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1.
EMBO J ; 40(1): e104416, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33185277

RESUMO

The transport of auxin controls the rate, direction and localization of plant growth and development. The course of auxin transport is defined by the polar subcellular localization of the PIN proteins, a family of auxin efflux transporters. However, little is known about the composition and regulation of the PIN protein complex. Here, using blue-native PAGE and quantitative mass spectrometry, we identify native PIN core transport units as homo- and heteromers assembled from PIN1, PIN2, PIN3, PIN4 and PIN7 subunits only. Furthermore, we show that endogenous flavonols stabilize PIN dimers to regulate auxin efflux in the same way as does the auxin transport inhibitor 1-naphthylphthalamic acid (NPA). This inhibitory mechanism is counteracted both by the natural auxin indole-3-acetic acid and by phosphomimetic amino acids introduced into the PIN1 cytoplasmic domain. Our results lend mechanistic insights into an endogenous control mechanism which regulates PIN function and opens the way for a deeper understanding of the protein environment and regulation of the polar auxin transport complex.


Assuntos
Proteínas de Arabidopsis/metabolismo , Transporte Biológico/fisiologia , Flavonóis/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Ftalimidas/metabolismo
2.
Bioconjug Chem ; 35(7): 922-933, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38654427

RESUMO

Bioorthogonal chemistry has gained widespread use in the study of many biological systems of interest, including protein prenylation. Prenylation is a post-translational modification, in which one or two 15- or 20-carbon isoprenoid chains are transferred onto cysteine residues near the C-terminus of a target protein. The three main enzymes─protein farnesyltransferase (FTase), geranylgeranyl transferase I (GGTase I), and geranylgeranyl transferase II (GGTase II)─that catalyze this process have been shown to tolerate numerous structural modifications in the isoprenoid substrate. This feature has previously been exploited to transfer an array of farnesyl diphosphate analogues with a range of functionalities, including an alkyne-containing analogue for copper-catalyzed bioconjugation reactions. Reported here is the synthesis of an analogue of the isoprenoid substrate embedded with norbornene functionality (C10NorOPP) that can be used for an array of applications, ranging from metabolic labeling to selective protein modification. The probe was synthesized in seven steps with an overall yield of 7% and underwent an inverse electron demand Diels-Alder (IEDDA) reaction with tetrazine-containing tags, allowing for copper-free labeling of proteins. The use of C10NorOPP for the study of prenylation was explored in the metabolic labeling of prenylated proteins in HeLa, COS-7, and astrocyte cells. Furthermore, in HeLa cells, these modified prenylated proteins were identified and quantified using label-free quantification (LFQ) proteomics with 25 enriched prenylated proteins. Additionally, the unique chemistry of C10NorOPP was utilized for the construction of a multiprotein-polymer conjugate for the targeted labeling of cancer cells. That construct was prepared using a combination of norbornene-tetrazine conjugation and azide-alkyne cycloaddition, highlighting the utility of the additional degree of orthogonality for the facile assembly of new protein conjugates with novel structures and functions.


Assuntos
Química Click , Farnesiltranstransferase , Norbornanos , Prenilação de Proteína , Norbornanos/química , Farnesiltranstransferase/metabolismo , Humanos , Animais
3.
Nat Chem Biol ; 18(10): 1125-1134, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35941237

RESUMO

Cellular therapies remain constrained by the limited availability of sensors for disease markers. Here we present an integrated target-to-receptor pipeline for constructing a customizable advanced modular bispecific extracellular receptor (AMBER) that combines our generalized extracellular molecule sensor (GEMS) system with a high-throughput platform for generating designed ankyrin repeat proteins (DARPins). For proof of concept, we chose human fibrin degradation products (FDPs) as markers with high clinical relevance and screened a DARPin library for FDP binders. We built AMBERs equipped with 19 different DARPins selected from 160 hits, and found 4 of them to be functional as heterodimers with a known single-chain variable fragments binder. Tandem receptors consisting of combinations of the validated DARPins are also functional. We demonstrate applications of these AMBER receptors in vitro and in vivo by constructing designer cell lines that detect pathological concentrations of FDPs and respond with the production of a reporter and a therapeutic anti-thrombotic protein.


