Molecular Biology Commons^™

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 Faculty Scholarship

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 …

Med13 Degradation Defines A New Receptor-Mediated Autophagy Pathway Activated By Nutrient Deprivation, Sara E. Hanley

Graduate School of Biomedical Sciences Theses and Dissertations

Cells are exposed to an enormous amount of diverse extracellular cues but have a limited arsenal of weapons for protecting and maintaining homeostasis. To overcome these restrictions, nature has engineered proteins that have multiple functions. The pleiotropy of using one protein to carry out a variety of functions allows cells to rapidly execute tailored responses to a diverse set of signals. The Cdk8 kinase module (CKM) is a conserved detachable unit of the Mediator complex predominantly known for its role in transcriptional regulation. The CKM is composed of four proteins, the scaffolding proteins Med13 and Med12, as well as the …

Characterization Of The Full-Length Bag3 Protein And Stress Induced Formation Of Bag3-Z, Ahmed Gamal Abdalla Zied

Master's Theses

Bcl2-associated athanogene-3 (BAG3) is a pro-autophagy co-chaperone that we havepreviously shown localizes to the cardiac sarcomere and is critical for proteostasis and maintenance of normal sarcomeric function. Indeed, BAG3 loss in heart failure (HF) results in accumulation of ubiquitinated sarcomeric proteins, and depressed maximum force generating capacity (Fmax). However, how BAG3 is regulated in the cell is not well understood, with uncertainty about its structure and proteoforms. During our analysis of human heart tissue, BAG3 appears as a “doublet”, with one band at 74 kDa (BAG3-Z) and a second at a higher 85 kDa (BAG3-FL). Previous studies hypothesized the full-length …

Calmodulin Like 38 Is Required For Autophagy Of Hypoxia-Induced Cytoplasmic Rna Granules In Arabidopsis Thaliana, Sterling Field

Doctoral Dissertations

In response to the energy crisis resulting from submergence stress and hypoxia, the model plant Arabidopsis thaliana limits non-essential mRNA translation, and accumulates cytosolic stress granules. Stress granules are phase-separated mRNA-protein particles that partition transcripts for various fates: storage, degradation, or return to translation after stress alleviation. Another response by the plant cell to low oxygen stress is the induction of the turnover pathway autophagy. Stress granule regulation by autophagy occurs by a ‘granulophagy’ pathway in yeast and mammalian systems through which parts or whole stress granules are degraded. Whether this occurs in plants has not been investigated.

A connection …

Synphilin-1 And Its Effects On Pathogenesis Of Parkinson’S Disease, Mirghani Mohamed

Honors Scholar Theses

Parkinson's Disease (PD) is a progressive neurodegenerative and movement disorder primarily caused by the degradation of dopaminergic neurons. Known markers of neurodegeneration in PD are Lewy Bodies, which are fibrillar aggregates that are found in the brains of PD patients. Lewy Bodies can accumulate from specific mutations in the SNCA gene that codes for alpha-synuclein, a protein enriched in presynaptic neurons. A mutated SNCA gene can cause conformational aggregates of alpha-synuclein to form toxic species mediating neuronal death. Research into alpha-synuclein has led to the discovery of a binding partner known as synphilin-1 that is also found in protein aggregates …

Post-Translational Modification And Degradation Mechanisms Of The Aryl Hydrocarbon Receptor, Yujie Yang

University of the Pacific Theses and Dissertations

The aryl hydrocarbon receptor (AHR) is a transcription factor first discovered to be activated by exogenous ligands, such as dioxins, and helps promote downstream gene (e.g. CYP1A1) transcription to metabolize the toxicants. With the reports of various AHR targets genes, the expression levels and activities of AHR have been implicated in many physiological and pathological situations. Understanding how AHR protein level is regulated would provide more information to target AHR. AHR stays in the cytosol in the absence of ligand in a complex with HSP90, p23 and XAP2. After ligand activation, AHR translocates into the nucleus, fulfilling its transactivation function …

Ionic Mechanism Of Lysosomal Function And Cell Metabolism, Jian Xiong

Dissertations & Theses (Open Access)

Two Pore Channels (TPCs) are endolysosomal ion channels that are permeable to sodium and calcium. Defects in TPCs have been implicated to impair vesicle trafficking, autophagy and cell metabolism control; however, the detailed mechanism remains largely unknown. In this study, I show that TPCs are critical for appropriate cargo delivery to the lysosomes and deletion of either TPC1 or TPC2 leads to delayed clearance of autophagosomes, resulting in enlarged lysosomes and accumulated contents inside the lysosomes. Cells with both TPC deleted also exhibit 50% reduction in lysosomal amino acids under normal culture conditions, leading to reduced homeostatic mTORC1 activation.

