scholarly journals Missense Mutations in Desmoplakin Plakin Repeat Domains Have Dramatic Effects on Domain Structure and Function

2022 ◽  
Vol 23 (1) ◽  
pp. 529
Author(s):  
Fiyaz Mohammed ◽  
Elena Odintsova ◽  
Martyn Chidgey
Keyword(s):  
Molecular Mechanisms ◽  
Structural Integrity ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Bacterial Cells ◽  
Missense Mutations ◽  
Tissue Integrity ◽  
Mutation Database ◽  
Increased Risk ◽  
And Function ◽  
Plakin Proteins

Plakin repeat domains (PRDs) are globular modules that mediate the interaction of plakin proteins with the intermediate filament (IF) cytoskeleton. These associations are vital for maintaining tissue integrity in cardiac muscle and epithelial tissues. PRDs are subject to mutations that give rise to cardiomyopathies such as arrhythmogenic right ventricular cardiomyopathy, characterised by ventricular arrhythmias and associated with an increased risk of sudden heart failure, and skin blistering diseases. Herein, we have examined the functional and structural effects of 12 disease-linked missense mutations, identified from the human gene mutation database, on the PRDs of the desmosomal protein desmoplakin. Five mutations (G2056R and E2193K in PRD-A, G2338R and G2375R in PRD-B and G2647D in PRD-C) rendered their respective PRD proteins either fully or partially insoluble following expression in bacterial cells. Each of the residues affected are conserved across plakin family members, inferring a crucial role in maintaining the structural integrity of the PRD. In transfected HeLa cells, the mutation G2375R adversely affected the targeting of a desmoplakin C-terminal construct containing all three PRDs to vimentin IFs. The deletion of PRD-B and PRD-C from the construct compromised its targeting to vimentin. Bioinformatic and structural modelling approaches provided multiple mechanisms by which the disease-causing mutations could potentially destabilise PRD structure and compromise cytoskeletal linkages. Overall, our data highlight potential molecular mechanisms underlying pathogenic missense mutations and could pave the way for informing novel curative interventions targeting cardiomyopathies and skin blistering disorders.

scholarly journals Fluoride Exposure Induces Inhibition of Sodium-and Potassium-Activated Adenosine Triphosphatase (Na+, K+-ATPase) Enzyme Activity: Molecular Mechanisms and Implications for Public Health

2019 ◽  
Vol 16 (8) ◽  
pp. 1427 ◽  
Author(s):  
Declan Timothy Waugh
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Molecular Mechanisms ◽  
Chemical Elements ◽  
Biological Pathways ◽  
Normal Brain ◽  
Biological Interface ◽  
Increased Risk ◽  
And Function ◽  
Risk Of Cancer

In this study, several lines of evidence are provided to show that Na + , K + -ATPase activity exerts vital roles in normal brain development and function and that loss of enzyme activity is implicated in neurodevelopmental, neuropsychiatric and neurodegenerative disorders, as well as increased risk of cancer, metabolic, pulmonary and cardiovascular disease. Evidence is presented to show that fluoride (F) inhibits Na + , K + -ATPase activity by altering biological pathways through modifying the expression of genes and the activity of glycolytic enzymes, metalloenzymes, hormones, proteins, neuropeptides and cytokines, as well as biological interface interactions that rely on the bioavailability of chemical elements magnesium and manganese to modulate ATP and Na + , K + -ATPase enzyme activity. Taken together, the findings of this study provide unprecedented insights into the molecular mechanisms and biological pathways by which F inhibits Na + , K + -ATPase activity and contributes to the etiology and pathophysiology of diseases associated with impairment of this essential enzyme. Moreover, the findings of this study further suggest that there are windows of susceptibility over the life course where chronic F exposure in pregnancy and early infancy may impair Na + , K + -ATPase activity with both short- and long-term implications for disease and inequalities in health. These findings would warrant considerable attention and potential intervention, not to mention additional research on the potential effects of F intake in contributing to chronic disease.

scholarly journals BARD1 is necessary for ubiquitylation of nucleosomal histone H2A and for transcriptional regulation of estrogen metabolism genes

