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1.
Mol Cell ; 63(2): 337-346, 2016 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-27425410

RESUMO

Upon heterologous overexpression, many proteins misfold or aggregate, thus resulting in low functional yields. Human acetylcholinesterase (hAChE), an enzyme mediating synaptic transmission, is a typical case of a human protein that necessitates mammalian systems to obtain functional expression. We developed a computational strategy and designed an AChE variant bearing 51 mutations that improved core packing, surface polarity, and backbone rigidity. This variant expressed at ∼2,000-fold higher levels in E. coli compared to wild-type hAChE and exhibited 20°C higher thermostability with no change in enzymatic properties or in the active-site configuration as determined by crystallography. To demonstrate broad utility, we similarly designed four other human and bacterial proteins. Testing at most three designs per protein, we obtained enhanced stability and/or higher yields of soluble and active protein in E. coli. Our algorithm requires only a 3D structure and several dozen sequences of naturally occurring homologs, and is available at http://pross.weizmann.ac.il.


Assuntos
Acetilcolinesterase/metabolismo , Biologia Computacional/métodos , Escherichia coli/enzimologia , Engenharia de Proteínas/métodos , Acetilcolinesterase/química , Acetilcolinesterase/genética , Algoritmos , Automação Laboratorial , Simulação por Computador , Desenho Assistido por Computador , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , DNA Metiltransferase 3A , Escherichia coli/genética , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Mutação , Hidrolases de Triester Fosfórico/genética , Hidrolases de Triester Fosfórico/metabolismo , Conformação Proteica , Desnaturação Proteica , Estabilidade Proteica , Sirtuínas/genética , Sirtuínas/metabolismo , Relação Estrutura-Atividade , Temperatura
2.
Adv Skin Wound Care ; 37(2): 76-84, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38241450

RESUMO

OBJECTIVE: To describe a virtual, competency-based skin and wound care (SWC) skills training model. The ECHO (Extension for Community Healthcare Outcomes) Ontario SWC pivoted from an in-person boot camp to a virtual format because of the COVID-19 pandemic. METHODS: An outcome-based program evaluation was conducted. Participants first watched guided commentary and videos of experts performing in nine SWC multiskills videos, then practiced and video-recorded themselves performing those skills; these recordings were assessed by facilitators. Data were collected using pre-post surveys and rubric-based assessments. Descriptive statistics and thematic analysis were applied to data analysis. RESULTS: Fifty-five healthcare professionals participated in the virtual boot camp, measured by the submission of at least one video. A total of 216 videos were submitted and 215 assessment rubrics were completed. Twenty-nine participants completed the pre-boot camp survey (53% response rate) and 26 responded to the post-boot camp survey (47% response rate). The strengths of the boot camp included the applicability of virtual learning to clinical settings, boot camp supplies, tool kits, and teaching strategies. The analysis of survey responses indicated that average proficiency scores were greater than 80% for three videos, 50% to 70% for three of the videos, and less than 50% for three of the videos. Participants received lower scores in local wound care and hand washing points of contact. The barriers of the boot camp included technical issues, time, level of knowledge required at times, and lack of equipment and access to interprofessional teams. CONCLUSIONS: This virtual ECHO SWC model expanded access to practical skills acquisition. The professional development model presented here is generalizable to other healthcare domains.


Assuntos
COVID-19 , Internato e Residência , Humanos , Ontário , Currículo , Pandemias , COVID-19/epidemiologia , Competência Clínica
3.
J Cell Biochem ; 2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36780339

RESUMO

FK506 binding protein 51 (FKBP51) is a molecular chaperone that influences stress response. In addition to having an integral role in the regulation of steroid hormone receptors, including glucocorticoid receptor, FKBP51 has been linked with several biological processes including metabolism and neuronal health. Genetic and epigenetic alterations in the gene that encodes FKBP51, FKBP5, are associated with increased susceptibility to multiple neuropsychiatric disorders, which has fueled much of the research on this protein. Because of the complexity of these processes, animal models have been important in understanding the role of FKBP51. This review examines each of the current mouse models of FKBP5, which include whole animal knockout, conditional knockout, overexpression, and humanized mouse models. The generation of each model and observational details are discussed, including behavioral phenotypes, molecular changes, and electrophysiological alterations basally and following various challenges. While much has been learned through these models, there are still many aspects of FKBP51 biology that remain opaque and future studies are needed to help illuminate these current gaps in knowledge. Overall, FKBP5 continues to be an exciting potential target for stress-related disorders.

