Modifications in the nanoparticle-protein interactions for tuning the protein adsorption and controlling the stability of complexes

2021 ◽  
Vol 118 (15) ◽  
pp. 153701
Author(s):  
Sugam Kumar ◽  
Debasish Saha ◽  
Shin-ichi Takata ◽  
Vinod K. Aswal ◽  
Hideki Seto
Keyword(s):  
Protein Adsorption ◽  
Protein Interactions ◽  
Stability Of Complexes ◽  
The Stability

scholarly journals Crosstalk between β-catenin and WT1 signalling activity in acute myeloid leukemia

2021 ◽  
Author(s):  
Megan Payne ◽  
Olga Tsaponina ◽  
Gillian Caalim ◽  
Hayley Greenfield ◽  
Leanne Milton-Harris ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Myeloid Leukemia ◽  
Normal Development ◽  
Signal Transduction Pathway ◽  
Myeloid Cell ◽  
Wnt Signalling ◽  
Protein Protein Interactions ◽  
The Stability ◽  
First Time ◽  
Acute Myeloid

Wnt signalling is an evolutionary conserved signal transduction pathway heavily implicated in normal development and disease. The central mediator of this pathway, β-catenin, is frequently overexpressed, mislocalised and overactive in acute myeloid leukaemia (AML) where it mediates the establishment, maintenance and drug resistance of leukaemia stem cells. Critical to the stability, localisation and activity of β-catenin are the protein-protein interactions it forms, yet these are poorly defined in AML. We recently performed the first β-catenin interactome study in blood cells of any kind and identified a plethora of novel interacting partners. This study shows for the first time that β-catenin interacts with Wilms tumour protein (WT1), a protein frequently overexpressed and mutated in AML, in both myeloid cell lines and also primary AML samples. We demonstrate crosstalk between the signalling activity of these two proteins in myeloid cells, and show that modulation of either protein can affect expression of the other. Finally, we demonstrate that WT1 mutations frequently observed in AML can increase stabilise β-catenin and augment Wnt signalling output. This study has uncovered new context-dependent molecular interactions for β-catenin which could inform future therapeutic strategies to target this dysregulated molecule in AML.

scholarly journals Guide snoRNAs: Drivers or Passengers in Human Disease?

Biology ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Manisha Deogharia ◽  
Mrinmoyee Majumder
Keyword(s):  
Protein Interactions ◽  
Human Disease ◽  
Critical Role ◽  
Mrna Translation ◽  
Causal Link ◽  
Rna Modification ◽  
Disease Manifestation ◽  
The Stability ◽  
Nucleoside Modification ◽  
Host Genes

In every domain of life, RNA-protein interactions play a significant role in co- and post-transcriptional modifications and mRNA translation. RNA performs diverse roles inside the cell, and therefore any aberrancy in their function can cause various diseases. During maturation from its primary transcript, RNA undergoes several functionally important post-transcriptional modifications including pseudouridylation and ribose 2′-O-methylation. These modifications play a critical role in the stability of the RNA. In the last few decades, small nucleolar RNAs (snoRNAs) were revealed to be one of the main components to guide these modifications. Due to their active links to the nucleoside modification, deregulation in the snoRNA expressions can cause multiple disorders in humans. Additionally, host genes carrying snoRNA-encoding sequences in their introns also show differential expression in disease. Although few reports support a causal link between snoRNA expression and disease manifestation, this emerging field will have an impact on the way we think about biomarkers or identify novel targets for therapy. This review focuses on the intriguing aspect of snoRNAs that function as a guide in post-transcriptional RNA modification, and regulation of their host genes in human disease.

scholarly journals Dissociation of the AT-specific bifunctional intercalator [N-MeCys3,N-MeCys7]TANDEM from TpA sites in DNA

1995 ◽  
Vol 306 (1) ◽  
pp. 15-19 ◽  
Author(s):  
M C Fletcher ◽  
R K Olsen ◽  
K R Fox
Keyword(s):  
Dissociation Rate ◽  
Dnase I ◽  
Time Dependent ◽  
Base Pairs ◽  
Unusual Structure ◽  
Dnase I Footprinting ◽  
Calf Thymus ◽  
Stability Of Complexes ◽  
Dna Fragment ◽  
The Stability