Assuntos
Repetição de Anquirina , Anticorpos de Cadeia Única , Proteínas de Transporte , Proteínas de Repetição de Anquirina Projetadas , Produtos de Degradação da Fibrina e do Fibrinogênio , Humanos , Ligação Proteica
4.
Age Ageing ; 52(3)2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36929844

RESUMO

OBJECTIVE: Patient-centredness (PC) is central to the health care of older adults with multimorbidity, but knowledge about the psychometric quality of instruments measuring it in this group is scarce. Based on an integrative model of PC, we aimed to identify assessment instruments of PC for this particular group and evaluate their psychometric properties. METHODS: We systematically searched six electronic databases (MEDLINE, CINAHL, EMBASE, PsycINFO, Web of Science and PSYNDEX), initially covering research published up to 2018 and updated later to include work up to July 2022. In evaluating the psychometric properties of identified instruments, we followed the COSMIN methodology. RESULTS: We identified 12 studies reporting on 10 instruments measuring PC in the health care of older adults with multimorbidity. For these instruments, structural validity and internal consistency were the psychometric properties reported most often. Based on the COSMIN criteria, eight instruments received favourable ratings for internal consistency with respect to methodological quality ('very good'), measurement property ('sufficient') and overall quality of evidence ('moderate'). Ratings of structural validity varied more largely, with three to seven instruments showing at least adequate methodological quality, sufficient structural validity or moderate quality of evidence. CONCLUSIONS: Similar to comparable previous reviews, evidence on the psychometric properties of instruments assessing PC in the health care of older adults with multimorbidity was rather limited. Informed by comprehensive models of PC, further research should aim at developing measures of PC that stand out on a broader range of psychometric properties.


Assuntos
Atenção à Saúde , Multimorbidade , Humanos , Idoso , Inquéritos e Questionários , Reprodutibilidade dos Testes , Psicometria/métodos
5.
Mol Pharm ; 19(10): 3576-3585, 2022 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-35434995

RESUMO

Designed ankyrin repeat proteins (DARPins) are genetically engineered proteins that exhibit high specificity and affinity toward specific targets. Here, the G3-DARPin, which binds the HER2/neu receptor, was site-specifically modified with enzymatic methods and 89Zr-radiolabeled for applications in positron emission tomography (PET). Sortase A transpeptidation was used to install a desferrioxamine B (DFO) chelate bearing a reactive triglycine group to the C-terminal sortase tag of the G3-DARPin, and 89Zr-radiolabeling produced a novel 89ZrDFO-G3-DARPin radiotracer that can detect HER2/neu-positive tumors. The triglycine probe, DFO-Gly3 (1), was synthesized in 29% overall yield. After sortase A transpeptidation and purification from the nonfunctionalized protein component, the DFO-G3-DARPin product was radiolabeled to give 89ZrDFO-G3-DARPin. Binding specificity was assessed in HER2/neu-expressing BT-474 and SK-OV-3 cellular assays. The pharmacokinetics, tumor uptake, and specificity of 89ZrDFO-G3-DARPin were measured in vivo by PET imaging and confirmed by final time point (24 h) biodistribution experiments in female athymic nude mice bearing BT-474 xenografts. Sortase A transpeptidation afforded the site-specific and stoichiometrically precise functionalization of DFO-G3-DARPin with one chelate per protein. The modified DFO-G3-DARPin was purified from the nonfunctionalized DARPin by using Ni-NTA affinity chromatography. 89ZrDFO-G3-DARPin was obtained with a radiochemical purity of >95% measured by radio-size-exclusion chromatography. BT-474 tumor uptake at 24 h postadministration reached 4.41 ± 0.67 %ID/g (n = 3) with an approximate ∼70% reduction in tumor-associated activity in the blocking group (1.26 ± 0.29 %ID/g; 24 h postadministration, n = 5, P-value of <0.001). Overall, the site-specific, enzyme-mediated functionalization and characterization of 89ZrDFO-G3-DARPin in HER2/neu positive BT-474 xenografts demonstrate that DARPins are an attractive platform for generating a new class of protein-based radiotracers for PET. The specific uptake and retention of 89ZrDFO-G3-DARPin in tumors and clearance from most background tissues produced PET images with high tumor-to-background contrast.


