Structural Insights into the Process of GPCR-G Protein Complex Formation.

The crystal structure of the ß2-adrenergic receptor (ß2AR) bound to the G protein adenylyl cyclase stimulatory G protein (Gs) captured the complex in a nucleotide-free state (ß2AR-Gsempty). Unfortunately, the ß2AR-Gsempty complex does not provide a clear explanation for G protein coupling specificity. Evidence from several sources suggests the existence of a transient complex between the ß2AR and GDP-bound Gs protein (ß2AR-GsGDP) that may represent an intermediate on the way to the formation of ß2AR-Gsempty and may contribute to coupling specificity. Here we present a structure of the ß2AR in complex with the carboxyl terminal 14 amino acids from Gαs along with the structure of the GDP-bound Gs heterotrimer. These structures provide evidence for an alternate interaction between the ß2AR and Gs that may represent an intermediate that contributes to Gs coupling specificity.

2D fin field-effect transistors integrated with epitaxial high-k gate oxide.

Precise integration of two-dimensional (2D) semiconductors and high-dielectric-constant (k) gate oxides into three-dimensional (3D) vertical-architecture arrays holds promise for developing ultrascaled transistors1-5, but has proved challenging. Here we report the epitaxial synthesis of vertically aligned arrays of 2D fin-oxide heterostructures, a new class of 3D architecture in which high-mobility 2D semiconductor fin Bi2O2Se and single-crystal high-k gate oxide Bi2SeO5 are epitaxially integrated. These 2D fin-oxide epitaxial heterostructures have atomically flat interfaces and ultrathin fin thickness down to one unit cell (1.2 nm), achieving wafer-scale, site-specific and high-density growth of mono-oriented arrays. The as-fabricated 2D fin field-effect transistors (FinFETs) based on Bi2O2Se/Bi2SeO5 epitaxial heterostructures exhibit high electron mobility (µ) up to 270 cm2 V-1 s-1, ultralow off-state current (IOFF) down to about 1 pA µm-1, high on/off current ratios (ION/IOFF) up to 108 and high on-state current (ION) up to 830 µA µm-1 at 400-nm channel length, which meet the low-power specifications projected by the International Roadmap for Devices and Systems (IRDS)6. The 2D fin-oxide epitaxial heterostructures open up new avenues for the further extension of Moore's law.

B Cells Are the Dominant Antigen-Presenting Cells that Activate Naive CD4+ T Cells upon Immunization with a Virus-Derived Nanoparticle Antigen.

B cells can present antigens to CD4+ T cells, but it is thought that dendritic cells (DCs) are the primary initiators of naive CD4+ T cell responses. Nanoparticles, including virus-like particles (VLPs), are attractive candidates as carriers for vaccines and drug delivery. Using RNA phage Qß-derived VLP (Qß-VLP) as a model antigen, we found that antigen-specific B cells were the dominant antigen-presenting cells that initiated naive CD4+ T cell activation. B cells were sufficient to induce T follicular helper cell development in the absence of DCs. Qß-specific B cells promoted CD4+ T cell proliferation and differentiation via cognate interactions and through Toll-like receptor signaling-mediated cytokine production. Antigen-specific B cells were also involved in initiating CD4+ T cell responses during immunization with inactivated influenza virus. These findings have implications for the rational design of nanoparticles as vaccine candidates, particularly for therapeutic vaccines that aim to break immune tolerance.

Green means go: Green light promotes hypocotyl elongation via brassinosteroid signaling.

Although many studies have elucidated the mechanisms by which different wavelengths of light (blue, red, far-red, or ultraviolet-B [UV-B]) regulate plant development, whether and how green light regulates plant development remains largely unknown. Previous studies reported that green light participates in regulating growth and development in land plants, but these studies have reported conflicting results, likely due to technical problems. For example, commercial green light-emitting diode light sources emit a little blue or red light. Here, using a pure green light source, we determined that unlike blue, red, far-red, or UV-B light, which inhibits hypocotyl elongation, green light promotes hypocotyl elongation in Arabidopsis thaliana and several other plants during the first 2-3 d after planting. Phytochromes, cryptochromes, and other known photoreceptors do not mediate green-light-promoted hypocotyl elongation, but the brassinosteroid (BR) signaling pathway is involved in this process. Green light promotes the DNA binding activity of BRI1-EMS-SUPPRESSOR 1 (BES1), a master transcription factor of the BR pathway, thus regulating gene transcription to promote hypocotyl elongation. Our results indicate that pure green light promotes elongation via BR signaling and acts as a shade signal to enable plants to adapt their development to a green-light-dominant environment under a canopy.

