Role of the FAD-dependent polyamine oxidase in the selective formation of N1,N8-bis(γ- glutamyl)spermidine protein cross-links1

2007 ◽  
Vol 35 (2) ◽  
pp. 396-400 ◽  
Author(s):  
A. Lentini ◽  
P. Mattioli ◽  
B. Provenzano ◽  
A. Abbruzzese ◽  
M. Caraglia ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Polyamine Oxidase ◽  
Polyamine Metabolism ◽  
Suitable Model ◽  
Cross Link ◽  
Cellular Mechanisms ◽  
Preferential Formation ◽  
Cross Links ◽  
Selective Formation

Protein-bound γ-glutamylpolyamines have highlighted a new pathway in polyamine metabolism. Human foreskin keratinocytes offer a suitable model for this study. Indeed, they develop polymerized envelopes, as they differentiate, rich in ϵ-(γ-glutamyl)lysine and N1,N8-bis(γ-glutamyl)spermidine cross-links. We have found that the selective oxidation of N1-(γ-glutamyl)spermidine and N-(γ-glutamyl)spermine by FAD-dependent polyamine oxidase (PAO) may be one of the cellular mechanisms regulating the preferential formation of a sterically defined bis(γ-glutamyl)spermidine cross-link. The significance of this finding is unknown, but it suggests that the target of this PAO-modulation is to achieve the biochemical prerequisite for production of a normal epidermal stratum corneum.

scholarly journals Thyrotropin cross-links to the thyrotropin receptor through both the α and β subunits

1986 ◽  
Vol 235 (3) ◽  
pp. 879-882 ◽  
Author(s):  
P R Buckland ◽  
C R Rickards ◽  
R D Howells ◽  
B R Smith
Keyword(s):  
Tsh Receptor ◽  
Alpha Subunit ◽  
Receptor Interaction ◽  
Cross Linking ◽  
Thyrotropin Receptor ◽  
Cross Link ◽  
Receptor Binding Site ◽  
Form Part ◽  
Cross Links

We have recently shown that the beta subunit of thyrotropin (TSH) can be cross-linked to the TSH receptor [Buckland, Strickland, Pierce & Rees Smith (1985) Endocrinology (Baltimore) 116, 2122-2124; Buckland, Strickland & Rees Smith (1985) Biochem. Soc. Trans. 13, 942-943]. We failed, however, to cross-link the alpha subunit to the receptor, leaving the role of this subunit in the TSH-TSH-receptor interaction uncertain. We now report the successful cross-linking of the TSH alpha subunit to the receptor by the use of two different cross-linking reagents. Our studies suggest therefore that both subunits of TSH form part of the hormone's receptor-binding site.

Homogeneous Zinc(II) Catalysis in Accelerated Vulcanization I. Reaction-Stage Modeling and Cross-Link Formation

1998 ◽  
Vol 71 (4) ◽  
pp. 750-765 ◽  
Author(s):  
Peter J. Nieuwenhuizen ◽  
Sandjai Timal ◽  
Jeroen M. van Veen ◽  
Jaap G. Haasnoot ◽  
Jan Reedijk
Keyword(s):  
Detailed Knowledge ◽  
Cross Link ◽  
Model Compounds ◽  
Zinc Compounds ◽  
Reaction Stage ◽  
Novel Approach ◽  
Cross Links ◽  
Link Formation ◽  
Stage Modeling

Abstract This paper reports a novel approach for the study of the mechanism of accelerated vulcanization, namely, Reaction-Stage Modeling (RSM). By carefully studying the reactivity of relevant model compounds under selected conditions, detailed knowledge about a particular reaction stage of vulcanization can be obtained. Background, experimental details and synthesis of model compounds are described. An RSM study after cross-link formation in the thiuram- and dithiocarbamate type vulcanization has been performed, and the role of zinc compounds herein was investigated. In contrast to earlier studies, it has appeared that at 140 °C, cross-links form from cross-link precursors solely via disproportionation. Allylic substitution was not observed. Zinc compounds act as catalysts for disproportionation, but especially ZDMC can be regarded as an efficient, soluble molecular turntable for sulfur atoms.