Assuntos
Proteínas de Repetição de Anquirina Projetadas , Receptor ErbB-2 , Animais , Linhagem Celular Tumoral , Desferroxamina/química , Feminino , Humanos , Camundongos , Camundongos Nus , Tomografia por Emissão de Pósitrons/métodos , Receptor ErbB-2/metabolismo , Distribuição Tecidual , Zircônio/química
6.
Proc Natl Acad Sci U S A ; 116(42): 20977-20983, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31570581

RESUMO

The Chip/LIM-domain binding protein (LDB)-single-stranded DNA-binding protein (SSDP) (ChiLS) complex controls numerous cell-fate decisions in animal cells, by mediating transcription of developmental control genes via remote enhancers. ChiLS is recruited to these enhancers by lineage-specific LIM-domain proteins that bind to its Chip/LDB subunit. ChiLS recently emerged as the core module of the Wnt enhanceosome, a multiprotein complex that primes developmental control genes for timely Wnt responses. ChiLS binds to NPFxD motifs within Pygopus (Pygo) and the Osa/ARID1A subunit of the BAF chromatin remodeling complex, which could synergize with LIM proteins in tethering ChiLS to enhancers. Chip/LDB and SSDP both contain N-terminal dimerization domains that constitute the bulk of their structured cores. Here, we report the crystal structures of these dimerization domains, in part aided by DARPin chaperones. We conducted systematic surface scanning by structure-designed mutations, followed by in vitro and in vivo binding assays, to determine conserved surface residues required for binding between Chip/LDB, SSDP, and Pygo-NPFxD. Based on this, and on the 4:2 (SSDP-Chip/LDB) stoichiometry of ChiLS, we derive a highly constrained structural model for this complex, which adopts a rotationally symmetrical SSDP2-LDB2-SSDP2 architecture. Integrity of ChiLS is essential for Pygo binding, and our mutational analysis places the NPFxD pockets on either side of the Chip/LDB dimer, each flanked by an SSDP dimer. The symmetry and multivalency of ChiLS underpin its function as an enhancer module integrating Wnt signals with lineage-specific factors to operate context-dependent transcriptional switches that are pivotal for normal development and cancer.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas com Domínio LIM/metabolismo , Complexos Multiproteicos/química , Fatores de Transcrição/metabolismo , Proteínas Wnt/metabolismo , Sequência de Aminoácidos , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Dimerização , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica , Humanos , Proteínas com Domínio LIM/química , Proteínas com Domínio LIM/genética , Modelos Moleculares , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Domínios Proteicos , Fatores de Transcrição/química , Fatores de Transcrição/genética , Proteínas Wnt/genética
7.
Int J Mol Sci ; 23(19)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36232839

