scholarly journals Epigenetic modification in the expression of p73 p73 - epigenetic target for anticancer therapy

2019 ◽  
Vol 13 (2) ◽  
Author(s):  
Faiza Naseer ◽  
Mohammad Saleem
Keyword(s):  
Conformational Changes ◽  
Posttranslational Modifications ◽  
Epigenetic Modification ◽  
Amino Acid Residues ◽  
P53 Family ◽  
After Effects ◽  
Cycle Arrest ◽  
C Terminus ◽  
Upstream Promoter

A p73 is a new member of p53 family of transcription factor, having two types. First is TAp73, transcriptionally active and expressed via upstream promoter as a tumor suppressor and vital apoptotic inductor, it also has a key role in cell cycle arrest/differentiation and Second is ΔNp73 that is transcriptionally inactive and expressed via downstream regulator as oncogenes. Both types are expressed in various isoforms, which originate from alternative splicing events at the C-terminus. Upon DNA damage, posttranslational modifications cause conformational changes in various amino acid residues via induction or inhibition of various proteins, which are present in the structural domains of p73. These modifications may cause up- or down-regulation of p73 expression levels, as well as alters the transcriptional activity and/or stability of the protein. In this review, we have made an effort to assemble all existing data regarding the role of p73, its modification and after effects in cancer.

scholarly journals Phosphorylation and O-GlcNAcylation of the PHF-1 Epitope of Tau Protein Induce Local Conformational Changes of the C-Terminus and Modulate Tau Self-Assembly Into Fibrillar Aggregates

2021 ◽  
Vol 14 ◽  
Author(s):  
François-Xavier Cantrelle ◽  
Anne Loyens ◽  
Xavier Trivelli ◽  
Oliver Reimann ◽  
Clément Despres ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Tau Protein ◽  
Posttranslational Modifications ◽  
Self Assembly ◽  
Critical Role ◽  
Small Peptides ◽  
C Terminus ◽  
The Impact

Phosphorylation of the neuronal microtubule-associated Tau protein plays a critical role in the aggregation process leading to the formation of insoluble intraneuronal fibrils within Alzheimer’s disease (AD) brains. In recent years, other posttranslational modifications (PTMs) have been highlighted in the regulation of Tau (dys)functions. Among these PTMs, the O-β-linked N-acetylglucosaminylation (O-GlcNAcylation) modulates Tau phosphorylation and aggregation. We here focus on the role of the PHF-1 phospho-epitope of Tau C-terminal domain that is hyperphosphorylated in AD (at pS396/pS404) and encompasses S400 as the major O-GlcNAc site of Tau while two additional O-GlcNAc sites were found in the extreme C-terminus at S412 and S413. Using high resolution NMR spectroscopy, we showed that the O-GlcNAc glycosylation reduces phosphorylation of PHF-1 epitope by GSK3β alone or after priming by CDK2/cyclin A. Furthermore, investigations of the impact of PTMs on local conformation performed in small peptides highlight the role of S404 phosphorylation in inducing helical propensity in the region downstream pS404 that is exacerbated by other phosphorylations of PHF-1 epitope at S396 and S400, or O-GlcNAcylation of S400. Finally, the role of phosphorylation and O-GlcNAcylation of PHF-1 epitope was probed in in-vitro fibrillization assays in which O-GlcNAcylation slows down the rate of fibrillar assembly while GSK3β phosphorylation stimulates aggregation counteracting the effect of glycosylation.

scholarly journals Deletion of the Actin-Associated Tropomyosin Tpm3 Leads to Reduced Cell Complexity in Cultured Hippocampal Neurons—New Insights into the Role of the C-Terminal Region of Tpm3.1

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 715
Author(s):  
Tamara Tomanić ◽  
Claire Martin ◽  
Holly Stefen ◽  
Esmeralda Parić ◽  
Peter Gunning ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Growth Cones ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
C Terminus ◽  
Primary Mouse ◽  
Terminal Amino

Tropomyosins (Tpms) have been described as master regulators of actin, with Tpm3 products shown to be involved in early developmental processes, and the Tpm3 isoform Tpm3.1 controlling changes in the size of neuronal growth cones and neurite growth. Here, we used primary mouse hippocampal neurons of C57/Bl6 wild type and Bl6Tpm3flox transgenic mice to carry out morphometric analyses in response to the absence of Tpm3 products, as well as to investigate the effect of C-terminal truncation on the ability of Tpm3.1 to modulate neuronal morphogenesis. We found that the knock-out of Tpm3 leads to decreased neurite length and complexity, and that the deletion of two amino acid residues at the C-terminus of Tpm3.1 leads to more detrimental changes in neurite morphology than the deletion of six amino acid residues. We also found that Tpm3.1 that lacks the 6 C-terminal amino acid residues does not associate with stress fibres, does not segregate to the tips of neurites, and does not impact the amount of the filamentous actin pool at the axonal growth cones, as opposed to Tpm3.1, which lacks the two C-terminal amino acid residues. Our study provides further insight into the role of both Tpm3 products and the C-terminus of Tpm3.1, and it forms the basis for future studies that aim to identify the molecular mechanisms underlying Tpm3.1 targeting to different subcellular compartments.

