). In our studies, we used a 2-hit model of cecal ligation and puncture (CLP) followed by P. aeruginosa secondary lung infection to investigate cellular and molecular mechanisms in the beneficial action of resolvin D2 (RvD2). Resolvins of the D-series are a group of fatty acids known …

A Conserved Mechanism For Hormesis In Molecular Systems, Sharon N. Greenwood, Regina G. Belz, Brian P. Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Hormesis refers to dose-response phenomena where low dose treatments elicit a response that is opposite the response observed at higher doses. Hormetic dose-response relationships have been observed throughout all of biology, but the underlying determinants of many reported hormetic dose-responses have not been identified. In this report, we describe a conserved mechanism for hormesis on the molecular level where low dose treatments enhance a response that becomes reduced at higher doses. The hormetic mechanism relies on the ability of protein homo-multimers to simultaneously interact with a substrate and a competitor on different subunits at low doses of competitor. In this …

Safety And Efficacy Of Silver-Coated Biomaterials In Vivo, Megan Klem, Darien L. Seidman, Rahyan Mahmoud, Manuella Adu, Lei Yu, Jeffrey Hettinger, Renee M Demarest

Rowan-Virtua Research Day

Overtreatment and overuse of antibiotics in healthcare and agricultural settings have contributed to the selective pressure on bacterial strains to develop resistance. Resistance can develop as a result of mutations and subsequent resistance genes that allow bacteria to survive against antibiotics. Novel silver-oxide coatings were developed and were previously demonstrated to prevent adhesion of gram-negative bacteria (Escherichia Coli and Pseudomonas Aeruginosa) to the disc, but did not prevent gram-positive bacterial adherence (Streptococcus Aureus). In order to determine whether the silver-oxide coatings are bacterial static and may be preventing progression to biofilm formation, in vivo analysis of S. Aureus attached to …

Modeling The Role Of Cyclin C In Connecting Stress-Induced Mitochondrial Fission To Apoptosis, Steven J. Doyle, Randy Strich

Rowan-Virtua Research Day

For normal cell function, exogenous signals must be correctly interpreted, and the proper response executed. The mitochondria are key regulatory nodes of cellular fate. For example, mitochondria undergo fission and fusion cycles depending on the energetic needs of the cell. Additionally, regulated cell death pathways also function at the mitochondria. Cyclin C is a transcriptional regulator of stress response and growth control genes. Following stress, a portion of cyclin C translocates to the cytoplasm, where it interacts with both the mitochondrial fission and apoptotic machinery. Based on these findings, we hypothesize that Cyclin C represents a key mediator linking transcription …

Substrate-Specific Effect On Sirtuin Conformation And Oligomerization, Jie Yang, Shannon L. Dwyer, Nathan I. Nicely, Brian P. Weiser

Rowan-Virtua Research Day

Human sirtuins are a family of nicotinamide adenine dinucleotide (NAD +)-dependent enzymes that are responsible for removing acyl modifications from lysine residues. Sirtuins are involved in the formation and proliferation of cancers and are thought to regulate the progression of neurodegenerative diseases. Although sirtuins can be pharmacologically targeted by small molecules, it is not easy to modulate the substrate selectivity of sirtuins despite the chemical diversity of their substrates. Here, we report substrate-specific effects on sirtuin conformation and oligomerization that regulate enzyme deacylase activity. We used fluorescent acyl peptide probes to study substrate interactions with two sirtuin isoforms: SIRT2 and …

Ung2 And Rpa Activity On Ssdna-Dsdna Junctions, Kathy Chen, Sharon Greenwood, Brian P. Weiser

Rowan-Virtua Research Day

Uracil DNA glycosylase, or UNG2, is an enzyme that is involved in DNA repair. Its primary job is to eliminate harmful uracil bases from DNA strands. To do this, the enzyme is assisted by replication protein A (RPA). RPA helps UNG2 in the identification of uracil bases by targeting UNG2 activity near ssDNA-dsDNA junctions (1-3). The results from assays presented here agree with published findings that showed UNG2 is heavily targeted by RPA to uracil bases that are close to ssDNA-dsDNA junctions (for example, uracil located 9 bps from the junction as opposed to 33 bps) (1,2). However, these previous …

Effect Of Uracil Dna Glycosylase Activity On The Efficacy Of Thymidylate Synthase Inhibitor/Hdac Inhibitor Combination Therapies In Colon Cancer, Rashmi Kulkarni, Brian P Weiser

