Divergent architecture of the heterotrimeric NatC complex explains N-terminal acetylation of cognate substrates

The heterotrimeric NatC complex, comprising the catalytic Naa30 and the two auxiliary subunits Naa35 and Naa38, co-translationally acetylates the N-termini of numerous eukaryotic target proteins. Despite its unique subunit composition, its essential role for many aspects of cellular function and its suggested involvement in disease, structure and mechanism of NatC have remained unknown. Here, we present the crystal structure of the Saccharomyces cerevisiae NatC complex, which exhibits a strikingly different architecture compared to previously described N-terminal acetyltransferase (NAT) complexes. Cofactor and ligand-bound structures reveal how the first four amino acids of cognate substrates are recognized at the Naa30–Naa35 interface. A sequence-specific, ligand-induced conformational change in Naa30 enables efficient acetylation. Based on detailed structure–function studies, we suggest a catalytic mechanism and identify a ribosome-binding patch in an elongated tip region of NatC. Our study reveals how NAT machineries have divergently evolved to N-terminally acetylate specific subsets of target proteins

Aktuelle Entwicklungen im Kontext von Online-Wahlen und digitalen Abstimmungen

Seit Beginn der Pandemie stehen viele Institutionen (inkl. Vereinen, Unternehmen und Behörden) vor der Frage, wie sie ihre Wahlen und geheimen Abstimmungen organisieren sollen – ohne die Gesundheit der Wähler*innen und Wahlhelfer*innen zu gefährden. Einige Wahlverantwortliche haben sich für die Durchführung von Online-Wahlen bzw. digitalen Abstimmungen entschieden. Erfahrungen anderer Wahlverantwortlicher, die bereits vor der Pandemie online gewählt haben, ab es in Deutschland kaum. Vor der Pandemie wurde das Thema Online-Wahlen in Deutschland – bedingt durch das sogenannte Wahlgeräte-Urteil des Bundesverfassungsgerichts (2009) – kaum diskutiert. Nach über einem Jahr Pandemie sieht die Lage anders aus: Inzwischen fanden einige Wahlen und Abstimmungen online statt. Allerdings entsprechen die dazu eingesetzten Systeme häufig nicht dem Stand der Forschung. Für zukünftige Nutzungen von Online-Wahlen und digitalen Abstimmungen (insbesondere auch nach der Pandemie) ist es daher wichtig, dass Wahlverantwortliche, Kandidat*innen und Wähler*innen verstehen, welches Risiko die bisher eingesetzten Systeme mit sich bringen und wie einzelne Entwicklungen im Kontext von Online-Wahlen und digitalen Abstimmungen einzuordnen sind. Nur so können informierte Entscheidungen im Hinblick auf die einzusetzenden Ansätze getroffen und die Demokratie auch in Zukunft geschützt werden

Nuclear pore component Nup98 is a potential tumor suppressor and regulates posttranscriptional expression of select p53 target genes

The p53 tumor suppressor utilizes multiple mechanisms to selectively regulate its myriad target genes, which in turn mediate diverse cellular processes. Here, using conventional and single-molecule mRNA analyses, we demonstrate that the nucleoporin Nup98 is required for full expression of p21, a key effector of the p53 pathway, but not several other p53 target genes. Nup98 regulates p21 mRNA levels by a posttranscriptional mechanism in which a complex containing Nup98 and the p21 mRNA 3\u27UTR protects p21 mRNA from degradation by the exosome. An in silico approach revealed another p53 target (14-3-3sigma) to be similarly regulated by Nup98. The expression of Nup98 is reduced in murine and human hepatocellular carcinomas (HCCs) and correlates with p21 expression in HCC patients. Our study elucidates a previously unrecognized function of wild-type Nup98 in regulating select p53 target genes that is distinct from the well-characterized oncogenic properties of Nup98 fusion proteins

