scholarly journals Laminin Polymerization and Inherited Disease: Lessons From Genetics

2021 ◽  
Vol 12 ◽  
Author(s):  
Liam Shaw ◽  
Conor J. Sugden ◽  
Kevin J. Hamill
Keyword(s):  
Point Mutations ◽  
Basement Membranes ◽  
Missense Mutations ◽  
Inherited Disease ◽  
Stem Cell Maintenance ◽  
Physiological Importance ◽  
Membrane Structure And Function ◽  
Assembly Kinetics ◽  
And Function

The laminins (LM) are a family of basement membranes glycoproteins with essential structural roles in supporting epithelia, endothelia, nerves and muscle adhesion, and signaling roles in regulating cell migration, proliferation, stem cell maintenance and differentiation. Laminins are obligate heterotrimers comprised of α, β and γ chains that assemble intracellularly. However, extracellularly these heterotrimers then assemble into higher-order networks via interaction between their laminin N-terminal (LN) domains. In vitro protein studies have identified assembly kinetics and the structural motifs involved in binding of adjacent LN domains. The physiological importance of these interactions has been identified through the study of pathogenic point mutations in LN domains that lead to syndromic disorders presenting with phenotypes dependent on which laminin gene is mutated. Genotype-phenotype comparison between knockout and LN domain missense mutations of the same laminin allows inferences to be drawn about the roles of laminin network assembly in terms of tissue function. In this review, we will discuss these comparisons in terms of laminin disorders, and the therapeutic options that understanding these processes have allowed. We will also discuss recent findings of non-laminin mediators of laminin network assembly and their implications in terms of basement membrane structure and function.

scholarly journals The Pathogenic R5L Mutation Disrupts Formation of Tau Complexes on the Microtubule by Altering Local N-Terminal Structure

2021 ◽  
Author(s):  
Alisa Cario ◽  
Adriana Savastano ◽  
Neil B. Wood ◽  
Zhu Liu ◽  
Michael J. Previs ◽  
...  
Keyword(s):  
Point Mutations ◽  
Intrinsically Disordered Protein ◽  
State Theory ◽  
Disease State ◽  
Missense Mutations ◽  
Microtubule Binding ◽  
Intrinsically Disordered ◽  
Projection Domain ◽  
Terminal Structure

The microtubule-associated protein (MAP) Tau is an intrinsically disordered protein (IDP) primarily expressed in axons, where it functions to regulate microtubule dynamics, modulate motor protein motility, and participate in signaling cascades. Tau misregulation and point mutations are linked to neurodegenerative diseases, including Progressive Supranuclear Palsy (PSP), Pick's Disease and Alzheimer's disease. Many disease-associated mutations in Tau occur in the C-terminal microtubule-binding domain of the protein. Effects of C-terminal mutations in Tau have led to the widely accepted disease-state theory that missense mutations in Tau reduce microtubule-binding affinity or increase Tau propensity to aggregate. Here, we investigate the effect of an N-terminal disease-associated mutation in Tau, R5L, on Tau-microtubule interactions using an in vitro reconstituted system. Contrary to the canonical disease-state theory, we determine the R5L mutation does not reduce Tau affinity for the microtubule using Total Internal Reflection Fluorescence (TIRF) Microscopy. Rather, the R5L mutation decreases the ability of Tau to form larger order complexes, or Tau patches, at high concentrations of Tau. Using Nuclear Magnetic Resonance (NMR), we show that the R5L mutation results in a local structural change that reduces interactions of the projection domain in the presence of microtubules. Altogether, these results challenge both the current paradigm of how mutations in Tau lead to disease and the role of the projection domain in modulating Tau behavior on the microtubule surface.

Study of the Protective Effect of Schizandra chinensis Polysaccharide on Oxidative Damage of Mouse Spermatozoa In Vitro

2014 ◽  
Vol 912-914 ◽  
pp. 1973-1977
Author(s):  
Dong Hai Zhao ◽  
Yan Zhang ◽  
Zhen Yuan ◽  
Meng Lu Li ◽  
Wei Yun Luo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Protective Effect ◽  
Damage Model ◽  
Membrane Lipid ◽  
Control Group ◽  
Stress Injury ◽  
Membrane Structure And Function ◽  
Stress Damage ◽  
And Function

