Role of hydrodynamic shear on activity and structure of proteins

2007 ◽  
pp. 47-71 ◽  
Author(s):  
C. B. Elias ◽  
J. B. Joshi
Keyword(s):  
Hydrodynamic Shear ◽  
Structure Of Proteins

Platelet-Mediated Mechanical Tensile Force Influences ADAMTS13 Localization and Regulation Of Thrombus Development At The Site Of Platelet Accumulation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 454-454
Author(s):  
Yasuaki Shida ◽  
Laura L. Swystun ◽  
Christine Brown ◽  
Jeff Mewburn ◽  
Kate Sponagle ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Tensile Force ◽  
Flow Chamber ◽  
High Shear ◽  
Wild Type ◽  
Hydrodynamic Shear ◽  
Chamber Model ◽  
Mechanical Tensile ◽  
Very High

Background The multimeric glycoprotein von Willebrand factor (VWF) mediates platelet adhesion and aggregation at the site of vessel injury. The adhesive property of VWF is regulated by its multimer length, such that ultra large VWF (ULVWF) multimers, newly released from the endothelium, have greater hemostatic activity. multimer size is regulated by the metalloprotease ADAMTS13, which cleaves the A2 domain to reduce VWF multimer size and functional activity. static conditions, VWF maintains a globular conformation and the ADAMTS13 cleavage site is inaccessible. However, the exposure of endothelial-anchored VWF to tensile forces mediated by platelets and hydrodynamic shear enhance the cleavage of VWF by ADAMTS13. releases VWF of optimal hemostatic length from the endothelium into the plasma. We have previously reported using a flow chamber model which demonstrates that in addition to regulating VWF length and activity at the site of release, ADAMTS13 also associates with VWF at the site of thrombus formation. observed that under conditions of high and very high shear, ADAMTS13 reduced the size of thrombus volume., multi-coloured immunostaining revealed that ADAMTS13 co-localized with VWF and platelets at the top and middle layers of the thrombus, in the presence of very high shear. Aim To better understand the mechanism by which ADAMTS13 regulates thrombus size in our flow chamber model, we assessed the contribution of platelet tensile force to the localization of ADAMTS13 at the site of the thrombus. this model, the contributions of platelet GPIb, GPIIbIIIa, and P-selectin to ADAMTS13 localization were observed. Method Full length mouse VWF and ADAMTS13 cDNA were cloned into pCIneo and pcDNA3.1 plasmid, respectively. The gain of platelet GPIb binding mutation V1316M, and loss of GPIIbIIIa binding mutation (RGD to RGG) were introduced by site-directed-mutagenesis. mCherry was cloned at the C terminus of ADAMTS13 with a 12AA linker. Recombinant mVWF and mADAMTS13-mCherry proteins were produced via HEK293T cells by calcium phosphate transient transfection. mADAMTS13-mCherry (2 U/mL) and wild type or mutant mVWF (4 U/mL) was added to whole blood obtained from VWF-/-/ADAMTS13-/- double knockout mice. Whole blood containing DiOC6-labeled platelets was perfused over a collagen coated flow chamber at very high shear (7500s-1). The role of P-selectin was also analyzed by adding a P-selectin blocking antibody to blood obtained from ADAMTS13-/-knockout mice prior to the flow chamber experiment. After the perfusion, thrombi were fixed and immunostaining was performed to further analyze the distribution of platelets, VWF and ADAMTS13. Result As previously reported, ADAMTS13 localization was observed in the top and middle layers of the thrombus in the presence of wild type mVWF. The GPIb gain-of-function mutation V1316M increased both platelet (126%, p<0.0001) and VWF (190% and p<0.0001) accumulation at the thrombus site. ADAMTS13 localization was also increased (135%, p<0.001) relative to the binding to wild type VWF. Interestingly, with this gain-of-function VWF mutant, ADAMTS13 localization was found throughout the entire thrombus. In contrast, the GPIIbIIIa RGD binding mutant demonstrated decreased VWF (56%, p<0.01), and ADAMTS13 (82%, p<0.05) intensity, although platelet intensity was unaffected. to wild type, ADAMTS13 localized to the middle and top layers of the thrombus. Finally, inhibition of P-selectin significantly decreased VWF (46%, p<0.01) and ADAMTS13 (34%, p<0.01) localization to the thrombus, but again did not significantly alter platelet binding. Conclusion These studies demonstrate the central role of platelet-mediated mechanical tensile force on the regulation of thrombus growth at the site of platelet accumulation. Enhanced tensile force induced by increased GPIb binding resulted in increased ADAMTS13 localization, while reduced tensile force through loss of GPIIbIIIa or P-selectin binding decreased ADAMTS13 localization. This suggests that ADAMTS13 activity at the site of thrombus formation is maintained by the combination of hydrodynamic shear force and platelet tethering. aggregate, these studies suggest that under conditions of shear, ADAMTS13 regulates thrombus size by preserving the hemostatic function of the thrombus, and preventing dysregulated thrombus growth. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Role of Glutaredoxin-1 and Glutathionylation in Cardiovascular Diseases