scholarly journals Processing of a Psoralen DNA Interstrand Cross-link by XPF-ERCC1 Complex in Vitro

2007 ◽  
Vol 283 (3) ◽  
pp. 1275-1281 ◽  
Author(s):  
Laura A. Fisher ◽  
Mika Bessho ◽  
Tadayoshi Bessho
Keyword(s):  
Strand Break ◽  
Double Strand Break ◽  
Dependent Manner ◽  
Cross Link ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
The Cross ◽  
Stalled Fork

The processing of stalled forks caused by DNA interstrand cross-links (ICLs) has been proposed to be an important step in initiating mammalian ICL repair. To investigate a role of the XPF-ERCC1 complex in this process, we designed a model substrate DNA with a single psoralen ICL at a three-way junction (Y-shaped DNA), which mimics a stalled fork structure. We found that the XPF-ERCC1 complex makes an incision 5′ to a psoralen lesion on Y-shaped DNA in a damage-dependent manner. Furthermore, the XPF-ERCC1 complex generates an ICL-specific incision on the 3′-side of an ICL. The ICL-specific 3′-incision, along with the 5′-incision, on the cross-linked Y-shaped DNA resulted in the separation of the two cross-linked strands (the unhooking of the ICL) and the induction of a double strand break near the cross-linked site. These results implicate the XPF-ERCC1 complex in initiating ICL repair by unhooking the ICL, which simultaneously induces a double strand break at a stalled fork.

scholarly journals Chk1-Mediated Phosphorylation of FANCE Is Required for the Fanconi Anemia/BRCA Pathway

2007 ◽  
Vol 27 (8) ◽  
pp. 3098-3108 ◽  
Author(s):  
XiaoZhe Wang ◽  
Richard D. Kennedy ◽  
Kallol Ray ◽  
Patricia Stuckert ◽  
Tom Ellenberger ◽  
...  
Keyword(s):  
Fanconi Anemia ◽  
Mutant Form ◽  
Cross Link ◽  
Core Complex ◽  
Core Enzyme ◽  
Cross Links ◽  
Phase Progression ◽  
Nuclear Foci ◽  
Fancd2 Monoubiquitination

ABSTRACT The eleven Fanconi anemia (FA) proteins cooperate in a novel pathway required for the repair of DNA cross-links. Eight of the FA proteins (A, B, C, E, F, G, L, and M) form a core enzyme complex, required for the monoubiquitination of FANCD2 and the assembly of FANCD2 nuclear foci. Here, we show that, in response to DNA damage, Chk1 directly phosphorylates the FANCE subunit of the FA core complex on two conserved sites (threonine 346 and serine 374). Phosphorylated FANCE assembles in nuclear foci and colocalizes with FANCD2. A nonphosphorylated mutant form of FANCE (FANCE-T346A/S374A), when expressed in a FANCE-deficient cell line, allows FANCD2 monoubiquitination, FANCD2 foci assembly, and normal S-phase progression. However, the mutant FANCE protein fails to complement the mitomycin C hypersensitivity of the transfected cells. Taken together, these results elucidate a novel role of Chk1 in the regulation of the FA/BRCA pathway and in DNA cross-link repair. Chk1-mediated phosphorylation of FANCE is required for a function independent of FANCD2 monoubiquitination.

Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

2020 ◽  
Author(s):  
Shubham Deolka ◽  
Orestes Rivada Wheelaghan ◽  
Sandra Aristizábal ◽  
Robert Fayzullin ◽  
Shrinwantu Pal ◽  
...  
Keyword(s):  
Alkyl Group ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Terminal Alkyne ◽  
Alkyl Aryl ◽  
Metal Metal ◽  
The Stability ◽  
Selective Formation ◽  
Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

mTORC and PKCε in Regulation of Alcohol Use Disorder

2020 ◽  
Vol 20 (17) ◽  
pp. 1696-1708 ◽  
Author(s):  
Athirah Hanim ◽  
Isa Naina Mohamed ◽  
Rashidi M. Pakri Mohamed ◽  
Srijit Das ◽  
Norefrina Shafinaz Md Nor ◽  
...  
Keyword(s):  
Alcohol Use ◽  
Alcohol Use Disorder ◽  
Alcohol Intake ◽  
Potential Role ◽  
Synaptic Proteins ◽  
Cellular Mechanisms ◽  
Kinase C ◽  
Protein Kinase C Epsilon ◽  
Seeking Behavior

