scholarly journals Mitophagy: mechanisms, pathophysiological roles, and analysis

2012 ◽  
Vol 393 (7) ◽  
pp. 547-564 ◽  
Author(s):  
Wen-Xing Ding ◽  
Xiao-Ming Yin
Keyword(s):  
Cell Death ◽  
Blood Cells ◽  
Energy Homeostasis ◽  
Recent Progress ◽  
Tissue Injury ◽  
Current Knowledge ◽  
Terminal Differentiation ◽  
Cellular Functions ◽  
Drug Induced ◽  
Cellular Energy

Abstract Mitochondria are essential organelles that regulate cellular energy homeostasis and cell death. The removal of damaged mitochondria through autophagy, a process called mitophagy, is thus critical for maintaining proper cellular functions. Indeed, mitophagy has been recently proposed to play critical roles in terminal differentiation of red blood cells, paternal mitochondrial degradation, neurodegenerative diseases, and ischemia or drug-induced tissue injury. Removal of damaged mitochondria through autophagy requires two steps: induction of general autophagy and priming of damaged mitochondria for selective autophagic recognition. Recent progress in mitophagy studies reveals that mitochondrial priming is mediated either by the Pink1-Parkin signaling pathway or the mitophagic receptors Nix and Bnip3. In this review, we summarize our current knowledge on the mechanisms of mitophagy. We also discuss the pathophysiological roles of mitophagy and current assays used to monitor mitophagy.

scholarly journals MEKK3-MEK5-ERK5 signaling promotes mitochondrial degradation

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jane E. Craig ◽  
Joseph N. Miller ◽  
Raju R. Rayavarapu ◽  
Zhenya Hong ◽  
Gamze B. Bulut ◽  
...  
Keyword(s):  
Cell Death ◽  
Mitochondrial Biogenesis ◽  
Energy Homeostasis ◽  
Cellular Function ◽  
Mitochondrial Content ◽  
Cellular Energy ◽  
Pharmacological Inhibition ◽  
Positive Regulator ◽  
Kinase Cascade ◽  
Mitochondrial Turnover

Abstract Mitochondria are vital organelles that coordinate cellular energy homeostasis and have important roles in cell death. Therefore, the removal of damaged or excessive mitochondria is critical for maintaining proper cellular function. The PINK1-Parkin pathway removes acutely damaged mitochondria through a well-characterized mitophagy pathway, but basal mitochondrial turnover occurs via distinct and less well-understood mechanisms. Here we report that the MEKK3-MEK5-ERK5 kinase cascade is required for mitochondrial degradation in the absence of exogenous damage. We demonstrate that genetic or pharmacological inhibition of the MEKK3-MEK5-ERK5 pathway increases mitochondrial content by reducing lysosome-mediated degradation of mitochondria under basal conditions. We show that the MEKK3-MEK5-ERK5 pathway plays a selective role in basal mitochondrial degradation but is not required for non-selective bulk autophagy, damage-induced mitophagy, or restraint of mitochondrial biogenesis. This illuminates the MEKK3-MEK5-ERK5 pathway as a positive regulator of mitochondrial degradation that acts independently of exogenous mitochondrial stressors.

scholarly journals Ferroptosis: molecular mechanisms and health implications

Cell Research ◽  
2020 ◽  
Author(s):  
Daolin Tang ◽  
Xin Chen ◽  
Rui Kang ◽  
Guido Kroemer
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Tissue Injury ◽  
Current Knowledge ◽  
Apoptotic Cell ◽  
Oxidation Products ◽  
Redox Active ◽  
Lipid Oxidation Products ◽  
Dependent Form ◽  
And Function