2020 ◽  
Vol 21 (18) ◽  
pp. 6803 ◽  
Author(s):  
Mannix Burns ◽  
Syed Husain Mustafa Rizvi ◽  
Yuko Tsukahara ◽  
David R. Pimentel ◽  
Ivan Luptak ◽  
...  
Keyword(s):  
Cardiovascular Diseases ◽  
Disulfide Bonds ◽  
Arterial Disease ◽  
Disulfide Bridges ◽  
Myocardial Ischemia And Reperfusion ◽  
Cellular Processes ◽  
Mixed Disulfide ◽  
Peripheral Arterial ◽  
Structure Of Proteins

Cardiovascular diseases are the leading cause of death worldwide, and as rates continue to increase, discovering mechanisms and therapeutic targets become increasingly important. An underlying cause of most cardiovascular diseases is believed to be excess reactive oxygen or nitrogen species. Glutathione, the most abundant cellular antioxidant, plays an important role in the body’s reaction to oxidative stress by forming reversible disulfide bridges with a variety of proteins, termed glutathionylation (GSylation). GSylation can alter the activity, function, and structure of proteins, making it a major regulator of cellular processes. Glutathione-protein mixed disulfide bonds are regulated by glutaredoxins (Glrxs), thioltransferase members of the thioredoxin family. Glrxs reduce GSylated proteins and make them available for another redox signaling cycle. Glrxs and GSylation play an important role in cardiovascular diseases, such as myocardial ischemia and reperfusion, cardiac hypertrophy, peripheral arterial disease, and atherosclerosis. This review primarily concerns the role of GSylation and Glrxs, particularly glutaredoxin-1 (Glrx), in cardiovascular diseases and the potential of Glrx as therapeutic agents.

Nobel Ideals and Noble Errors

2017 ◽  
Author(s):  
Douglas Allchin
Keyword(s):  
Nobel Prize ◽  
Role Models ◽  
Nutrient Deficiency ◽  
Alpha Helix ◽  
Bacterial Disease ◽  
Intimate Knowledge ◽  
The Common ◽  
Structure Of Proteins ◽  
Paul Boyer

Christiaan Eijkman shared a 1929 Nobel Prize “for his discovery of the antineuritic vitamin.” His extensive studies on chickens and prison inmates on the island of Java in the 1890s helped establish a white rice diet as a cause of beriberi, and the rice coating as a remedy. Eijkman reported that he had traced a bacterial disease, its toxin, and its antitoxin. Beriberi, however, is a nutrient deficiency. Eijkman was wrong. Ironically, Eijkman even rejected the current explanation when it was first introduced in 1910. Although he earned a Nobel Prize for his important contribution on the role of diet, Eijkman’s original conclusion about the bacterium was just plain mistaken. Eijkman’s error may seem amusing, puzzling, or even downright disturbing—an exception to conventional expectations. Isn’t the scientific method, properly applied, supposed to protect science from error? And who can better exemplify science than Nobel Prize winners? If not, how can we trust science? And who else is to serve as role models for students and aspiring scientists? Eijkman’s case, however, is not unusual. Nobel Prize–winning scientists have frequently erred. Here I profile a handful of such cases (Figure 11.1). Among them is one striking pair, Peter Mitchell and Paul Boyer, who advocated alternative theories of energetics in the cell. Each used his perspective to understand and correct an error of the other! Ultimately, all these cases offer an occasion to reconsider another sacred bovine—that science is (or should be) free of error, and that the measure of a good scientist is how closely he or she meets that ideal. Consider first Linus Pauling, the master protein chemist. Applying his intimate knowledge of bond angles, he deciphered the alpha-helix structure of proteins in 1950, which earned him a Nobel Prize in 1954. He also reasoned fruitfully about sickle cell hemoglobin, leading to molecular understanding of its altered protein structure. Yet Pauling also believed that megadoses of vitamin C could cure the common cold. Evidence continues to indicate otherwise, although Pauling’s legacy still seems to shape popular beliefs.

