Proteasome-Independent Functions of Ubiquitin in Endocytosis and Signaling

Science ◽  
2007 ◽  
Vol 315 (5809) ◽  
pp. 201-205 ◽  
Author(s):  
Debdyuti Mukhopadhyay ◽  
Howard Riezman
Keyword(s):  
Neurodegenerative Disorders ◽  
Posttranslational Modification ◽  
Protein Trafficking ◽  
Cellular Proteins ◽  
Cellular Processes ◽  
Signal Transduction Protein ◽  
Major Player ◽  
Independent Functions ◽  
Inflammatory Immune Response ◽  
Ubiquitination System

Ubiquitination is a reversible posttranslational modification of cellular proteins, in which a 76–amino acid polypeptide, ubiquitin, is primarily attached to the ϵ-amino group of lysines in target proteins. Ubiquitination is a major player in regulating a broad host of cellular processes, including cell division, differentiation, signal transduction, protein trafficking, and quality control. Aberrations in the ubiquitination system are implicated in pathogenesis of some diseases, certain malignancies, neurodegenerative disorders, and pathologies of the inflammatory immune response. Here, we discuss the proteasome-independent roles of ubiquitination in signaling and endocytosis.

SNF1-related protein kinase 1: the many-faced signaling hub regulating developmental plasticity in plants

2021 ◽  
Author(s):  
Muhammed Jamsheer K ◽  
Manoj Kumar ◽  
Vibha Srivastava
Keyword(s):  
Protein Kinase ◽  
Environmental Conditions ◽  
Protein Trafficking ◽  
Developmental Plasticity ◽  
Inositol Phosphate ◽  
Future Research ◽  
Primary Metabolism ◽  
Related Protein ◽  
Comprehensive Overview ◽  
Cellular Processes

AbstractThe Snf1-related protein kinase 1 (SnRK1) is the plant homolog of the heterotrimeric AMP-activated protein kinase/sucrose non-fermenting 1 (AMPK/Snf1), which works as a major regulator of growth under nutrient-limiting conditions in eukaryotes. Along with its conserved role as a master regulator of sugar starvation responses, SnRK1 is involved in controlling the developmental plasticity and resilience under diverse environmental conditions in plants. In this review, through mining and analyzing the interactome and phosphoproteome data of SnRK1, we are highlighting its role in fundamental cellular processes such as gene regulation, protein synthesis, primary metabolism, protein trafficking, nutrient homeostasis, and autophagy. Along with the well-characterized molecular interaction in SnRK1 signaling, our analysis highlights several unchartered regions of SnRK1 signaling in plants such as its possible communication with chromatin remodelers, histone modifiers, and inositol phosphate signaling. We also discuss potential reciprocal interactions of SnRK1 signaling with other signaling pathways and cellular processes, which could be involved in maintaining flexibility and homeostasis under different environmental conditions. Overall, this review provides a comprehensive overview of the SnRK1 signaling network in plants and suggests many novel directions for future research.

Mechanistic roles for altered O-GlcNAcylation in neurodegenerative disorders

2021 ◽  
Vol 478 (14) ◽  
pp. 2733-2758
Author(s):  
Aaron T. Balana ◽  
Matthew R. Pratt
Keyword(s):  
Neurodegenerative Diseases ◽  
Neurodegenerative Disorders ◽  
Posttranslational Modification ◽  
Protein Quality ◽  
Neuronal Dysfunction ◽  
Neuronal Communication ◽  
Programmed Death ◽  
Growing Body ◽  
Potential Strategy ◽  
Therapeutic Avenue