CD44v6 specific CAR-NK cells for targeted immunotherapy of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a major challenge for current therapies. CAR-T cells have shown promising results in blood cancers, however, their effectiveness against solid tumors remains a hurdle. Recently, CD44v6-directed CAR-T cells demonstrated efficacy in controlling tumor growth in multiple myeloma and solid tumors such as HNSCC, lung and ovarian adenocarcinomas. Apart from CAR-T cells, CAR-NK cells offer a safe and allogenic alternative to autologous CAR-T cell therapy. In this paper, we investigated the capacity of CAR-NK cells redirected against CD44v6 to execute cytotoxicity against HNSCC. Anti-CD44v6 CAR-NK cells were generated from healthy donor peripheral blood-derived NK cells using gamma retroviral vectors (gRVs). The NK cell transduction was optimized by exploring virus envelope proteins derived from the baboon endogenous virus envelope (BaEV), feline leukemia virus (FeLV, termed RD114-TR) and gibbon ape leukemia virus (GaLV), respectively. BaEV pseudotyped gRVs induced the highest transduction rate compared to RD114-TR and GaLV envelopes as measured by EGFP and surface CAR expression of transduced NK cells. CAR-NK cells showed a two- to threefold increase in killing efficacy against various HNSCC cell lines compared to unmodified, cytokine-expanded primary NK cells. Anti-CD44v6 CAR-NK cells were effective in eliminating tumor cell lines with high and low CD44v6 expression levels. Overall, the improved cytotoxicity of CAR-NK cells holds promise for a therapeutic option for the treatment of HNSCC. However, further preclinical trials are necessary to test in vivo efficacy and safety, as well to optimize the treatment regimen of anti-CD44v6 CAR-NK cells against solid tumors

Signatures of technetium oxidation states: a new approach

A general strategy for the determination of Tc oxidation state by new approach involving X-ray absorption near edge spectroscopy (XANES) at the Tc L-3 edge is shown. A comprehensive series of Tc-99 compounds, ranging from oxidation states I to VII, was measured and subsequently simulated within the framework of crystal-field multiplet theory. The observable trends in the absorption edge energy shift in combination with the spectral shape allow for a deeper understanding of complicated Tc coordination chemistry. This approach can be extended to numerous studies of Tc systems as this method is one of the most sensitive methods for accurate Tc oxidation state and ligand characterization

Водный режим почвы и урожайность сельскохозяйственных культур при различных технологиях возделывания в Кулундинской степи Алтайского края