2018 ◽  
Vol 115 (6) ◽  
pp. 1316-1321 ◽  
Author(s):  
Mikaela D. Stewart ◽  
Elena Zelin ◽  
Abhinav Dhall ◽  
Tom Walsh ◽  
Esha Upadhyay ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Transcriptional Repression ◽  
Suppressor Gene ◽  
Ring Domain ◽  
Estrogen Metabolism ◽  
Missense Mutations ◽  
Histone H2a ◽  
Increased Risk ◽  
Binding Residues ◽  
And Function

Missense mutations that disrupt the RING domain of the tumor suppressor gene BRCA1 lead to increased risk of breast and ovarian cancer. The BRCA1 RING domain is a ubiquitin ligase, whose structure and function rely critically on forming a heterodimer with BARD1, which also harbors a RING domain. The function of the BARD1 RING domain is unknown. In families severely affected with breast cancer, we identified inherited BARD1 missense mutations Cys53Trp, Cys71Tyr, and Cys83Arg that alter three zinc-binding residues of the BARD1 RING domain. Each of these mutant BARD1 proteins retained the ability to form heterodimeric complexes with BRCA1 to make an active ubiquitin ligase, but the mutant BRCA1/BARD1 complexes were deficient in binding to nucleosomes and in ubiquitylating histone H2A. The BARD1 mutations also caused loss of transcriptional repression of BRCA1-regulated estrogen metabolism genes CYP1A1 and CYP3A4; breast epithelial cells edited to create heterozygous loss of BARD1 showed significantly higher expression of CYP1A1 and CYP3A4. Reintroduction of wild-type BARD1 into these cells restored CYP1A1 and CYP3A4 transcription to normal levels, but introduction of the cancer-predisposing BARD1 RING mutants failed to do so. These results indicate that an intact BARD1 RING domain is critical to BRCA1/BARD1 binding to nucleosomes and hence to ubiquitylation of histone H2A and also critical to transcriptional repression of BRCA1-regulated genes active in estrogen metabolism.

Molecular genetic characterization of Drosophila ATM conserved functional domains

Genome ◽  
2010 ◽  
Vol 53 (10) ◽  
pp. 778-786 ◽  
Author(s):  
M. Pedersen ◽  
S. Tiong ◽  
S. D. Campbell
Keyword(s):  
Molecular Mechanisms ◽  
Structural Integrity ◽  
Molecular Genetic ◽  
Telomere Maintenance ◽  
Temperature Sensitive ◽  
Missense Mutations ◽  
Dna Double Strand Breaks ◽  
Gene Encoding ◽  
Atm Kinase

ATM-related kinases promote repair of DNA double-strand breaks and maintenance of chromosome telomeres, functions that are essential for chromosome structural integrity in all eukaryotic organisms. In humans, loss of ATM function is associated with ataxia telangiectasia, a neurodegenerative disease characterized by extreme sensitivity to DNA damage. Drosophila melanogaster has recently emerged as a useful animal model for analyzing the molecular functions of specific domains of this large, multifunctional kinase. The gene encoding Drosophila ATM kinase (dATM) was originally designated tefu because of the telomere fusion defects observed in atm mutants. In this report, molecular characterization of eight atm (tefu) alleles identified nonsense mutations predicted to truncate conserved C-terminal domains of the dATM protein, as well as two interesting missense mutations. One of these missense mutations localized within a putative HEAT repeat in the poorly characterized N-terminal domain of dATM (atm4), whereas another associated with a temperature-sensitive allele (atm8) changed the last amino acid of the conserved FATC domain. Leveraging this molecular information with the powerful genetic tools available in Drosophila should facilitate future analysis of conserved ATM-mediated molecular mechanisms that are important for telomere maintenance, DNA repair, and neurodegeneration.

scholarly journals Is the commonly used UV filter benzophenone-3 a risk factor for the nervous system?