RESUMO

Protein-based conjugates have been extensively utilized in various biotechnological and therapeutic applications. In order to prepare homogeneous conjugates, site-specific modification methods and efficient purification strategies are both critical factors to be considered. The development of general and facile conjugation and purification strategies is therefore highly desirable. Here, we apply a capture and release strategy to create protein conjugates based on Designed Ankyrin Repeat Proteins (DARPins), which are engineered antigen-binding proteins with prominent affinity and selectivity. In this case, DARPins that target the epithelial cell adhesion molecule (EpCAM), a diagnostic cell surface marker for many types of cancer, were employed. The DARPins were first genetically modified with a C-terminal CVIA sequence to install an enzyme recognition site and then labeled with an aldehyde functional group employing protein farnesyltransferase. Using a capture and release strategy, conjugation of the labeled DARPins to a TAMRA fluorophore was achieved with either purified proteins or directly from crude E. coli lysate and used in subsequent flow cytometry and confocal imaging analysis. DARPin-MMAE conjugates were also prepared yielding a construct manifesting an IC50 of 1.3 nM for cell killing of EpCAM positive MCF-7 cells. The method described here is broadly applicable to enable the streamlined one-step preparation of protein-based conjugates.


Assuntos
Repetição de Anquirina , Proteínas de Repetição de Anquirina Projetadas , Aldeídos/metabolismo , Alquil e Aril Transferases , Molécula de Adesão da Célula Epitelial/genética , Molécula de Adesão da Célula Epitelial/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Proteínas/química
8.
BMC Geriatr ; 21(1): 567, 2021 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663223

RESUMO

BACKGROUND: Patient-centeredness (PC) aims to adapt health care to the individual needs and preferences of patients. An existing integrative model of PC comprises several dimensions of PC which have not yet been investigated from the patients' perspective. Older patients with multimorbidity represent a target group for patient-centered care, as their care needs are particularly complex and should be addressed individually. We aimed to assess the perspective that older patients with multimorbidity have of patient-centered care and to examine the transferability of the integrative model of PC to this specific population. METHOD: We performed 4 guided focus group interviews with a total of 20 older individuals with multimorbidity. The focus group interviews were audio-recorded and transcribed verbatim. Patients' statements were content-analyzed applying an a priori designed system of categories that included the dimensions of PC from the integrative model and the additional category 'prognosis and life expectancy', which had emerged from an initial literature search on aspects of PC specific to the multimorbid elderly. RESULTS: The new category 'prognosis and life expectancy' was confirmed and expanded to 'individual care needs related to aging and chronic disesase'. All dimensions of our integrative PC model were confirmed for older patients with multimorbidity. Among these, we found that eight dimensions (individual care needs related to aging and chronic disease, biopsychosocial perspective, clinician-patient communication, essential characteristics of the clinician, clinician-patient-relationship, involvement of family and friends, coordination and continuity of care, access to care) were complemented by aspects specific to this target population. CONCLUSIONS: The integrative PC model is applicable to the population of older patients with multimorbidity. For a population-specific adaptation, it might be complemented by the dimension 'individual care needs in aging and chronic disease', in conjunction with age-specific aspects within existing dimensions. Together with corresponding results from a Delphi survey, our adapted PC model will serve as the basis for a subsequent systematic review of instruments measuring PC in older patients with multimorbidity. TRIAL REGISTRATION: PROSPERO ( https://www.crd.york.ac.uk/prospero; CRD42018084057; 2018/02/01), German Clinical Trials Register ( www.drks.de ; DRKS00013309; 2018/01/23).


Assuntos
Multimorbidade , Assistência Centrada no Paciente , Idoso , Doença Crônica , Atenção à Saúde , Grupos Focais , Humanos
9.
Molecules ; 24(8)2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31027189

RESUMO

The scope of targets investigated in pharmaceutical research is continuously moving into uncharted territory. Consequently, finding suitable chemical matter with current compound collections is proving increasingly difficult. Encoded library technologies enable the rapid exploration of large chemical space for the identification of ligands for such targets. These binders facilitate drug discovery projects both as tools for target validation, structural elucidation and assay development as well as starting points for medicinal chemistry. Novartis internalized two complementing encoded library platforms to accelerate the initiation of its drug discovery programs. For the identification of low-molecular weight ligands, we apply DNA-encoded libraries. In addition, encoded peptide libraries are employed to identify cyclic peptides. This review discusses how we apply these two platforms in our research and why we consider it beneficial to run both pipelines in-house.


