Structure and function of the N-terminal extension of the formin INF2.

In INF2-a formin linked to inherited renal and neurological disease in humans-the DID is preceded by a short N-terminal extension of unknown structure and function. INF2 activation is achieved by Ca2+-dependent association of calmodulin (CaM). Here, we show that the N-terminal extension of INF2 is organized into two α-helices, the first of which is necessary to maintain the perinuclear F-actin ring and normal cytosolic F-actin content. Biochemical assays indicated that this helix interacts directly with CaM and contains the sole CaM-binding site (CaMBS) detected in INF2. The residues W11, L14 and L18 of INF2, arranged as a 1-4-8 motif, were identified as the most important residues for the binding, W11 being the most critical of the three. This motif is conserved in vertebrate INF2 and in the human population. NMR and biochemical analyses revealed that CaM interacts directly through its C-terminal lobe with the INF2 CaMBS. Unlike control cells, INF2 KO cells lacked the perinuclear F-actin ring, had little cytosolic F-actin content, did not respond to increased Ca2+ concentrations by making more F-actin, and maintained the transcriptional cofactor MRTF predominantly in the cytoplasm. Whereas expression of intact INF2 restored all these defects, INF2 with inactivated CaMBS did not. Our study reveals the structure of the N-terminal extension, its interaction with Ca2+/CaM, and its function in INF2 activation.

Risk of recurrence of small-for-gestational-age foetus after first pregnancy.

The aim of this study was to assess the incidence of and to analyse factors related to the recurrence of small-for-gestational-age (SGA) neonates in the second pregnancy. A prospective observational study was conducted at a tertiary university hospital in Granada, Spain. A total of 7896 women who delivered their first and second singleton pregnancies at the hospital from 2003-2013 were included and evaluated all birth weights. Women whose first pregnancy was complicated by a SGA birth had a fivefold increased risk of recurrence (23.6% vs. 5.7%, p < .001). Multivariate analyses revealed that only SGA at first birth retained a statistically significant relationship, revealing that the other variables (maternal age, gestational age, interdelivery interval, maternal pre-pregnancy body mass index, occupation of the mother, smoking, hypertension, and diabetes mellitus) were confounders. Prevention of SGA in subsequent pregnancies by modification of established risk factors could be of limited utility based on the present results, supporting a genetic contribution to SGA recurrence. Impact statement The results support a genetic contribution on recurrence of SGA.

Quantification of sugars in wheat flours with an HPAEC-PAD method.

An HPAEC-PAD method has been developed and validated for the simultaneous determination and quantification of six sugars (glucose, isomaltose, maltose, maltotriose, maltotetraose and maltopentaose) in wheat flours, by extraction with water and precipitation of proteins with Carrez II. Analyses were carried out on a Hamilton RCX-30 column with a gradient elution of NaOH 50mM (A) and NaOH 50mM+NaAcO 500 mM (B). Total run time was 38 min. Detector conditions were as follows: E1, +100 mV; E2, +550 mV; E3, -100 mV. The method was validated, with LODs ranging between 0.03-0.21 mg L(-1) and LOQs between 0.10-0.71 mg L(-1), R(2) between 0.9941 and 0.9983; recoveries were from 74.16% to 110.86% and RSDs for intraday repeatability, interday repeatability and reproducibility between 0.35-8.34%, 2.34-6.64% and 1.90-5.68%, respectively. The method was successfully applied to quantification of these sugars in wheat flours.

Phosphatidylinositol 4,5-bisphosphate triggers activation of focal adhesion kinase by inducing clustering and conformational changes.

Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase (NRTK) with key roles in integrating growth and cell matrix adhesion signals, and FAK is a major driver of invasion and metastasis in cancer. Cell adhesion via integrin receptors is well known to trigger FAK signaling, and many of the players involved are known; however, mechanistically, FAK activation is not understood. Here, using a multidisciplinary approach, including biochemical, biophysical, structural, computational, and cell biology approaches, we provide a detailed view of a multistep activation mechanism of FAK initiated by phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. Interestingly, the mechanism differs from canonical NRTK activation and is tailored to the dual catalytic and scaffolding function of FAK. We find PI(4,5)P2 induces clustering of FAK on the lipid bilayer by binding a basic region in the regulatory 4.1, ezrin, radixin, moesin homology (FERM) domain. In these clusters, PI(4,5)P2 induces a partially open FAK conformation where the autophosphorylation site is exposed, facilitating efficient autophosphorylation and subsequent Src recruitment. However, PI(4,5)P2 does not release autoinhibitory interactions; rather, Src phosphorylation of the activation loop in FAK results in release of the FERM/kinase tether and full catalytic activation. We propose that PI(4,5)P2 and its generation in focal adhesions by the enzyme phosphatidylinositol 4-phosphate 5-kinase type Iγ are important in linking integrin signaling to FAK activation.

