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Articles 1 - 12 of 12

Full-Text Articles in Cell Biology

The Nf-Kappab Factor Relish Regulates Atg1 Expression And Controls Autophagy, Anubhab Nandy, Lin Lin, Panagiotis D. Velentzas, Louisa P. Wu, Eric H. Baehrecke, Neal S. Silverman Nov 2018

The Nf-Kappab Factor Relish Regulates Atg1 Expression And Controls Autophagy, Anubhab Nandy, Lin Lin, Panagiotis D. Velentzas, Louisa P. Wu, Eric H. Baehrecke, Neal S. Silverman

Open Access Articles

Macroautophagy and cell death both contribute to innate immunity, but little is known about how these processes integrate. Drosophila larval salivary glands require autophagy for developmentally programmed cell death, and innate immune signaling factors increase in these dying cells. Here, we show that the nuclear factor kappaB (NF-kappaB) factor Relish, a component of the immune deficiency (Imd) pathway, is required for salivary gland degradation. Surprisingly, of the classic Imd pathway components, only Relish and the PGRP receptors were involved in salivary gland degradation. Significantly, Relish controls salivary gland degradation by regulating autophagy but not caspases. In addition, expression of either ...


Role Of Jip1-Jnk Signaling In Beta-Cell Function And Autophagy, Seda Barutcu Jan 2018

Role Of Jip1-Jnk Signaling In Beta-Cell Function And Autophagy, Seda Barutcu

GSBS Dissertations and Theses

Proper functioning of endocrine cells is crucial for organismal homeostasis. The underlying mechanisms that fine-tune the amount, and the timing of hormone secretion are not clear. JIP1 / MAPK8IP1 (JNK interacting protein 1) is a scaffold protein that mediates cellular stress response, and is highly expressed in endocrine cells, including insulin secreting b-cells in pancreas islets. However, the role of JIP1 in b-cells is unclear. This study demonstrates that b-cell specific Jip1 ablation results in decreased glucose-induced insulin secretion, without a change in Insulin1 and Insulin2 gene expression. Inhibition of both JIP1-kinesin interaction, and JIP1-JNK interaction by genetic mutations also resulted ...


Complement-Related Regulates Autophagy In Neighboring Cells, Lin Lin Jun 2017

Complement-Related Regulates Autophagy In Neighboring Cells, Lin Lin

GSBS Dissertations and Theses

Autophagy is a conserved process that cells use to degrade their own cytoplasmic components by delivery to lysosomes. Autophagy ensures intracellular quality control and is associated with diseases such as cancer and immune disorders. The process of autophagy is controlled by core autophagy (Atg) genes that are conserved from yeast to mammal. Most Atg proteins and their regulators were identified through pioneering studies of the single cell yeast Saccharomyces cerevisiae, and little is known about factors that systematically coordinate autophagy within the tissues of multicellular animals. The goal of this thesis is to identify new autophagy regulators and provide a ...


Hlh-30/Tfeb-Mediated Autophagy Functions In A Cell-Autonomous Manner For Epithelium Intrinsic Cellular Defense Against Bacterial Pore-Forming Toxin In C. Elegans, Huan-Da Chen, Raffi V. Aroian, Chang-Shi Chen Feb 2017

Hlh-30/Tfeb-Mediated Autophagy Functions In A Cell-Autonomous Manner For Epithelium Intrinsic Cellular Defense Against Bacterial Pore-Forming Toxin In C. Elegans, Huan-Da Chen, Raffi V. Aroian, Chang-Shi Chen

Open Access Articles

Autophagy is an evolutionarily conserved intracellular system that maintains cellular homeostasis by degrading and recycling damaged cellular components. The transcription factor HLH-30/TFEB-mediated autophagy has been reported to regulate tolerance to bacterial infection, but less is known about the bona fide bacterial effector that activates HLH-30 and autophagy. Here, we reveal that bacterial membrane pore-forming toxin (PFT) induces autophagy in an HLH-30-dependent manner in Caenorhabditis elegans. Moreover, autophagy controls the susceptibility of animals to PFT toxicity through xenophagic degradation of PFT and repair of membrane-pore cell-autonomously in the PFT-targeted intestinal cells in C. elegans. These results demonstrate that autophagic pathways ...


Two Components Of Maintaining Developmental Competence: Microrna-21 In The Maturing Oocyte And Autophagy Induction In The Follicular Stage Ovary, Benjamin J. Hale Jan 2017

Two Components Of Maintaining Developmental Competence: Microrna-21 In The Maturing Oocyte And Autophagy Induction In The Follicular Stage Ovary, Benjamin J. Hale

Graduate Theses and Dissertations

This dissertation describes two processes that the oocyte and ovary potentially utilize to maintain reproductive competence: autophagy in response to heat stress and microRNA-21 function during meiotic maturation. Heat stress (HS) occurs when heat accumulation (from internal and external sources) exceeds heat dissipation. HS is associated with seasonal infertility and therefore is a production issue and profitability constraint in the swine industry. Autophagy is the process by which somatic cells recycle cellular components and it is activated by a variety of stressors. Therefore, characterizing autophagy in the ovary and oocyte is valuable because of the potential of autophagy to mitigate ...