4.
J Biol Chem ; 297(3): 101067, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34384785

RESUMO

Recombinant antibodies with well-characterized epitopes and known conformational specificities are critical reagents to support robust interpretation and reproducibility of immunoassays across biomedical research. For myocilin, a protein prone to misfolding that is associated with glaucoma and an emerging player in other human diseases, currently available antibodies are unable to differentiate among the numerous disease-associated protein states. This fundamentally constrains efforts to understand the connection between myocilin structure, function, and disease. To address this concern, we used protein engineering methods to develop new recombinant antibodies that detect the N-terminal leucine zipper structural domain of myocilin and that are cross-reactive for human and mouse myocilin. After harvesting spleens from immunized mice and in vitro library panning, we identified two antibodies, 2A4 and 1G12. 2A4 specifically recognizes a folded epitope while 1G12 recognizes a range of conformations. We matured antibody 2A4 for improved biophysical properties, resulting in variant 2H2. In a human IgG1 format, 2A4, 1G12, and 2H2 immunoprecipitate full-length folded myocilin present in the spent media of human trabecular meshwork (TM) cells, and 2H2 can visualize myocilin in fixed human TM cells using fluorescence microscopy. These new antibodies should find broad application in glaucoma and other research across multiple species platforms.


Assuntos
Proteínas do Citoesqueleto/imunologia , Epitopos/imunologia , Proteínas do Olho/imunologia , Glicoproteínas/imunologia , Zíper de Leucina/imunologia , Animais , Anticorpos/imunologia , Proteínas do Citoesqueleto/metabolismo , Epitopos/metabolismo , Proteínas do Olho/metabolismo , Feminino , Glaucoma/metabolismo , Glicoproteínas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Conformação Molecular , Conformação Proteica , Domínios Proteicos/imunologia , Proteínas Recombinantes/imunologia , Reprodutibilidade dos Testes , Malha Trabecular/metabolismo
6.
J Biol Chem ; 294(34): 12717-12728, 2019 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-31270212

RESUMO

Nonsynonymous gene mutations can be beneficial, neutral, or detrimental to the stability, structure, and biological function of the encoded protein, but the effects of these mutations are often not readily predictable. For example, the ß-propeller olfactomedin domain of myocilin (mOLF) exhibits a complex interrelationship among structure(s), stability, and aggregation. Numerous mutations within mOLF are linked to glaucoma; the resulting variants are less stable, aggregation-prone, and sequestered intracellularly, causing cytotoxicity. Here, we report the first stable mOLF variants carrying substitutions in the calcium-binding site that exhibit solution characteristics indistinguishable from those of glaucoma variants. Crystal structures of these stable variants at 1.8-2.0-Å resolution revealed features that we could not predict by molecular dynamics simulations, including loss of loop structure, helix unwinding, and a blade shift. Double mutants that combined a stabilizing substitution and a selected glaucoma-causing single-point mutant rescued in vitro folding and stability defects. In the context of full-length myocilin, secretion of stable single variants was indistinguishable from that of the WT protein, and the double mutants were secreted to varying extents. In summary, our finding that mOLF can tolerate particular substitutions that render the protein stable despite a conformational switch emphasizes the complexities in differentiating between benign and glaucoma-causing variants and provides new insight into the possible biological function of myocilin.