Assuntos
Descoberta de Drogas/métodos , RNA Mensageiro , Bibliotecas de Moléculas Pequenas
10.
Anal Bioanal Chem ; 409(7): 1827-1836, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27987025

RESUMO

We report on the direct coupling of surface plasmon resonance imaging (SPRi) with matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the investigation of specific, non-covalent interactions, using the example of designed ankyrin repeat proteins (DARPins) and ribosomal protein S6 kinase 2 (RPS6KA2) directly from lysate of SH-SY5Y cells, derived from human bone marrow. Due to an array format, tracing of binding kinetics of numerous DARPins simultaneously and in real time becomes possible. By optimizing both the proteolytic digest directly on the SPRi chip (amount of trypsin, incubation time, and temperature) as well as the MALDI matrix application (concentration of matrix and number of spray cycles), we are able to identify the specific interaction with RPS6KA2 directly from the cell lysate at a surface coverage of only 0.8 fmol/mm2. Graphical Abstract Workflow of the direct coupling of SPRi with MALDI mass spectrometry.


Assuntos
Repetição de Anquirina , Fosfotransferases/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Ressonância de Plasmônio de Superfície/métodos , Humanos , Proteólise
11.
ACS Nano ; 18(12): 8919-8933, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38489155

RESUMO

The orchestrated assembly of actin and actin-binding proteins into cytoskeletal structures coordinates cell morphology changes during migration, cytokinesis, and adaptation to external stimuli. The accurate and unbiased visualization of the diverse actin assemblies within cells is an ongoing challenge. We describe here the identification and use of designed ankyrin repeat proteins (DARPins) as synthetic actin binders. Actin-binding DARPins were identified through ribosome display and validated biochemically. When introduced or expressed inside living cells, fluorescently labeled DARPins accumulated at actin filaments, validated through phalloidin colocalization on fixed cells. Nevertheless, different DARPins displayed different actin labeling patterns: some DARPins labeled efficiently dynamic structures, such as filopodia, lamellipodia, and blebs, while others accumulated primarily in stress fibers. This differential intracellular distribution correlated with DARPin-actin binding kinetics, as measured by fluorescence recovery after photobleaching experiments. Moreover, the rapid arrest of actin dynamics induced by pharmacological treatment led to the fast relocalization of DARPins. Our data support the hypothesis that the localization of actin probes depends on the inherent dynamic movement of the actin cytoskeleton. Compared to the widely used LifeAct probe, one DARPin exhibited enhanced signal-to-background ratio while retaining a similar ability to label stress fibers. In summary, we propose DARPins as promising actin-binding proteins for labeling or manipulation in living cells.


Assuntos
Actinas , Proteínas de Repetição de Anquirina Projetadas , Actinas/metabolismo , Citoesqueleto/metabolismo , Citoesqueleto de Actina/metabolismo , Proteínas dos Microfilamentos/metabolismo
12.
Nat Commun ; 14(1): 8317, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38110403

RESUMO

In this study, we characterize Designed Ankyrin Repeat Proteins (DARPins) as investigative tools to probe botulinum neurotoxin A1 (BoNT/A1) structure and function. We identify DARPin-F5 that completely blocks SNAP25 substrate cleavage by BoNT/A1 in vitro. X-ray crystallography reveals that DARPin-F5 inhibits BoNT/A1 activity by interacting with a substrate-binding region between the α- and ß-exosite. This DARPin does not block substrate cleavage of BoNT/A3, indicating that DARPin-F5 is a subtype-specific inhibitor. BoNT/A1 Glu-171 plays a critical role in the interaction with DARPin-F5 and its mutation to Asp, the residue found in BoNT/A3, results in a loss of inhibition of substrate cleavage. In contrast to the in vitro results, DARPin-F5 promotes faster substrate cleavage of BoNT/A1 in primary neurons and muscle tissue by increasing toxin translocation. Our findings could have important implications for the application of BoNT/A1 in therapeutic areas requiring faster onset of toxin action combined with long persistence.