Rowan-Virtua Research Day

Human uracil DNA glycosylase (UNG2) is responsible for removing uracil bases from DNA and initiates base excision repair pathways. Accumulation of uracil or its fluorinated analogs in DNA is one of the killing mechanisms of thymidylate synthase (TS) inhibitors in cancer cells, and depletion of UNG2 often enhances the toxicity of these anticancer drugs. We tested the effect of UNG2 KO on the efficacy of multiple TS inhibitors (5-fluorouracil, fluorodeoxyuridine, and pemetrexed) and we determined that, except for 5-fluorouracil, all other TS inhibitors were significantly more potent in UNG2 KO cells compared to wild-type HT29 cells. Interestingly, UNG2 protein levels …

Interaction Of Fluorescent Probes With Sirtuin Proteins, James Fusco, Brian P Weiser

Rowan-Virtua Research Day

Sirtuins are a class of proteins belonging to the Sir2 (Silencing information regulator 2) family of NAD+ dependent protein lysine deacylases. Different Isoforms (SIRT1-SIRT7) differ in their specific deacylase activity and cellular location. They have roles in DNA repair, glucose metabolism, and cellular proliferation which make them highly desirable targets for carcinoma therapeutics. We previously used 1-aminoanthracene’s (AMA) fluorescent properties when bound with SIRT2 (Kd of 37 μM) to develop a high-throughput screen to identify novel ligands that inhibit SIRT2’s enzymatic activities. We hope to reveal other potential probes for future high-throughput screening with all the sirtuin isotopes. 1-AMA’s fluorescence …

The Brodmann Area 39/40 Of The Brain In Alzheimer’S, Mild Cognitive Impairment, And No Cognitive Impairment Subjects At Advanced Age Demonstrate Comparable Levels Of Blood-Brain Barrier Breach, Dhara Rana, Forum Mangrola, Randel L. Swanson, Venkat Venkataraman, David A. Bennett, Zoe Arvanitakis, David Libon, Robert Nagele, Nimish Acharya

Rowan-Virtua Research Day

• Alzheimer’s disease (AD) is one of the most common form of dementia

• Mild cognitive impairment (MCI), specifically amnestic subtype, more likely to progress to AD

• Pathogenesis Theories:

• o Accumulation of amyloid-beta peptides and neurofibrillary tangles containing hyperphosphorylated neuronal tau protein
• o Blood Brain Barrier (BBB) dysfunction is associated with AD pathogenesis

• Brodmann area 39/40: regions of parietal cortex are responsible for language, spatial cognition, memory retrieval, attention, phonological processing, and emotional processing

• Hypothesis: An increased BBB permeability in Brodmann area 39/40 of AD and age-matched MCI and no cognitive impairment (NCI) subjects

Cdk8 Kinase Module Modifies Expression Of Specific Translation-Related Proteins Before And After Stress, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

Translation is tightly coupled to growth status. Efficient protein synthesis is necessary for cell growth in nutrient rich environments, while global translation inhibition combined with selective translation of stress-responsive mRNAs helps limit growth in times of stress. Environmental stress cues which inhibit the nutrient-sensing complex TORC1 are known to reduce general translation, but how does the cell alter protein synthesis machinery to adapt to these conditions? A few mechanisms to promote cell survival in nitrogen starvation include post-translational modification and selective degradation of specific mRNA-binding translation factors, as well as inhibition of activators of genes whose products are required for …

Cyclin C Is Sufficient For Myoblast Differentiation-Induced Mitochondrial Fragmentation, Alicia N. Campbell, Randy Strich

Rowan-Virtua Research Day

One of the largest and most dynamic tissues in the body, skeletal muscle, requires constant regeneration and upkeep. Dysregulation of this regeneration process has been implicated in many neuromuscular diseases and myotonic dystrophies. Regeneration requires the differentiation of myogenic lineages including exiting the cell cycle, gene expression changes, and fusing of myoblasts into multinucleate myotubes. Part of this reconstruction requires the breakdown and repopulation of mitochondrial networks. At the early onset of myoblast differentiation, there is an upregulation of dynamin-related protein, Drp1, and an increase in mitophagy mediated by sequestosome (SQSTM1) removal of mitochondria.

Previously, our lab has shown that …

Conservation And Divergence In The Heterochronic Pathway Of C. Elegans And C. Briggsae, Maria Ivanova, Eric G. Moss

Rowan-Virtua Research Day

The heterochronic pathway of Caenorhabditis elegans is exemplary as a mechanism of developmental timing: mutations in genes of this pathway alter the relative timing of diverse developmental events independent of spatial or cell type specific regulation. It is the most thoroughly characterized developmental timing pathway known. Most of the heterochronic genes are conserved across great evolutionary time, and a few homologs seem to have developmental timing roles in certain contexts. The degree to which other organisms have explicit developmental timing mechanisms, and what factors comprise those mechanisms, isn’t generally known.

