116 research outputs found
Phylogeny of Tec Family Kinases: Identification of a Pre-Metazoan Origin of Btk, Bmx, Itk, Tec, Txk and the Btk Regulator SH3BP5
It is generally considered mammals and birds have five Tec family kinases
(TFKs): Btk, Bmx (also known as Etk), Itk, Tec, and Txk (also known as Rlk).
Here, we discuss the domains and their functions and regulation in TFKs. Over
the last few years, a large number of genomes from various phyla have been
sequenced making it possible to study evolutionary relationships at the molecular
and sequence level. Using bioinformatics tools, we for the first time demonstrate
that a TFK ancestor exists in the unicellular choanoflagellate Monosiga brevicollis,
which is the closest known relative to metazoans with a sequenced genome. The
analysis of the genomes for sponges, insects, hagfish, and frogs suggests that these
species encode a single TFK. The insect form has a divergent and unique
N-terminal region. Duplications generating the five members took place prior
to the emergence of vertebrates. Fishes have two or three forms and the platypus,
Ornithorhynchus anatinus, has four (lacks Txk). Thus, not all mammals have all
five TFKs. The single identified TFK in frogs is an ortholog of Tec. Bmx seems to
be unique to mammals and birds. SH3BP5 is a negative regulator of Btk. It is
conserved in choanoflagellates and interestingly exists also in nematodes, which
do not express TFKs, suggesting a broader function in addition to Btk regulation.
The related SH3BP5-like protein is not found in Nematodes
Journal Staff
Primary Immunodeficiencies (PID) are genetically inherited disorders characterized by defects of the immune system, leading to increased susceptibility to infection. Due to the variety of clinical symptoms and the complexity of current diagnostic procedures, accurate diagnosis of PID is often difficult in daily clinical practice. Thanks to the advent of "next generation'' sequencing technologies and target enrichment methods, the development of multiplex diagnostic assays is now possible. In this study, we applied a selector-based target enrichment assay to detect disease-causing mutations in 179 known PID genes. The usefulness of this assay for molecular diagnosis of PID was investigated by sequencing DNA from 33 patients, 18 of which had at least one known causal mutation at the onset of the experiment. We were able to identify the disease causing mutations in 60% of the investigated patients, indicating that the majority of PID cases could be resolved using a targeted sequencing approach. Causal mutations identified in the unknown patient samples were located in STAT3, IGLL1, RNF168 and PGM3. Based on our results, we propose a stepwise approach for PID diagnostics, involving targeted resequencing, followed by whole transcriptome and/or whole genome sequencing if causative variants are not found in the targeted exons
Resistance Mutations to BTK Inhibitors Originate From the NF-ÎșB but Not From the PI3K-RAS-MAPK Arm of the B Cell Receptor Signaling Pathway
Since the first clinical report in 2013, inhibitors of the intracellular kinase BTK (BTKi) have profoundly altered the treatment paradigm of B cell malignancies, replacing chemotherapy with targeted agents in patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenströmâs macroglobulinemia. There are over 20 BTKi, both irreversible and reversible, in clinical development. While loss-of-function (LoF) mutations in the BTK gene cause the immunodeficiency X-linked agammaglobulinemia, neither inherited, nor somatic BTK driver mutations are known. Instead, BTKi-sensitive malignancies are addicted to BTK. BTK is activated by upstream surface receptors, especially the B cell receptor (BCR) but also by chemokine receptors, and adhesion molecules regulating B cell homing. Consequently, BTKi therapy abrogates BCR-driven proliferation and the tissue homing capacity of the malignant cells, which are being redistributed into peripheral blood. BTKi resistance can develop over time, especially in MCL and high-risk CLL patients. Frequently, resistance mutations affect the BTKi binding-site, cysteine 481, thereby reducing drug binding. Less common are gain-of-function (GoF) mutations in downstream signaling components, including phospholipase CÎł2 (PLCÎł2). In a subset of patients, mechanisms outside of the BCR pathway, related e.g. to resistance to apoptosis were described. BCR signaling depends on many proteins including SYK, BTK, PI3K; still based on the resistance pattern, BTKi therapy only selects GoF alterations in the NF-ÎșB arm, whereas an inhibitor of the p110ÎŽ subunit of PI3K instead selects resistance mutations in the RAS-MAP kinase pathway. BTK and PLCÎł2 resistance mutations highlight BTKâs non-redundant role in BCR-mediated NF-ÎșB activation. Of note, mutations affecting BTK tend to generate clone sizes larger than alterations in PLCÎł2. This infers that BTK signaling may go beyond the PLCÎł2-regulated NF-ÎșB and NFAT arms. Collectively, when comparing the primary and acquired mutation spectrum in BTKi-sensitive malignancies with the phenotype of the corresponding germline alterations, we find that certain observations do not readily fit with the existing models of BCR signaling