2021 ◽  
Author(s):  
Agnieszka Wnuk ◽  
Małgorzata Kajta
Keyword(s):  
Nervous System ◽  
Molecular Mechanisms ◽  
Neuronal Cells ◽  
Industrial Applications ◽  
Mammalian Brain ◽  
Human Environment ◽  
Developmental Abnormalities ◽  
Increased Risk ◽  
Wide Range ◽  
And Function

Benzophenone-3 (2-hydroxy-4-methoxybenzophenone, oxybenzone, or BP-3) is one of the most frequently used UV radiation absorbents, which are commonly referred to as sunscreen filters. Its widespread use in industrial applications provides protection against the photodegradation of a wide range of products but at the same time creates the risk of human exposure to benzophenone-3 unbeknownst to the individuals exposed. Topically applied benzophenone-3 penetrates individual skin layers, enters the bloodstream, and is excreted in the urine. In addition, benzophenone-3 easily crosses the placental barrier, which creates the risk of exposure to this substance in the prenatal period. Despite the widespread use and occurrence of benzophenone-3 in the human environment, little knowledge of the mechanisms underlying the effect of benzophenone-3 on the nervous system was available until recently. Only the most recent research, including studies by our group, has enabled the identification of new molecular mechanisms through which benzophenone-3 affects embryonic neuronal cells and the developing mammalian brain. Benzophenone-3 has been shown to induce neurotoxicity and apoptotic processes and inhibit autophagy in embryonic neuronal cells. Benzophenone-3 also alters expression and impairs function of receptors necessary for the proper development and function of the nervous system. The most worrying finding seems to be that benzophenone-3 contributes to an increased risk of developmental abnormalities and/or epigenetically based degeneration of neuronal cells by changing the epigenetic status of neuronal cells.

scholarly journals A Rho signaling network links microtubules to PKD controlled carrier transport to focal adhesions

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Stephan A Eisler ◽  
Filipa Curado ◽  
Gisela Link ◽  
Sarah Schulz ◽  
Melanie Noack ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Carrier Transport ◽  
Molecular Mechanisms ◽  
Structural Integrity ◽  
Focal Adhesions ◽  
Signaling Network ◽  
Protein Kinase D ◽  
Golgi Membranes ◽  
Network Coordinates ◽  
And Function

Protein kinase D (PKD) is a family of serine/threonine kinases that is required for the structural integrity and function of the Golgi complex. Despite its importance in the regulation of Golgi function, the molecular mechanisms regulating PKD activity are still incompletely understood. Using the genetically encoded PKD activity reporter G-PKDrep we now uncover a Rho signaling network comprising GEF-H1, the RhoGAP DLC3, and the Rho effector PLCε that regulate the activation of PKD at trans-Golgi membranes. We further show that this molecular network coordinates the formation of TGN-derived Rab6-positive transport carriers delivering cargo for localized exocytosis at focal adhesions.

scholarly journals Putative Role of MicroRNA-Regulated Pathways in Comorbid Neurological and Cardiovascular Disorders

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Sébastien S. Hébert
Keyword(s):  
Mirna Expression ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Heart Cell ◽  
Cardiovascular Disorders ◽  
Increased Risk ◽  
Mirna Expression Profiles ◽  
And Function ◽  
The Brain

Background. The conserved noncoding microRNAs (miRNAs) that function to regulate gene expression are essential for the development and function of the brain and heart. Changes in miRNA expression profiles are associated with an increased risk for developing neurodegenerative disorders as well as heart failure. Here, the hypothesis of how miRNA-regulated pathways could contribute to comorbid neurological and cardiovascular disorders will be discussed. Presentation. Changes in miRNA expression occurring in the brain and heart could have an impact on coexisting neurological and cardiovascular characteristics by (1) modulating organ function, (2) accentuating cellular stress, and (3) impinging on neuronal and/or heart cell survival. Testing. Evaluation of miRNA expression profiles in the brain and heart tissues from individuals with comorbid neurodegenerative and cardiovascular disorders will be of great importance and relevance. Implications. Careful experimental design will shed light to the deeper understanding of the molecular mechanisms tying up those different but yet somehow connected diseases.