scholarly journals Role of the Pilot Protein YscW in the Biogenesis of the YscC Secretin in Yersinia enterocolitica

2004 ◽  
Vol 186 (16) ◽  
pp. 5366-5375 ◽  
Author(s):  
Peter Burghout ◽  
Frank Beckers ◽  
Emmie de Wit ◽  
Ria van Boxtel ◽  
Guy R. Cornelis ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Yersinia Enterocolitica ◽  
Amino Acid Residues ◽  
Wild Type ◽  
C Terminus ◽  
Outer Membrane Lipoprotein ◽  
Protein Secretion System ◽  
Membrane Lipoprotein ◽  
Type Iii Protein Secretion

ABSTRACT The YscC secretin is a major component of the type III protein secretion system of Yersinia enterocolitica and forms an oligomeric structure in the outer membrane. In a mutant lacking the outer membrane lipoprotein YscW, secretion is strongly reduced, and it has been proposed that YscW plays a role in the biogenesis of the secretin. To study the interaction between the secretin and this putative pilot protein, YscC and YscW were produced in trans in a Y. enterocolitica strain lacking all other components of the secretion machinery. YscW expression increased the yield of oligomeric YscC and was required for its outer membrane localization, confirming the function of YscW as a pilot protein. Whereas the pilot-binding site of other members of the secretin family has been identified in the C terminus, a truncated YscC derivative lacking the C-terminal 96 amino acid residues was functional and stabilized by YscW. Pulse-chase experiments revealed that ∼30 min were required before YscC oligomerization was completed. In the absence of YscW, oligomerization was delayed and the yield of YscC oligomers was strongly reduced. An unlipidated form of the YscW protein was not functional, although it still interacted with the secretin and caused mislocalization of YscC even in the presence of wild-type YscW. Hence, YscW interacts with the unassembled YscC protein and facilitates efficient oligomerization, likely at the outer membrane.

scholarly journals Conformational Landscape Reduction of a Dynamic 29-Residue Peptide by a Perfluoroaromatic Small Molecule

2020 ◽  
Author(s):  
ethan evans
Keyword(s):  
Small Molecule ◽  
Conformational Changes ◽  
Dynamic Systems ◽  
Biochemical Properties ◽  
State Dependent ◽  
C Terminus ◽  
Explicit Solvent ◽  
Conformational Landscape

Conformationally dynamic peptides and proteins display both important biochemical properties and present a challenge for computational modeling. Characterizing the accessible structural landscape represents one route to understand their function with molecular level detail. We characterize a self-labeling 29-residue peptide, MP01-Gen4, that undergoes structural alterations in the presence of a perfluoroaromatic reaction partner. Replica exchange molecular dynamics (REMD) shows MP01 to access a broad set of states, that microsecond-long explicit solvent simulations only minimally sample. REMD and structural network analysis find an altered and reduced conformational landscape when MP01 interacts non-covalently or is covalently attached to the perfluoroaromatic small molecule. Residues throughout the peptide, notably at the C-terminus, interact with the small molecule in conformational state-dependent manners. The results help explain and generate hypotheses for experimental observations including the importance of flexibility and the role of the N- and C-terminal regions, both of which are distant from the active cysteine. The simulations highlight the importance of substantial sampling in minimally stabilized, conformationally dynamic systems and supplies a case study for small molecule-mediated, peptide conformational changes.<br>

scholarly journals Role of C-Terminal Cysteine Residues of Aspergillus fumigatus Allergen Asp f 4 in Immunoglobulin E Binding

2004 ◽  
Vol 11 (2) ◽  
pp. 261-265 ◽  
Author(s):  
Harikrishnan Ramachandran ◽  
Banani Banerjee ◽  
Paul A. Greenberger ◽  
Kevin J. Kelly ◽  
Jordan N. Fink ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Conformational Changes ◽  
Immunoglobulin E ◽  
Allergic Bronchopulmonary Aspergillosis ◽  
Allergic Diseases ◽  
Cysteine Residues ◽  
Conformational Structure ◽  
C Terminus ◽  
Function Relationship