Neurodegenerative diseases such as Alzheimer's and Parkinson's remain highly prevalent and incurable disorders. A major challenge in fully understanding and combating the progression of these diseases is the complexity of the network of processes that lead to progressive neuronal dysfunction and death. An ideal therapeutic avenue is conceivably one that could address many if not all of these multiple misregulated mechanisms. Over the years, chemical intervention for the up-regulation of the endogenous posttranslational modification (PTM) O-GlcNAc has been proposed as a potential strategy to slow down the progression of neurodegeneration. Through the development and application of tools that allow dissection of the mechanistic roles of this PTM, there is now a growing body of evidence that O-GlcNAc influences a variety of important neurodegeneration-pertinent mechanisms, with an overall protective effect. As a PTM that is appended onto numerous proteins that participate in protein quality control and homeostasis, metabolism, bioenergetics, neuronal communication, inflammation, and programmed death, O-GlcNAc has demonstrated beneficence in animal models of neurodegenerative diseases, and its up-regulation is now being pursued in multiple clinical studies.

scholarly journals The role of SCF ubiquitin-ligase complex at the beginning of life

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Jiayan Xie ◽  
Yimei Jin ◽  
Guang Wang
Keyword(s):  
Cell Cycle ◽  
Ubiquitin Ligase ◽  
Cellular Proteins ◽  
Cell Cycle Regulators ◽  
Signal Transducers ◽  
E3 Ligases ◽  
Cellular Processes ◽  
Ubiquitin Ligase Complex ◽  
Scf Ubiquitin Ligase

AbstractAs the largest family of E3 ligases, the Skp1-cullin 1-F-box (SCF) E3 ligase complex is comprised of Cullins, Skp1 and F-box proteins. And the SCF E3 ubiquitin ligases play an important role in regulating critical cellular processes, which promote degradation of many cellular proteins, including signal transducers, cell cycle regulators, and transcription factors. We review the biological roles of the SCF ubiquitin-ligase complex in gametogenesis, oocyte-to-embryo transition, embryo development and the regulation for estrogen and progestin. We find that researches about the SCF ubiquitin-ligase complex at the beginning of life are not comprehensive, thus more in-depth researches will promote its eventual clinical application.

scholarly journals Analysis of HIV-1 Gag Protein Interactions via Biotin Ligase Tagging

2015 ◽  
Vol 89 (7) ◽  
pp. 3988-4001 ◽  
Author(s):  
Christopher Ritchie ◽  
Isabel Cylinder ◽  
Emily J. Platt ◽  
Eric Barklis
Keyword(s):  
Lipid Metabolism ◽  
Rna Processing ◽  
Protein Trafficking ◽  
Cellular Proteins ◽  
Wild Type ◽  
Gag Protein ◽  
Gag Proteins ◽  
Biotin Ligase ◽  
Close Proximity ◽  
Hiv 1

ABSTRACTWe have examined the interactions of wild-type (WT) and matrix protein-deleted (ΔMA) HIV-1 precursor Gag (PrGag) proteins in virus-producing cells using a biotin ligase-tagging approach. To do so, WT and ΔMA PrGag proteins were tagged with theEscherichia colipromiscuous biotin ligase (BirA*), expressed in cells, and examined. Localization patterns of PrGag proteins and biotinylated proteins overlapped, consistent with observations that BirA*-tagged proteins biotinylate neighbor proteins that are in close proximity. Results indicate that BirA*-tagged PrGag proteins biotinylated themselves as well as WT PrGag proteins intrans. Previous data have shown that the HIV-1 Envelope (Env) protein requires an interaction with MA for assembly into virions. Unexpectedly, ΔMA proteins biotinylated Env, whereas WT BirA*-tagged proteins did not, suggesting that the presence of MA made Env inaccessible to biotinylation. We also identified over 50 cellular proteins that were biotinylated by BirA*-tagged PrGag proteins. These included membrane proteins, cytoskeleton-associated proteins, nuclear transport factors, lipid metabolism regulators, translation factors, and RNA-processing proteins. The identification of these biotinylated proteins offers new insights into HIV-1 Gag protein trafficking and activities and provides new potential targets for antiviral interference.IMPORTANCEWe have employed a novel strategy to analyze the interactions of the HIV-1 structural Gag proteins, which involved tagging wild-type and mutant Gag proteins with a biotin ligase. Expression of the tagged proteins in cells allowed us to analyze proteins that came in close proximity to the Gag proteins as they were synthesized, transported, assembled, and released from cells. The tagged proteins biotinylated proteins encoded by the HIV-1polgene and neighbor Gag proteins, but, surprisingly, only the mutant Gag protein biotinylated the HIV-1 Envelope protein. We also identified over 50 cellular proteins that were biotinylated, including membrane and cytoskeletal proteins and proteins involved in lipid metabolism, nuclear import, translation, and RNA processing. Our results offer new insights into HIV-1 Gag protein trafficking and activities and provide new potential targets for antiviral interference.