Assuntos
Proteínas do Citoesqueleto/genética , Proteínas da Matriz Extracelular/genética , Proteínas do Olho/genética , Glaucoma/genética , Glicoproteínas/genética , Mutação , Proteínas do Citoesqueleto/química , Proteínas da Matriz Extracelular/química , Proteínas do Olho/química , Variação Genética/genética , Glicoproteínas/química , Células HEK293 , Humanos , Simulação de Dinâmica Molecular
7.
Int J Mol Sci ; 21(15)2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32751642

RESUMO

Misfolding, aggregation and accumulation of proteins are toxic elements in the progression of a broad range of neurodegenerative diseases. Molecular chaperones enable a cellular defense by reducing or compartmentalizing these insults. Small heat shock proteins (sHsps) engage proteins early in the process of misfolding and can facilitate their proper folding or refolding, sequestration, or clearance. Here, we evaluate the effects of the sHsp Hsp22, as well as a pseudophosphorylated mutant and an N-terminal domain deletion (NTDΔ) variant on tau aggregation in vitro and tau accumulation and aggregation in cultured cells. Hsp22 wild-type (WT) protein had a significant inhibitory effect on heparin-induced aggregation in vitro and the pseudophosphorylated mutant Hsp22 demonstrated a similar effect. When co-expressed in a cell culture model with tau, these Hsp22 constructs significantly reduced soluble tau protein levels when transfected at a high ratio relative to tau. However, the Hsp22 NTDΔ protein drastically reduced the soluble protein expression levels of both tau WT and tau P301L/S320F even at lower transfection ratios, which resulted in a correlative reduction of the triton-insoluble tau P301L/S320F aggregates.


Assuntos
Proteínas de Choque Térmico/genética , Chaperonas Moleculares/genética , Doenças Neurodegenerativas/genética , Proteínas tau/genética , Animais , Regulação da Expressão Gênica/genética , Proteínas de Choque Térmico Pequenas/genética , Humanos , Camundongos , Camundongos Transgênicos , Doenças Neurodegenerativas/patologia , Agregação Patológica de Proteínas/genética , Ligação Proteica/genética , Deficiências na Proteostase/genética
8.
Biochemistry ; 58(13): 1718-1727, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30802039

RESUMO

Mutations in myocilin, predominantly within its olfactomedin (OLF) domain, are causative for the heritable form of open angle glaucoma in humans. Surprisingly, mice expressing Tyr423His mutant myocilin, corresponding to a severe glaucoma-causing mutation (Tyr437His) in human subjects, exhibit a weak, if any, glaucoma phenotype. To address possible protein-level discrepancies between mouse and human OLFs, which might lead to this outcome, biophysical properties of mouse OLF were characterized for comparison with those of human OLF. The 1.55 Å resolution crystal structure of mouse OLF reveals an asymmetric 5-bladed ß-propeller that is nearly indistinguishable from previous structures of human OLF. Wild-type and selected mutant mouse OLFs mirror thermal stabilities of their human OLF counterparts, including characteristic stabilization in the presence of calcium. Mouse OLF forms thioflavin T-positive aggregates with a similar end-point morphology as human OLF, but amyloid aggregation kinetic rates of mouse OLF are faster than human OLF. Simulations and experiments support the interpretation that kinetics of mouse OLF are faster because of a decreased charge repulsion arising from more neutral surface electrostatics. Taken together, phenotypic differences observed in mouse and human studies of mutant myocilin could be a function of aggregation kinetics rates, which would alter the lifetime of putatively toxic protofibrillar intermediates.


Assuntos
Amiloide/química , Proteínas do Citoesqueleto/química , Proteínas da Matriz Extracelular/química , Proteínas do Olho/química , Glaucoma/genética , Glicoproteínas/química , Amiloide/genética , Animais , Cristalografia por Raios X , Proteínas do Citoesqueleto/genética , Proteínas do Olho/genética , Glicoproteínas/genética , Humanos , Camundongos , Modelos Moleculares , Mutação Puntual , Agregados Proteicos , Conformação Proteica , Domínios Proteicos , Dobramento de Proteína , Estabilidade Proteica
9.
Rural Remote Health ; 19(4): 5156, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31675244