scholarly journals Molecular Tunnels in Enzymes and Thermophily: A Case Study on the Relationship to Growth Temperature

2018 ◽  
Vol 6 (4) ◽  
pp. 109 ◽  
Author(s):  
Juan Gonzalez
Keyword(s):  
Glutamate Dehydrogenase ◽  
High Temperatures ◽  
Living Cells ◽  
Enzymatic Reactions ◽  
Molecular Tunnels ◽  
The Relationship ◽  
Phosphoribosylpyrophosphate Amidotransferase ◽  
Structure Of Proteins

Developments in protein expression, analysis and computational capabilities are decisively contributing to a better understanding of the structure of proteins and their relationship to function. Proteins are known to be adapted to the growth rate of microorganisms and some microorganisms (named (hyper)thermophiles) thrive optimally at high temperatures, even above 100 °C. Nevertheless, some biomolecules show great instability at high temperatures and some of them are universal and required substrates and cofactors in multiple enzymatic reactions for all (both mesophiles and thermophiles) living cells. Only a few possibilities have been pointed out to explain the mechanisms that thermophiles use to successfully thrive under high temperatures. As one of these alternatives, the role of molecular tunnels or channels in enzymes has been suggested but remains to be elucidated. This study presents an analysis of channels in proteins (i.e., substrate tunnels), comparing two different protein types, glutamate dehydrogenase and glutamine phosphoribosylpyrophosphate amidotransferase, which are supposed to present a different strategy on the requirement for substrate tunnels with low and high needs for tunneling, respectively. The search and comparison of molecular tunnels in these proteins from microorganisms thriving optimally from 15 °C to 100 °C suggested that those tunnels in (hyper)thermophiles are required and optimized to specific dimensions at high temperatures for the enzyme glutamine phosphoribosylpyrophosphate amidotransferase. For the enzyme glutamate dehydrogenase, a reduction of empty spaces within the protein could explain the optimization at increasing temperatures. This analysis provides further evidence on molecular channeling as a feasible mechanism in hyperthermophiles with multiple relevant consequences contributing to better understand how they live under those extreme conditions.

Emerging Role of Protein Post-Translational Modification in the Potential Clinical Application of Cancer

Nano LIFE ◽  
2020 ◽  
Vol 10 (01n02) ◽  
pp. 2040008 ◽  
Author(s):  
Xiangfei Xue ◽  
Xiao Zhang ◽  
Fenyong Sun ◽  
Jiayi Wang
Keyword(s):  
Disease Surveillance ◽  
Large Scale ◽  
Post Translational Modification ◽  
Early Diagnosis Of Cancer ◽  
The World ◽  
Significant Burden ◽  
Diagnosis Of Cancer ◽  
Cancer Types ◽  
Structure Of Proteins

Cancer, one of the largest public health problems in the world, greatly endangers human health. Every country in the world faces a significant burden due to cancer. Protein post-translational modification (PTM) plays a very important role in life. PTM makes the structure of proteins more complex and the functions more perfect. Common PTM processes include methylation, acetylation, phosphorylation, glycosylation and ubiquitination. In this paper, we introduce several common types of PTMs that were discovered in recent years in various cancer types, especially the early stages of cancer, and we explore the role of related molecules in cancer screening, diagnosis, disease surveillance and prognosis. We look forward to using PTM-relevant molecules as markers for the early diagnosis of cancer, after further in-depth research and large-scale clinical trials, to contribute to the early and accurate diagnosis of cancer, thereby improving the prognosis.

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