The structure of the C-terminal actin-binding domain of talin

Talin is a large dimeric protein that couples integrins to cytoskeletal actin. Here, we report the structure of the C-terminal actin-binding domain of talin, the core of which is a five-helix bundle linked to a C-terminal helix responsible for dimerisation. The NMR structure of the bundle reveals a conserved surface-exposed hydrophobic patch surrounded by positively charged groups. We have mapped the actin-binding site to this surface and shown that helix 1 on the opposite side of the bundle negatively regulates actin binding. The crystal structure of the dimerisation helix reveals an antiparallel coiled-coil with conserved residues clustered on the solvent-exposed face. Mutagenesis shows that dimerisation is essential for filamentous actin (F-actin) binding and indicates that the dimerisation helix itself contributes to binding. We have used these structures together with small angle X-ray scattering to derive a model of the entire domain. Electron microscopy provides direct evidence for binding of the dimer to F-actin and indicates that it binds to three monomers along the long-pitch helix of the actin filament

Structural and biophysical properties of the integrin-associated cytoskeletal protein talin

Talin is a large cytoskeletal protein (2541 amino acid residues) which plays a key role in integrin-mediated events that are crucial for cell adhesion, migration, proliferation and survival. This review summarises recent work on the structure of talin and on some of the structurally better defined interactions with other proteins. The N-terminal talin head (approx. 50 kDa) consists of an atypical FERM domain linked to a long flexible rod (approx. 220 kDa) made up of a series of amphipathic helical bundle domains. The F3 FERM subdomain in the head binds the cytoplasmic tail of integrins, but this interaction can be inhibited by an interaction of F3 with a helical bundle in the talin rod, the so-called “autoinhibited form” of the molecule. The talin rod contains a second integrin-binding site, at least two actin-binding sites and a large number of binding sites for vinculin, which is important in reinforcing the initial integrin–actin link mediated by talin. The vinculin binding sites are defined by hydrophobic residues buried within helical bundles, and these must unfold to allow vinculin binding. Recent experiments suggest that this unfolding may be mediated by mechanical force exerted on the talin molecule by actomyosin contraction

Structure of a double ubiquitin-like domain in the talin head: a role in integrin activation

Talin is a 270-kDa protein that activates integrins and couples them to cytoskeletal actin. Talin contains an N-terminal FERM domain comprised of F1, F2 and F3 domains, but it is atypical in that F1 contains a large insert and is preceded by an extra domain F0. Although F3 contains the binding site for β-integrin tails, F0 and F1 are also required for activation of β1-integrins. Here, we report the solution structures of F0, F1 and of the F0F1 double domain. Both F0 and F1 have ubiquitin-like folds joined in a novel fixed orientation by an extensive charged interface. The F1 insert forms a loop with helical propensity, and basic residues predicted to reside on one surface of the helix are required for binding to acidic phospholipids and for talin-mediated activation of β1-integrins. This and the fact that basic residues on F2 and F3 are also essential for integrin activation suggest that extensive interactions between the talin FERM domain and acidic membrane phospholipids are required to orientate the FERM domain such that it can activate integrins

How do parents manage irritability, challenging behavior, non-compliance and anxiety in children with Autism Spectrum Disorders? A meta-synthesis

Although there is increasing research interest in the parenting of children with ASD, at present, little is known about everyday strategies used to manage problem behaviour. We conducted a meta-synthesis to explore what strategies parents use to manage irritability, non-compliance, challenging behaviour and anxiety in their children with ASD. Approaches included: (1) accommodating the child; (2) modifying the environment; (3) providing structure, routine and occupation; (4) supervision and monitoring; (5) managing non-compliance with everyday tasks; (6) responding to problem behaviour; (7) managing distress; (8) maintaining safety and (9) analysing and planning. Results suggest complex parenting demands in children with ASD and problem behaviour. Findings will inform the development of a new measure to quantify parenting strategies relevant to ASD

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC

Adaptação sócio-comunicativa no espectro autístico: dados obtidos com pais e terapeutas Social communicative adaptation in the autistic spectrum: data provided by parents and therapists

