SR proteins, named for their multiple arginine/serine (RS) dipeptide repeats, are critical components of the spliceosome, influencing both constitutive and alternative splicing of pre-mRNA. SR ...protein function is regulated through phosphorylation of their RS domains by multiple kinases, including a family of evolutionarily conserved SR protein-specific kinases (SRPKs). The SRPK family of kinases is unique in that they are capable of phosphorylating repetitive RS domains with remarkable specificity and efficiency. Here, we carried out kinetic experiments specially developed to investigate how SRPK1 phosphorylates the model human SR protein, ASF/SF2. By using the start-trap strategy, we monitored the progress curve for ASF/SF2 phosphorylation in the absence and presence of an inhibitor peptide directed at the active site of SRPK1. ASF/SF2 modification is not altered when the inhibitor peptide (trap) is added with ATP (start). However, when the trap is added first and allowed to incubate for a specific delay time, the decrease in phosphate content of the enzyme-substrate complex follows a simple exponential decline corresponding to the release rate of SRPK1. These data demonstrate that SRPK1 phosphorylates a specific region within the RS domain of ASF/SF2 by using a fully processive catalytic mechanism, in which the splicing factor remains "locked" onto SRPK1 during RS domain modification.
Sky1p is the only member of the SR protein kinase (SRPK) family in Saccharomyces cerevisiae. SRPKs are constitutively active kinases that display remarkable substrate specificity and have been ...implicated in RNA processing. Here we present the three-dimensional structure of a fully active truncated Sky1p. Analysis of the structure and structure-based functional studies reveal that the C-terminal tail, an unusual Glu residue located in the P+1 loop, and a unique mechanism for the positioning of helix alpha C act together to render Sky1p constitutively active. We have modeled a substrate peptide bound to Sky1p. The modeled complex combined with mutagenesis studies illustrate the molecular basis for substrate recognition by this kinase and suggest a mechanism by which SRPKs catalyze a sequential phosphorylation reaction of the consecutive RS dipeptide repeats characteristic of mammalian SRPK substrates.
Arp2/3 complex, a crucial actin filament nucleator, undergoes structural rearrangements during activation by nucleation-promoting factors (NPFs). However, the conformational pathway leading to the ...nucleation-competent state is unclear due to lack of high-resolution structures of the activated state. Here we report a ~3.9 Å resolution cryo-EM structure of activated Schizosaccharomyces pombe Arp2/3 complex bound to the S. pombe NPF Dip1 and attached to the end of the nucleated actin filament. The structure reveals global and local conformational changes that allow the two actin-related proteins in Arp2/3 complex to mimic a filamentous actin dimer and template nucleation. Activation occurs through a clamp-twisting mechanism, in which Dip1 forces two core subunits in Arp2/3 complex to pivot around one another, shifting half of the complex into a new activated position. By showing how Dip1 stimulates activation, the structure reveals how NPFs can activate Arp2/3 complex in diverse cellular processes.
Preterm birth remains a common cause of neonatal mortality, with a disproportionately high burden in low-income and middle-income countries. Meta-analyses of low-dose aspirin to prevent pre-eclampsia ...suggest that the incidence of preterm birth might also be decreased, particularly if initiated before 16 weeks of gestation.
ASPIRIN was a randomised, multicountry, double-masked, placebo-controlled trial of low-dose aspirin (81 mg daily) initiated between 6 weeks and 0 days of pregnancy, and 13 weeks and 6 days of pregnancy, in nulliparous women with an ultrasound confirming gestational age and a singleton viable pregnancy. Participants were enrolled at seven community sites in six countries (two sites in India and one site each in the Democratic Republic of the Congo, Guatemala, Kenya, Pakistan, and Zambia). Participants were randomly assigned (1:1, stratified by site) to receive aspirin or placebo tablets of identical appearance, via a sequence generated centrally by the data coordinating centre at Research Triangle Institute International (Research Triangle Park, NC, USA). Treatment was masked to research staff, health providers, and patients, and continued until 36 weeks and 7 days of gestation or delivery. The primary outcome of incidence of preterm birth, defined as the number of deliveries before 37 weeks' gestational age, was analysed in randomly assigned women with pregnancy outcomes at or after 20 weeks, according to a modified intention-to-treat (mITT) protocol. Analyses of our binary primary outcome involved a Cochran-Mantel-Haenszel test stratified by site, and generalised linear models to obtain relative risk (RR) estimates and associated confidence intervals. Serious adverse events were assessed in all women who received at least one dose of drug or placebo. This study is registered with ClinicalTrials.gov, NCT02409680, and the Clinical Trial Registry-India, CTRI/2016/05/006970.