RESUMO

INTRODUCTION: Abortion has been legal in the Australian state of Victoria since 2008 and medical termination of pregnancy (MTOP) available since 2012. While these developments were expected to improve Victorian rural women's access to abortion, this has not been borne out in practice. General practitioners (GPs), particularly in rural areas, are women's first point of contact when faced with an unintended pregnancy. The objective of this study was to understand rural GPs' knowledge and practice in relation to unintended pregnancy and referral for abortion, using the Grampians region of Victoria as a case study. Parts of this region, like other rural and regional areas, experience teenage pregnancy rates double the national average and more than four times that of major cities, and access to abortion services is known to be limited. Findings from the study will inform rural health service development to improve rural women's access to abortion. METHODS: This article reports on the findings from a mixed methods study which explored GP knowledge, understanding and practice in relation to unintended pregnancy services in seven local government areas in the Grampians. Data were collected between April and August 2017. GPs from all practices in this region were invited to participate. A total of 84 GPs were approached, 23 (27%) completed the survey and, of these, five also took part in a semi-structured telephone interview. The quantitative survey data were analysed descriptively while the open-ended survey responses and qualitative interviews were analysed thematically. RESULTS: Of the GPs surveyed, 38% indicated that they 'refer to a colleague due to a conscientious objection' when women present with an unintended pregnancy. No GP always discussed telehealth medical abortion with women and only 27% said that they 'always' discussed medical abortion with women. A range of views were expressed about the adequacy and location of services, with the majority indicating services in the region were limited or inadequate. Interviews with GPs who had conscientious objections to abortion indicated that 'conscientious objection' occurred in different forms and included a range of behaviours. Rural GPs who were interested in becoming MTOP providers faced barriers such as lack of access to timely ultrasounds and surgical backup. CONCLUSION: The results indicate high levels of conscientious objection and wide variation in knowledge of services. In addition, the provision of tele-abortion and medical abortion is extremely limited in this region, even while these are considered ideal ways to address rural access to abortion. It is likely the promise of tele-abortion is far from fulfilled in the Grampians region and possibly in other rural areas in Victoria. There is a need to improve GPs' knowledge of available services and adherence to legal and professional obligations, and there are clear opportunities to achieve this, with all interview participants expressing strong support for the prevention of unintended pregnancy, and many highlighting the need for good support for women up until the point of termination.


Assuntos
Aborto Induzido/psicologia , Aborto Induzido/estatística & dados numéricos , Clínicos Gerais/psicologia , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Gravidez não Planejada/psicologia , Serviços de Saúde Rural/estatística & dados numéricos , População Rural/estatística & dados numéricos , Adulto , Atitude do Pessoal de Saúde , Feminino , Clínicos Gerais/estatística & dados numéricos , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Gravidez , Vitória
10.
Exp Eye Res ; 173: 109-112, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29752947

RESUMO

The presence of myocilin is often used in the process of validating trabecular meshwork (TM) cells and eye tissues, but the antibody reagents used for detection are poorly characterized. Indeed, for over a century, researchers have been using antibodies to track proteins of interest in a variety of biological contexts, but many antibodies remain ill-defined at the molecular level and in their target epitope. Such issues have prompted efforts from major funding agencies to validate reagents and combat reproducibility issues across biomedical sciences. Here we characterize the epitopes recognized by four commercial myocilin antibodies, aided by structurally and biochemically characterized myocilin fragments. All four antibodies recognize enriched myocilin secreted from human TM cell media. The detection of myocilin fragments by ELISA and Western blot reveal a variety of epitopes across the myocilin polypeptide chain. A more precise understanding of myocilin antibody targets, including conformational specificity, should aid the community in standardizing protocols across laboratories and in turn, lead to a better understanding of eye physiology and disease.


Assuntos
Anticorpos/imunologia , Proteínas do Citoesqueleto/imunologia , Mapeamento de Epitopos/métodos , Proteínas do Olho/imunologia , Glicoproteínas/imunologia , Epitopos Imunodominantes/imunologia , Anticorpos Monoclonais/imunologia , Western Blotting , Células Cultivadas , Comércio , Ensaio de Imunoadsorção Enzimática , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Proteínas Recombinantes , Malha Trabecular/metabolismo
11.
Hum Mol Genet ; 24(8): 2111-24, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25524706

