Phosphorylation of the MLKL pseudokinase by the RIPK3 kinase leads to MLKL oligomerization, translocation to, and permeabilization of, the plasma membrane to induce necroptotic cell death. The ...precise choreography of MLKL activation remains incompletely understood. Here, we report Monobodies, synthetic binding proteins, that bind the pseudokinase domain of MLKL within human cells and their crystal structures in complex with the human MLKL pseudokinase domain. While Monobody-32 constitutively binds the MLKL hinge region, Monobody-27 binds MLKL via an epitope that overlaps the RIPK3 binding site and is only exposed after phosphorylated MLKL disengages from RIPK3 following necroptotic stimulation. The crystal structures identified two distinct conformations of the MLKL pseudokinase domain, supporting the idea that a conformational transition accompanies MLKL disengagement from RIPK3. These studies provide further evidence that MLKL undergoes a large conformational change upon activation, and identify MLKL disengagement from RIPK3 as a key regulatory step in the necroptosis pathway.
The necroptosis cell death pathway has been implicated in host defense and in the pathology of inflammatory diseases. While phosphorylation of the necroptotic effector pseudokinase Mixed Lineage ...Kinase Domain-Like (MLKL) by the upstream protein kinase RIPK3 is a hallmark of pathway activation, the precise checkpoints in necroptosis signaling are still unclear. Here we have developed monobodies, synthetic binding proteins, that bind the N-terminal four-helix bundle (4HB) “killer” domain and neighboring first brace helix of human MLKL with nanomolar affinity. When expressed as genetically encoded reagents in cells, these monobodies potently block necroptotic cell death. However, they did not prevent MLKL recruitment to the “necrosome” and phosphorylation by RIPK3, nor the assembly of MLKL into oligomers, but did block MLKL translocation tomembranes where activatedMLKL normally disrupts membranes to kill cells. An X-ray crystal structure revealed a monobodybinding site centered on the α4 helix of the MLKL 4HB domain, which mutational analyses showed was crucial for reconstitution of necroptosis signaling. These data implicate the α4 helix of its 4HB domain as a crucial site for recruitment of adaptor proteins that mediatemembrane translocation, distinct from known phospholipid binding sites.
Patterns of Cognitive Appraisal in Emotion Smith, Craig A; Ellsworth, Phoebe C
Journal of personality and social psychology,
04/1985, Letnik:
48, Številka:
4
Journal Article
Recenzirano
There has long been interest in describing emotional experience in terms of underlying
dimensions, but traditionally only two dimensions,
pleasantness
and
arousal
, have been reliably found. The ...reasons for these findings are
reviewed, and integrating this review with two recent theories of emotions (
Roseman, 1984
;
Scherer, 1982
), we propose eight cognitive appraisal dimensions
to differentiate emotional experience. In an investigation of this model, subjects recalled
past experiences associated with each of 15 emotions, and rated them along the proposed
dimensions. Six orthogonal dimensions,
pleasantness, anticipated effort, certainty,
attentional activity, self-other responsibility/control
, and
situational
control
, were recovered, and the emotions varied systematically along each of these
dimensions, indicating a strong relation between the appraisal of one's circumstances and one's
emotional state. The patterns of appraisal for the different emotions, and the role of each of
the dimensions in differentiating emotional experience are discussed.
Recent research has suggested strong relations between characteristic patterns of appraisal along emotionally relevant dimensions and the experience of specific emotions. However, this work has ...relied primarily upon ratings of remembered or imagined past events associated with the experience of relatively pure emotions. The present investigation is an attempt to examine cognitive appraisals and emotions
during
an emotional event in which subjects experience complex emotional blends. Subjects described both their cognitive appraisals and their emotional states just before taking a college midterm examination and, again, immediately after receiving their grades on the exam. Analysis of the ratings revealed that at both times the majority of subjects who felt emotion experienced complex blends of two or more emotions. Correlation and regression analyses indicated that even in the context of these blends, patterns of appraisal, highly similar to those discovered in our earlier research on remembered emotions (
Smith & Ellsworth, 1985
), characterized the experience of emotions as they were actually felt.