Glutamine …

Cloning And Expression Of Human Synaptosome Associated Protein 29 In E. Coli, Logan M. Ryals

Honors Theses

Acting as the chief mediators of vesicular fusion, soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) play a role in many intracellular trafficking events by moving opposing membranes into close proximity. One such event takes place in the process of autophagy. A key SNARE involved in autophagy is Synaptosome Associated Protein 29 (SNAP-29), which acts on the autophagosome membrane to promote autophagosome and lysosome fusion. Kaposi’s Sarcoma Herpesvirus (KSHV) proteins ORF33 and ORF38 were demonstrated to interact with SNAP-29. The exact mechanism of this interaction is yet to be elucidated but it is hypothesized that these interactions allow KSHV to modulate …

Novel Post-Translational Modification And Function Of Fus: The Relevance To Amyotrophic Lateral Sclerosis, Alexandra Arenas

Theses and Dissertations--Toxicology and Cancer Biology

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by the preferential death of motor neurons. Approximately 10% of ALS cases are familial and 90% are sporadic. Fused in Sarcoma (FUS) is a ubiquitously expressed RNA binding protein implicated in familial ALS and frontotemporal dementia (FTD). FUS is ubiquitously expressed in cells and has a variety of functions in the nucleus and cytoplasm. FUS mutations in the nuclear localization sequence (NLS) causes mislocalization of FUS in the cytoplasm, where it can undergo liquid-liquid phase separation and become stress granules or protein inclusions. Although FUS inclusion bodies can be found in …

Investigating Autophagy Dysfunction Induced By A Parkinson's Disease-Causing Mutation In Vps35, Abir Ashfakur Rahman

Boise State University Theses and Dissertations

Parkinson’s Disease (PD) is an idiopathic disorder with no known cure. With number of cases steadily rising around the world, it is imperative to turn to the underlying cellular and molecular mechanisms of the disease manifestation and neurodegeneration to craft novel modes of therapy. VPS35 is one of the few genes that have identified and definitively linked to familial PD. The particular mutation that has been associated is known to cause dysfunction of a key cellular process known as autophagy. This process is primarily responsible for clearance of unwanted, damaged or misfolded proteins, among other things. Our study reveals an …

Mechanisms Adopted By Dengue-2 Viruses To Induce Autophagy In Mammalian Cells, Sounak Ghosh Roy

Dissertations, Theses, and Capstone Projects

Dengue, the most rapidly spreading flavivirus, threatens to affect almost half of the human global population. We previously showed that dengue-2 protects canine kidney cells (MDCK) from cytotoxic chemicals. We showed, independently, that cell protection, as well as viral replication and maturation, are positively regulated by PI3K-dependent autophagy. However, we had not identified the specific pathway that induces autophagy in infected cells. The current study explores the role of a specific branch of the endoplasmic reticulum (ER) stress-mediated Unfolded Protein Response (UPR), the PERK/eIF2α/ATF4 pathway in the induction of autophagy by …

Till Death Do Us Part: The Marriage Of Autophagy And Apoptosis., Katrina F Cooper

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Autophagy is a widely conserved catabolic process that is necessary for maintaining cellular homeostasis under normal physiological conditions and driving the cell to switch back to this status quo under times of starvation, hypoxia, and oxidative stress. The potential similarities and differences between basal autophagy and stimulus-induced autophagy are still largely unknown. Both act by clearing aberrant or unnecessary cytoplasmic material, such as misfolded proteins, supernumerary and defective organelles. The relationship between reactive oxygen species (ROS) and autophagy is complex. Cellular ROS is predominantly derived from mitochondria. Autophagy is triggered by this event, and by clearing the defective organelles effectively, …

Syk Promotes Tgf-Beta-Induced P-Body Clearance In Breast Cancer Cells Through The Enhancement Of Autophagy, Shana D. Hardy

Open Access Dissertations

SYK is a protein tyrosine kinase that plays an essential role in the development and activation of immune cells. Its expression, however, is not limited to immune cells. SYK is expressed in a variety of epithelial cell types and epithelial-derived tumors. Reports regarding the role of SYK expression in these diverse cell types and tumors have been opposing. In breast cancer, SYK expression has been overwhelmingly associated with tumor suppression. The loss of Syk expression is observed in invasive breast carcinoma tissue and cell lines and the reintroduction of Syk into metastatic breast cancer cells suppresses tumor growth and metastasis. …

