Surfaces and Function

2021 ◽  
pp. 1-34
Keyword(s):  
Surface Texture ◽  
Structural Integrity ◽  
Textural Features ◽  
Fundamental Factor ◽  
Tribological System ◽  
Main Emphasis ◽  
Design Paradigm ◽  
And Function ◽  
Texture Design

This chapter reviews the origins of surface-system considerations. It highlights the fundamental role a surface plays in preserving the structural integrity of a tribological system and the crucial role of surface texture in maintaining the state of a rubbing material. Here the authors make the case for custom engineering of texture. It is shown that the idea of engineering textural features, while being fundamental, is not easy to implement. They discuss the complexity of the factors involved and how they render the customization process industrially demanding. The main emphasis is on one fundamental factor, namely, the absence of a texture design paradigm that caters to the multi-functionality requirement for futuristic surfaces.

Mutational and structural study of RipA, a key enzyme inMycobacterium tuberculosiscell division: evidence for theL-to-Dinversion of configuration of the catalytic cysteine

2014 ◽  
Vol 70 (9) ◽  
pp. 2295-2300 ◽  
Author(s):  
Flavia Squeglia ◽  
Alessia Ruggiero ◽  
Maria Romano ◽  
Luigi Vitagliano ◽  
Rita Berisio
Keyword(s):  
Structural Integrity ◽  
Cysteine Proteases ◽  
Enzyme Inactivation ◽  
Side Chain ◽  
Catalytic Cysteine ◽  
Key Enzyme ◽  
And Function ◽  
The Impact ◽  
Daughter Cell Separation

RipA is a key cysteine protease ofMycobacterium tuberculosisas it is responsible for bacterial daughter-cell separation. Although it is an important target for antimicrobial development, its mechanism of action and its interaction pattern with its substrate are hitherto unknown. By combining crystallographic and mutational studies with functional assays and molecular modelling, it is shown that the catalytic activity of the enzyme relies on a Cys–His–Glu triad and the impact of the mutation of each residue of the triad on the structure and function of RipA is analysed. Unexpectedly, the crystallographic analyses reveal that mutation of the glutamic acid to alanine results in inversion of the configuration of the catalytic cysteine. The consequent burial of the catalytic cysteine side chain explains the enzyme inactivation upon mutation. These data point to a novel role of the acidic residue often present in the triad of cysteine proteases as a supervisor of cysteine configuration through preservation of the local structural integrity.

Surfaces — A Link between Manufacture and Function

1978 ◽  
Vol 192 (1) ◽  
pp. 179-188 ◽  
Author(s):  
D. J. Whitehouse
Keyword(s):  
Random Process ◽  
Surface Texture ◽  
Manufacturing Process ◽  
Process Analysis ◽  
Digital Methods ◽  
And Function

The role of surface texture as a control of the manufacturing process and its importance are discussed. It is shown that it is only recently, since the advent of digital methods and random process analysis, that its real significance has been realized.

Caveolins, caveolae, and lipid rafts in cellular transport, signaling, and disease

2004 ◽  
Vol 82 (1) ◽  
pp. 129-144 ◽  
Author(s):  
Andrew F.G Quest ◽  
Lisette Leyton ◽  
Mario Párraga
Keyword(s):  
Lipid Rafts ◽  
Structural Integrity ◽  
Membrane Microdomains ◽  
Cellular Transport ◽  
Knock Out ◽  
Caveolin 1 ◽  
Membrane Compartments ◽  
Knock Out Mice ◽  
And Function

Caveolae were initially described some 50 years ago. For many decades, they remained predominantly of interest to structural biologists. The identification of a molecular marker for these domains, caveolin, combined with the possibility to isolate such cholesterol- and sphingolipid-rich regions as detergent-insoluble membrane complexes paved the way to more rigorous characterization of composition, regulation, and function. Experiments with knock-out mice for the caveolin genes clearly demonstrate the importance of caveolin-1 and -3 in formation of caveolae. Nonetheless, detergent-insoluble domains are also found in cells lacking caveolin expression and are referred to here as lipid rafts. Caveolae and lipid rafts were shown to represent membrane compartments enriched in a large number of signaling molecules whose structural integrity is essential for many signaling processes. Caveolin-1 is an essential structural component of cell surface caveolae, important for regulating trafficking and mobility of these vesicles. In addition, caveolin-1 is found at many other intracellular locations. Variations in subcellular localization are paralleled by a plethora of ascribed functions for this protein. Here, more recent data addressing the role of caveolin-1 in cellular signaling and the development of diseases like cancer will be preferentially discussed.Key words: caveolae, rafts, membrane microdomains, caveolins, signal transduction, disease, cancer.

scholarly journals EB1 Is Essential during Drosophila Development and Plays a Crucial Role in the Integrity of Chordotonal Mechanosensory Organs

2005 ◽  
Vol 16 (2) ◽  
pp. 891-901 ◽  
Author(s):  
Sarah L. Elliott ◽  
C. Fiona Cullen ◽  
Nicola Wrobel ◽  
Maurice J. Kernan ◽  
Hiroyuki Ohkura
Keyword(s):  
Cell Division ◽  
Crucial Role ◽  
Structural Integrity ◽  
Cultured Cells ◽  
Structure And Function ◽  
Cell Cortex ◽  
Microtubule Organization ◽  
Electrophysiological Measurements ◽  
And Function