OBJETIVO: Verificar a efetividade da aplicação do protocolo de adaptação sócio-comunicativa a diferentes fontes de informação, neste caso, pais e terapeutas, na identificação de diferenças individuais em crianças com Distúrbios do Espectro Autístico. MÉTODOS: Participaram deste estudo 48 crianças, entre três anos e 11 anos e dez meses de idade, com diagnóstico clínico incluído no espectro autístico. Foram também sujeitos deste trabalho, 46 mães e dois pais, bem como 15 terapeutas, responsáveis legais e pelo atendimento fonoaudiológico especializado, respectivamente, das mesmas crianças, por um período mínimo de aproximadamente 12 meses, sendo que estes participaram respondendo a um questionário sobre o relacionamento social das crianças, sujeitos deste estudo. RESULTADOS: Genericamente, pode-se dizer que as respostas sobre a adaptação sócio-comunicativa, obtidas por meio de diferentes fontes de informação, ou seja, pais e terapeutas foram semelhantes. Entretanto, analisando os dados brutos observa-se que os pais apresentaram consistentemente um número maior de respostas positivas do que as terapeutas, para as questões relativas ao desempenho social. CONCLUSÃO: O estabelecimento de dados de adaptação sócio-comunicativa pode caracterizar esta população, demonstrando que este instrumento pode ser aplicado a diferentes informantes; as respostas dadas pelos mesmos foram homogêneas, reforçando a fidedignidade dos dados, apesar de existirem diferenças significativas na comparação entre os níveis e estágios sócio-comunicativos. A aplicação do questionário e protocolo de adaptação sócio-comunicativa a diferentes informantes pode fornecer um resultado bastante homogêneo, sendo possível realizar de forma fidedigna a caracterização das habilidades de relacionamento social dessas crianças.<br>PURPOSE: To verify if the application of the social-communicative adaptation protocol with different information sources, in this case, parents and therapists, is effective to identify individual differences in children of the autistic spectrum. METHODS: Subjects were 48 children, with ages ranging from three to 11 years and ten months, with psychiatric diagnosis included in the autistic spectrum. The parents of those children (46 mothers and two fathers) and 15 speech therapists, who were, respectively, legal caregivers and responsible for their speech-language therapy for at least 12 months, were also subjects of the study. They answered a questionnaire regarding each child's social relation performance. RESULTS: Generically, it is possible to say that the answers obtained from different sources (parents and therapists) were similar. However, the analysis of raw data showed that parents consistently presented higher number of positive answers when compared to therapists, in questions regarding social performance. CONCLUSION: The determination of data about social-communicative adaptation could characterize these subjects, demonstrating that this protocol can be used with different information sources; the answers provided by parents and therapists were homogeneous, confirming data reliability despite of significant differences in the comparison among social-communicative stages and levels. The application of the questionnaire and the social communicative protocol to different information sources can provided homogeneous results, allowing a reliable characterization of these children's social abilities

Monotherapy treatment with chlorthalidone or amlodipine in the systolic blood pressure intervention trial (SPRINT)

This post hoc analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) examined the performance of chlorthalidone (C) versus amlodipine (A) monotherapies. ANOVA was used to analyze the differences in systolic blood pressure (SBP) response between C and A. Logistic regression was used to examine monotherapy failure (adding a second antihypertensive agent or switching to a different antihypertensive agent) rates. Four hundred ninety‐one participants were treated with C monotherapy (n = 210, mean dose = 22 mg/day) or A monotherapy (n = 281, mean dose = 7 mg/day). There was a significant difference in mean SBP reduction between the C and A monotherapies at the third visit (higher reduction with A, adjusted p = .018). Unadjusted analysis showed a higher failure with C in the standard treatment group. Although the average SBP at failure was higher and above the 140 mm Hg cutoff that indicated monotherapy failure with A (142.60) compared with C (138.40), more participants on C failed despite having SBP below the 140 cutoff. This was probably due to decisions made by the investigative teams to change the antihypertensive regimen, because, in their opinion, the clinical picture required it. After adjusting for baseline characteristics, C had higher failure than A only in the standard treatment group (1.64 odds ratio [OR], 95% CI 1.06–2.56, p = .028). A sub‐analysis including participants who had never used antihypertensive treatment before randomization had similar results (2.57 OR, 95% CI 1.34–5.02, p = .004). Overall, in SPRINT chlorthalidone was associated with higher monotherapy failure than amlodipine in the standard treatment group because of decisions of the investigative teams