Emerging Evidence For Beneficial Macrophage Functions In Atherosclerosis And Obesity-Induced Insulin Resistance, Timothy P. Fitzgibbons, Michael P. Czech Mar 2016

Emerging Evidence For Beneficial Macrophage Functions In Atherosclerosis And Obesity-Induced Insulin Resistance, Timothy P. Fitzgibbons, Michael P. Czech

University of Massachusetts Medical School Faculty Publications

The discovery that obesity promotes macrophage accumulation in visceral fat led to the emergence of a new field of inquiry termed "immunometabolism". This broad field of study was founded on the premise that inflammation and the corresponding increase in macrophage number and activity was a pathologic feature of metabolic diseases. There is abundant data in both animal and human studies that supports this assertation. Established adverse effects of inflammation in visceral fat include decreased glucose and fatty acid uptake, inhibition of insulin signaling, and ectopic triglyceride accumulation. Likewise, in the atherosclerotic plaque, macrophage accumulation and activation results in plaque expansion ...


Current Questions And Possible Controversies In Autophagy, L M. Lindqvist, A K. Simon, Eric H. Baehrecke Nov 2015

Current Questions And Possible Controversies In Autophagy, L M. Lindqvist, A K. Simon, Eric H. Baehrecke

Open Access Articles

Interest in autophagy has exploded over the last decade, with publications highlighting crosstalk with several other cellular processes including secretion, endocytosis, and cell suicide pathways including apoptosis. Autophagy proteins have also been implicated in other cellular processes independently of their roles in autophagy, creating complexities in the interpretation of autophagy (Atg) mutant gene data. Interestingly, this self-eating process is a survival mechanism that can also promote cell death, but when and how autophagy may 'switch' its function is still under debate. Indeed, there are currently many models of how autophagy actually influences cell death. In this review, we highlight some ...


Role And Regulation Of Autophagy During Developmental Cell Death In Drosophila Melanogaster: A Dissertation, Kirsten M. Tracy Apr 2015

Role And Regulation Of Autophagy During Developmental Cell Death In Drosophila Melanogaster: A Dissertation, Kirsten M. Tracy

GSBS Dissertations and Theses

Autophagy is a conserved catabolic process that traffics cellular components to the lysosome for degradation. Autophagy is required for cell survival during nutrient restriction, but it has also been implicated in programmed cell death. It is associated with several diseases, including cancer. Cancer is a disease characterized by aberrant cell growth and proliferation. To support this growth, the tumor cell often deregulates several metabolic processes, including autophagy. Interestingly, autophagy plays paradoxical roles in tumorigenesis. It has been shown to be both tumor suppressive through cell death mechanisms and tumor promoting through its cytoprotective properties. However, the mechanisms regulating the balance ...


Microrna Regulation Of Autophagy During Programmed Cell Death: A Dissertation, Charles J. Nelson Mar 2015

Microrna Regulation Of Autophagy During Programmed Cell Death: A Dissertation, Charles J. Nelson

GSBS Dissertations and Theses

Autophagy delivers cytoplasmic material to the lysosome for degradation, and has been implicated in many cellular processes, including stress, infection, survival, and death. Although the regulation and role that autophagy plays in stress, infection, and survival is apparent, its involvement during cell death remains relatively unclear. In this thesis I summarize what is known about the roles autophagy can play in cell death, and the differences between the utilization of autophagy during nutrient deprivation and cell death. Utilizing Drosophila melanogaster as a model system, the roles autophagy plays in both of these contexts can be studied. The goal of this ...


A Novel Autophagy Regulatory Mechanism That Functions During Programmed Cell Death: A Dissertation, Tsun-Kai Chang Sep 2013

A Novel Autophagy Regulatory Mechanism That Functions During Programmed Cell Death: A Dissertation, Tsun-Kai Chang

GSBS Dissertations and Theses

Autophagy is a cellular process that delivers cytoplasmic materials for degradation by the lysosomes. Autophagy-related (Atg) genes were identified in yeast genetic screens for vehicle formation under stress conditions, and Atg genes are conserved from yeast to human. When cells or animals are under stress, autophagy is induced and Atg8 (LC3 in mammal) is activated by E1 activating enzyme Atg7. Atg8-containing membranes form and surround cargos, close and mature to become the autophagosomes. Autophagosomes fuse with lysosomes, and cargos are degraded by lysosomal enzymes to sustain cell viability. Therefore, autophagy is most frequently considered to function in cell survival. Whether ...


Role Of Autophagy In Post-Mitotic Midbody Fate And Function: A Dissertation, Tse-Chun Kuo Mar 2013

Role Of Autophagy In Post-Mitotic Midbody Fate And Function: A Dissertation, Tse-Chun Kuo

GSBS Dissertations and Theses

The midbody (MB) is a proteinaceous complex formed between the two daughter cells during cell division and is required for the final cell separation event in late cytokinesis. After cell division, the post-mitotic midbody, or midbody derivative (MBd), can be retained and accumulated in a subpopulation of cancer cells and stem cells, but not in normal diploid differentiated cells. However, the mechanisms by which MBds accumulate and function are unclear. Based on this, I hypothesize that the MBd is degraded by autophagy after cell division in normal diploid differentiated cells, whereas non-differentiated cells have low autophagic ...


Jnk Regulates Foxo-Dependent Autophagy In Neurons, Ping Xu, Madhumita Das, Judith Reilly, Roger J. Davis Feb 2011

Jnk Regulates Foxo-Dependent Autophagy In Neurons, Ping Xu, Madhumita Das, Judith Reilly, Roger J. Davis

Davis Lab Publications

The cJun N-terminal kinase (JNK) signal transduction pathway is implicated in the regulation of neuronal function. JNK is encoded by three genes that play partially redundant roles. Here we report the creation of mice with targeted ablation of all three Jnk genes in neurons. Compound JNK-deficient neurons are dependent on autophagy for survival. This autophagic response is caused by FoxO-induced expression of Bnip3 that displaces the autophagic effector Beclin-1 from inactive Bcl-XL complexes. These data identify JNK as a potent negative regulator of FoxO-dependent autophagy in neurons.