We have examined the dissociation of [N-MeCys3,N-MeCys7]TANDEM, an AT-selective bifunctional intercalator, from TpA sites in mixed-sequence DNAs by a modification of the footprinting technique. Dissociation of complexes between the ligand and radiolabelled DNA fragments was initiated by adding a vast excess of unlabelled calf thymus DNA. Portions of this mixture were subjected to DNAse I footprinting at various times after adding the competitor DNA. Dissociation of the ligand from each site was seen by the time-dependent disappearance of the footprinting pattern. Within a natural DNA fragment (tyrT) the ligand dissociates from TTAT faster than from ATAT. We found that the stability of complexes with isolated TpA steps decreases in the order ATAT > TTAA > TATA. Dissociation from each of these sites is much faster than from longer regions of (AT)n. These results confirm the requirement for A and T base-pairs surrounding the TpA step and suggest that the interaction is strongest with regions of alternating AT, possibly as a result of its unusual structure. The ligand dissociates more slowly from the centre of (AT)n tracts than from the edges, suggesting that variations in dissociation rate arise from sequence-dependent variations in local DNA structure.

scholarly journals Sphingomyelin-enriched Microdomains at the Golgi Complex

2001 ◽  
Vol 12 (6) ◽  
pp. 1819-1833 ◽  
Author(s):  
Ioannis Gkantiragas ◽  
Britta Brügger ◽  
Ernstpeter Stüven ◽  
Dora Kaloyanova ◽  
Xue-Yi Li ◽  
...  
Keyword(s):  
Golgi Complex ◽  
Protein Interactions ◽  
Dynamic Equilibrium ◽  
Buoyant Density ◽  
Brefeldin A ◽  
Vacuolar Atpase ◽  
Morphological Data ◽  
Temperature Sensitive ◽  
Cell Extracts ◽  
The Stability

Sphingomyelin- and cholesterol-enriched microdomains can be isolated as detergent-resistant membranes from total cell extracts (total-DRM). It is generally believed that this total-DRM represents microdomains of the plasma membrane. Here we describe the purification and detailed characterization of microdomains from Golgi membranes. These Golgi-derived detergent-insoluble complexes (GICs) have a low buoyant density and are highly enriched in lipids, containing 25% of total Golgi phospholipids including 67% of Golgi-derived sphingomyelin, and 43% of Golgi-derived cholesterol. In contrast to total-DRM, GICs contain only 10 major proteins, present in nearly stoichiometric amounts, including the α- and β-subunits of heterotrimeric G proteins, flotillin-1, caveolin, and subunits of the vacuolar ATPase. Morphological data show a brefeldin A-sensitive and temperature-sensitive localization to the Golgi complex. Strikingly, the stability of GICs does not depend on its membrane environment, because, after addition of brefeldin A to cells, GICs can be isolated from a fused Golgi-endoplasmic reticulum organelle. This indicates that GIC microdomains are not in a dynamic equilibrium with neighboring membrane proteins and lipids. After disruption of the microdomains by cholesterol extraction with cyclodextrin, a subcomplex of several GIC proteins including the B-subunit of the vacuolar ATPase, flotillin-1, caveolin, and p17 could still be isolated by immunoprecipitation. This indicates that several of the identified GIC proteins localize to the same microdomains and that the microdomain scaffold is not required for protein interactions between these GIC proteins but instead might modulate their affinity.

Bis-phosphonio-isophosphindolide Copper Complexes

1999 ◽  
Vol 54 (10) ◽  
pp. 1244-1252 ◽  
Author(s):  
Dietrich Gudat ◽  
Andreas W. Holderberg ◽  
Nikolaus Korber ◽  
Martin Nieger ◽  
Martin Schrott
Keyword(s):  
Copper Complexes ◽  
Dynamic Equilibrium ◽  
Solid Phase ◽  
Lone Pair ◽  
Binuclear Complexes ◽  
Exchange Reactions ◽  
Nmr Studies ◽  
Bonding Parameters ◽  
Stability Of Complexes ◽  
The Stability

Bis-triphenylphosphonio-isophosphindolide salts 1[X] react with Cu(I)-halides CuX to give isolable products of composition [(1)Cu2X3 ]. X-ray crystal structure analyses confirmed that for X = Br, Cl dinuclear complexes [(μ-1 )(μ-X)Cu2X2] with μ2, η1(P)-bridging cations 1 are formed, while for X = I a solid phase containing a salt (1)2[Cu4I6] and a complex [(1)2Cu4I6] with a terminal η1(P)-coordinated ligand 1 was obtained. The bonding parameters in the two types of complexes suggest that l i s a hybrid between a phosphenium cation and a phospholide anion whose π-system is less nucleophilic than the phosphorus lone-pair.31P NMR studies revealed that in solution in all cases binuclear complexes [(1)Cu2X3] are in dynamic equilibrium with small amounts of mononuclear species and free 1. The same equilibria were detected in the system 1[OTf]/CuOTf. NMR studies of ligand exchange reactions indicated that the stability of complexes [(1)Cu2X3 ] increases in the order X = OTf < I < Br, Cl, and titration of [(1)Cu2Br3] with Et4NBr allowed to determine the equilibrium constant of the complex formation reaction.

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