This article presents the results of crop yield in areas with different technologies of cultivation based on the network of automatic stations that provide data on climatic and soil-hydrological monitoring in the dry steppe during the vegetation period of May–September 2013–2016 . These data  on regional ecological and climatic parameters are of great interest to the ecologists, plant physiologists, and farmers working in the Kulunda Plain (Altai Territory). We compared the following options for cropping technologies: the modern system, which is the "no-till", technology without autumn tillage;the intensive technology of deep autumn tillage by plough PG-3-5 at a depth of 22–24 cm. Cultivation of crops was carried out using the following scheme of crop rotation: the modern system: 1–2–3–4 (wheat – peas – wheat – rape); the intensive system: 5/6 – 7/8 – 9/10 (fallow – wheat – wheat). We believe that the use of modern technology in these conditions is better due to exchange between the different layers of soil. When  the ordinary Soviet system , the so-called "plow sole" , was used , at a depth of 24 cm , we observed that this creates a water conductivity barrier that seems to preclude the possibility of lifting water from the lower horizons. Results of the study of infiltration of soil moisture at the depth of 30 and 60 cm  have shown in some years the advantages of the modern technology over the ordinary Soviet system: in the version with the use of modern technology we can trace better exchange between the various horizons and , probably,  moisture replenishment from the lower horizons. Differences in individual observation periods are comparatively large due to the redistribution of soil moisture, depending on the weather conditions, the crops used in the crop rotations, and cultivation techniques. Moreover, the average moisture reserves within the one meter layer did not show any significant differences during the growing seasons of 2013–2016 . In terms of soil moisture usage and productive grain yield according to the four year experiment, the application of the modern technology with crop rotation "wheat – rape – wheat – peas" was more effective than the ordinary Soviet system with crop rotation "wheat – fallow – wheat – wheat". The four-year observation period is clearly insufficient to identify the advantages of the modern system, as during this time it is impossible to significantly improve soil quality indicators, which will continue to determine its water-retaining properties and moisture accumulation.Приведены результаты урожайности сельскохозяйственных культур на участках при различных технологиях возделывания с учетом данных сети автоматических станций климатического и почвенно-гидрологического мониторинга в сухой степи (за вегетационные периоды май – сентябрь 2013–2016 гг.). Опубликованны региональные данные по значимым эколого-климатическим параметрам, представляющие интерес для экологов, физиологов растений и фермеров, работающих на Кулундинской равнине. Сравнивали следующие варианты технологий возделывания культур: современная система, представляющая технологию “no-till”, без осенней обработки почвы; интенсивная технология глубокой осенней обработки почвы орудием ПГ-3-5 на глубину 22–24 см. Возделывание культур осуществляли с использованием следующей схемы севооборотов: современная система: 1 – 2 – 3 – 4 (пшеница – горох – пшеница – рапс); интенсивная система: 5/6 – 7/8 – 9/10 (пар – пшеница – пшеница). При использовании современной технологии наблюдается лучшая связь между различными слоями почвы. В варианте обычной советской системы так называемая «плужная подошва» на глубине 24 см создает барьер водопроницаемости, что, видимо, препятствует подъему влаги с более низких горизонтов. Результаты изучения хода влажности почвы на глубинах 30 и 60 см за отдельные годы показали преимущества современной технологии перед обычной системой: в варианте с использованием современной технологии прослеживается лучшая связь между различными горизонтами и, вероятно, происходит восполнение влаги с более низких горизонтов. Различия в отдельные периоды наблюдений во многом обусловлены перераспределением влаги в почве в зависимости от погодных условий, культур в севообороте и технологии их возделывания. Причем средняя величина влагозапасов за период вегетации 2013–2016 гг. в метровом слое существенно не отличалась. С точки зрения использования почвенной влаги и получения прибавки урожая по данным за четыре года применение современной технологии с севооборотом «пшеница – рапс – пшеница – горох» было более эффективным, чем обычная система с севооборотом «пшеница – пар – пшеница – пшеница». Четырехлетний период наблюдений явно недостаточен для выявления преимуществ современной системы, поскольку за это время невозможно существенно улучшить качественные показатели почвы, которые в дальнейшем будут определять ее водоудерживающие характеристики и влагонакопление. Приведены результаты урожайности сельскохозяйственных культур на участках при различных технологиях возделывания с учетом данных сети автоматических станций климатического и почвенно-гидрологического мониторинга в сухой степи (за вегетационные периоды май – сентябрь 2013–2016 гг.). Опубликованны региональные данные по значимым эколого-климатическим параметрам, представляющие интерес для экологов, физиологов растений и фермеров, работающих на Кулундинской равнине. Сравнивали следующие варианты технологий возделывания культур: современная система, представляющая технологию “no-till”, без осенней обработки почвы; интенсивная технология глубокой осенней обработки почвы орудием ПГ-3-5 на глубину 22–24 см. Возделывание культур осуществляли с использованием следующей схемы севооборотов: современная система: 1 – 2 – 3 – 4 (пшеница – горох – пшеница – рапс); интенсивная система: 5/6 – 7/8 – 9/10 (пар – пшеница – пшеница). При использовании современной технологии наблюдается лучшая связь между различными слоями почвы. В варианте обычной советской системы так называемая «плужная подошва» на глубине 24 см создает барьер водопроницаемости, что, видимо, препятствует подъему влаги с более низких горизонтов. Результаты изучения хода влажности почвы на глубинах 30 и 60 см за отдельные годы показали преимущества современной технологии перед обычной системой: в варианте с использованием современной технологии прослеживается лучшая связь между различными горизонтами и, вероятно, происходит восполнение влаги с более низких горизонтов. Различия в отдельные периоды наблюдений во многом обусловлены перераспределением влаги в почве в зависимости от погодных условий, культур в севообороте и технологии их возделывания. Причем средняя величина влагозапасов за период вегетации 2013–2016 гг. в метровом слое существенно не отличалась. С точки зрения использования почвенной влаги и получения прибавки урожая по данным за четыре года применение современной технологии с севооборотом «пшеница – рапс – пшеница – горох» было более эффективным, чем обычная система с севооборотом «пшеница – пар – пшеница – пшеница». Четырехлетний период наблюдений явно недостаточен для выявления преимуществ современной системы, поскольку за это время невозможно существенно улучшить качественные показатели почвы, которые в дальнейшем будут определять ее водоудерживающие характеристики и влагонакопление.