scholarly journals Deubiquitinating Function of Adenovirus Proteinase

2002 ◽  
Vol 76 (12) ◽  
pp. 6323-6331 ◽  
Author(s):  
Maxim Y. Balakirev ◽  
Michel Jaquinod ◽  
Arthur L. Haas ◽  
Jadwiga Chroboczek
Keyword(s):  
Structural Model ◽  
Proteolytic Processing ◽  
Host Cells ◽  
Cellular Proteins ◽  
Viral Gene ◽  
Cellular Processes ◽  
Infected Cells ◽  
Substrate Binding Sites

ABSTRACT The invasion strategy of many viruses involves the synthesis of viral gene products that mimic the functions of the cellular proteins and thus interfere with the key cellular processes. Here we show that adenovirus infection is accompanied by an increased ubiquitin-cleaving (deubiquitinating) activity in the host cells. Affinity chromatography on ubiquitin aldehyde (Ubal), which was designed to identify the deubiquitinating proteases, revealed the presence of adenovirus L3 23K proteinase (Avp) in the eluate from adenovirus-infected cells. This proteinase is known to be necessary for the processing of viral precursor proteins during virion maturation. We show here that in vivo Avp deubiquitinates a number of cellular proteins. Analysis of the substrate specificity of Avp in vitro demonstrated that the protein deubiquitination by this enzyme could be as efficient as proteolytic processing of viral proteins. The structural model of the Ubal-Avp interaction revealed some similarity between S1-S4 substrate binding sites of Avp and ubiquitin hydrolases. These results may reflect the acquisition of an advantageous property by adenovirus and may indicate the importance of ubiquitin pathways in viral infection.

scholarly journals Who's really in control: microbial regulation of protein trafficking in the epithelium

2014 ◽  
Vol 306 (3) ◽  
pp. C187-C197 ◽  
Author(s):  
Matthew R. Hendricks ◽  
Jennifer M. Bomberger
Keyword(s):  
Epithelial Cell ◽  
Protein Trafficking ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Cell Physiology ◽  
Cellular Physiology ◽  
Cellular Processes ◽  
Complex Interactions ◽  
Host Pathogen ◽  
Host Tissues

Due to evolutionary pressure, there are many complex interactions at the interface between pathogens and eukaryotic host cells wherein host cells attempt to clear invading microorganisms and pathogens counter these mechanisms to colonize and invade host tissues. One striking observation from studies focused on this interface is that pathogens have multiple mechanisms to modulate and disrupt normal cellular physiology to establish replication niches and avoid clearance. The precision by which pathogens exert their effects on host cells makes them excellent tools to answer questions about cell physiology of eukaryotic cells. Furthermore, an understanding of these mechanisms at the host-pathogen interface will benefit our understanding of how pathogens cause disease. In this review, we describe a few examples of how pathogens disrupt normal cellular physiology and protein trafficking at epithelial cell barriers to underscore how pathogens modulate cellular processes to cause disease and how this knowledge has been utilized to learn about cellular physiology.

scholarly journals Redox Homeostasis and Prospects for Therapeutic Targeting in Neurodegenerative Disorders