Assuntos
Toxinas Botulínicas Tipo A , Toxinas Botulínicas , Clostridium botulinum , Proteínas de Repetição de Anquirina Projetadas , Toxinas Botulínicas Tipo A/metabolismo , Clostridium botulinum/genética
13.
Cell Death Dis ; 14(10): 674, 2023 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-37828008

RESUMO

The two p53 homologues p63 and p73 regulate transcriptional programs in epithelial tissues and several cell types in these tissues express both proteins. All members of the p53 family form tetramers in their active state through a dedicated oligomerization domain that structurally assembles as a dimer of dimers. The oligomerization domain of p63 and p73 share a high sequence identity, but the p53 oligomerization domain is more divergent and it lacks a functionally important C-terminal helix present in the other two family members. Based on these structural differences, p53 does not hetero-oligomerize with p63 or p73. In contrast, p63 and p73 form hetero-oligomers of all possible stoichiometries, with the hetero-tetramer built from a p63 dimer and a p73 dimer being thermodynamically more stable than the two homo-tetramers. This predicts that in cells expressing both proteins a p632/p732 hetero-tetramer is formed. So far, the tools to investigate the biological function of this hetero-tetramer have been missing. Here we report the generation and characterization of Designed Ankyrin Repeat Proteins (DARPins) that bind with high affinity and selectivity to the p632/p732 hetero-tetramer. Using these DARPins we were able to confirm experimentally the existence of this hetero-tetramer in epithelial mouse and human tissues and show that its level increases in squamous cell carcinoma.


Assuntos
Carcinoma de Células Escamosas , Fatores de Transcrição , Animais , Humanos , Camundongos , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Proteínas de Repetição de Anquirina Projetadas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteína Tumoral p73/genética , Proteína Tumoral p73/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/metabolismo
14.
Nat Commun ; 14(1): 3787, 2023 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-37355687

RESUMO

The actin cytoskeleton is of fundamental importance for cellular structure and plasticity. However, abundance and function of filamentous actin in the nucleus are still controversial. Here we show that the actin-based molecular motor myosin VI contributes to the stabilization of stalled or reversed replication forks. In response to DNA replication stress, myosin VI associates with stalled replication intermediates and cooperates with the AAA ATPase Werner helicase interacting protein 1 (WRNIP1) in protecting these structures from DNA2-mediated nucleolytic attack. Using functionalized affinity probes to manipulate myosin VI levels in a compartment-specific manner, we provide evidence for the direct involvement of myosin VI in the nucleus and against a contribution of the abundant cytoplasmic pool during the replication stress response.


Assuntos
Replicação do DNA , Proteínas de Ligação a DNA , Proteínas de Ligação a DNA/metabolismo , Actinas/metabolismo , Núcleo Celular/metabolismo
15.
Nat Commun ; 14(1): 4930, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37582753

RESUMO

Diversity-oriented synthesis (DOS) is a powerful strategy to prepare molecules with underrepresented features in commercial screening collections, resulting in the elucidation of novel biological mechanisms. In parallel to the development of DOS, DNA-encoded libraries (DELs) have emerged as an effective, efficient screening strategy to identify protein binders. Despite recent advancements in this field, most DEL syntheses are limited by the presence of sensitive DNA-based constructs. Here, we describe the design, synthesis, and validation experiments performed for a 3.7 million-member DEL, generated using diverse skeleton architectures with varying exit vectors and derived from DOS, to achieve structural diversity beyond what is possible by varying appendages alone. We also show screening results for three diverse protein targets. We will make this DEL available to the academic scientific community to increase access to novel structural features and accelerate early-phase drug discovery.