The aim of the study: This study was conducted to evaluate oxidative stress damage model caused by reactive oxygen species production was prepared by heating injury and protective effect of SCP on spermatozoa membrane structure and function in vitro. Materials and methods: mouse eupyrene sperm suspensions were prepared and were randomly divided into six groups. The control group was maintained with PBS. The positive medicine group was received PBS contained vitamin E (0.25 mg /ml) .The SCP group was then given SCP (0.2, 0.4 and 0.8 mg /ml) respectively. All the groups except control group were treated with using heat stress injury. Degree of injury of spermatozoa membrane lipid peroxidation was detected. Results: The vitality of total superoxide dismutase (T-SOD) was increased and the quality of malondialdehyde (MDA) was decreased in different degree with each concentration of SCP. The protective effect of 0.4 mg /ml and 0.8 mg /ml SCP on spermatozoa membrane was obviously surpass to positive medicine group. These findings indicate that SCP could be potentially useful for the treatment of oxidative stress damage in spermatozoa.

scholarly journals Examination of Ferrochelatase Mutations That Cause Erythropoietic Protoporphyria

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3980-3985 ◽  
Author(s):  
V.M. Sellers ◽  
T.A. Dailey ◽  
H.A. Dailey
Keyword(s):  
Enzyme Activity ◽  
Amino Acid ◽  
Biosynthetic Pathway ◽  
Chain Termination ◽  
Missense Mutations ◽  
Inherited Disease ◽  
Erythropoietic Protoporphyria ◽  
Human Inherited Disease

Abstract Ferrochelatase (E.C. 4.99.1.1), the enzyme that catalyzes the terminal step in the heme biosynthetic pathway, is the site of defect in the human inherited disease erythropoietic protoporphyria (EPP). Previously it has been demonstrated that patients with EPP may have missense mutations leading to amino acid substitutions, early chain termination, or exon deletions. While it has been clearly demonstrated that two missense mutations result in lowered enzyme activity, it has never been shown what effect specific exon deletions may have. In the current work, recombinant human ferrochelatase has been engineered to have individual exon deletions corresponding to exons 3 through 11. When expressed in Escherichia coli, none of these possesses significant enzyme activity and all lack the [2Fe-2S] cluster. One of the human missense mutations, F417S, and a series of amino acid replacements at this site (ie, F417W, F417Y, and F417L) were examined. With the exception of F417L, all lacked enzyme activity and did not contain the [2Fe-2S] cluster in vivo or as isolated in vitro.

scholarly journals Examination of Ferrochelatase Mutations That Cause Erythropoietic Protoporphyria

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3980-3985
Author(s):  
V.M. Sellers ◽  
T.A. Dailey ◽  
H.A. Dailey
Keyword(s):  
Enzyme Activity ◽  
Amino Acid ◽  
Biosynthetic Pathway ◽  
Chain Termination ◽  
Missense Mutations ◽  
Inherited Disease ◽  
Erythropoietic Protoporphyria ◽  
Human Inherited Disease

Ferrochelatase (E.C. 4.99.1.1), the enzyme that catalyzes the terminal step in the heme biosynthetic pathway, is the site of defect in the human inherited disease erythropoietic protoporphyria (EPP). Previously it has been demonstrated that patients with EPP may have missense mutations leading to amino acid substitutions, early chain termination, or exon deletions. While it has been clearly demonstrated that two missense mutations result in lowered enzyme activity, it has never been shown what effect specific exon deletions may have. In the current work, recombinant human ferrochelatase has been engineered to have individual exon deletions corresponding to exons 3 through 11. When expressed in Escherichia coli, none of these possesses significant enzyme activity and all lack the [2Fe-2S] cluster. One of the human missense mutations, F417S, and a series of amino acid replacements at this site (ie, F417W, F417Y, and F417L) were examined. With the exception of F417L, all lacked enzyme activity and did not contain the [2Fe-2S] cluster in vivo or as isolated in vitro.

scholarly journals In Vitro Resistance of Staphylococcus aureus to Thrombin-Induced Platelet Microbicidal Protein Is Associated with Alterations in Cytoplasmic Membrane Fluidity

2000 ◽  
Vol 68 (6) ◽  
pp. 3548-3553 ◽  
Author(s):  
Arnold S. Bayer ◽  
Rajendra Prasad ◽  
Jyotsna Chandra ◽  
Anjni Koul ◽  
M. Smriti ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Membrane ◽  
Membrane Fluidity ◽  
Cytoplasmic Membrane ◽  
Membrane Lipids ◽  
Serial Passage ◽  
Membrane Structure And Function ◽  
Platelet Microbicidal Protein ◽  
And Function

