scholarly journals Unique structural features of the mitochondrial AAA+ protease AFG3L2 reveal the molecular basis for activity in health and disease

2019 ◽  
Author(s):  
Cristina Puchades ◽  
Bojian Ding ◽  
Albert Song ◽  
R. Luke Wiseman ◽  
Gabriel C. Lander ◽  
...  
Keyword(s):  
Neurodegenerative Disorders ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Structural Data ◽  
Structural Features ◽  
Genetic Mutations ◽  
Biological Functions ◽  
Catalytic Core ◽  
Structural Framework ◽  
Health And Disease

AbstractMitochondrial AAA+ quality control proteases regulate diverse aspects of mitochondrial biology through specialized protein degradation, but the underlying molecular mechanisms that define the diverse activities of these enzymes remain poorly defined. The mitochondrial AAA+ protease AFG3L2 is of particular interest, as genetic mutations localized throughout AFG3L2 are linked to diverse neurodegenerative disorders. However, a lack of structural data has limited our understanding of how mutations impact enzymatic activity. Here, we used cryo-EM to determine a substrate-bound structure of the catalytic core of human AFG3L2. This structure identifies multiple specialized structural features within AFG3L2 that integrate with conserved structural motifs required for hand-over-hand ATP-dependent substrate translocation to engage, unfold and degrade targeted proteins. Mapping disease-relevant AFG3L2 mutations onto our structure demonstrates that many of these mutations localize to these unique structural features of AFG3L2 and distinctly influence its activity and stability. Our results provide a molecular basis for neurological phenotypes associated with different AFG3L2 mutations, and establish a structural framework to understand how different members of the AAA+ superfamily achieve specialized, diverse biological functions.

scholarly journals Mitochondrial Iron in Human Health and Disease

2019 ◽  
Vol 81 (1) ◽  
pp. 453-482 ◽  
Author(s):  
Diane M. Ward ◽  
Suzanne M. Cloonan
Keyword(s):  
Human Health ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Innate Immune ◽  
Biological Functions ◽  
Mitochondrial Homeostasis ◽  
Innate Immune Signaling ◽  
Mitochondrial Iron ◽  
Health And Disease

Mitochondria are an iconic distinguishing feature of eukaryotic cells. Mitochondria encompass an active organellar network that fuses, divides, and directs a myriad of vital biological functions, including energy metabolism, cell death regulation, and innate immune signaling in different tissues. Another crucial and often underappreciated function of these dynamic organelles is their central role in the metabolism of the most abundant and biologically versatile transition metals in mammalian cells, iron. In recent years, cellular and animal models of mitochondrial iron dysfunction have provided vital information in identifying new proteins that have elucidated the pathways involved in mitochondrial homeostasis and iron metabolism. Specific signatures of mitochondrial iron dysregulation that are associated with disease pathogenesis and/or progression are becoming increasingly important. Understanding the molecular mechanisms regulating mitochondrial iron pathways will help better define the role of this important metal in mitochondrial function and in human health and disease.

scholarly journals Unique Structural Features of the Mitochondrial AAA+ Protease AFG3L2 Reveal the Molecular Basis for Activity in Health and Disease

2019 ◽  
Vol 75 (5) ◽  
pp. 1073-1085.e6 ◽  
Author(s):  
Cristina Puchades ◽  
Bojian Ding ◽  
Albert Song ◽  
R. Luke Wiseman ◽  
Gabriel C. Lander ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Structural Features ◽  
Health And Disease

scholarly journals Molecular mechanisms of telomere biology disorders

2020 ◽  
pp. jbc.REV120.014017
Author(s):  
Sherilyn Grill ◽  
Jayakrishnan Nandakumar
Keyword(s):  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Wide Spectrum ◽  
Significant Proportion ◽  
Dyskeratosis Congenita ◽  
Telomere Maintenance ◽  
Genetic Mutations ◽  
Hematopoietic Stem ◽  
Telomere Biology ◽  
Underlying Mechanisms

