scholarly journals Dynamic posttranslational modifications of cytoskeletal proteins unveil hot spots under nitroxidative stress

Redox Biology ◽  
2021 ◽  
pp. 102014
Author(s):  
Eva Griesser ◽  
Venukumar Vemula ◽  
Andreia Mónico ◽  
Dolores Pérez-Sala ◽  
Maria Fedorova
Keyword(s):  
Posttranslational Modifications ◽  
Hot Spots ◽  
Cytoskeletal Proteins ◽  
Nitroxidative Stress

scholarly journals Dynamic posttranslational modifications of cytoskeletal proteins unveil hot spots under nitroxidative stress

2021 ◽  
Author(s):  
Eva Griesser ◽  
Venukumar Vemula ◽  
Andreia Mónico ◽  
Dolores Pérez-Sala ◽  
Maria Fedorova
Keyword(s):  
Posttranslational Modifications ◽  
Hot Spots ◽  
High Resolution Mass Spectrometry ◽  
Cysteine Residue ◽  
Reactive Species ◽  
Cytoskeletal Proteins ◽  
Dependent Manner ◽  
Cell Dynamics ◽  
Interacting Protein ◽  
Nitroxidative Stress

AbstractThe cytoskeleton is a supramolecular structure consisting of interacting protein networks that support cell dynamics in essential processes such as migration and division, as well as in responses to stress. Fast cytoskeletal remodeling is achieved with the participation of regulatory proteins and posttranslational modifications (PTMs). Redox-related PTMs are emerging as critical players in cytoskeletal regulation. Here we used a cellular model of mild nitroxidative stress in which a peroxynitrite donor induced transient changes in the organization of three key cytoskeletal proteins, i.e., vimentin, actin and tubulin. Nitroxidative stress-induced reconfiguration of intermediate filaments, microtubules and actin structures were further correlated with their PTM profiles and dynamics of the PTM landscape. Using high-resolution mass spectrometry, 62 different PTMs were identified and relatively quantified in vimentin, actin and tubulin proteins, including 12 enzymatic, 13 oxidative and 2 nitric oxide-derived modifications as well as 35 modifications by carbonylated lipid peroxidation products, thus evidencing the occurrence of a chain reaction with formation of reactive species and the activation of multiple signaling pathways. Our results unveil the presence of certain modifications under basal conditions and their modulation in response to stress in a target-, residue- and reactive species-dependent manner. Moreover, we identified protein PTM “hot spots”, such as the single cysteine residue of vimentin, supporting its role in PTM cross-talk and redox sensing. Finally, identification of novel PTMs in these proteins may pave the way for unveiling novel cytoskeleton regulatory mechanisms.

scholarly journals Neurofilament Phosphorylation during Development and Disease: Which Came First, the Phosphorylation or the Accumulation?

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Jeffrey M. Dale ◽  
Michael L. Garcia
Keyword(s):  
Posttranslational Modifications ◽  
Protein Function ◽  
Radial Growth ◽  
Cytoskeletal Proteins ◽  
Myelinated Axons ◽  
Neurofilament Light ◽  
Type Iv ◽  
Axonal Diameter ◽  
Neuronal Proteins ◽  
And Function

Posttranslational modification of proteins is a ubiquitous cellular mechanism for regulating protein function. Some of the most heavily modified neuronal proteins are cytoskeletal proteins of long myelinated axons referred to as neurofilaments (NFs). NFs are type IV intermediate filaments (IFs) that can be composed of four subunits, neurofilament heavy (NF-H), neurofilament medium (NF-M), neurofilament light (NF-L), and α-internexin. Within wild type axons, NFs are responsible for mediating radial growth, a process that determines axonal diameter. NFs are phosphorylated on highly conserved lysine-serine-proline (KSP) repeats located along the C-termini of both NF-M and NF-H within myelinated axonal regions. Phosphorylation is thought to regulate aspects of NF transport and function. However, a key pathological hallmark of several neurodegenerative diseases is ectopic accumulation and phosphorylation of NFs. The goal of this review is to provide an overview of the posttranslational modifications that occur in both normal and diseased axons. We review evidence that challenges the role of KSP phosphorylation as essential for radial growth and suggests an alternative role for NF phosphorylation in myelinated axons. Furthermore, we demonstrate that regulation of NF phosphorylation dynamics may be essential to avoiding NF accumulations.

scholarly journals Mechanotransduction and Metabolism in Cardiomyocyte Microdomains

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Francesco S. Pasqualini ◽  
Alexander P. Nesmith ◽  
Renita E. Horton ◽  
Sean P. Sheehy ◽  
Kevin Kit Parker
Keyword(s):  
Posttranslational Modifications ◽  
Energy Production ◽  
Cytoskeletal Proteins ◽  
Hierarchical Organization ◽  
Energy Utilization ◽  
Emergent Properties ◽  
Cardiac Diseases ◽  
Contraction Coupling ◽  
T Tubules ◽  
The Impact

Efficient contractions of the left ventricle are ensured by the continuous transfer of adenosine triphosphate (ATP) from energy production sites, the mitochondria, to energy utilization sites, such as ionic pumps and the force-generating sarcomeres. To minimize the impact of intracellular ATP trafficking, sarcomeres and mitochondria are closely packed together and in proximity with other ultrastructures involved in excitation-contraction coupling, such as t-tubules and sarcoplasmic reticulum junctions. This complex microdomain has been referred to as the intracellular energetic unit. Here, we review the literature in support of the notion that cardiac homeostasis and disease are emergent properties of the hierarchical organization of these units. Specifically, we will focus on pathological alterations of this microdomain that result in cardiac diseases through energy imbalance and posttranslational modifications of the cytoskeletal proteins involved in mechanosensing and transduction.