Proteasome activator complex PA28 identified as an accessible target in prostate cancer by in vivo selection of human antibodies.

Antibody cancer therapies rely on systemically accessible targets and suitable antibodies that exert a functional activity or deliver a payload to the tumor site. Here, we present proof-of-principle of in vivo selection of human antibodies in tumor-bearing mice that identified a tumor-specific antibody able to deliver a payload and unveils the target antigen. By using an ex vivo enrichment process against freshly disaggregated tumors to purge the repertoire, in combination with in vivo biopanning at optimized phage circulation time, we have identified a human domain antibody capable of mediating selective localization of phage to human prostate cancer xenografts. Affinity chromatography followed by mass spectrometry analysis showed that the antibody recognizes the proteasome activator complex PA28. The specificity of soluble antibody was confirmed by demonstrating its binding to the active human PA28αß complex. Whereas systemically administered control phage was confined in the lumen of blood vessels of both normal tissues and tumors, the selected phage spread from tumor vessels into the perivascular tumor parenchyma. In these areas, the selected phage partially colocalized with PA28 complex. Furthermore, we found that the expression of the α subunit of PA28 [proteasome activator complex subunit 1 (PSME1)] is elevated in primary and metastatic human prostate cancer and used anti-PSME1 antibodies to show that PSME1 is an accessible marker in mouse xenograft tumors. These results support the use of PA28 as a tumor marker and a potential target for therapeutic intervention in prostate cancer.

pSM19035-encoded zeta toxin induces stasis followed by death in a subpopulation of cells.

The toxin-antitoxin operon of pSM19035 encodes three proteins: the omega global regulator, the epsilon labile antitoxin and the stable zeta toxin. Accumulation of zeta toxin free of epsilon antitoxin induced loss of cell proliferation in both Bacillus subtilis and Escherichia coli cells. Induction of a zeta variant (zetaY83C) triggered stasis, in which B. subtilis cells were viable but unable to proliferate, without selectively affecting protein translation. In E. coli cells, accumulation of free zeta toxin induced stasis, but this was fully reversed by expression of the epsilon antitoxin within a defined time window. The time window for reversion of zeta toxicity by expression of epsilon antitoxin was dependent on the initial cellular level of zeta. After 240 min of constitutive expression, or inducible expression of high levels of zeta toxin for 30 min, expression of epsilon failed to reverse the toxic effect exerted by zeta in cells growing in minimal medium. Under the latter conditions, zeta inhibited replication, transcription and translation and finally induced death in a fraction (approximately 50 %) of the cell population. These results support the view that zeta interacts with its specific target and reversibly inhibits cell proliferation, but accumulation of zeta might lead to cell death due to pleiotropic effects.

[Educational intervention for preventing unwanted pregnancies and sexually-transmitted diseases among teenagers in the city of Toledo, Spain]. / Intervención educativa para la prevención de embarazos no deseados y enfermedades de transmisión sexual en adolescentes de la ciudad de toledo.

BACKGROUND: No-one doubts the need of effectively providing teenagers with information about birth control and sexually-transmitted diseases. This study is aimed at evaluating the results of an educational intervention related to these matters. METHODS: Before-and-after study of an educational intervention (based on lectures and handing out documentation) without a control group. A questionnaire was passed out before and after the intervention to assess changes in knowledge and attitudes of the 4th-year Compulsory Secondary Education students at five schools in Toledo. RESULTS: The questionnaire was answered by 238 of the 268 students. The average age was 15.59. A total of 54.66% were females. In all, 24.03% had had some sexual relation. The birth control method used most often was the condom (98.24%). The girls more refuse more unprotected relations (76.5% vs. 48.6%; p<0.001) and share the same classroom with a student having AIDS (80.47% vs. 60.38%; p<0.001). Six months following the start of the intervention, a total of 197 students answered the second questionnaire. Proper condom use rose from 62.13% to 73.46%. CONCLUSIONS: Following the intervention, an improvement has been noted in the degree of knowledge related to birth control methods and AIDS transmission and a more positive attitude regarding HIV.

[Efficacy of oral sildenafil as rescue therapy in patients with severe pulmonary arterial hypertension chronically treated with prostacyclin. Long-term results]. / Eficacia del sildenafilo por vía oral como terapia de rescate en pacientes con hipertensión arterial pulmonar severa en tratamiento crónico con prostaciclina. Resultados a largo plazo.