RESUMO

Olfactomedin (OLF) domain-containing proteins play roles in fundamental cellular processes and have been implicated in disorders ranging from glaucoma, cancers and inflammatory bowel disorder, to attention deficit disorder and childhood obesity. We solved crystal structures of the OLF domain of myocilin (myoc-OLF), the best studied such domain to date. Mutations in myoc-OLF are causative in the autosomal dominant inherited form of the prevalent ocular disorder glaucoma. The structures reveal a new addition to the small family of five-bladed ß-propellers. Propellers are most well known for their ability to act as hubs for protein-protein interactions, a function that seems most likely for myoc-OLF, but they can also act as enzymes. A calcium ion, sodium ion and glycerol molecule were identified within a central hydrophilic cavity that is accessible via movements of surface loop residues. By mapping familial glaucoma-associated lesions onto the myoc-OLF structure, three regions sensitive to aggregation have been identified, with direct applicability to differentiating between neutral and disease-causing non-synonymous mutations documented in the human population worldwide. Evolutionary analysis mapped onto the myoc-OLF structure reveals conserved and divergent regions for possible overlapping and distinctive functional protein-protein or protein-ligand interactions across the broader OLF domain family. While deciphering the specific normal biological functions, ligands and binding partners for OLF domains will likely continue to be a challenging long-term experimental pursuit, atomic detail structural knowledge of myoc-OLF is a valuable guide for understanding the implications of glaucoma-associated mutations and will help focus future studies of this biomedically important domain family.


Assuntos
Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/metabolismo , Proteínas do Olho/química , Proteínas do Olho/metabolismo , Glaucoma/metabolismo , Glicoproteínas/química , Glicoproteínas/metabolismo , Deficiências na Proteostase/metabolismo , Cristalização , Proteínas do Citoesqueleto/genética , Proteínas do Olho/genética , Glaucoma/genética , Glicoproteínas/genética , Humanos , Modelos Moleculares , Mutação , Dobramento de Proteína , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Deficiências na Proteostase/genética
12.
Surf Sci ; 652: 200-205, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27458322

RESUMO

Previously we reported estimates of the maximum etch rates of C on TiO2 by oxidizers including NO, O3 and H2O2 when irradiated by a spatially-non-uniform beam of extreme ultraviolet (EUV) radiation at 13.5 nm (Faradzhev et al., 2013). Here we extend that work by presenting temporally and spatially resolved measurements of the C etching by these oxidizers as a function of EUV intensity in the range (0.3 to 3) mW/mm2 [(0.2 to 2) × 1016 photons s-1 cm-2]. We find that the rates for NO scale linearly with intensity and are smaller than those for O3, which exhibit a weak, sub-linear intensity dependence in this range. We demonstrate that these behaviors are consistent with adsorption of the oxidizing precursor on the C surface followed by a photon-stimulated reaction resulting in volatile C-containing products. The kinetics of photon-induced C etching by hydrogen peroxide, however, appear to be more complex. The spatially resolved measurements reveal that C removal by H2O2 begins at the edges of the C spot, where the light intensity is the lowest, and proceeds toward the center of the spot. This localization of the reaction may occur because hydroxyl radicals are produced efficiently on the catalytically active TiO2 surface.

13.
Nat Commun ; 15(1): 155, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38168102

RESUMO

Studies of folded-to-misfolded transitions using model protein systems reveal a range of unfolding needed for exposure of amyloid-prone regions for subsequent fibrillization. Here, we probe the relationship between unfolding and aggregation for glaucoma-associated myocilin. Mutations within the olfactomedin domain of myocilin (OLF) cause a gain-of-function, namely cytotoxic intracellular aggregation, which hastens disease progression. Aggregation by wild-type OLF (OLFWT) competes with its chemical unfolding, but only below the threshold where OLF loses tertiary structure. Representative moderate (OLFD380A) and severe (OLFI499F) disease variants aggregate differently, with rates comparable to OLFWT in initial stages of unfolding, and variants adopt distinct partially folded structures seen along the OLFWT urea-unfolding pathway. Whether initiated with mutation or chemical perturbation, unfolding propagates outward to the propeller surface. In sum, for this large protein prone to amyloid formation, the requirement for a conformational change to promote amyloid fibrillization leads to direct competition between unfolding and aggregation.