Alcohol use disorder (AUD) is characterized by compulsive binge alcohol intake, leading to various health and social harms. Protein Kinase C epsilon (PKCε), a specific family of PKC isoenzyme, regulates binge alcohol intake, and potentiates alcohol-related cues. Alcohol via upstream kinases like the mammalian target to rapamycin complex 1 (mTORC1) or 2 (mTORC2), may affect the activities of PKCε or vice versa in AUD. mTORC2 phosphorylates PKCε at hydrophobic and turn motif, and was recently reported to be associated with alcohol-seeking behavior, suggesting the potential role of mTORC2-PKCε interactions in the pathophysiology of AUD. mTORC1 regulates translation of synaptic proteins involved in alcohol-induced plasticity. Hence, in this article, we aimed to review the molecular composition of mTORC1 and mTORC2, drugs targeting PKCε, mTORC1, and mTORC2 in AUD, upstream regulation of mTORC1 and mTORC2 in AUD and downstream cellular mechanisms of mTORCs in the pathogenesis of AUD.

scholarly journals Reconstitution in Proteoliposomes of the Recombinant Human Riboflavin Transporter 2 (SLC52A2) Overexpressed in E. coli

2019 ◽  
Vol 20 (18) ◽  
pp. 4416 ◽  
Author(s):  
Lara Console ◽  
Maria Tolomeo ◽  
Matilde Colella ◽  
Maria Barile ◽  
Cesare Indiveri
Keyword(s):  
Cardiovascular Disease ◽  
Amino Acids ◽  
Risk Factor ◽  
Biologically Active ◽  
Suitable Model ◽  
Native Protein ◽  
E Coli ◽  
Few Data ◽  
Riboflavin Transport

Background: the SLC52A2 gene encodes for the riboflavin transporter 2 (RFVT2). This transporter is ubiquitously expressed. It mediates the transport of Riboflavin across cell membranes. Riboflavin plays a crucial role in cells since its biologically active forms, FMN and FAD, are essential for the metabolism of carbohydrates, amino acids, and lipids. Mutation of the Riboflavin transporters is a risk factor for anemia, cancer, cardiovascular disease, neurodegeneration. Inborn mutations of SLC52A2 are associated with Brown-Vialetto-van Laere syndrome, a rare neurological disorder characterized by infancy onset. In spite of the important metabolic and physio/pathological role of this transporter few data are available on its function and regulation. Methods: the human recombinant RFVT2 has been overexpressed in E. coli, purified and reconstituted into proteoliposomes in order to characterize its activity following the [3H]Riboflavin transport. Results: the recombinant hRFVT2 showed a Km of 0.26 ± 0.07 µM and was inhibited by lumiflavin, FMN and Mg2+. The Riboflavin uptake was also regulated by Ca2+. The native protein extracted from fibroblast and reconstituted in proteoliposomes also showed inhibition by FMN and lumiflavin. Conclusions: proteoliposomes represent a suitable model to assay the RFVT2 function. It will be useful for screening the mutation of RFVT2.

scholarly journals Interactome Analysis of KIN (Kin17) Shows New Functions of This Protein

2021 ◽  
Vol 43 (2) ◽  
pp. 767-781
Author(s):  
Vanessa Pinatto Gaspar ◽  
Anelise Cardoso Ramos ◽  
Philippe Cloutier ◽  
José Renato Pattaro Junior ◽  
Francisco Ferreira Duarte Junior ◽  
...  
Keyword(s):  
Dna Replication ◽  
Protein Interactions ◽  
Ribosome Biogenesis ◽  
Cell Metabolism ◽  
Cell Types ◽  
Protein Protein Interactions ◽  
Cellular Mechanisms ◽  
Cancerous Cell ◽  
First Time