ABSTRACT Platelet microbicidal proteins (PMPs) are small, cationic peptides which possess potent microbicidal activities against common bloodstream pathogens, such as Staphylococcus aureus. We previously showed that S. aureus strains exhibiting resistance to thrombin-induced PMP (tPMP-1) in vitro have an enhanced capacity to cause human and experimental endocarditis (T. Wu, M. R. Yeaman, and A. S. Bayer, Antimicrob. Agents Chemother. 38:729–732, 1994; A. S. Bayer et al., Antimicrob. Agents Chemother. 42:3169–3172, 1998; V. K. Dhawan et al., Infect. Immun. 65:3293–3299, 1997). However, the mechanisms mediating tPMP-1 resistance in S. aureus are not fully delineated. The S. aureus cell membrane appears to be a principal target for the action of tPMP-1. To gain insight into the basis of tPMP-1 resistance, we compared several parameters of membrane structure and function in three tPMP-1-resistant (tPMP-1r) strains and their genetically related, tPMP-1-susceptible (tPMP-1s) counterpart strains. The tPMP-1rstrains were derived by three distinct methods: transposon mutagenesis, serial passage in the presence of tPMP-1 in vitro, or carriage of a naturally occurring multiresistance plasmid (pSK1). All tPMP-1r strains were found to possess elevated levels of longer-chain, unsaturated membrane lipids, in comparison to their tPMP-1s counterparts. This was reflected in corresponding differences in cell membrane fluidity in the strain pairs, with tPMP-1r strains exhibiting significantly higher degrees of fluidity as assessed by fluorescence polarization. These data provide further support for the concept that specific alterations in the cytoplasmic membrane of S. aureus strains are associated with tPMP-1 resistance in vitro.

Clinical and molecular characterisation of 21 patients affected by quantitative fibrinogen deficiency

2015 ◽  
Vol 113 (03) ◽  
pp. 567-576 ◽  
Author(s):  
Rosanna Asselta ◽  
Manuela Platè ◽  
Michela Robusto ◽  
Munira Borhany ◽  
Ilaria Guella ◽  
...  
Keyword(s):  
Point Mutations ◽  
Compound Heterozygous ◽  
Molecular Characterisation ◽  
Missense Mutations ◽  
Large Deletions ◽  
Mutational Screening ◽  
Premature Termination Codons ◽  
Polypeptide Chains ◽  
Compound Heterozygous State

SummaryFibrinogen is a plasma glycoprotein mainly synthesised by hepatocytes and circulating as a 340-kDa hexamer consisting of two sets of three different polypeptide chains (Aα, Bβ, and γ, encoded by the FGA, FGB, and FGG gene, respectively). Congenital afibrinogenaemia and hypofibrinogenaemia are rare bleeding disorders characterised by abnormally low levels of functional and immunoreactive fibrinogen in plasma, associated with haemorrhagic manifestations of variable severity. While afibrinogenaemia is caused by mutations in the homozygous or compound heterozygous state in one of the three fibrinogen genes, hypofibrinogenaemia is generally due to heterozygous mutations, and is usually characterised by a milder phenotype. The mutational spectrum of these quantitative fibrinogen disorders includes large deletions, point mutations causing premature termination codons, and missense mutations often affecting fibrinogen assembly and/or secretion. Here we report the clinical and molecular characterisation of 13 unrelated afibrinogenaemic and eight hypofibrino - genaemic patients, leading to the identification of 17 different mutations (10 hitherto unknown). All the newly-identified missense and splicing mutations were in vitro expressed to verify their pathogenic role. Our data increase the number of mutations causing quantitative fibrinogen deficiencies by about 7 %. The high number of private mutations identified in the analysed probands indicates that the full mutational screening of the three fibrinogen genes is still required for molecular diagnosis.

scholarly journals PIWIL-2 and piRNAs are regularly expressed in epithelia of the skin and their expression is related to differentiation

2020 ◽  
Vol 312 (10) ◽  
pp. 705-714 ◽  
Author(s):  
Johannes Pammer ◽  
Heidi Rossiter ◽  
Martin Bilban ◽  
Leopold Eckhart ◽  
Maria Buchberger ◽  
...  
Keyword(s):  
Stem Cell ◽  
Regulation Of Gene Expression ◽  
Germline Stem Cell ◽  
Normal Human Skin ◽  
Protein Coding ◽  
Stem Cell Maintenance ◽  
Cell Compartments ◽  
And Function ◽  
Pirna Pathway