INTRODUCTION AND OBJECTIVE: Prostacyclin therapy is an effective treatment for severe pulmonary hypertension. Sildenafil, a selective phosphodiesterase type 5 inhibitor, induces selective vasodilatation of the pulmonary vessels. A synergistic effect has been described for these two drugs. The aim of this study was to evaluate the efficacy and safety of sildenafil as rescue therapy in patients with severe pulmonary hypertension on chronic treatment with prostacyclin whose clinical or functional course was unsatisfactory. PATIENTS AND METHOD: Observational study of 11 patients (7 men, 4 women, mean age 42 [8] years) diagnosed as having severe idiopathic pulmonary hypertension, who were receiving chronic prostacyclin therapy. Sildenafil was started after a worsening of their clinical or functional status. Baseline, 3-month and 12-month follow-up evaluations were based on functional status (NYHA functional class and 6-minute walking test), the presence of decompensated right heart failure and echocardiogram. RESULTS: Seven of the 11 patients showed significant improvements in exercise capacity (distance walked in 6 minutes) at 3 (+25 m) and 12 months' follow-up (+36 m). Improvements in functional class were seen, and heart failure disappeared. No significant adverse effects of sildenafil were detected. The echocardiographic parameters showed a significant reduction in right ventricular end-diastolic diameter and left ventricular diastolic eccentricity index. One patient died after 4 months of follow-up from sudden cardiac death. CONCLUSIONS: The addition of oral sildenafil to chronic prostacyclin treatment in patients with severe pulmonary hypertension improved functional capacity and reduced episodes of decompensated right heart failure, with good tolerance and no significant adverse effects.

[C677T and A1298C MTHFR polymorphisms in the etiology of neural tube defects in Spanish population]. / Implicación de los polimorfismos C677T y A1298C del gen MTHFR en el desarrollo de los defectos del tubo neural en la población española.

BACKGROUND AND OBJECTIVE: The etiology of neural tube defects (NTDs) is multifactorial. The presence of mutated genotypes of C677T and A1298C polymorphisms, and their combined heterozygosity, have been considered risk factors for the occurrence and recurrence of NTDs in some populations. SUBJECTS AND METHOD: This case-control study included 159 healthy controls, 27 NTDs patients, 28 patients' mothers and 23 siblings. The polymorphism study was performed by PCR. For fragment digestion, we used the restriction enzymes Hinf I (C677T) and Mbo II (A1298C). RESULTS: There was no significant difference (p = 0.991) in C677T genotypes between controls (CC: 35%, CT: 50% and TT: 15%) and patients (37, 52 and 11%, respectively), patients' mothers (39, 50 and 11%, respectively) and siblings (35, 48 and 17%, respectively). The prevalence of A1298C genotypes in controls (AA: 49%, AC: 45% and CC: 6%) was similar (p = 0.917) to the prevalence in patients (41, 56 and 4%, respectively), patients' mothers (43, 50 and 7%, respectively) and siblings (52, 39 and 9%, respectively). CONCLUSIONS: The absence of differences in the two polymorphisms between these groups makes us conclude that there is no association with NTDs in the Spanish population.

Covalent immobilization of cyclodextrin glucosyltransferase (CGTase) in activated silica and Sepharose.

Cyclodextrin glucanotransferase is a non-Leloir glycosyltransferase that directly employs the free energy of cleavage of starch to produce cyclodextrins. In presence of appropriate acceptors, this enzyme synthesizes oligosaccharides containing alpha(1-->4) bonds. We have investigated the covalent immobilization of CGTase onto different activated supports. Silica was aminated and further activated with glutaraldehyde. The maximum amount of bound protein was about 4 mg CGTase per gram of support; however, the catalytic efficiency of the immobilized enzyme was lower than 6%. Sepharose 4B activated with cyanogen bromide (CNBr-activated Sepharose) and Sepharose 4B with a spacer arm of 1,6-diaminohexane (EAH Sepharose) were also assayed. These gels react with the amino and carboxylic groups of CGTase, respectively. With CNBr-activated Sepharose, a low percentage of enzyme was bound to the support but with a significant catalytic efficiency (29%). A higher recovery of protein was obtained with EAH Sepharose (62%), but only 2.4% of the initial activity was present in the immobilized biocatalyst. The results were discussed in terms of CGTase structure and mechanism. In addition, the solvent accessibility of amino or carboxylic groups, calculated using the NACCESS software, was considered.