Inhibiting The Interaction Between Grp94 And Myocilin To Treat Primary Open-Angle Glaucoma, Andrew Stothert

USF Tampa Graduate Theses and Dissertations

Glaucoma is a neurodegenerative protein misfolding disorder classified by increases in IOP, damage to retinal ganglion cells (RGCs), optic nerve (ON) head damage, and progressive irreversible blindness. Primary open-angle glaucoma (POAG) is the most common form of glaucoma, constituting over 90% of clinical cases. POAG is observed in patients where normal outflow channels, mainly the trabecular meshwork (TM), are exposed at the angle formed by the iris and cornea. However, due to TM cellular dysfunction, aqueous outflow resistance is increased preventing normal circulation of aqueous humor. Recent studies have shown that in 2-4% of POAG cases, increased intracellular levels of …

Axonal Transport And Life Cycle Of Mitochondria In Parkinson's Disease Model, Hyun Sung

Open Access Dissertations

In neurons, normal distribution and selective removal of mitochondria are essential for preserving compartmentalized cellular function. Parkin, an E3 ubiquitin ligase associated with familial Parkinson’s disease, has been implicated in mitochondrial dynamics and removal. However, it is not clear how Parkin plays a role in mitochondrial turnover in vivo, and whether the mature neurons possess a compartmentalized Parkin-dependent mitochondrial life cycle. Using the live Drosophila nervous system, here, I investigate the involvement of Parkin in mitochondrial dynamics; organelle distribution, morphology and removal. Parkin deficient animals displayed less number of axonal mitochondria without disturbing organelle motility behaviors, morphology and metabolic state. …

Decorin As A Multivalent Therapeutic Agent Against Cancer., Thomas Neill, Liliana Schaefer, Renato V. Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Decorin is a prototypical small leucine-rich proteoglycan that epitomizes the multifunctional nature of this critical gene family. Soluble decorin engages multiple receptor tyrosine kinases within the target-rich environment of the tumor stroma and tumor parenchyma. Upon receptor binding, decorin initiates signaling pathways within endothelial cells downstream of VEGFR2 that ultimately culminate in a Peg3/Beclin 1/LC3-dependent autophagic program. Concomitant with autophagic induction, decorin blunts capillary morphogenesis and endothelial cell migration, thereby significantly compromising tumor angiogenesis. In parallel within the tumor proper, decorin binds multiple RTKs with high affinity, including Met, for a multitude of oncosuppressive functions including growth inhibition, tumor cell …

Mir494 Reduces Renal Cancer Cell Survival Coinciding With Increased Lipid Droplets And Mitochondrial Changes, Punashi Dutta, Edward Haller, Arielle Sharp, Meera Nanjundan

Molecular Biosciences Faculty Publications

Background: miRNAs can regulate cellular survival in various cancer cell types. Recent evidence implicates the formation of lipid droplets as a hallmark event during apoptotic cell death response. It is presently unknown whether MIR494, located at 14q32 which is deleted in renal cancers, reduces cell survival in renal cancer cells and if this process is accompanied by changes in the number of lipid droplets.

Methods: 769-P renal carcinoma cells were utilized for this study. Control or MIR494 mimic was expressed in these cells following which cell viability (via crystal violet) and apoptotic cell numbers (via Annexin V/PI staining) were …

Effect Of Hydroxychloroquine And Characterization Of Autophagy In A Mouse Model Of Endometriosis, A. Ruiz, S. Rockfield, N. Taran, E. Haller, Robert Engelman, I Flores, P Panina-Bordignon, Meera Nanjundan

Molecular Biosciences Faculty Publications

In endometriosis, the increased survival potential of shed endometrial cells (which normally undergo anoikis) is suggested to promote lesion development. One mechanism that may alter anoikis is autophagy. Using an autophagic flux inhibitor hydroxychloroquine (HCQ), we identified that it reduces the in vitro survival capacity of human endometriotic and endometrial T-HESC cells. We also identified that HCQ could decrease lesion numbers and disrupt lesion histopathology, as well as increase the levels of peritoneal macrophages and the IP-10 (10 kDa interferon-γ-induced protein) chemokine in a mouse model of endometriosis. We noted that RNA levels of a subset of autophagic …

Autophagy And Its Potential Role In Stress And Feed Efficiency Using Avian Lines, Alissa Laura Piekarski