KIN (Kin17) protein is overexpressed in a number of cancerous cell lines, and is therefore considered a possible cancer biomarker. It is a well-conserved protein across eukaryotes and is ubiquitously expressed in all cell types studied, suggesting an important role in the maintenance of basic cellular function which is yet to be well determined. Early studies on KIN suggested that this nuclear protein plays a role in cellular mechanisms such as DNA replication and/or repair; however, its association with chromatin depends on its methylation state. In order to provide a better understanding of the cellular role of this protein, we investigated its interactome by proximity-dependent biotin identification coupled to mass spectrometry (BioID-MS), used for identification of protein–protein interactions. Our analyses detected interaction with a novel set of proteins and reinforced previous observations linking KIN to factors involved in RNA processing, notably pre-mRNA splicing and ribosome biogenesis. However, little evidence supports that this protein is directly coupled to DNA replication and/or repair processes, as previously suggested. Furthermore, a novel interaction was observed with PRMT7 (protein arginine methyltransferase 7) and we demonstrated that KIN is modified by this enzyme. This interactome analysis indicates that KIN is associated with several cell metabolism functions, and shows for the first time an association with ribosome biogenesis, suggesting that KIN is likely a moonlight protein.

scholarly journals Hippocampal Interneurons are Required for Trace Eyeblink Conditioning in Mice

2021 ◽  
Author(s):  
Wei-Wei Zhang ◽  
Rong-Rong Li ◽  
Jie Zhang ◽  
Jie Yan ◽  
Qian-Hui Zhang ◽  
...  
Keyword(s):  
Eyeblink Conditioning ◽  
Pyramidal Cells ◽  
Conditioned Eyeblink ◽  
Cellular Mechanisms ◽  
Sustained Activity ◽  
Early Acquisition ◽  
Freely Moving ◽  
Trace Eyeblink Conditioning

AbstractWhile the hippocampus has been implicated in supporting the association among time-separated events, the underlying cellular mechanisms have not been fully clarified. Here, we combined in vivo multi-channel recording and optogenetics to investigate the activity of hippocampal interneurons in freely-moving mice performing a trace eyeblink conditioning (tEBC) task. We found that the hippocampal interneurons exhibited conditioned stimulus (CS)-evoked sustained activity, which predicted the performance of conditioned eyeblink responses (CRs) in the early acquisition of the tEBC. Consistent with this, greater proportions of hippocampal pyramidal cells showed CS-evoked decreased activity in the early acquisition of the tEBC. Moreover, optogenetic suppression of the sustained activity in hippocampal interneurons severely impaired acquisition of the tEBC. In contrast, suppression of the sustained activity of hippocampal interneurons had no effect on the performance of well-learned CRs. Our findings highlight the role of hippocampal interneurons in the tEBC, and point to a potential cellular mechanism subserving associative learning.

scholarly journals Circulating Tfh cell and subsets distribution are associated with low‐responsiveness to hepatitis B vaccination

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Mingjuan Yin ◽  
Yongzhen Xiong ◽  
Dongmei Liang ◽  
Hao Tang ◽  
Qian Hong ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Hepatitis B Vaccine ◽  
Hepatitis B Vaccination ◽  
Cellular Mechanisms ◽  
Immunological Responses ◽  
Follicular Helper ◽  
Low Responders ◽  
Specific Subset ◽  
Antibody Titers

Abstract Background An estimated 5–10 % of healthy vaccinees lack adequate antibody response following receipt of a standard three-dose hepatitis B vaccination regimen. The cellular mechanisms responsible for poor immunological responses to hepatitis B vaccine have not been fully elucidated to date. Methods There were 61 low responders and 56 hyper responders involved in our study. Peripheral blood samples were mainly collected at D7, D14 and D28 after revaccinated with a further dose of 20 µg of recombinant hepatitis B vaccine. Results We found low responders to the hepatitis B vaccine presented lower frequencies of circulating follicular helper T (cTfh) cells, plasmablasts and a profound skewing away from cTfh2 and cTfh17 cells both toward cTfh1 cells. Importantly, the skewing of Tfh cell subsets correlated with IL-21 and protective antibody titers. Based on the key role of microRNAs involved in Tfh cell differentiation, we revealed miR-19b-1 and miR-92a-1 correlated with the cTfh cell subsets distribution and antibody production. Conclusions Our findings highlighted a decrease in cTfh cells and specific subset skewing contribute to reduced antibody responses in low responders.

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