ABSTRACT Among the several allergens cloned and expressed from Aspergillus fumigatus, Asp f 4 is a major one associated with allergic bronchopulmonary aspergillosis (ABPA). The structure-function relationship of allergens is important in understanding the immunopathogenesis, diagnosis, and treatment of allergic diseases. These include the epitopes, conformational or linear, deletion of the N or C terminus or both N and C termini, and glycosylation or nonglycosylation, all of which affect immune responses. Similarly, the role of cysteine residues present in allergens may yield useful information regarding the conformational structure of allergens and the immunoglobulin E (IgE) epitope interaction. Such information may help in developing new strategies towards immunotherapy. In order to define the role of cysteine in the interaction of the antibody with Asp f 4, we have constructed mutants by selectively deleting cysteine residues from the C-terminal region of the Asp f 4. Immunological evaluation of these engineered recombinant constructs was conducted by using sera from patients with ABPA, Aspergillus skin test-positive asthmatics, and healthy controls. The results demonstrate strong IgE binding with Asp f 4 and two truncated mutants, Asp f 41-234 (amino acids [aa] 1 to 234) and Asp f 41-241 (aa 1 to 241), while another mutant, Asp f 41-196 (aa 1 to 196), showed reactivity with fewer patients. The result suggests that deletion of cysteines and the alteration of IgE epitopes at the C-terminal end resulted in conformational changes, which may have a potential role in the immunomodulation of the disease.

scholarly journals A GIPC1-Palmitate Switch Modulates Dopamine Drd3 Receptor Trafficking and Signaling

2016 ◽  
Vol 36 (6) ◽  
pp. 1019-1031 ◽  
Author(s):  
Margarita Arango-Lievano ◽  
Ozge Sensoy ◽  
Amélie Borie ◽  
Maithé Corbani ◽  
Gilles Guillon ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Signaling Proteins ◽  
Interacting Protein ◽  
Mutant Proteins ◽  
C Terminus ◽  
Biased Signaling ◽  
Dopamine D3 ◽  
Dynamics Simulations

Palmitoylation is involved in several neuropsychiatric and movement disorders for which a dysfunctional signaling of the dopamine D3 receptor (Drd3) is hypothesized. Computational modeling of Drd3's homologue, Drd2, has shed some light on the putative role of palmitoylation as a reversible switch for dopaminergic receptor signaling. Drd3 is presumed to be palmitoylated, based on sequence homology with Drd2, but the functional attributes afforded by Drd3 palmitoylation have not been studied. Since these receptors are major targets of antipsychotic and anti-Parkinsonian drugs, a better characterization of Drd3 signaling and posttranslational modifications, like palmitoylation, may improve the prospects for drug development. Using molecular dynamics simulations, we evaluatedin silicohow Drd3 palmitoylation could elicit significant remodeling of the C-terminal cytoplasmic domain to expose docking sites for signaling proteins. We tested this modelin celluloby using the interaction of Drd3 with the G-alpha interacting protein (GAIP) C terminus 1 (GIPC1) as a template. From a series of biochemical studies, live imaging, and analyses of mutant proteins, we propose that Drd3 palmitoylation acts as a molecular switch for Drd3-biased signaling via a GIPC1-dependent route, which is likely to affect the mode of action of antipsychotic drugs.

scholarly journals The role of the C terminus of the SNARE protein SNAP-25 in fusion pore opening and a model for fusion pore mechanics

2008 ◽  
Vol 105 (40) ◽  
pp. 15388-15392 ◽  
Author(s):  
Qinghua Fang ◽  
Khajak Berberian ◽  
Liang-Wei Gong ◽  
Ismail Hafez ◽  
Jakob B. Sørensen ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Mechanistic Model ◽  
Snare Complex ◽  
Fusion Pore ◽  
Snare Protein ◽  
C Terminus ◽  
Target Membrane ◽  
Pore Opening ◽  
Fusion Pores

Formation of a fusion pore between a vesicle and its target membrane is thought to involve the so-called SNARE protein complex. However, there is no mechanistic model explaining how the fusion pore is opened by conformational changes in the SNARE complex. It has been suggested that C-terminal zipping triggers fusion pore opening. A SNAP-25 mutant named SNAP-25Δ9 (lacking the last nine C-terminal residues) should lead to a less-tight C-terminal zipping. Single exocytotic events in chromaffin cells expressing this mutant were characterized by carbon fiber amperometry and cell-attached patch capacitance measurements. Cells expressing SNAP-25Δ9 displayed smaller amperometric “foot-current” currents, reduced fusion pore conductances, and lower fusion pore expansion rates. We propose that SNARE/lipid complexes form proteolipid fusion pores. Fusion pores involving the SNAP-25Δ9 mutant will be less tightly zipped and may lead to a longer fusion pore structure, consistent with the observed decrease of fusion pore conductance.