Large-scale expansions of Friedreich's ataxia GAAâąTTC repeats in an experimental human system: role of DNA replication and prevention by LNA-DNA oligonucleotides and PNA oligomers
Friedreich's ataxia (FRDA) is caused by expansions of GAAâąTTC repeats in the first intron of the human FXN gene that occur during both intergenerational transmissions and in somatic cells. Here we describe an experimental system to analyze large-scale repeat expansions in cultured human cells. It employs a shuttle plasmid that can replicate from the SV40 origin in human cells or be stably maintained in S. cerevisiae utilizing ARS4-CEN6. It also contains a selectable cassette allowing us to detect repeat expansions that accumulated in human cells upon plasmid transformation into yeast. We indeed observed massive expansions of GAAâąTTC repeats, making it the first genetically tractable experimental system to study large-scale repeat expansions in human cells. Further, GAAâąTTC repeats stall replication fork progression, while the frequency of repeat expansions appears to depend on proteins implicated in replication fork stalling, reversal, and restart. Locked nucleic acid (LNA)-DNA mixmer oligonucleotides and peptide nucleic acid (PNA) oligomers, which interfere with triplex formation at GAAâąTTC repeats in vitro, prevented the expansion of these repeats in human cells. We hypothesize, therefore, that triplex formation by GAAâąTTC repeats stall replication fork progression, ultimately leading to repeat expansions during replication fork restart
CTG repeat-targeting oligonucleotides for down-regulating Huntingtin expression
Sjuksköterskeyrket innebĂ€r ofta lĂ„ngvarig stress och bristfĂ€llig arbetsmiljö. Personalbrist, hög arbetsbelastning och bristande inflytande pĂ„ arbetsplatsen Ă€r orsaker till att sjuksköterskor vĂ€ljer att sluta inom yrket. För lite forskning gĂ€llande den upplevda stressen pĂ„ arbetsplatsen inom sjuksköterskeyrket rĂ„der. DĂ€rför finns anledning till ökad kunskap kring Ă€mnet. Syftet med studien Ă€r att undersöka i hur hög utstrĂ€ckning sjuksköterskor upplever stress i sin arbetsmiljö, och studien Ă€r baserad pĂ„ 1044 yrkesverksamma sjuksköterskor över hela landet som Ă€r medlemmar i Facebookgruppen âSjuksköterskanâ. Dessa personer har fĂ„tt svara pĂ„ enkĂ€ten Work Stress Questionnaire med 21 frĂ„gor. Resultatet frĂ„n denna studie visar att arbetsbelastningen ökat och personalen har inte möjlighet att pĂ„verka beslut som tas pĂ„ arbetsplatsen. Konflikter Ă€r ocksĂ„ förekommande dĂ€r chefen, i de flesta fall, inte gör nĂ„got för att lösa dessa konflikter. Sjuksköterskorna sĂ€tter höga krav pĂ„ sig sjĂ€lva och Ă€r mycket engagerade i arbetet, men har ofta svĂ„rt att sĂ€tta grĂ€nser. Resultatet visar ocksĂ„ att en hög andel har svĂ„rt att hinna med familj, vĂ€nner och fritidsintressen. Det finns tidigare studier med samma mĂ€tinstrument som visar att arbetsbelastningen och ansvarstagandet har ökat under de senaste Ă„ren. Eventuellt kan detta i slutĂ€ndan innebĂ€ra en risk för ökad utbrĂ€ndhet och fler sjukskrivningar
Sequence-selective DNA recognition and enhanced cellular up-take by peptideâsteroid conjugates
Several GCN4 bZIP TF models have previously been designed and synthesized. However, the synthetic routes towards these constructs are typically tedious and difficult. We here describe the substitution of the Leucine zipper domain of the protein by a deoxycholic acid derivative appending the two GCN4 binding region peptides through
an optimized double azideâalkyne cycloaddition click reaction. In addition to achieving sequence specific dsDNA binding, we have investigated the potential of these compounds to enter cells. Confocal microscopy and flow cytometry show the beneficial influence of the steroid on cell uptake. This unique synthetic model of the bZIP TF thus combines sequence specific dsDNA binding properties with enhanced cell-uptake. Given the unique properties of deoxycholic acid and the convergent nature of the synthesis, we believe this work represents a key achievement in the field of TF mimicry
Landesque capital as an alternative to food storage in Melanesia: Irrigated taro terraces in New Georgia, Solomon Islands
In the Pacific islands, subsistence diversity made possible continuous production of food while welldeveloped exchange networks redistributed these foodstuffs as well as items within the prestige economy. All these were aspects of the âstorage structuresâ that enabled social and nutritional value to be saved, accumulated and later mobilised. In addition, there were investments in the land, landesque capital, which secured future food surpluses and so provided an alternative to food storage, in a region where the staple foods were mostly perishable, yams excepted, and food preservation was difficult. Landesque capital included such long-term improvements to productivity as terraces, mounds, irrigation channels, drainage ditches, soil structural changes and tree planting. These investments provided an effective alternative to food storage and made possible surplus production for exchange purposes. As an example, in the New Georgia group of the western Solomon