Abstract PIWI proteins play multiple roles in germline stem cell maintenance and self-renewal. PIWI-interacting RNAs (piRNAs) associate with PIWI proteins, form effector complexes and maintain genome integrity and function in the regulation of gene expression by epigenetic modifications. Both are involved in cancer development. In this study, we investigated the expression of PIWIL-2 and piRNAs in normal human skin and epithelial tumors and its regulation during keratinocyte (KC) differentiation. Immunohistochemistry showed that PIWIL-2 was regularly expressed in the epidermis and adnexal tissue with strongest expression in sebaceous glands. Cell culture studies revealed an association of PIWIL-2 expression with the state of differentiated KC. In contrast, the PIWIL-2 expression pattern did not correlate with stem cell compartments or malignancy. piRNAs were consistently detected in KC in vitro by next-generation sequencing and the expression levels of numerous piRNAs were regulated during KC differentiation. Epidermal piRNAs were predominantly derived from processed snoRNAs (C/D-box snoRNAs), tRNAs and protein coding genes. Our data indicate that components of the PIWIL-2—piRNA pathway are present in epithelial cells of the skin and are regulated in the context of KC differentiation, suggesting a role of somatic gene regulation. However, putative roles in the maintenance of stem cell compartments or the development of malignancy in the skin were not supported by this study.

scholarly journals Mutations associated with familial Parkinson’s disease alter the initiation and amplification steps of α-synuclein aggregation

2016 ◽  
Vol 113 (37) ◽  
pp. 10328-10333 ◽  
Author(s):  
Patrick Flagmeier ◽  
Georg Meisl ◽  
Michele Vendruscolo ◽  
Tuomas P. J. Knowles ◽  
Christopher M. Dobson ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Amyloid Fibrils ◽  
Single Point ◽  
Point Mutations ◽  
Lewy Bodies ◽  
In Vitro Study ◽  
Missense Mutations ◽  
Theoretical Approaches

Parkinson’s disease is a highly debilitating neurodegenerative condition whose pathological hallmark is the presence in nerve cells of proteinacious deposits, known as Lewy bodies, composed primarily of amyloid fibrils of α-synuclein. Several missense mutations in the gene encoding α-synuclein have been associated with familial variants of Parkinson’s disease and have been shown to affect the kinetics of the aggregation of the protein. Using a combination of experimental and theoretical approaches, we present a systematic in vitro study of the influence of disease-associated single-point mutations on the individual processes involved in α-synuclein aggregation into amyloid fibrils. We find that lipid-induced fibril production and surface catalyzed fibril amplification are the processes most strongly affected by these mutations and show that familial mutations can induce dramatic changes in the crucial processes thought to be associated with the initiation and spreading of the aggregation of α-synuclein.

Lipid Metabolism as a Site of Herbicide Action

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 477-480 ◽  
Author(s):  
J. B. St. John ◽  
J. L. Hilton
Keyword(s):  
Membrane Lipids ◽  
Lipid Synthesis ◽  
Membrane Lipid ◽  
Cell Membrane Permeability ◽  
Glyceride Synthesis ◽  
Membrane Structure And Function ◽  
And Function ◽  
A Site

Dinoseb (2-sec-butyl-4,6-dinitrophenol) and MBR 8251 [1,1 1-trifluoro-4′-(phenylsulfonyl)-methanesulfono-o-toluidide] inhibited enzymic synthesis of glycerides in vitro. The physiological significance of this inhibition was confirmed in intact wheat [Triticum aestivumL., ‘Mediterranean’ (C.I. 5303)] seedlings; dinoseb and MBR 8251 inhibition of glyceride synthesis in vivo was evidenced by a buildup in free fatty acids and a decrease in neutral and polar lipids. Glyceride synthesis and growth were reduced approximately equally by dinoseb and MBR 8251. However, polar (membrane) lipids were reduced more drastically than growth. It is suggested that dinoseb and MBR 8251 alter membrane structure and function through an inhibition of membrane lipid synthesis. DNP (dinitrophenol) was only slightly inhibitory in either the in vitro or in vivo system. Dinoseb was more effective than MBR 8251 in destruction of cell membrane permeability of intact roots immediately after treatment.

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