Assuntos
Descoberta de Drogas , Bibliotecas de Moléculas Pequenas , Bibliotecas de Moléculas Pequenas/química , Descoberta de Drogas/métodos , Biblioteca Gênica , DNA/genética , DNA/química
16.
Prog Transplant ; 32(1): 55-66, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35006009

RESUMO

INTRODUCTION: Acknowledging the evolved landscape in thoracic transplantation, professional employment becomes an important outcome measure to quantify the success of this costly procedure. OBJECTIVE: We aimed to assess rates of and characterize factors associated with professional employment in patients following thoracic transplantation, and create an evidence-base on the relationship between professional employment and relevant outcome parameters. METHODS: We systematically searched Medline, Cinahl, and GoogleScholar to identify studies published between 1998 and 2021 reporting on professional employment following heart and lung transplantation. RESULTS: Twenty-two studies from 11 countries with varying sample sizes (N = 27; 10 066) were included. Employment rates ranged from 19.7% to 69.4% for heart, and from 7.4% to 50.8% for lung transplant recipients. Most frequently reported positively associated factors with employment after transplant were younger age, higher education, and history of pretransplant employment. Longer duration of unemployment prior to transplantation and Medicaid coverage were the most frequently reported negatively associated factors. Relationships between professional employment and clinical outcomes included lower rates of acute and chronic rejection, less infection episodes, and better quality of life among working patients; one study reported a lower 5-year-mortality rate. Reasons not to work were "physical or mental health-related," "employment-related," "financial reasons," and "lifestyle choices." DISCUSSION: Substantial proportions of patients following thoracic transplantation are not professionally employed, potentially diminishing the success of transplantation on individual and societal levels. Considering adverse clinical outcomes in employed transplant recipients were low, more efforts are needed to identify modifiable factors for employment in these populations.


Assuntos
Transplante de Coração , Transplante de Pulmão , Emprego , Humanos , Qualidade de Vida , Fatores de Tempo
17.
Cell Death Differ ; 29(12): 2445-2458, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35717504

RESUMO

The function of the p53 transcription factor family is dependent on several folded domains. In addition to a DNA-binding domain, members of this family contain an oligomerization domain. p63 and p73 also contain a C-terminal Sterile α-motif domain. Inhibition of most transcription factors is difficult as most of them lack deep pockets that can be targeted by small organic molecules. Genetic knock-out procedures are powerful in identifying the overall function of a protein, but they do not easily allow one to investigate roles of individual domains. Here we describe the characterization of Designed Ankyrin Repeat Proteins (DARPins) that were selected as tight binders against all folded domains of p63. We determine binding affinities as well as specificities within the p53 protein family and show that DARPins can be used as intracellular inhibitors for the modulation of transcriptional activity. By selectively inhibiting DNA binding of the ΔNp63α isoform that competes with p53 for the same promoter sites, we show that p53 can be reactivated. We further show that inhibiting the DNA binding activity stabilizes p63, thus providing evidence for a transcriptionally regulated negative feedback loop. Furthermore, the ability of DARPins to bind to the DNA-binding domain and the Sterile α-motif domain within the dimeric-only and DNA-binding incompetent conformation of TAp63α suggests a high structural plasticity within this special conformation. In addition, the developed DARPins can also be used to specifically detect p63 in cell culture and in primary tissue and thus constitute a very versatile research tool for studying the function of p63.