Assuntos
Amiloide , Glaucoma , Humanos , Amiloide/metabolismo , Glaucoma/genética , Mutação , Peptídeos beta-Amiloides/genética , Proteínas Amiloidogênicas/genética , Dobramento de Proteína
14.
Artigo em Inglês | MEDLINE | ID: mdl-38884838

RESUMO

Brief, school-based mental health interventions hold promise for reducing barriers to mental health support access, a critical endeavor in light of increasing rates of mental health concerns among youth. However, there is no consensus on whether or not brief school-based interventions are effective at reducing mental health concerns or improving well-being. This systematic review and meta-analysis aims to provide consensus and determine directions for future work. Articles were included if they examined a brief (≤ four sessions or 240 min of intervention time) psychosocial intervention, were conducted within a Pre-K through 12th-grade school setting, included at least one treatment outcome evaluating mental health or well-being, and were published since 2000. A total of 6,702 papers were identified through database searching, of which 81 papers (k studies = 75) were ultimately selected for inclusion. A total of 40,498 students were included across studies and a total of 75 unique interventions were examined. A total of 324 effect sizes were extracted. On average, interventions led to statistically significant improvements in mental health/well-being outcomes versus control conditions up to one-month (g = .18, p = .004), six-month (g = .15, p = .006), and one-year (g = .10, p = .03) post-intervention. There may be benefits to brief school-based interventions from a preventative public health standpoint; future research may focus on how to optimize their real-world utility. Prospero pre-registration: CRD42021255079.

15.
J Biol Chem ; 287(52): 43370-7, 2012 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-23129764

RESUMO

Myocilin is a protein found in the trabecular meshwork extracellular matrix tissue of the eye that plays a role in regulating intraocular pressure. Both wild-type and certain myocilin variants containing mutations in the olfactomedin (OLF) domain are linked to the optic neuropathy glaucoma. Because calcium ions are important biological cofactors that play numerous roles in extracellular matrix proteins, we examined the calcium binding properties of the myocilin OLF domain (myoc-OLF). Our study reveals an unprecedented high affinity calcium binding site within myoc-OLF. The calcium ion remains bound to wild-type OLF at neutral and acidic pH. A glaucoma-causing OLF variant, myoc-OLF(D380A), is calcium-depleted. Key differences in secondary and tertiary structure between myoc-OLF(D380A) and wild-type myoc-OLF, as well as limited access to chelators, indicate that the calcium binding site is largely buried in the interior of the protein. Analysis of six conserved aspartate or glutamate residues and an additional 18 disease-causing variants revealed two other candidate residues that may be involved in calcium coordination. Our finding expands our knowledge of calcium binding in extracellular matrix proteins; provides new clues into domain structure, function, and pathogenesis for myocilin; and offers insights into highly conserved, biomedically relevant OLF domains.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Proteínas do Olho/metabolismo , Glaucoma/metabolismo , Glicoproteínas/metabolismo , Animais , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/genética , Bovinos , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/genética , Proteínas da Matriz Extracelular/genética , Proteínas do Olho/química , Proteínas do Olho/genética , Glaucoma/genética , Glaucoma/patologia , Glaucoma/fisiopatologia , Glicoproteínas/química , Glicoproteínas/genética , Humanos , Concentração de Íons de Hidrogênio , Pressão Intraocular/genética , Camundongos , Mutação , Estrutura Terciária de Proteína , Suínos , Malha Trabecular/metabolismo , Malha Trabecular/patologia , Malha Trabecular/fisiopatologia
16.
J Biol Chem ; 287(48): 40661-9, 2012 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-23035116