Islands irrigated terraces, termed ruta, were constructed for growing the root crop taro (Colocasia esculenta). Surplus taro from ruta enabled inland groups to participate in regional exchange networks and so obtain the shell valuables that were produced by coastal groups. In this paper, we reconstruct how this exchange system worked in New Georgia using ethno-archaeological evidence, we chart its prehistoric rise and post-colonial fall, and we outline the factors that constrained its long-term expansion.Our gratitude for support during earlier fieldwork in the New Georgia group has already been expressed in previous publications. The 2014 project was supported by the Smuts Fund and Foreign Travel Fund, University of Cambridge, and by St Johnâs College, Cambridge.This is the accepted manuscript. The final version is available from Maney at http://dx.doi.org/10.1179/1749631414Y.000000004
Novel endosomolytic compounds enable highly potent delivery of antisense oligonucleotides
The therapeutic and research potentials of oligonucleotides (ONs) have been hampered in part by their inability to effectively escape endosomal compartments to reach their cytosolic and nuclear targets. Splice-switching ONs (SSOs) can be used with endosomolytic small molecule compounds to increase functional delivery. So far, development of these compounds has been hindered by a lack of high-resolution methods that can correlate SSO trafficking with SSO activity. Here we present in-depth characterization of two novel endosomolytic compounds by using a combination of microscopic and functional assays with high spatiotemporal resolution. This system allows the visualization of SSO trafficking, evaluation of endosomal membrane rupture, and quantitates SSO functional activity on a protein level in the presence of endosomolytic compounds. We confirm that the leakage of SSO into the cytosol occurs in parallel with the physical engorgement of LAMP1-positive late endosomes and lysosomes. We conclude that the new compounds interfere with SSO trafficking to the LAMP1-positive endosomal compartments while inducing endosomal membrane rupture and concurrent ON escape into the cytosol. The efficacy of these compounds advocates their use as novel, potent, and quick-acting transfection reagents for antisense ONs
ANKRD54 preferentially selects Bruton's Tyrosine Kinase (BTK) from a Human Src-Homology 3 (SH3) domain library
Bruton's Tyrosine Kinase (BTK) is a cytoplasmic protein tyrosine kinase with a fundamental role in B-lymphocyte development and activation. The nucleocytoplasmic shuttling of BTK is specifically modulated by the Ankyrin Repeat Domain 54 (ANKRD54) protein and the interaction is known to be exclusively SH3-dependent. To identify the spectrum of the ANKRD54 SH3-interactome, we applied phage-display screening of a library containing all the 296 human SH3 domains. The BTK-SH3 domain was the prime interactor. Quantitative western blotting analysis demonstrated the accuracy of the screening procedure. Revealing the spectrum and specificity of ANKRD54-interactome is a critical step toward functional analysis in cells and tissues.Peer reviewe
Perceived discrimination is associated with severity of positive and depression/anxiety symptoms in immigrants with psychosis: a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Immigration status is a significant risk factor for psychotic disorders, and a number of studies have reported more severe positive and affective symptoms among immigrant and ethnic minority groups. We investigated if perceived discrimination was associated with the severity of these symptoms among immigrants in Norway with psychotic disorders.</p> <p>Methods</p> <p>Cross-sectional analyses of 90 immigrant patients (66% first-generation, 68% from Asia/Africa) in treatment for psychotic disorders were assessed for DSM-IV diagnoses with the Structured Clinical Interview for DSM Disorders (SCID-I, sections A-E) and for present symptom severity by The Structured Positive and Negative Syndrome Scale (SCI-PANSS). Perceived discrimination was assessed by a self-report questionnaire developed for the Immigrant Youth in Cultural Transition Study.</p> <p>Results</p> <p>Perceived discrimination correlated with positive psychotic (r = 0.264, p < 0.05) and depression/anxiety symptoms (r = 0.282, p < 0.01), but not negative, cognitive, or excitement symptoms. Perceived discrimination also functioned as a partial mediator for symptom severity in African immigrants. Multiple linear regression analyses controlling for possible confounders revealed that perceived discrimination explained approximately 10% of the variance in positive and depression/anxiety symptoms in the statistical model.</p> <p>Conclusions</p> <p>Among immigrants with psychotic disorders, visible minority status was associated with perceived discrimination and with more severe positive and depression/anxiety symptoms. These results suggest that context-specific stressful environmental factors influence specific symptom patterns and severity. This has important implications for preventive strategies and treatment of this vulnerable patient group.</p
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