Maternal protein malnutrition throughout pregnancy and lactation compromises brain development in late gestation and after birth, affecting structural, biochemical, and pathway dynamics with lasting ...consequences for motor and cognitive function. However, the importance of nutrition during the preimplantation period for brain development is unknown. We have previously shown that maternal low-protein diet (LPD) confined to the preimplantation period (Emb-LPD) in mice, with normal nutrition thereafter, is sufficient to induce cardiometabolic and locomotory behavioral abnormalities in adult offspring. Here, using a range of in vivo and in vitro techniques, we report that Emb-LPD and sustained LPD reduce neural stem cell (NSC) and progenitor cell numbers at E12.5, E14.5, and E17.5 through suppressed proliferation rates in both ganglionic eminences and cortex of the fetal brain. Moreover, Emb-LPD causes remaining NSCs to up-regulate the neuronal differentiation rate beyond control levels, whereas in LPD, apoptosis increases to possibly temper neuron formation. Furthermore, Emb-LPD adult offspring maintain the increase in neuron proportion in the cortex, display increased cortex thickness, and exhibit short-term memory deficit analyzed by the novel-object recognition assay. Last, we identify altered expression of fragile X family genes as a potential molecular mechanism for adverse programming of brain development. Collectively, these data demonstrate that poor maternal nutrition from conception is sufficient to cause abnormal brain development and adult memory loss.
•Reviews particle collection techniques with focus on GEOTRACES-relevant methods.•Collection methods for sinking and suspended particles discussed.•Methodological improvements and intercomparisons ...needed to advance understanding.
Marine particles play a central role in controlling the transport, cycling, and inventories of many major elements and trace elements and isotopes throughout the oceans. Studies seeking to elucidate the biogeochemical roles of marine particles often require reliable ways to collect them from the ocean. Here, we review the oceanographic toolbox of techniques and instrumentation that are employed to collect both suspended and sinking particles. With these tools, it is possible to determine both the concentrations and vertical fluxes of important elements and individual particle types. We describe the various methods for quantifying the concentrations of particulate matter with in situ pumps, towed sampling devices, bottle collectors, and large volume capture devices. The uses of various types of flux collection platforms are discussed including surface tethered, neutrally buoyant, and bottom moored devices. We address the issues of sediment trap collection biases and the apparent inconsistencies that can arise due to differences in the temporal and spatial scales sampled by the various methodologies. Special attention is given to collection considerations made for the analysis of trace metals and isotopes, as these methodologies are of high importance to the ongoing GEOTRACES program which seeks to identify the processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean. With the emergence of new particle collection methodologies and the continued reliance on traditional collection methods, it is imperative that we combine these multiple approaches in ways that will help improve their accuracy and precision while enhancing their utility in advancing understanding of the biogeochemical and ecological roles of marine particles.
The relationship between biodiversity and stability, or its inverse, temporal variability, is multidimensional and complex. Temporal variability in aggregate properties, like total biomass or ...abundance, is typically lower in communities with higher species diversity (i.e., the diversity–stability relationship DSR). At broader spatial extents, regional‐scale aggregate variability is also lower with higher regional diversity (in plant systems) and with lower spatial synchrony. However, focusing exclusively on aggregate properties of communities may overlook potentially destabilizing compositional shifts. It is not yet clear how diversity is related to different components of variability across spatial scales, nor whether regional DSRs emerge across a broad range of organisms and ecosystem types. To test these questions, we compiled a large collection of long‐term metacommunity data spanning a wide range of taxonomic groups (e.g., birds, fish, plants, invertebrates) and ecosystem types (e.g., deserts, forests, oceans). We applied a newly developed quantitative framework for jointly analyzing aggregate and compositional variability across scales. We quantified DSRs for composition and aggregate variability in local communities and metacommunities. At the local scale, more diverse communities were less variable, but this effect was stronger for aggregate than compositional properties. We found no stabilizing effect of γ‐diversity on metacommunity variability, but β‐diversity played a strong role in reducing compositional spatial synchrony, which reduced regional variability. Spatial synchrony differed among taxa, suggesting differences in stabilization by spatial processes. However, metacommunity variability was more strongly driven by local variability than by spatial synchrony. Across a broader range of taxa, our results suggest that high γ‐diversity does not consistently stabilize aggregate properties at regional scales without sufficient spatial β‐diversity to reduce spatial synchrony.
An analysis of surveillance data on inpatients younger than 21 years of age who had multisystem inflammatory syndrome in children and were hospitalized between March 15 and October 31, 2020, showed ...that initial treatment with IVIG plus glucocorticoids was associated with a lower risk of cardiovascular dysfunction and a lower incidence of adjunctive therapy use than IVIG alone.
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