Graduate Theses and Dissertations

Autophagy is a highly conserved cellular mechanism that is responsible for the degradation and recycling of damaged organelles. Recently, autophagy has been involved in critical roles during overall development of the organism and degradation of damaged cellular components. This pathway has witnessed dramatic growth in the last few years and has been extensively studied in yeast and mammals, however, there is a paucity of information in avian (non-mammalian) species. First, we characterized genes involved in the autophagy pathway in male and female Jungle Fowl to determine gender and tissue specific differences. Secondly, tissue and genotype differences in Japanese quail selected …

Leptin Regulates The Expression Of Autophagy-Related Genes In Chickens, Peter Olawale Ishola

Graduate Theses and Dissertations

Autophagy or cellular self-digestion, a lysosomal degradation pathway that is conserved from yeast to human, plays a key role in recycling cellular constituents, including damaged organelles. It also plays a pivotal role in the adaptation of cells to a plethora of distinct stressors including starvation. Autophagy has been extensively studied in mammals and yeast, but little is known in avian species. Thus, the major objective of the present study was to determine the effects of leptin on autophagy-related genes in chicken hypothalamus, muscle and liver. Leptin is an adipocytokine that is mostly produced by white adipose cells in mammals (as …

A Protective Role Of Autophagy In A Drosophila Model Of Friedreich's Ataxia (Frda), Luan Wang

Wayne State University Dissertations

Friedreich’s ataxia (FRDA) is an inherited autosomal recessive neurodegenerative disease. It affects 1 in every 50,000 people in central Europe and North America. FRDA is caused by deficiency of Frataxin, an essential mitochondrial iron chaperone protein, and the associated oxidative stress damages. Autophagy, a housekeeping process responsible for the bulk degradation and turnover of long half-life proteins and organelles, is featured by the formation of double-membrane vacuoles and lysosomal degradation. Previous researches indicate that Danon’s disease, the inherited neural disorder disease that shares similar symptoms with FRDA, is due to the malfunction of autophagy. Based on this, we raise the …

Cardiolipin Regulates Mitophagy Through The Pkc Pathway, Zheni Shen

Wayne State University Dissertations

Cardiolipin (CL), the signature phospholipid of mitochondrial membranes, is important for cardiovascular health. Perturbation of CL metabolism is implicated in cardiovascular disease (CVD). The link between CL and CVD may be explained by the physiological roles of CL in pathways that are cardioprotective, such as autophagy/mitophagy and the mitogen-activated protein kinase (MAPK) pathways. My dissertation work focuses on elucidating how CL influences mitophagy and MAPK pathways.

crd1Δ was synthetically lethal/sick with the general autophagy mutants atg8Δ, atg18Δ and mitophagy mutant atg32Δ, suggesting that autophagy/mitophagy may be deficient in cells lacking CL. Microscopic examination of mitophagy revealed decreased translocation of GFP-tagged …

Potential Targeted Therapeutic Strategies For Overcoming Resistance In Braf Wild Type Melanoma, Vito William Rebecca

USF Tampa Graduate Theses and Dissertations

Melanoma manifests itself from the malignant transformation of melanocytes and represents the deadliest form of skin cancer, being responsible for the disproportionate majority of all skin cancer deaths. The 2002 discovery that 50% of all melanoma patients possess activating BRAF mutations ignited a significant paradigm shift in the way the melanoma field approached research and how patients were treated [1]. The era of targeted therapy had begun and with it came successful targeted BRAF inhibitor therapy regimens, which have accomplished improved clinical benefit (response rate, progression free survival, and overall survival) compared with treatment with chemotherapy in three phase III …

Signals Delivered By Interleukin-7 Regulate The Activities Of Bim And Jund In T Lymphocytes, Shannon Moore Ruppert

Electronic Theses and Dissertations

Interleukin-7 (IL-7) is an essential cytokine for lymphocyte growth that has the potential for promoting proliferation and survival. While the survival and proliferative functions of IL-7 are well established, the identities of IL-7 signaling components in pathways other than JAK/STAT, that accomplish these tasks remain poorly defined. To this end, we used IL-7 dependent T-cells to examine those components necessary for cell growth and survival. Our studies revealed two novel signal transducers of the IL-7 growth signal: BimL and JunD. IL-7 promoted the activity of JNK (Jun N-terminal Kinase), and that JNK, in turn, drove the expression of JunD, a …

Molecular Mechanism Of Agc Kinases In Human Malignant, Shaokun Shu

USF Tampa 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 …