From March 23, 2016 to June 30, 2018, 14 361 women were screened for inclusion and 11 976 women aged 14–40 years were randomly assigned to receive low-dose aspirin (5990 women) or placebo (5986 women). 5780 women in the aspirin group and 5764 in the placebo group were evaluable for the primary outcome. Preterm birth before 37 weeks occurred in 668 (11·6%) of the women who took aspirin and 754 (13·1%) of those who took placebo (RR 0·89 95% CI 0·81 to 0·98, p=0·012). In women taking aspirin, we also observed significant reductions in perinatal mortality (0·86 0·73–1·00, p=0·048), fetal loss (infant death after 16 weeks' gestation and before 7 days post partum; 0·86 0·74–1·00, p=0·039), early preterm delivery (<34 weeks; 0·75 0·61–0·93, p=0·039), and the incidence of women who delivered before 34 weeks with hypertensive disorders of pregnancy (0·38 0·17–0·85, p=0·015). Other adverse maternal and neonatal events were similar between the two groups.
In populations of nulliparous women with singleton pregnancies from low-income and middle-income countries, low-dose aspirin initiated between 6 weeks and 0 days of gestation and 13 weeks and 6 days of gestation resulted in a reduced incidence of preterm delivery before 37 weeks, and reduced perinatal mortality.
Eunice Kennedy Shriver National Institute of Child Health and Human Development.
The Stanley Foundation Bipolar Network (SFBN) evaluates treatments, course and clinical and neurobiological markers of response in bipolar illness.
To give a preliminary summary of emerging findings ...in these areas.
Studies with established and potentially antimanic, antidepressant and mood-stabilising agents range from open case series to double-blind randomised clinical trials, and use the same core assessment methodology, thereby optimising the comparability of the outcomes. The National Institute of Mental Health Life Chart Method is the core instrument for retrospective and prospective longitudinal illness description.
The first groups of patients enrolled show a considerable degree of past and present symptomatology, psychiatric comorbidity and functional impairment. There are associations of both genetic and early environmental factors with more severe courses of illness. Open case series with add-on olanzapine, lamotrigine, gabapentin or topiramate show a differential spectrum of effectiveness in refractory patients.
The SFBN provides important new data for the understanding and treatment of bipolar disorder.
Arp2/3 complex is a key actin cytoskeletal regulator that creates branched actin filament networks in response to cellular signals. WASP-activated Arp2/3 complex assembles branched actin networks by ...nucleating new filaments from the sides of pre-existing ones. WASP-mediated activation requires seed filaments, to which the WASP-bound Arp2/3 complex can bind to form branches, but the source of the first substrate filaments for branching is unknown.
Here we show that Dip1, a member of the WISH/DIP/SPIN90 family of actin regulators, potently activates Arp2/3 complex without preformed filaments. Unlike other Arp2/3 complex activators, Dip1 does not bind actin monomers or filaments, and it interacts with the complex using a non-WASP-like binding mode. In addition, Dip1-activated Arp2/3 complex creates linear instead of branched actin filament networks.
Our data show the mechanism by which Dip1 and other WISH/DIP/SPIN90 proteins can provide seed filaments to Arp2/3 complex to serve as master switches in initiating branched actin assembly. This mechanism is distinct from other known activators of Arp2/3 complex.
•Dip1 is a potent activator of Arp2/3 complex•Dip1-mediated activation of Arp2/3 complex does not require preformed actin filaments•Dip1 mechanism may allow it to provide seed filaments for branched network assembly•The mechanism of Dip1 is conserved in the WISH/DIP/SPIN90 family
Computational needs for the RIA accelerator systems Ostroumov, P.N.; Nolen, J.A.; Mustapha, B.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2006, Letnik:
558, Številka:
1
Journal Article
Recenzirano
This paper discusses the computational needs for the full design and simulation of the RIA accelerator systems. Beam dynamics simulations are essential to first define and optimize the architectural ...design for both the driver linac and the post-accelerator. They are also important to study different design options and various off-normal modes in order to decide on the most-performing and cost-effective design. Due to the high-intensity primary beams, the beam-stripper interaction is a source of both radioactivation and beam contamination and should be carefully investigated and simulated for proper beam collimation and shielding. The targets and fragment separators area needs also very special attention in order to reduce any radiological hazards by careful shielding design. For all these simulations parallel computing is an absolute necessity.
Plaque ulceration is a marker of previous plaque rupture. We studied the association between atherosclerotic plaque composition at baseline and plaque ulceration at baseline and follow-up.
We ...included symptomatic patients with a carotid stenosis of <70% who underwent MDCTA and MR imaging at baseline (
= 180). MDCTA was repeated at 2 years (
= 73). We assessed the presence of ulceration using MDCTA. Baseline MR imaging was used to assess the vessel wall volume and the presence and volume of plaque components (intraplaque hemorrhage, lipid-rich necrotic core, and calcifications) and the fibrous cap status. Associations at baseline were evaluated with binary logistic regression and reported with an OR and its 95% CI. Simple statistical testing was performed in the follow-up analysis.