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Musbau Adewumi Akanji ◽  
Damilare Emmanuel Rotimi ◽  
Tobiloba Christiana Elebiyo ◽  
Oluwakemi Josephine Awakan ◽  
Oluyomi Stephen Adeyemi
Keyword(s):  
Neurodegenerative Diseases ◽  
Neurodegenerative Disorders ◽  
Redox Homeostasis ◽  
Reactive Species ◽  
Cellular Damage ◽  
Cellular Mechanisms ◽  
Cellular Redox ◽  
Redox Imbalance ◽  
Cellular Processes ◽  
The Brain

Reactive species, such as those of oxygen, nitrogen, and sulfur, are considered part of normal cellular metabolism and play significant roles that can impact several signaling processes in ways that lead to either cellular sustenance, protection, or damage. Cellular redox processes involve a balance in the production of reactive species (RS) and their removal because redox imbalance may facilitate oxidative damage. Physiologically, redox homeostasis is essential for the maintenance of many cellular processes. RS may serve as signaling molecules or cause oxidative cellular damage depending on the delicate equilibrium between RS production and their efficient removal through the use of enzymatic or nonenzymatic cellular mechanisms. Moreover, accumulating evidence suggests that redox imbalance plays a significant role in the progression of several neurodegenerative diseases. For example, studies have shown that redox imbalance in the brain mediates neurodegeneration and alters normal cytoprotective responses to stress. Therefore, this review describes redox homeostasis in neurodegenerative diseases with a focus on Alzheimer’s and Parkinson’s disease. A clearer understanding of the redox-regulated processes in neurodegenerative disorders may afford opportunities for newer therapeutic strategies.

scholarly journals Structures of Human Transglutaminase 2: Finding Clues for Interference in Cross-linking Mediated Activity

2020 ◽  
Vol 21 (6) ◽  
pp. 2225
Author(s):  
Gi Eob Kim ◽  
Hyun Ho Park
Keyword(s):  
Neurodegenerative Disorders ◽  
Active Site ◽  
Drug Target ◽  
Structural Information ◽  
Transglutaminase 2 ◽  
Cross Linking ◽  
Targeted Drugs ◽  
Clinical Use ◽  
Structural Studies ◽  
Cellular Processes

Human transglutaminase 2 (TGase2) has various functions, including roles in various cellular processes such as apoptosis, development, differentiation, wound healing, and angiogenesis, and is linked to many diseases such as cancer. Although TGase2 has been considered an optimized drug target for the treatment of cancer, fibrosis, and neurodegenerative disorders, it has been difficult to generate TGase2-targeted drugs for clinical use because of the relatively flat and broad active site on TGase2. To design more specific and powerful inhibitors, detailed structural information about TGase2 complexed with various effector and inhibitor molecules is required. In this review, we summarized the current structural studies on TGase2, which will aid in designing drugs that can overcome the aforementioned limitations.

An Insight Into Mitochondrial Dysfunction and its Implications in Neuro-logical Diseases

2020 ◽  
Vol 22 ◽  
Author(s):  
Asimul Islam ◽  
Anas Shamsi ◽  
Rashid Waseem ◽  
Syed Kazim
Keyword(s):  
Mitochondrial Dysfunction ◽  
Neurodegenerative Disorders ◽  
Large Body ◽  
Ros Generation ◽  
Cell Organelles ◽  
Ischemic Brain ◽  
Cellular Processes ◽  
Vital Cell ◽  
Insight Into

Abstract:: In the last few years, a massive increase in the research has been observed that focusses on investigating the role of mitochondria in pathogenesis of several neurodegenerative disorders. Mitochondria are vital cell organelles having im-portant roles in different cellular processes including energy production, calcium signaling, ROS generation, apoptosis, etc. Therefore, healthy mitochondria are necessary for cell survival and functioning. It would seem feasible that mitochondrial dysfunction will have implications in various pathological conditions. A large body of evidence indicates the role of mito-chondrion as a potential key player in the loss or dysfunction of neurons in various neurodegenerative disorders. In this review, we provide an insight into the mitochondrial dysfunction and its involvement in the pathology of several neurolog-ical diseases such as Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis, Hypoxic-Ischemic Brain Injury and many more.

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