AbstractCell death can be executed through different subroutines. Since the description of ferroptosis as an iron-dependent form of non-apoptotic cell death in 2012, there has been mounting interest in the process and function of ferroptosis. Ferroptosis can occur through two major pathways, the extrinsic or transporter-dependent pathway and the intrinsic or enzyme-regulated pathway. Ferroptosis is caused by a redox imbalance between the production of oxidants and antioxidants, which is driven by the abnormal expression and activity of multiple redox-active enzymes that produce or detoxify free radicals and lipid oxidation products. Accordingly, ferroptosis is precisely regulated at multiple levels, including epigenetic, transcriptional, posttranscriptional and posttranslational layers. The transcription factor NFE2L2 plays a central role in upregulating anti-ferroptotic defense, whereas selective autophagy may promote ferroptotic death. Here, we review current knowledge on the integrated molecular machinery of ferroptosis and describe how dysregulated ferroptosis is involved in cancer, neurodegeneration, tissue injury, inflammation, and infection.

scholarly journals MEKK3-MEK5-ERK5 Signaling Promotes Mitochondrial Degradation

2020 ◽  
Author(s):  
Jane E. Craig ◽  
Joseph N. Miller ◽  
Raju R. Rayavarapu ◽  
Zhenya Hong ◽  
Gamze B. Bulut ◽  
...  
Keyword(s):  
Cell Death ◽  
Mitochondrial Biogenesis ◽  
Energy Homeostasis ◽  
Cellular Function ◽  
Mitochondrial Content ◽  
Cellular Energy ◽  
Pharmacological Inhibition ◽  
Positive Regulator ◽  
Kinase Cascade ◽  
Mitochondrial Turnover

AbstractMitochondria are vital organelles that coordinate cellular energy homeostasis and have important roles in cell death. Therefore, the removal of damaged or excessive mitochondria is critical for maintaining proper cellular function. The PINK1-Parkin pathway removes acutely damaged mitochondria through a well-characterized mitophagy pathway, but basal mitochondrial turnover occurs via distinct and less well-understood mechanisms. Here we report that the MEKK3-MEK5-ERK5 kinase cascade is required for mitochondrial degradation in the absence of exogenous damage. We demonstrate that genetic or pharmacological inhibition of the MEKK3-MEK5-ERK5 pathway increases mitochondrial content by reducing lysosome-mediated degradation of mitochondria under basal conditions. We show that the MEKK3-MEK5-ERK5 pathway plays a selective role in basal mitochondrial degradation but is not required for non-selective bulk autophagy, damage-induced mitophagy, or restraint of mitochondrial biogenesis. This illuminates the MEKK3-MEK5-ERK5 pathway as a positive regulator of mitochondrial degradation that acts independently of exogenous mitochondrial stressors.

Paracrystalline Aggregates of Psoriatic Keratin and Their Relation to Normal Keratin Structure

1985 ◽  
Vol 43 ◽  
pp. 680-681
Author(s):  
S. Trachtenberg ◽  
P.M. Steinert ◽  
B.L. Trus ◽  
A.C. Steven
Keyword(s):  
Cell Death ◽  
Stratum Corneum ◽  
Intermediate Filament ◽  
Skin Disease ◽  
Amorphous Matrix ◽  
Terminal Differentiation ◽  
Proteolytic Degradation ◽  
Horny Layer ◽  
Chronic Skin ◽  
Chronic Skin Disease

During terminal differentiation of vertebrate epidermis, certain specific keratin intermediate filament (KIF) proteins are produced. Keratinization of the epidermis involves cell death and disruption of the cytoplasm, leaving a network of KIF embedded in an amorphous matrix which forms the outer horny layer known as the stratum corneum. Eventually these cells are shed (desquamation). Normally, the processes of differentiation, keratinization, and desquamation are regulated in an orderly manner. In psoriasis, a chronic skin disease, a hyperkeratotic stratum corneum is produced, resulting in abnormal desquamation of unusually large scales. In this disease, the normal KIF proteins are diminished in amount or absent, and other proteins more typical of proliferative epidermal cells are present. There is also evidence of proteolytic degradation of the KIF.