Genetic mutations that affect telomerase function or telomere maintenance result in a variety of diseases collectively called telomeropathies. This wide spectrum of disorders, which include dyskeratosis congenita (DC), pulmonary fibrosis (PF) and aplastic anemia (AA), is characterized by severely short telomeres, often resulting in hematopoietic stem cell failure in the most severe cases. Recent work has focused on understanding the molecular basis of these diseases. Mutations in the catalytic TERT and TR subunits of telomerase compromise activity, while others, such as those found in the telomeric protein TPP1, reduce the recruitment of telomerase to the telomere. Mutant telomerase-associated proteins TCAB1 and dyskerin, and the telomerase RNA maturation component PARN, affect the maturation and stability of telomerase. In contrast, disease-associated mutations in either CTC1 or RTEL1 are more broadly associated with telomere replication defects. Yet even with the recent surge in studies decoding the mechanisms underlying these diseases, a significant proportion of DC mutations remain uncharacterized or poorly understood. Here we review the current understanding of the molecular basis of telomeropathies and highlight experimental data that illustrate how genetic mutations drive telomere shortening and dysfunction in these patients. This review connects insights from both clinical and molecular studies to create a comprehensive view of the underlying mechanisms that drive these diseases. Through this, we emphasize recent advances in therapeutics and pin-point disease-associated variants that remain poorly defined in their mechanism of action. Finally, we suggest future avenues of research that will deepen our understanding of telomere biology and telomere-related disease.

scholarly journals Catechins as Tools to Understand the Molecular Basis of Neurodegeneration

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3571
Author(s):  
Karla Martinez Pomier ◽  
Rashik Ahmed ◽  
Giuseppe Melacini
Keyword(s):  
Phenolic Compounds ◽  
Neurodegenerative Disorders ◽  
Molecular Basis ◽  
Protein Misfolding ◽  
Molecular Mechanisms ◽  
Amyloid Aggregation ◽  
Amyloid Aggregates ◽  
Parkinson’S Diseases ◽  
Pharmacokinetic Properties ◽  
Self Association

Protein misfolding as well as the subsequent self-association and deposition of amyloid aggregates is implicated in the progression of several neurodegenerative disorders including Alzheimer’s and Parkinson’s diseases. Modulators of amyloidogenic aggregation serve as essential tools to dissect the underlying molecular mechanisms and may offer insight on potential therapeutic solutions. These modulators include green tea catechins, which are potent inhibitors of amyloid aggregation. Although catechins often exhibit poor pharmacokinetic properties and bioavailability, they are still essential tools for identifying the drivers of amyloid aggregation and for developing other aggregation modulators through structural mimicry. As an illustration of such strategies, here we review how catechins have been used to map the toxic surfaces of oligomeric amyloid-like species and develop catechin-based phenolic compounds with enhanced anti-amyloid activity.

scholarly journals Recent insights into natural product inhibitors of matrix metalloproteinases

MedChemComm ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 2024-2037 ◽  
Author(s):  
Geetha B. Kumar ◽  
Bipin G. Nair ◽  
J. Jefferson P. Perry ◽  
David B. C. Martin
Keyword(s):  
Cardiovascular Disease ◽  
Matrix Metalloproteinases ◽  
Matrix Metalloproteinase ◽  
Natural Product ◽  
Human Health ◽  
Neurodegenerative Disorders ◽  
Biological Functions ◽  
Mmp Inhibitors ◽  
The Matrix ◽  
Health And Disease

Members of the matrix metalloproteinase (MMP) family have biological functions that are central to human health and disease, and MMP inhibitors have been investigated for the treatment of cardiovascular disease, cancer and neurodegenerative disorders.

scholarly journals MARTs and MARylation in the Cytosol: Biological Functions, Mechanisms of Action, and Therapeutic Potential