RESUMO

BACKGROUND: Mutant myocilin accumulates in the endoplasmic reticulum for unknown reasons. RESULTS: Glucose-regulated protein (Grp) 94 depletion reduces mutant myocilin by engaging autophagy. CONCLUSION: Grp94 triages mutant myocilin through ER-associated degradation, subverting autophagy. SIGNIFICANCE: Treating glaucoma could be possible by inhibiting Grp94 and reducing its novel client, mutant myocilin. Clearance of misfolded proteins in the endoplasmic reticulum (ER) is traditionally handled by ER-associated degradation (ERAD), a process that requires retro-translocation and ubiquitination mediated by a luminal chaperone network. Here we investigated whether the secreted, glaucoma-associated protein myocilin was processed by this pathway. Myocilin is typically transported through the ER/Golgi network, but inherited mutations in myocilin lead to its misfolding and aggregation within trabecular meshwork cells, and ultimately, ER stress-induced cell death. Using targeted knockdown strategies, we determined that glucose-regulated protein 94 (Grp94), the ER equivalent of heat shock protein 90 (Hsp90), specifically recognizes mutant myocilin, triaging it through ERAD. The addition of mutant myocilin to the short list of Grp94 clients strengthens the hypothesis that ß-strand secondary structure drives client association with Grp94. Interestingly, the ERAD pathway is incapable of efficiently handling the removal of mutant myocilin, but when Grp94 is depleted, degradation of mutant myocilin is shunted away from ERAD toward a more robust clearance pathway for aggregation-prone proteins, the autophagy system. Thus ERAD inefficiency for distinct aggregation-prone proteins can be subverted by manipulating ER chaperones, leading to more effective clearance by the autophagic/lysosomal pathway. General Hsp90 inhibitors and a selective Grp94 inhibitor also facilitate clearance of mutant myocilin, suggesting that therapeutic approaches aimed at inhibiting Grp94 could be beneficial for patients suffering from some cases of myocilin glaucoma.


Assuntos
Autofagia , Proteínas do Citoesqueleto/genética , Degradação Associada com o Retículo Endoplasmático , Retículo Endoplasmático/metabolismo , Proteínas do Olho/genética , Glaucoma de Ângulo Aberto/metabolismo , Glicoproteínas/genética , Glicoproteínas de Membrana/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas do Olho/metabolismo , Glaucoma de Ângulo Aberto/genética , Glicoproteínas/metabolismo , Humanos , Glicoproteínas de Membrana/genética , Mutação , Ligação Proteica
17.
J Chem Phys ; 139(12): 121901, 2013 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-24089713

RESUMO

Deposits of fibrils formed by disease-specific proteins are the molecular hallmark of such diverse human disorders as Alzheimer's disease, type II diabetes, or rheumatoid arthritis. Amyloid fibril formation by structurally and functionally unrelated proteins exhibits many generic characteristics, most prominently the cross ß-sheet structure of their mature fibrils. At the same time, amyloid formation tends to proceed along one of two separate assembly pathways yielding either stiff monomeric filaments or globular oligomers and curvilinear protofibrils. Given the focus on oligomers as major toxic species, the very existence of an oligomer-free assembly pathway is significant. Little is known, though, about the structure of the various intermediates emerging along different pathways and whether the pathways converge towards a common or distinct fibril structures. Using infrared spectroscopy we probed the structural evolution of intermediates and late-stage fibrils formed during in vitro lysozyme amyloid assembly along an oligomeric and oligomer-free pathway. Infrared spectroscopy confirmed that both pathways produced amyloid-specific ß-sheet peaks, but at pathway-specific wavenumbers. We further found that the amyloid-specific dye thioflavin T responded to all intermediates along either pathway. The relative amplitudes of thioflavin T fluorescence responses displayed pathway-specific differences and could be utilized for monitoring the structural evolution of intermediates. Pathway-specific structural features obtained from infrared spectroscopy and Thioflavin T responses were identical for fibrils grown at highly acidic or at physiological pH values and showed no discernible effects of protein hydrolysis. Our results suggest that late-stage fibrils formed along either pathway are amyloidogenic in nature, but have distinguishable structural fingerprints. These pathway-specific fingerprints emerge during the earliest aggregation events and persist throughout the entire cascade of aggregation intermediates formed along each pathway.