Assuntos
Proteínas de Repetição de Anquirina Projetadas , Proteína Supressora de Tumor p53 , Proteína Supressora de Tumor p53/metabolismo , Proteína Tumoral p73/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , DNA/química
18.
Cell Rep ; 39(4): 110736, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35476995

RESUMO

The deacetylase HDAC6 has tandem catalytic domains and a zinc finger domain (ZnF) binding ubiquitin (Ub). While the catalytic domain has an antiviral effect, the ZnF facilitates influenza A virus (IAV) infection and cellular stress responses. By recruiting Ub via the ZnF, HDAC6 promotes the formation of aggresomes and stress granules (SGs), dynamic structures associated with pathologies such as neurodegeneration. IAV subverts the aggresome/HDAC6 pathway to facilitate capsid uncoating during early infection. To target this pathway, we generate designed ankyrin repeat proteins (DARPins) binding the ZnF; one of these prevents interaction with Ub in vitro and in cells. Crystallographic analysis shows that it blocks the ZnF pocket where Ub engages. Conditional expression of this DARPin reversibly impairs infection by IAV and Zika virus; moreover, SGs and aggresomes are downregulated. These results validate the HDAC6 ZnF as an attractive target for drug discovery.


Assuntos
Vírus da Influenza A , Influenza Humana , Infecção por Zika virus , Zika virus , Desacetilase 6 de Histona/metabolismo , Humanos , Vírus da Influenza A/metabolismo , Ubiquitina/metabolismo , Zika virus/metabolismo
19.
Nat Commun ; 13(1): 1045, 2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35210418

RESUMO

Adenylyl cyclase 9 (AC9) is a membrane-bound enzyme that converts ATP into cAMP. The enzyme is weakly activated by forskolin, fully activated by the G protein Gαs subunit and is autoinhibited by the AC9 C-terminus. Although our recent structural studies of the AC9-Gαs complex provided the framework for understanding AC9 autoinhibition, the conformational changes that AC9 undergoes in response to activator binding remains poorly understood. Here, we present the cryo-EM structures of AC9 in several distinct states: (i) AC9 bound to a nucleotide inhibitor MANT-GTP, (ii) bound to an artificial activator (DARPin C4) and MANT-GTP, (iii) bound to DARPin C4 and a nucleotide analogue ATPαS, (iv) bound to Gαs and MANT-GTP. The artificial activator DARPin C4 partially activates AC9 by binding at a site that overlaps with the Gαs binding site. Together with the previously observed occluded and forskolin-bound conformations, structural comparisons of AC9 in the four conformations described here show that secondary structure rearrangements in the region surrounding the forskolin binding site are essential for AC9 activation.


Assuntos
Adenilil Ciclases , Transdução de Sinais , Adenilil Ciclases/metabolismo , Colforsina/farmacologia , Guanosina Trifosfato , Nucleotídeos
20.
Nat Commun ; 12(1): 6435, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34750371

RESUMO

How morphogen gradients control patterning and growth in developing tissues remains largely unknown due to lack of tools manipulating morphogen gradients. Here, we generate two membrane-tethered protein binders that manipulate different aspects of Decapentaplegic (Dpp), a morphogen required for overall patterning and growth of the Drosophila wing. One is "HA trap" based on a single-chain variable fragment (scFv) against the HA tag that traps HA-Dpp to mainly block its dispersal, the other is "Dpp trap" based on a Designed Ankyrin Repeat Protein (DARPin) against Dpp that traps Dpp to block both its dispersal and signaling. Using these tools, we found that, while posterior patterning and growth require Dpp dispersal, anterior patterning and growth largely proceed without Dpp dispersal. We show that dpp transcriptional refinement from an initially uniform to a localized expression and persistent signaling in transient dpp source cells render the anterior compartment robust against the absence of Dpp dispersal. Furthermore, despite a critical requirement of dpp for the overall wing growth, neither Dpp dispersal nor direct signaling is critical for lateral wing growth after wing pouch specification. These results challenge the long-standing dogma that Dpp dispersal is strictly required to control and coordinate overall wing patterning and growth.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Asas de Animais/metabolismo , Animais , Animais Geneticamente Modificados , Padronização Corporal/genética , Proteínas Morfogenéticas Ósseas/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Discos Imaginais/crescimento & desenvolvimento , Discos Imaginais/metabolismo , Microscopia Confocal , Mutação , Transdução de Sinais/genética , Asas de Animais/crescimento & desenvolvimento
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