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 313
Author(s):  
Sridevi Challa ◽  
MiKayla S. Stokes ◽  
W. Lee Kraus
Keyword(s):  
Stress Responses ◽  
Molecular Mechanisms ◽  
Neuronal Development ◽  
New Technologies ◽  
Therapeutic Potential ◽  
Structural Features ◽  
Cellular Transport ◽  
Biological Functions ◽  
Post Translational Modification

Mono(ADP-ribosyl)ation (MARylation) is a regulatory post-translational modification of proteins that controls their functions through a variety of mechanisms. MARylation is catalyzed by mono(ADP-ribosyl) transferase (MART) enzymes, a subclass of the poly(ADP-ribosyl) polymerase (PARP) family of enzymes. Although the role of PARPs and poly(ADP-ribosyl)ation (PARylation) in cellular pathways, such as DNA repair and transcription, is well studied, the role of MARylation and MARTs (i.e., the PARP ‘monoenzymes’) are not well understood. Moreover, compared to PARPs, the development of MART-targeted therapeutics is in its infancy. Recent studies are beginning to shed light on the structural features, catalytic targets, and biological functions of MARTs. The development of new technologies to study MARTs have uncovered essential roles for these enzymes in the regulation of cellular processes, such as RNA metabolism, cellular transport, focal adhesion, and stress responses. These insights have increased our understanding of the biological functions of MARTs in cancers, neuronal development, and immune responses. Furthermore, several novel inhibitors of MARTs have been developed and are nearing clinical utility. In this review, we summarize the biological functions and molecular mechanisms of MARTs and MARylation, as well as recent advances in technology that have enabled detection and inhibition of their activity. We emphasize PARP-7, which is at the forefront of the MART subfamily with respect to understanding its biological roles and the development of therapeutically useful inhibitors. Collectively, the available studies reveal a growing understanding of the biochemistry, chemical biology, physiology, and pathology of MARTs.

scholarly journals Gating and Regulatory Mechanisms of TMEM16 Ion Channels and Scramblases

2021 ◽  
Vol 12 ◽  
Author(s):  
Son C. Le ◽  
Pengfei Liang ◽  
Augustus J. Lowry ◽  
Huanghe Yang
Keyword(s):  
Ion Channels ◽  
Molecular Mechanisms ◽  
Transmembrane Protein ◽  
Structural Features ◽  
Regulatory Mechanisms ◽  
Membrane Bilayer ◽  
Flip Flop ◽  
The Past ◽  
Activation Gating ◽  
Health And Disease

The transmembrane protein 16 (TMEM16) family consists of Ca2+-activated ion channels and Ca2+-activated phospholipid scramblases (CaPLSases) that passively flip-flop phospholipids between the two leaflets of the membrane bilayer. Owing to their diverse functions, TMEM16 proteins have been implicated in various human diseases, including asthma, cancer, bleeding disorders, muscular dystrophy, arthritis, epilepsy, dystonia, ataxia, and viral infection. To understand TMEM16 proteins in health and disease, it is critical to decipher their molecular mechanisms of activation gating and regulation. Structural, biophysical, and computational characterizations over the past decade have greatly advanced the molecular understanding of TMEM16 proteins. In this review, we summarize major structural features of the TMEM16 proteins with a focus on regulatory mechanisms and gating.

scholarly journals Proton-Sensing GPCRs in Health and Disease

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2050
Author(s):  
Marco Sisignano ◽  
Michael J. M. Fischer ◽  
Gerd Geisslinger
Keyword(s):  
Intestinal Inflammation ◽  
Tumor Biology ◽  
Structural Features ◽  
G Protein Coupled Receptors ◽  
Biological Functions ◽  
Future Studies ◽  
Health And Disease ◽  
G Protein Coupled ◽  
Potential Use