Assuntos
Muramidase/química , Muramidase/síntese química , Mapeamento de Peptídeos , Animais , Galinhas , Muramidase/metabolismo , Tamanho da Partícula , Conformação Proteica , Propriedades de Superfície
18.
Int J Biol Macromol ; 253(Pt 7): 127486, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37852393

RESUMO

The aberrant accumulation of tau protein is implicated as a pathogenic factor in many neurodegenerative diseases. Tau seeding may underlie its predictable spread in these diseases. Molecular chaperones can modulate tau pathology, but their effects have mainly been studied in isolation. This study employed a semi-high throughput assay to identify molecular chaperones influencing tau seeding using Tau RD P301S FRET Biosensor cells, which express a portion of tau containing the frontotemporal dementia-related P301S tau mutation fused to a FRET biosensor. Approximately fifty chaperones from five major families were screened using live cell imaging to monitor FRET-positive tau seeding. Among the tested chaperones, five exhibited significant effects on tau in the primary screen. Notably, three of these were from the DnaJ family. In subsequent studies, overexpression of DnaJA2, DnaJB1, and DnaJB6b resulted in significant reductions in tau levels. Knockdown experiments by shRNA revealed an inverse correlation between DnaJB1 and DnaJB6b with tau levels. DnaJB6b overexpression, specifically, reduced total tau levels in a cellular model with a pre-existing pool of tau, partially through enhanced proteasomal degradation. Further, DnaJB6b interacted with tau complexes. These findings highlight the potent chaperone activity within the DnaJ family, particularly DnaJB6b, towards tau.


Assuntos
Demência Frontotemporal , Proteínas tau , Humanos , Proteínas tau/genética , Proteínas tau/metabolismo , Demência Frontotemporal/genética , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP40/metabolismo
19.
Sci Adv ; 9(5): eadd9789, 2023 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-36724228

RESUMO

Alzheimer's disease and related tauopathies are characterized by the pathogenic misfolding and aggregation of the microtubule-associated protein tau. Understanding how endogenous chaperones modulate tau misfolding could guide future therapies. Here, we show that the immunophilin FKBP12, the 12-kDa FK506-binding protein (also known as FKBP prolyl isomerase 1A), regulates the neuronal resilience by chaperoning a specific structure in monomeric tau. Using a combination of mouse and cell experiments, in vitro aggregation experiments, nuclear magnetic resonance-based structural analysis of monomeric tau, site-specific phosphorylation and mutation, as well as structure-based analysis using the neural network-based structure prediction program AlphaFold, we define the molecular factors that govern the binding of FKBP12 to tau and its influence on tau-induced neurotoxicity. We further demonstrate that tyrosine phosphorylation of tau blocks the binding of FKBP12 to two highly specific structural motifs in tau. Our data together with previous results demonstrating FKBP12/tau colocalization in neurons and neurofibrillary tangles support a critical role of FKBP12 in regulating tau pathology.


Assuntos
Doença de Alzheimer , Tauopatias , Humanos , Proteína 1A de Ligação a Tacrolimo/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Proteínas de Ligação a Tacrolimo/metabolismo , Tauopatias/metabolismo , Neurônios/metabolismo , Chaperonas Moleculares/metabolismo
20.
Sci Rep ; 13(1): 317, 2023 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609440

RESUMO

Shifts in normal aging set stage for neurodegeneration and dementia affecting 1 in 10 adults. The study demonstrates that lncRNA GAS5 is decreased in aged and Alzheimer's disease brain. The role and targets of lncRNA GAS5 in the aging brain were elucidated using a GAS5-targeting small molecule NPC86, a frontier in lncRNA-targeting therapeutic. Robust techniques such as molecular dynamics simulation of NPC86 binding to GAS5, in vitro functional assays demonstrating that GAS5 regulates insulin signaling, neuronal survival, phosphorylation of tau, and neuroinflammation via toll-like receptors support the role of GAS5 in maintaining healthy neurons. The study demonstrates the safety and efficacy of intranasal NPC86 treatment in aged mice to improve cellular functions with transcriptomic analysis in response to NPC86. In summary, the study demonstrates that GAS5 contributes to pathways associated with neurodegeneration and NPC86 has tremendous therapeutic potential to prevent the advent of neurodegenerative diseases and dementias.


Assuntos
MicroRNAs , RNA Longo não Codificante , Camundongos , Animais , Insulina/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Doenças Neuroinflamatórias , Transdução de Sinais , Modelos Animais de Doenças , Neurônios/metabolismo , MicroRNAs/genética
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