How plants coordinate their development in response to light and temperature signals.

Light and temperature change constantly under natural conditions and profoundly affect plant growth and development. Light and warmer temperatures promote flowering, higher light intensity inhibits hypocotyl and petiole elongation, and warmer temperatures promote hypocotyl and petiole elongation. Moreover, exogenous light and temperature signals must be integrated with endogenous signals to fine-tune phytohormone metabolism and plant morphology. Plants perceive and respond to light and ambient temperature using common sets of factors, such as photoreceptors and multiple light signal transduction components. These highly structured signaling networks are critical for plant survival and adaptation. This review discusses how plants respond to variable light and temperature conditions using common elements to coordinate their development. Future directions for research on light and temperature signaling pathways are also discussed.

Legionella effectors SidC/SdcA ubiquitinate multiple small GTPases and SNARE proteins to promote phagosomal maturation.

Protein ubiquitination is one of the most important posttranslational modifications (PTMs) in eukaryotes and is involved in the regulation of almost all cellular signaling pathways. The intracellular bacterial pathogen Legionella pneumophila translocates at least 26 effectors to hijack host ubiquitination signaling via distinct mechanisms. Among these effectors, SidC/SdcA are novel E3 ubiquitin ligases with the adoption of a Cys-His-Asp catalytic triad. SidC/SdcA are critical for the recruitment of endoplasmic reticulum (ER)-derived vesicles to the Legionella-containing vacuole (LCV). However, the ubiquitination targets of SidC/SdcA are largely unknown, which restricts our understanding of the mechanisms used by these effectors to hijack the vesicle trafficking pathway. Here, we demonstrated that multiple Rab small GTPases and target soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins are bona fide ubiquitination substrates of SidC/SdcA. SidC/SdcA-mediated ubiquitination of syntaxin 3 and syntaxin 4 promotes their unconventional pairing with the vesicle-SNARE protein Sec22b, thereby contributing to the membrane fusion of ER-derived vesicles with the phagosome. In addition, our data reveal that ubiquitination of Rab7 by SidC/SdcA is critical for its association with the LCV membrane. Rab7 ubiquitination could impair its binding with the downstream effector Rab-interacting lysosomal protein (RILP), which partially explains why LCVs avoid fusion with lysosomes despite the acquisition of Rab7. Taken together, our study reveals the biological mechanisms employed by SidC/SdcA to promote the maturation of the LCVs.

SIRT2-mediated deacetylation of ACLY promotes the progression of oesophageal squamous cell carcinoma.

ATP citrate lyase (ACLY), as a key enzyme in lipid metabolism, plays an important role in energy metabolism and lipid biosynthesis of a variety of tumours. Many studies have shown that ACLY is highly expressed in various tumours, and its pharmacological or gene inhibition significantly inhibits tumour growth and progression. However, the roles of ACLY in oesophageal squamous cell carcinoma (ESCC) remain unclear. Here, our data showed that ACLY inhibitor significantly attenuated cell proliferation, migration, invasion and lipid synthesis in different ESCC cell lines, whereas the proliferation, migration, invasion and lipid synthesis of ESCC cells were enhanced after ACLY overexpression. Furthermore, ACLY inhibitor dramatically suppressed tumour growth and lipid metabolism in ESCC cells xenografted tumour model, whereas ACLY overexpression displayed the opposite effect. Mechanistically, ACLY protein harboured acetylated modification and interacted with SIRT2 protein in ESCC cells. The SIRT2 inhibitor AGK2 significantly increased the acetylation level of ACLY protein and inhibited the proliferation and migration of ESCC cells, while overexpression of ACLY partially reversed the inhibitory effect of AGK2 on ESCC cells. Overall, these results suggest that targeting the SIRT2/ACLY signalling axis may be a potential therapeutic strategy for ESCC patients.