scholarly journals Denaturing HPLC-Based Approach for Detecting RYR2 Mutations Involved in Malignant Arrhythmias

2004 ◽  
Vol 50 (7) ◽  
pp. 1148-1155 ◽  
Author(s):  
Alessia Bagattin ◽  
Caterina Veronese ◽  
Barbara Bauce ◽  
Wim Wuyts ◽  
Luca Settimo ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Mutation Screening ◽  
Cost Effective ◽  
Pcr Primers ◽  
Polymorphic Ventricular Tachycardia ◽  
Missense Mutations ◽  
Negative Results ◽  
And Function ◽  
Dhplc Analysis

Abstract Background: Mutations in the RYR2 gene, which encodes the cardiac ryanodine receptor, have been reported in patients showing either arrhythmogenic right ventricular cardiomyopathy, type 2, or stress-induced polymorphic ventricular tachycardia. Both clinical phenotypes are characterized by a high risk of sudden death. Detection of RYR2 mutations is particularly important because beta-blocker treatment has been shown to be effective in preventing fatal arrhythmias in affected patients. Methods: We used denaturing HPLC (DHPLC) to identify mutations in the human RYR2 gene. Fifty-three single exons, possibly targeted by mutations, were identified by comparison with the distribution of pathogenic mutations of the RYR1 gene, the skeletal muscle counterpart of RYR2. PCR primers for amplification of the entire coding sequence (116 amplicons, corresponding to 105 exons) were tested, and optimal DHPLC conditions were established. DHPLC analysis of critical exons was performed on 22 unrelated patients with effort-induced polymorphic ventricular arrhythmias but lacking a precise diagnosis. Results: We identified four novel missense mutations among 22 patients. Their pathogenic role was related to present knowledge of the structure and function of RyR2 protein. Conclusions: Under optimized conditions, DHPLC is a cost-effective, highly sensitive, rapid, and efficient method for mutation screenings. A four-step approach is proposed for mutation screening of the RYR2 gene: (a) DHPLC analysis of 48 critical exons (2–4, 6–15, 17–20, 39–49, 83, 84, 87–97, and 99–105); (b) DNA sequencing of 5 critical exons unsuitable for DHPLC; then, in case of negative results, (c) DHPLC analysis of the remaining 39 exons and (d) DNA sequencing of the last 13 amplicons unsuitable for DHPLC analysis.

A Mucin-Specific Protease Enables Molecular and Functional Analysis of Human Cancer-Associated Mucins

2018 ◽  
Author(s):  
Stacy A. Malaker ◽  
Kayvon Pedram ◽  
Michael J. Ferracane ◽  
Elliot C. Woods ◽  
Jessica Kramer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Mechanisms ◽  
Cultured Cells ◽  
High Resolution Mass Spectrometry ◽  
Human Cancer ◽  
Glycosylation Sites ◽  
Bacterial Protease ◽  
Specific Protease ◽  
To Come ◽  
And Function

<div> <div> <div> <p>Mucins are a class of highly O-glycosylated proteins that are ubiquitously expressed on cellular surfaces and are important for human health, especially in the context of carcinomas. However, the molecular mechanisms by which aberrant mucin structures lead to tumor progression and immune evasion have been slow to come to light, in part because methods for selective mucin degradation are lacking. Here we employ high resolution mass spectrometry, polymer synthesis, and computational peptide docking to demonstrate that a bacterial protease, called StcE, cleaves mucin domains by recognizing a discrete peptide-, glycan-, and secondary structure- based motif. We exploited StcE’s unique properties to map glycosylation sites and structures of purified and recombinant human mucins by mass spectrometry. As well, we found that StcE will digest cancer-associated mucins from cultured cells and from ovarian cancer patient-derived ascites fluid. Finally, using StcE we discovered that Siglec-7, a glyco-immune checkpoint receptor, specifically binds sialomucins as biological ligands, whereas the related Siglec-9 receptor does not. Mucin-specific proteolysis, as exemplified by StcE, is therefore a powerful tool for the study of glycoprotein structure and function and for deorphanizing mucin-binding receptors. </p> </div> </div> </div>

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