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

Receptor Mediated Binding of the Fibrinolytic Components, Plasminogen and Urokinase, to Peripheral Blood Cells

1987 ◽  
Vol 58 (03) ◽  
pp. 936-942 ◽  
Author(s):  
Lindsey A Miles ◽  
Edward F Plow
Keyword(s):  
T Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Binding Sites ◽  
Blood Cells ◽  
High Capacity ◽  
Red Cells ◽  
Peripheral Blood Cells ◽  
Cellular Functions ◽  
Fibrinolytic Proteins

SummaryGlu-plasminogen binds to platelets; the monocytoid line, U937, and the human fetal fibroblast line, GM1380 bind both plasminogen and its activator, urokinase. This study assesses the interaction of these fibrinolytic proteins with circulating human blood cells. Plasminogen bound minimally to red cells but bound saturably and reversibly to monocytes, granulocytes and lymphocytes with apparent Kd values of 0.9-1.4 μM. The interactions were of high capacity with 1.6 to 49 × 105 sites/cell and involved the lysine binding sites of plasminogen. Both T cells and non-rosetting lymphocytes and two B cell lines saturably bound plasminogen. Urokinase bound saturably to gianulocytes, monocytes, non-rosetting lymphocytes and a B cell line, but minimally to T cells, platelets and red cells. Therefore, plasminogen binding sites of high capacity, of similar affinities, and with common recognition specificities are expressed by many peripheral blood cells. Urokinase receptors are also widely distributed, but less so than plasminogen binding sites. The binding ol plasminogen and/ or urokinase to these cells may lead to generation of cell- associated proteolytic activity which contributes to a variety of cellular functions.

Recent Progress in Prediction Systems for Drug-induced Liver Injury Using in vitro Cell Culture

2020 ◽  
Vol 14 ◽  
Author(s):  
Shogo Ozawa ◽  
Toshitaka Miura ◽  
Jun Terashima ◽  
Wataru Habano ◽  
Seiichi Ishida
Keyword(s):  
Cell Culture ◽  
Recent Progress ◽  
Inflammatory Cells ◽  
Protein Adducts ◽  
In Vitro Assays ◽  
Drug Induced ◽  
Drug Induced Liver Injury ◽  
Culture Systems ◽  
Cell Culture Systems

Background: In order to avoid drug-induced liver injury (DILI), in vitro assays, which enable the assessment of both metabolic activation and immune reaction processes that ultimately result in DILI, are needed. Objective: In this study, the recent progress in the application of in vitro assays using cell culture systems is reviewed for potential DILI-causing drugs/xenobiotics and a mechanistic study on DILI, as well as for the limitations of in vitro cell culture systems for DILI research. Methods: Information related to DILI was collected through a literature search of the PubMed database. Results: The initial biological event for the onset of DILI is the formation of cellular protein adducts after drugs have been metabolically activated by drug metabolizing enzymes. The damaged peptides derived from protein adducts lead to the activation of CD4+ helper T lymphocytes and recognition by CD8+ cytotoxic T lymphocytes, which destroy hepatocytes through immunological reactions. Because DILI is a major cause of drug attrition and drug withdrawal, numerous in vitro systems consisting of hepatocytes and immune/inflammatory cells, or spheroids of human primary hepatocytes containing non-parenchymal cells have been developed. These cellular-based systems have identified DILIinducing drugs with approximately 50% sensitivity and 90% specificity. Conclusion: Different co-culture systems consisting of human hepatocyte-derived cells and other immune/inflammatory cells have enabled the identification of DILI-causing drugs and of the actual mechanisms of action.

scholarly journals Bone morphogenetic proteins, breast cancer, and bone metastases: striking the right balance