The group of proton-sensing G-protein coupled receptors (GPCRs) consists of the four receptors GPR4, TDAG8 (GPR65), OGR1 (GPR68), and G2A (GPR132). These receptors are cellular sensors of acidification, a property that has been attributed to the presence of crucial histidine residues. However, the pH detection varies considerably among the group of proton-sensing GPCRs and ranges from pH of 5.5 to 7.8. While the proton-sensing GPCRs were initially considered to detect acidic cellular environments in the context of inflammation, recent observations have expanded our knowledge about their physiological and pathophysiological functions and many additional individual and unique features have been discovered that suggest a more differentiated role of these receptors in health and disease. It is known that all four receptors contribute to different aspects of tumor biology, cardiovascular physiology, and asthma. However, apart from their overlapping functions, they seem to have individual properties, and recent publications identify potential roles of individual GPCRs in mechanosensation, intestinal inflammation, oncoimmunological interactions, hematopoiesis, as well as inflammatory and neuropathic pain. Here, we put together the knowledge about the biological functions and structural features of the four proton-sensing GPCRs and discuss the biological role of each of the four receptors individually. We explore all currently known pharmacological modulators of the four receptors and highlight potential use. Finally, we point out knowledge gaps in the biological and pharmacological context of proton-sensing GPCRs that should be addressed by future studies.

scholarly journals Review of the Isolation, Characterization, Biological Function, and Multifarious Therapeutic Approaches of Exosomes

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 307 ◽  
Author(s):  
Sangiliyandi Gurunathan ◽  
Min-Hee Kang ◽  
Muniyandi Jeyaraj ◽  
Muhammad Qasim ◽  
Jin-Hoi Kim
Keyword(s):  
Molecular Mechanisms ◽  
Cell Communication ◽  
Biological Functions ◽  
Research Attention ◽  
Diagnosis And Prognosis ◽  
Imaging Probes ◽  
Health And Disease ◽  
The Stability ◽  
And Function ◽  
Invasive Diagnostics

Exosomes are extracellular vesicles that contain a specific composition of proteins, lipids, RNA, and DNA. They are derived from endocytic membranes and can transfer signals to recipient cells, thus mediating a novel mechanism of cell-to-cell communication. They are also thought to be involved in cellular waste disposal. Exosomes play significant roles in various biological functions, including the transfer of biomolecules such as RNA, proteins, enzymes, and lipids and the regulation of numerous physiological and pathological processes in various diseases. Because of these properties, they are considered to be promising biomarkers for the diagnosis and prognosis of various diseases and may contribute to the development of minimally invasive diagnostics and next generation therapies. The biocompatible nature of exosomes could enhance the stability and efficacy of imaging probes and therapeutics. Due to their potential use in clinical applications, exosomes have attracted much research attention on their roles in health and disease. To explore the use of exosomes in the biomedical arena, it is essential that the basic molecular mechanisms behind the transport and function of these vesicles are well-understood. Herein, we discuss the history, biogenesis, release, isolation, characterization, and biological functions of exosomes, as well as the factors influencing their biogenesis and their technical and biological challenges. We conclude this review with a discussion on the future perspectives of exosomes.

Astrocytes in health and disease

2007 ◽  
Vol 148 (15) ◽  
pp. 697-702 ◽  
Author(s):  
Marianna Murányi ◽  
Zsombor Lacza
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Free Radicals ◽  
Molecular Mechanisms ◽  
Neuronal Dysfunction ◽  
Supporting Cells ◽  
Neuronal Synapses ◽  
Health And Disease ◽  
Novel Targets ◽  
Therapeutic Tools

It is now known that astrocytes are not merely supporting cells but they also play an important role in neuronal funcions. Astrocytes tightly ensheat neuronal synapses and regulate the excitation of neurons by uptaking neurotransmitters; reglulate the cerebral blood flow, cerebral fluid volume and extracellular concentrations of ions. They also supply fuel in the form of lactate and provide free radical scavangers such as glutathione for active neurons. These facts indicate that impaired function of astrocytes may lead to neuronal dysfunction. After brain injury (stroke, trauma or tumors) astrocytes are swollen and release active molecules such as glutamate or free radicals resulting in neuronal dysfunction. Thus, investigation of the molecular mechanisms of astrocyte function may reveal novel targets for the development of therapeutic tools in neuronal diseases.

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