Posttranslational modifications of nerve cytoskeletal proteins in experimental diabetes

1992 ◽  
Vol 6 (2-3) ◽  
pp. 225-237 ◽  
Author(s):  
W. Graham McLean ◽  
Can Pekiner ◽  
Nicola A. Cullum ◽  
Ian F. Casson
Keyword(s):  
Posttranslational Modifications ◽  
Experimental Diabetes ◽  
Cytoskeletal Proteins

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Neurofilaments and Paired Helical Filaments

1985 ◽  
Vol 43 ◽  
pp. 740-743
Author(s):  
J. Metuzals
Keyword(s):  
Animal Model ◽  
Posttranslational Modifications ◽  
Posttranslational Modification ◽  
Giant Axon ◽  
Paired Helical Filaments ◽  
Squid Giant Axon ◽  
In Vitro Experiments ◽  
Thin Sections ◽  
Structural Relationships

It has been demonstrated that the neurofibrillary tangles in biopsies of Alzheimer patients, composed of typical paired helical filaments (PHF), consist also of typical neurofilaments (NF) and 15nm wide filaments. Close structural relationships, and even continuity between NF and PHF, have been observed. In this paper, such relationships are investigated from the standpoint that the PHF are formed through posttranslational modifications of NF. To investigate the validity of the posttranslational modification hypothesis of PHF formation, we have identified in thin sections from frontal lobe biopsies of Alzheimer patients all existing conformations of NF and PHF and ordered these conformations in a hypothetical sequence. However, only experiments with animal model preparations will prove or disprove the validity of the interpretations of static structural observations made on patients. For this purpose, the results of in vitro experiments with the squid giant axon preparations are compared with those obtained from human patients. This approach is essential in discovering etiological factors of Alzheimer's disease and its early diagnosis.

Modulated polarization microscopy displays the dynamics of cytoskeletal structures in living, motile cells

1995 ◽  
Vol 53 ◽  
pp. 902-903
Author(s):  
J. R. Kuhn ◽  
M. Poenie
Keyword(s):  
Mitotic Spindle ◽  
Actin Filaments ◽  
Cell Shape ◽  
Dynamic Structure ◽  
Living Cells ◽  
Cytoskeletal Proteins ◽  
Polarization Microscopy ◽  
Video Enhancement ◽  
Ultrastructural Studies ◽  
Motile Cells

Cell shape and movement are controlled by elements of the cytoskeleton including actin filaments an microtubules. Unfortunately, it is difficult to visualize the cytoskeleton in living cells and hence follow it dynamics. Immunofluorescence and ultrastructural studies of fixed cells while providing clear images of the cytoskeleton, give only a static picture of this dynamic structure. Microinjection of fluorescently Is beled cytoskeletal proteins has proved useful as a way to follow some cytoskeletal events, but long terry studies are generally limited by the bleaching of fluorophores and presence of unassembled monomers.Polarization microscopy has the potential for visualizing the cytoskeleton. Although at present, it ha mainly been used for visualizing the mitotic spindle. Polarization microscopy is attractive in that it pro vides a way to selectively image structures such as cytoskeletal filaments that are birefringent. By combing ing standard polarization microscopy with video enhancement techniques it has been possible to image single filaments. In this case, however, filament intensity depends on the orientation of the polarizer and analyzer with respect to the specimen.

Structural and Chemical Studies of Pathological Fibers in Human Neurofibrillary Degeneration

1985 ◽  
Vol 43 ◽  
pp. 726-729
Author(s):  
K.S. Kosik ◽  
L.K. Duffy ◽  
S. Bakalis ◽  
C. Abraham ◽  
D.J. Selkoe
Keyword(s):  
Monoclonal Antibodies ◽  
Alzheimer Disease ◽  
Human Brain ◽  
Neurofibrillary Tangles ◽  
Morphological Analysis ◽  
High Specificity ◽  
Cytoskeletal Proteins ◽  
Neuritic Plaque ◽  
Protein Chemistry ◽  
Chemical Studies

The major structural lesions of the human brain during aging and in Alzheimer disease (AD) are the neurofibrillary tangles (NFT) and the senile (neuritic) plaque. Although these fibrous alterations have been recognized by light microscopists for almost a century, detailed biochemical and morphological analysis of the lesions has been undertaken only recently. Because the intraneuronal deposits in the NFT and the plaque neurites and the extraneuronal amyloid cores of the plaques have a filamentous ultrastructure, the neuronal cytoskeleton has played a prominent role in most pathogenetic hypotheses.The approach of our laboratory toward elucidating the origin of plaques and tangles in AD has been two-fold: the use of analytical protein chemistry to purify and then characterize the pathological fibers comprising the tangles and plaques, and the use of certain monoclonal antibodies to neuronal cytoskeletal proteins that, despite high specificity, cross-react with NFT and thus implicate epitopes of these proteins as constituents of the tangles.

World Bank pinpoints disaster hot spots

Nature ◽  
2005 ◽  
Author(s):  
Deirdre Lockwood
Keyword(s):  
World Bank ◽  
Hot Spots
Sign in / Sign up

Export Citation Format

Share Document