Nuclear accessibility of beta-actin mRNA is measured by 3D single-molecule real-time tracking

Imaging single proteins or RNAs allows direct visualization of the inner workings of the cell. Typically, three-dimensional (3D) images are acquired by sequentially capturing a series of 2D sections. The time required to step through the sample often impedes imaging of large numbers of rapidly moving molecules. Here we applied multifocus microscopy (MFM) to instantaneously capture 3D single-molecule real-time images in live cells, visualizing cell nuclei at 10 volumes per second. We developed image analysis techniques to analyze messenger RNA (mRNA) diffusion in the entire volume of the nucleus. Combining MFM with precise registration between fluorescently labeled mRNA, nuclear pore complexes, and chromatin, we obtained globally optimal image alignment within 80-nm precision using transformation models. We show that beta-actin mRNAs freely access the entire nucleus and fewer than 60% of mRNAs are more than 0.5 microm away from a nuclear pore, and we do so for the first time accounting for spatial inhomogeneity of nuclear organization

Bimodal antagonism of PKA signalling by ARHGAP36

Protein kinase A is a key mediator of cAMP signalling downstream of G-protein-coupled receptors, a signalling pathway conserved in all eukaryotes. cAMP binding to the regulatory subunits (PKAR) relieves their inhibition of the catalytic subunits (PKAC). Here we report that ARHGAP36 combines two distinct inhibitory mechanisms to antagonise PKA signalling. First, it blocks PKAC activity via a pseudosubstrate motif, akin to the mechanism employed by the protein kinase inhibitor proteins. Second, it targets PKAC for rapid ubiquitin-mediated lysosomal degradation, a pathway usually reserved for transmembrane receptors. ARHGAP36 thus dampens the sensitivity of cells to cAMP. We show that PKA inhibition by ARHGAP36 promotes derepression of the Hedgehog signalling pathway, thereby providing a simple rationale for the upregulation of ARHGAP36 in medulloblastoma. Our work reveals a new layer of PKA regulation that may play an important role in development and disease

Covid-19 triage in the emergency department 2.0: how analytics and AI transform a human-made algorithm for the prediction of clinical pathways

The Covid-19 pandemic has pushed many hospitals to their capacity limits. Therefore, a triage of patients has been discussed controversially primarily through an ethical perspective. The term triage contains many aspects such as urgency of treatment, severity of the disease and pre-existing conditions, access to critical care, or the classification of patients regarding subsequent clinical pathways starting from the emergency department. The determination of the pathways is important not only for patient care, but also for capacity planning in hospitals. We examine the performance of a human-made triage algorithm for clinical pathways which is considered a guideline for emergency departments in Germany based on a large multicenter dataset with over 4,000 European Covid-19 patients from the LEOSS registry. We find an accuracy of 28 percent and approximately 15 percent sensitivity for the ward class. The results serve as a benchmark for our extensions including an additional category of palliative care as a new label, analytics, AI, XAI, and interactive techniques. We find significant potential of analytics and AI in Covid-19 triage regarding accuracy, sensitivity, and other performance metrics whilst our interactive human-AI algorithm shows superior performance with approximately 73 percent accuracy and up to 76 percent sensitivity. The results are independent of the data preparation process regarding the imputation of missing values or grouping of comorbidities. In addition, we find that the consideration of an additional label palliative care does not improve the results

Is technology optimism justified? A discussion towards a comprehensive narrative

This paper is based on a discussion developed by one of the thematic working groups at the Biennial International Workshop Advances in Energy Studies (BIWAES) 2017 hold in Naples, Italy. The topic was the role of technology in energy transition and global problems. Owing to the heterogeneity of the participants in the working group, different viewpoints were put together, leading to some shared conclusions. In particular, the role played by the different narratives used in discussing the role of technology in facing global problems was pointed out as the origin of cognitive dissonance. The presented reflections address some conceptual weaknesses in the current debate on technology and global issues, framed in global policies that appear incapable to obtain tangible results. The technology optimism seems, in fact, to be based on the elusive use of both the concepts of technology and sustainability, that are put together for narrative purposes without an explicit conceptual assessment. On one hand, the factual role of technology and its beneficiary are almost never clearly addressed in the debate. On the other hand, the fact that any new technology will serve the cause of sustainability is not questioned whatsoever, without taking into account the social, political and ethical framework in which technology is supposed to be operated