scholarly journals The Role of ATG16 in Autophagy and The Ubiquitin Proteasome System

Cells ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 2 ◽  
Author(s):  
Qiuhong Xiong ◽  
Wenjing Li ◽  
Ping Li ◽  
Min Yang ◽  
Changxin Wu ◽  
...  

Autophagy and the ubiquitin proteasome system (UPS) are the two major cellular degradation pathways, which are critical for the maintenance of cell homeostasis. The two pathways differ in their mechanisms and clients. The evolutionary conserved ATG16 plays a key role in autophagy and appears to link autophagy with the UPS. Here, we review the role of ATG16 in different species. We summarize the current knowledge of its functions in autophagosome membrane expansion and autophagosome formation, in Crohn’s disease, and in bacterial sequestration. In addition, we provide information on its autophagy-independent functions and its role in the crosstalk between autophagy and the UPS.

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
Ruey-Hwa Chen ◽  
Yu-Hsuan Chen ◽  
Tzu-Yu Huang

Abstract Autophagy is a major degradation pathway that utilizes lysosome hydrolases to degrade cellular constituents and is often induced under cellular stress conditions to restore cell homeostasis. Another prime degradation pathway in the cells is ubiquitin-proteasome system (UPS), in which proteins tagged by certain types of polyubiquitin chains are selectively recognized and removed by proteasome. Although the two degradation pathways are operated independently with different sets of players, recent studies have revealed reciprocal cross talks between UPS and autophagy at multiple layers. In this review, we summarize the roles of protein ubiquitination and deubiquitination in controlling the initiation, execution, and termination of bulk autophagy as well as the role of ubiquitination in signaling certain types of selective autophagy. We also highlight how dysregulation of ubiquitin-mediated autophagy pathways is associated with a number of human diseases and the potential of targeting these pathways for disease intervention.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Mónika Lippai ◽  
Péter Lőw

The ubiquitin-proteasome system and autophagy were long viewed as independent, parallel degradation systems with no point of intersection. By now we know that these degradation pathways share certain substrates and regulatory molecules and show coordinated and compensatory function. Two ubiquitin-like protein conjugation pathways were discovered that are required for autophagosome biogenesis: the Atg12-Atg5-Atg16 and Atg8 systems. Autophagy has been considered to be essentially a nonselective process, but it turned out to be at least partially selective. Selective substrates of autophagy include damaged mitochondria, intracellular pathogens, and even a subset of cytosolic proteins with the help of ubiquitin-binding autophagic adaptors, such as p62/SQSTM1, NBR1, NDP52, and Optineurin. These proteins selectively recognize autophagic cargo and mediate its engulfment into autophagosomes by binding to the small ubiquitin-like modifiers that belong to the Atg8/LC3 family.


Author(s):  
Julia Jülg ◽  
Laura Strohm ◽  
Christian Behrends

Besides the ubiquitin-proteasome-system, autophagy is a major degradation pathway within cells. It delivers invading pathogens, damaged organelles, aggregated proteins and other macromolecules from the cytosol to the lysosome for bulk degradation. This so-called canonical autophagy activity contributes to the maintenance of organelle, protein and metabolite homeostasis as well as innate immunity. Over the past years, numerous studies rapidly deepened our knowledge on the autophagy machinery and its regulation; driven by the fact that impairment of autophagy is associated with several human pathologies including cancer, immune diseases and neurodegenerative disorders. Unexpectedly, components of the autophagic machinery were also found to participate in various processes that did not involve lysosomal delivery of cytosolic constituents. These functions are hereafter defined as non-canonical autophagy. Regarding neurodegenerative diseases, most research was performed in neurons, while for a long-time microglia received considerably less attention. Concomitant with the notion that microglia greatly contribute to brain health, the understanding of the role of autophagy in microglia expanded. To facilitate an overview of the current knowledge, we present herein the fundamentals as well as the recent advances of canonical and non-canonical autophagy functions in microglia.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Cecilia Vasti ◽  
Henning Witt ◽  
Matilde Said ◽  
Patricia Sorroche ◽  
Hernán García-Rivello ◽  
...  

The accumulating evidence demonstrates the essential role of neuregulin-1 signaling in the adult heart, and, moreover, indicates that an impaired neuregulin signaling exacerbates the doxorubicin-mediated cardiac toxicity. Despite this strong data, the specific cardiomyocyte targets of the active erbB2/erbB4 heterodimer remain unknown. In this paper, we examined pathways involved in cardiomyocyte damage as a result of the cardiac sensitization to anthracycline toxicity in the ventricular muscle-specific erbB4 knockout mouse. We performed morphological analyses to evaluate the ventricular remodeling and employed a cDNA microarray to assess the characteristic gene expression profile, verified data by real-time RT-PCR, and then grouped into functional categories and pathways. We confirm the upregulation of genes related to the classical signature of a hypertrophic response, implicating an erbB2-dependent mechanism in doxorubicin-treated erbB4-KO hearts. Our results indicate the remarkable downregulation of IGF-I/PI-3′ kinase pathway and extends our current knowledge by uncovering an altered ubiquitin-proteasome system leading to cardiomyocyte autophagic vacuolization.


Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 241 ◽  
Author(s):  
Antonia Wiegering ◽  
Ulrich Rüther ◽  
Christoph Gerhardt

Protein degradation is a pivotal process for eukaryotic development and homeostasis. The majority of proteins are degraded by the ubiquitin–proteasome system and by autophagy. Recent studies describe a crosstalk between these two main eukaryotic degradation systems which allows for establishing a kind of safety mechanism. If one of these degradation systems is hampered, the other compensates for this defect. The mechanism behind this crosstalk is poorly understood. Novel studies suggest that primary cilia, little cellular protrusions, are involved in the regulation of the crosstalk between the two degradation systems. In this review article, we summarise the current knowledge about the association between cilia, the ubiquitin–proteasome system and autophagy.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Elena Bellavista ◽  
Aurelia Santoro ◽  
Daniela Galimberti ◽  
Cristoforo Comi ◽  
Fabio Luciani ◽  
...  

The ubiquitin-proteasome system is the major intracellular molecular machinery for protein degradation and maintenance of protein homeostasis in most human cells. As ubiquitin-proteasome system plays a critical role in the regulation of the immune system, it might also influence the development and progression of multiple sclerosis (MS). Bothex vivoanalyses and animal models suggest that activity and composition of ubiquitin-proteasome system are altered in MS. Proteasome isoforms endowed of immunosubunits may affect the functionality of different cell types such as CD8+and CD4+T cells and B cells as well as neurons during MS development. Furthermore, the study of proteasome-related biomarkers, such as proteasome antibodies and circulating proteasomes, may represent a field of interest in MS. Proteasome inhibitors are already used as treatment for cancer and the recent development of inhibitors selective for immunoproteasome subunits may soon represent novel therapeutic approaches to the different forms of MS. In this review we describe the current knowledge on the potential role of proteasomes in MS and discuss thepro et contraof possible therapies for MS targeting proteasome isoforms.


2020 ◽  
Vol 158 (3) ◽  
pp. S21-S22
Author(s):  
Peilin Zhang ◽  
Lawrence Minardi ◽  
J. Todd Kuenstner ◽  
Steve Zekan ◽  
Rusty Kruzelock

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