2017 ◽  
Vol 24 (10) ◽  
pp. R349-R366 ◽  
Author(s):  
Catherine Zabkiewicz ◽  
Jeyna Resaul ◽  
Rachel Hargest ◽  
Wen Guo Jiang ◽  
Lin Ye
Keyword(s):  
Breast Cancer ◽  
Cancer Progression ◽  
Bone Morphogenetic Proteins ◽  
Therapeutic Potential ◽  
Current Knowledge ◽  
Breast Tumour ◽  
Cellular Functions ◽  
Foetal Development ◽  
Key Factor ◽  
The Right

Bone morphogenetic proteins (BMPs) belong to the TGF-β super family, and are essential for the regulation of foetal development, tissue differentiation and homeostasis and a multitude of cellular functions. Naturally, this has led to the exploration of aberrance in this highly regulated system as a key factor in tumourigenesis. Originally identified for their role in osteogenesis and bone turnover, attention has been turned to the potential role of BMPs in tumour metastases to, and progression within, the bone niche. This is particularly pertinent to breast cancer, which commonly metastasises to bone, and in which studies have revealed aberrations of both BMP expression and signalling, which correlate clinically with breast cancer progression. Ultimately a BMP profile could provide new prognostic disease markers. As the evidence suggests a role for BMPs in regulating breast tumour cellular function, in particular interactions with tumour stroma and the bone metastatic microenvironment, there may be novel therapeutic potential in targeting BMP signalling in breast cancer. This review provides an update on the current knowledge of BMP abnormalities and their implication in the development and progression of breast cancer, particularly in the disease-specific bone metastasis.

Neuroligin-2 as a central organizer of inhibitory synapses in health and disease

2020 ◽  
Vol 13 (663) ◽  
pp. eabd8379
Author(s):  
Heba Ali ◽  
Lena Marth ◽  
Dilja Krueger-Burg
Keyword(s):  
Synaptic Transmission ◽  
Synapse Formation ◽  
Current Knowledge ◽  
Protein Complexes ◽  
Inhibitory Synapses ◽  
Molecular Architecture ◽  
Cellular Functions ◽  
Altered Expression ◽  
Health And Disease ◽  
Flow Of Information

Postsynaptic organizational protein complexes play central roles both in orchestrating synapse formation and in defining the functional properties of synaptic transmission that together shape the flow of information through neuronal networks. A key component of these organizational protein complexes is the family of synaptic adhesion proteins called neuroligins. Neuroligins form transsynaptic bridges with presynaptic neurexins to regulate various aspects of excitatory and inhibitory synaptic transmission. Neuroligin-2 (NLGN2) is the only member that acts exclusively at GABAergic inhibitory synapses. Altered expression and mutations in NLGN2 and several of its interacting partners are linked to cognitive and psychiatric disorders, including schizophrenia, autism, and anxiety. Research on NLGN2 has fundamentally shaped our understanding of the molecular architecture of inhibitory synapses. Here, we discuss the current knowledge on the molecular and cellular functions of mammalian NLGN2 and its role in the neuronal circuitry that regulates behavior in rodents and humans.

The DEAH helicase DHX36 and its role in G-quadruplex-dependent processes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Philipp Schult ◽  
Katrin Paeschke
Keyword(s):  
Current Knowledge ◽  
Future Research ◽  
Transcriptional Level ◽  
Cellular Functions ◽  
Multiple Functions ◽  
Open Questions ◽  
G Quadruplex ◽  
Cellular Pathways ◽  
Nucleic Acid Structures ◽  
Dependent Processes

AbstractDHX36 is a member of the DExD/H box helicase family, which comprises a large number of proteins involved in various cellular functions. Recently, the function of DHX36 in the regulation of G-quadruplexes (G4s) was demonstrated. G4s are alternative nucleic acid structures, which influence many cellular pathways on a transcriptional and post-transcriptional level. In this review we provide an overview of the current knowledge about DHX36 structure, substrate specificity, and mechanism of action based on the available models and crystal structures. Moreover, we outline its multiple functions in cellular homeostasis, immunity, and disease. Finally, we discuss the open questions and provide potential directions for future research.

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