EB1 is a conserved microtubule plus end tracking protein considered to play crucial roles in microtubule organization and the interaction of microtubules with the cell cortex. Despite intense studies carried out in yeast and cultured cells, the role of EB1 in multicellular systems remains to be elucidated. Here, we describe the first genetic study of EB1 in developing animals. We show that one of the multiple Drosophila EB1 homologues, DmEB1, is ubiquitously expressed and has essential functions during development. Hypomorphic DmEB1 mutants show neuromuscular defects, including flightlessness and uncoordinated movement, without any general cell division defects. These defects can be partly explained by the malfunction of the chordotonal mechanosensory organs. In fact, electrophysiological measurements indicated that the auditory chordotonal organs show a reduced response to sound stimuli. The internal organization of the chordotonal organs also is affected in the mutant. Consistently, DmEB1 is enriched in those regions important for the structure and function of the organs. Therefore, DmEB1 plays a crucial role in the functional and structural integrity of the chordotonal mechanosensory organs in Drosophila.

Copper deficiency and cardiovascular disease: role of peroxidation, glycation, and nitration

2000 ◽  
Vol 78 (10) ◽  
pp. 848-855 ◽  
Author(s):  
Jack T Saari
Keyword(s):  
Nitric Oxide ◽  
Blood Vessels ◽  
Energy Use ◽  
Copper Deficiency ◽  
Structural Integrity ◽  
Dietary Copper ◽  
Cardiovascular Defects ◽  
And Function ◽  
Reduced Activity

Dietary copper deficiency causes a variety of cardiovascular deficits. Systemic effects include high blood pressure, enhancement of inflammation, anemia, reduced blood clotting, and possibly arteriosclerosis. Effects on specific organs or tissues include weakened structural integrity of the heart and blood vessels, impairment of energy use by the heart, reduced ability of the heart to contract, altered ability of blood vessels to control their diameter and grow, and altered structure and function of circulating blood cells. In some instances, the cause of a defect can be directly attributed to reduced activity of a specific copper-dependent enzyme. However, three nonspecific mechanisms of damage have been implicated in cardiovascular defects of copper deficiency. They are peroxidation, the interaction of oxygen-derived free radicals with lipids and proteins (possibly DNA); glycation, the nonenzymatic glycosylation of proteins; and nitration, the interaction of nitric oxide and its metabolites with peptides and proteins. Though independently these mechanisms present great potential for damage, the possibility that they may interact presents an added reason for concern. Furthermore, the fact that at least two of these mechanisms are associated with diabetes and aging suggests that copper deficiency may exacerbate deficits associated with these two conditions.Key words: copper, heart, circulation, peroxidation, glycation, nitric oxide.

scholarly journals The effect of dietary lipid changes on the fatty acid composition and function of liver, heart and brain mitochondria in the rat at different ages

1994 ◽  
Vol 71 (2) ◽  
pp. 193-202 ◽  
Author(s):  
V. Barzanti ◽  
M. Battino ◽  
A. Baracca ◽  
M. Cavazzoni ◽  
M. Cocchi ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Structural Integrity ◽  
Brain Mitochondria ◽  
Dietary Lipid ◽  
Dietary Lipids ◽  
And Function ◽  
Fatty Acid Compositions

A correlation between dietary lipids and cellular enzyme activities is a problem that has only been partially addressed by nutritionists. Therefore, changes in the fatty acid composition and the activities of some key metabolic enzymes (ubiquinol-2-cytochrome c reductase (EC 1.10.2.2), cytochrome oxidase (EC 1.9.3.1) and ATPase (EC 3.6.1.3)) in the mitochondria of liver, heart and brain of rats fed on diets differing extensively in their polyunsaturated fatty acid compositions have been investigated. The results showed that fatty acid compositional changes brought about by the dietary differences were associated with extensive changes in the activities of these key enzymes in the mitochondria. The extent of the influence differed considerably with the period over which the diets were fed. The role of dietary lipids to effect changes through the preservation of membrane structural integrity is discussed.

O-GlcNAc cycling and the regulation of nucleocytoplasmic dynamics

2017 ◽  
Vol 45 (2) ◽  
pp. 427-436 ◽  
Author(s):  
Moriah Eustice ◽  
Michelle R. Bond ◽  
John A. Hanover
Keyword(s):  
Structural Integrity ◽  
Complex Structure ◽  
Nutrient Sensing ◽  
Nuclear Pore ◽  
Post Translational Modification ◽  
Nucleocytoplasmic Trafficking ◽  
Protein Targets ◽  
Multifunctional Enzymes ◽  
And Function

The dynamic carbohydrate post-translational modification (PTM) O-linked β-N-acetyl glucosamine (O-GlcNAc) is found on thousands of proteins throughout the nucleus and cytoplasm, and rivals phosphorylation in terms of the number of substrates and pathways influenced. O-GlcNAc is highly conserved and essential in most organisms, with disruption of O-GlcNAc cycling linked to diseases ranging from cancer to neurodegeneration. Nuclear pore proteins were the first identified O-GlcNAc-modified substrates, generating intense and ongoing interest in understanding the role of O-GlcNAc cycling in nuclear pore complex structure and function. Recent advances in detecting and altering O-GlcNAcylation levels have provided insights into many mechanisms by which O-GlcNAcylation influences the nucleocytoplasmic localization and stability of protein targets. The emerging view is that the multifunctional enzymes of O-GlcNAc cycling are critical nutrient-sensing components of a complex network of signaling cascades involving multiple PTMs. Furthermore, O-GlcNAc plays a role in maintaining the structural integrity of the nuclear pore and regulating its function as the gatekeeper of nucleocytoplasmic trafficking.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

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