Developmental pathways evolve even if the resulting morphology remains the …

Investigating The Role Of The Basolateral Amygdala Plays In The Incubation Of Cue-Induced Cocaine Seeking Behavior, Claire Marie Corbett

Graduate School of Biomedical Sciences Theses and Dissertations

Cocaine use disorder is a chronic, relapsing brain disease. Sex and ovarian hormones are known to influence cocaine addiction liability and relapse vulnerability. However, little is known regarding the cellular and synaptic mechanisms contributing to sex differences in relapse vulnerability, including how these measures are influenced by hormonal fluctuations. To investigate sex differences in relapse vulnerability we use a rodent model of cocaine craving and relapse called the incubation model in which cue-induced seeking progressively increases or “incubates” during the first month of withdrawal from extended-access cocaine self-administration. Using this model, we have recently shown that females in the estrus …

Differentiating The Mechanistic Role And Chemotherapeutic Potential Of Src And Podoplanin In Oncogenic Transformation, Edward P. Retzbach

Graduate School of Biomedical Sciences Theses and Dissertations

There were an estimated 20 million new cancer cases worldwide in 2020, resulting in nearly 1000 deaths per hour [1]. Oral cancer exemplifies the difficulties of treating cancer patients. The first line for oral cancer treatment is surgery and radiation that can lead to patient disfigurement and decreased quality of life in cancer survivors [2-4]. Though there have been many developments in chemotherapy in the last 30 years, the 50% mortality rate associated with oral cancer has not changed [4, 5]. Longitudinal studies that track survival rates in oral cancer patients demonstrate a 3-fold reduction in patient deaths when patients …

Contact Normalization And The Role Of Maackia Amurensis Seed Lectin As A Novel Chemotherapeutic And Antiviral Agent, Stephanie A. Sheehan

Graduate School of Biomedical Sciences Theses and Dissertations

Cells communicate with each other to coordinate tissue function and homeostasis. Diseases including cancer, arthritis, and acute respiratory disease syndrome (ARDS) require a breakdown in this intercellular communication. For example, cancer progression is suppressed by junctional communication between nontransformed and transformed cells. This process is called contact normalization. Junctional communication must be disrupted to enable transformed cells to grow into malignancies. However, the junctions and mechanisms by which nontransformed cells normalize cell behavior have not been clearly defined. My project aimed to identify junctions and elucidate mechanisms underlying contact normalization. We discovered that cadherins, specifically N-cadherin, form junctions that enable …

Investigations In The Cellular And Molecular Biology Of Human Airway Mucociliary Tissue, Vincent Manna

Graduate School of Biomedical Sciences Theses and Dissertations

Our laboratory has integrated the use of a human-derived, in vitro model of airway mucociliary tissue. We isolate human nasal epithelial cells (HNECs) from the nasal mucociliary tissue of donors with a small brush and expand the airway progenitor cells in culture. The HNECs are then seeded onto semi-permeable transwell inserts. The inserts are in contact with the media in the lower chamber but don’t contain media in the upper chamber therefore the cells are exposed to the air while drawing nutrients from the media below, this is called the Air-Liquid Interface (ALI). HNECs cultured at the ALI initiate a …

Replication Protein A (Rpa) Targeting Of Uracil Dna Glycosylase (Ung2), Derek Chen, Brian P Weiser

Rowan-Virtua Research Day

Replication Protein A (RPA) is a single stranded DNA binding protein which stabilizes ssDNA for replication and repair. One function of RPA is to bind the DNA repair enzyme uracil DNA glycosylase (UNG2) and direct its activity towards ssDNA dsDNA junctions.

UNG2 removes uracil bases from DNA which can appear through dUMP misincorporation or through cytosine deamination. If uracil is present instead of a cytosine, then the original GC pair becomes a GU pair. The uracil will then base pair to adenine in the replicated daughter strand. This results in a GC → AT mutation that could contribute to cancer …

Substrate-Dependent Modulation Of Sirt2 By A Fluorescent Probe, 1-Aminoanthracene, David Bi, Prashit Parikh, Jie Yang, Brian P Weiser

Rowan-Virtua Research Day

Sirtuin isoform 2 (SIRT2) is an enzyme that catalyzes the removal of acyl groups from lysine residues. SIRT2’s catalytic domain has a hydrophobic tunnel where its substrate acyl groups bind. Here, we report that the fluorescent probe 1-aminoanthracene (AMA) binds within SIRT2’s hydrophobic tunnel in a substrate-dependent manner. AMA’s interaction with SIRT2 was characterized by its enhanced fluorescence upon protein binding (>10-fold). AMA interacted weakly with SIRT2 alone in solution (Kd = 37 μM). However, when SIRT2 was equilibrated with a decanoylated peptide substrate, AMA’s affinity for SIRT2 was enhanced ∼10-fold (Kd = 4μM). The peptide’s decanoyl chain and …