At baseline, the prevalence of plaque ulceration was 27% (49/180). Increased wall volume (OR = 12.1; 95% CI, 3.5-42.0), higher relative lipid-rich necrotic core (OR = 1.7; 95% CI, 1.3-2.2), higher relative intraplaque hemorrhage volume (OR = 1.7; 95% CI, 1.3-2.2), and a thin-or-ruptured fibrous cap (OR = 3.4; 95% CI, 1.7-6.7) were associated with the presence of ulcerations at baseline. In 8% (6/73) of the patients, a new ulcer developed. Plaques with a new ulceration at follow-up had at baseline a larger wall volume (1.04 cm
IQR, 0.97-1.16 cm
versus 0.86 cm
IQR, 0.73-1.00 cm
;
= .029), a larger relative lipid-rich necrotic core volume (23% IQR, 13-31% versus 2% IQR, 0-14%;
= .002), and a larger relative intraplaque hemorrhage volume (14% IQR, 8-24% versus 0% IQR, 0-5%;
< .001).
Large atherosclerotic plaques and plaques with intraplaque hemorrhage and lipid-rich necrotic cores were associated with plaque ulcerations at baseline and follow-up.
Rhebergen D, Batelaan NM, de Graaf R, Nolen WA, Spijker J, Beekman ATF, Penninx BWJH. The 7‐year course of depression and anxiety in the general population.
Objective: Insight into the long‐term ...course of depression and anxiety.
Method: Data were derived from Netherlands Mental Health Survey and Incidence Study/Netherlands Study of Depression and Anxiety, epidemiologic surveys in the adult population in the Netherlands. Three hundred and three respondents with depressive and/or anxiety Composite International Diagnostic Interview (CIDI) disorder were interviewed, examining the 7‐year course of depression (n = 141), anxiety (n = 102) and the comorbid state (n = 60) and possible prognostic factors. Outcomes were CIDI diagnostic status after 7 years and percentage of time during 7 years with depressive and/or anxiety symptoms, retrospectively assessed by the Life Chart Interview (LCI).
Results: After 7 years, 60.7% of the subjects were free from a 12‐month CIDI depression or anxiety diagnosis. The odds were higher for subjects with anxiety and comorbidity compared to subjects with depression. Low physical functioning and high neuroticism predicted the presence of a diagnosis after 7 years.
During 7‐year follow‐up, 37.3% of the subjects were free from depressive and anxiety symptoms according to the LCI, 51.8% had symptoms <50% of the time, and 10.9%≥50% of the time. (Comorbid) anxiety resulted in a poorer course. High neuroticism and childhood adversity predicted more follow‐up time with symptoms.
Conclusion: Course trajectories were more favorable than expected, although comorbidity resulted in poorer course. Neuroticism, physical functioning, and childhood adversity predicted an unfavorable course.
Objective The purpose of this study was to characterize the urinary microbiota in women who are planning treatment for urgency urinary incontinence and to describe clinical associations with urinary ...symptoms, urinary tract infection, and treatment outcomes. Study Design Catheterized urine samples were collected from multisite randomized trial participants who had no clinical evidence of urinary tract infection; 16S ribosomal RNA gene sequencing was used to dichotomize participants as either DNA sequence-positive or sequence-negative. Associations with demographics, urinary symptoms, urinary tract infection risk, and treatment outcomes were determined. In sequence-positive samples, microbiotas were characterized on the basis of their dominant microorganisms. Results More than one-half (51.1%; 93/182) of the participants’ urine samples were sequence-positive. Sequence-positive participants were younger (55.8 vs 61.3 years old; P = .0007), had a higher body mass index (33.7 vs 30.1 kg/m2 ; P = .0009), had a higher mean baseline daily urgency urinary incontinence episodes (5.7 vs 4.2 episodes; P < .0001), responded better to treatment (decrease in urgency urinary incontinence episodes, –4.4 vs –3.3; P = .0013), and were less likely to experience urinary tract infection (9% vs 27%; P = .0011). In sequence-positive samples, 8 major bacterial clusters were identified; 7 clusters were dominated not only by a single genus, most commonly Lactobacillus (45%) or Gardnerella (17%), but also by other taxa (25%). The remaining cluster had no dominant genus (13%). Conclusion DNA sequencing confirmed urinary bacterial DNA in many women with urgency urinary incontinence who had no signs of infection. Sequence status was associated with baseline urgency urinary incontinence episodes, treatment response, and posttreatment urinary tract infection risk.
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