scholarly journals The Role of Mutant p63 in Female Fertility

2021 ◽  
Vol 22 (16) ◽  
pp. 8968
Author(s):  
Yi Luan ◽  
Pauline Xu ◽  
Seok-Yeong Yu ◽  
So-Youn Kim
Keyword(s):  
Germ Cells ◽  
Essential Role ◽  
Primordial Germ Cells ◽  
Genomic Integrity ◽  
Biological Functions ◽  
Ovarian Insufficiency ◽  
P53 Family ◽  
C Terminus ◽  
N Terminus

The transcription factor p63, one of the p53 family members, plays an essential role in regulating maternal reproduction and genomic integrity as well as epidermal development. TP63 (human)/Trp63 (mouse) produces multiple isoforms: TAp63 and ΔNp63, which possess a different N-terminus depending on two different promoters, and p63a, p63b, p63g, p63δ, and p63ε as products of alternative splicing at the C-terminus. TAp63 expression turns on in the nuclei of primordial germ cells in females and is maintained mainly in the oocyte nuclei of immature follicles. It has been established that TAp63 is the genomic guardian in oocytes of the female ovaries and plays a central role in determining the oocyte fate upon oocyte damage. Lately, there is increasing evidence that TP63 mutations are connected with female infertility, including isolated premature ovarian insufficiency (POI) and syndromic POI. Here, we review the biological functions of p63 in females and discuss the consequences of p63 mutations, which result in infertility in human patients.

scholarly journals Full length RTEL1 is required for the elongation of the single-stranded telomeric overhang by telomerase

2020 ◽  
Author(s):  
Aya Awad ◽  
Galina Glousker ◽  
Noa Lamm ◽  
Shadi Tawil ◽  
Noa Hourvitz ◽  
...  
Keyword(s):  
Bone Marrow Failure ◽  
Ectopic Expression ◽  
Telomere Shortening ◽  
Telomere Elongation ◽  
Cycle Arrest ◽  
C Terminus ◽  
Common Etiology ◽  
Cellular Phenotypes ◽  
Dna Ends

Abstract Telomeres cap the ends of eukaryotic chromosomes and distinguish them from broken DNA ends to suppress DNA damage response, cell cycle arrest and genomic instability. Telomeres are elongated by telomerase to compensate for incomplete replication and nuclease degradation and to extend the proliferation potential of germ and stem cells and most cancers. However, telomeres in somatic cells gradually shorten with age, ultimately leading to cellular senescence. Hoyeraal-Hreidarsson syndrome (HHS) is characterized by accelerated telomere shortening and diverse symptoms including bone marrow failure, immunodeficiency, and neurodevelopmental defects. HHS is caused by germline mutations in telomerase subunits, factors essential for its biogenesis and recruitment to telomeres, and in the helicase RTEL1. While diverse phenotypes were associated with RTEL1 deficiency, the telomeric role of RTEL1 affected in HHS is yet unknown. Inducible ectopic expression of wild-type RTEL1 in patient fibroblasts rescued the cells, enabled telomerase-dependent telomere elongation and suppressed the abnormal cellular phenotypes, while silencing its expression resulted in gradual telomere shortening. Our observations reveal an essential role of the RTEL1 C-terminus in facilitating telomerase action at the telomeric 3′ overhang. Thus, the common etiology for HHS is the compromised telomerase action, resulting in telomere shortening and reduced lifespan of telomerase positive cells.

scholarly journals Conformational Landscape Reduction of a Dynamic 29-Residue Peptide by a Perfluoroaromatic Small Molecule

2020 ◽  
Author(s):  
ethan evans
Keyword(s):  
Small Molecule ◽  
Conformational Changes ◽  
Dynamic Systems ◽  
Biochemical Properties ◽  
State Dependent ◽  
C Terminus ◽  
Explicit Solvent ◽  
Conformational Landscape

Conformationally dynamic peptides and proteins display both important biochemical properties and present a challenge for computational modeling. Characterizing the accessible structural landscape represents one route to understand their function with molecular level detail. We characterize a self-labeling 29-residue peptide, MP01-Gen4, that undergoes structural alterations in the presence of a perfluoroaromatic reaction partner. Replica exchange molecular dynamics (REMD) shows MP01 to access a broad set of states, that microsecond-long explicit solvent simulations only minimally sample. REMD and structural network analysis find an altered and reduced conformational landscape when MP01 interacts non-covalently or is covalently attached to the perfluoroaromatic small molecule. Residues throughout the peptide, notably at the C-terminus, interact with the small molecule in conformational state-dependent manners. The results help explain and generate hypotheses for experimental observations including the importance of flexibility and the role of the N- and C-terminal regions, both of which are distant from the active cysteine. The simulations highlight the importance of substantial sampling in minimally stabilized, conformationally dynamic systems and supplies a case study for small molecule-mediated, peptide conformational changes.<br>

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