UV-B photoreceptor UVR8 interacts with MYB73/MYB77 to regulate auxin responses and lateral root development.

The UV-B photoreceptor UVR8 mediates multiple UV-B responses in plants, but the function of UVR8 in regulating root development has not previously been investigated. Here, we show that UV-B light inhibits Arabidopsis lateral root growth in a UVR8-dependent manner. Monomeric UVR8 inhibits auxin responses in a tissue-autonomous manner and thereby regulates lateral root growth. Genome-wide gene expression analysis demonstrated that auxin and UV-B irradiation antagonistically regulate auxin-regulated gene expression. We further show that UVR8 physically interacts with MYB73/MYB77 (MYB DOMAIN PROTEIN 73/77) in a UV-B-dependent manner. UVR8 inhibits lateral root development via regulation of MYB73/MYB77. When activated by UV-B light, UVR8 localizes to the nucleus and inhibits the DNA-binding activities of MYB73/MYB77 and directly represses the transcription of their target auxin-responsive genes. Our results demonstrate that UV-B light and UVR8 are critical for both shoot morphogenesis and root development. The UV-B-dependent interaction of UVR8 and MYB73/MYB77 serves as an important module that integrates light and auxin signaling and represents a new UVR8 signaling mechanism in plants.

Synergistically Utilizing a Liquid Bridge and Interconnected Porous Superhydrophilic Structures to Achieve a One-Step Fog Collection Mode.

Conventional fog collection efficiency is subject to the inherent inefficiencies of its three constituent steps: fog capture, coalescence, and transportation. This study presents a liquid bridge synergistic fog collection system (LSFCS) by synergistically utilizing a liquid bridge and interconnected porous superhydrophilic structures (IPHS). The results indicate that the introduction of liquid bridge not only greatly accelerates water droplet transportation, but also facilitates the IPHS in maintaining rough structures that realize stable and efficient fog capture. During fog collection, the lower section of the IPHS is covered by a water layer, however due to the effect of the liquid bridge, the upper section protrudes out, while covered by a connective thin water film that does not obscure the microstructures of the upper section. Under these conditions, a one-step fog collection mode is realized. Once captured by the IPHS, fog droplets immediately coalesce with the water film, and are simultaneously transported into a container under the effect of the liquid bridge. The LSFCS achieves a collection efficiency of 6.5 kg m-2 h-1, 2.3 times that of a system without a liquid bridge. This study offers insight on improving fog collection efficiency, and holds promise for condensation water collection or droplet manipulation.

Glutaminase potentiates the glycolysis in esophageal squamous cell carcinoma by interacting with PDK1.

Increasing evidence has demonstrated that glutaminase (GLS) as a key mitochondrial enzyme plays a pivotal role in glutaminolysis, which widely participates in glutamine metabolism serving as main energy sources and building blocks for tumor growth. However, the roles and molecular mechanisms of GLS in esophageal squamous cell carcinoma (ESCC) remains unknown. Here, we found that GLS was highly expressed in ESCC tissues and cells. GLS inhibitor CB-839 significantly suppressed cell proliferation, colony formation, migration and invasion of ESCC cells, whereas GLS overexpression displayed the opposite effects. In addition, CB-839 markedly suppressed glucose consumption and lactate production, coupled with the downregulation of glycolysis-related proteins HK2, PFKM, PKM2 and LDHA, whereas GLS overexpression exhibited the adverse results. In vivo animal experiment revealed that CB-839 dramatically suppressed tumor growth, whereas GLS overexpression promoted tumor growth in ESCC cells xenografted nude mice. Mechanistically, GLS was localized in mitochondria of ESCC cells, which interacted with PDK1 protein. CB-839 attenuated the interaction of GLS and PDK1 in ESCC cells by suppressing PDK1 expression, which further evoked the downregulation of p-PDHA1 (s293), however, GLS overexpression markedly enhanced the level of p-PDHA1 (s293). These findings suggest that interaction of GLS with PDK1 accelerates the glycolysis of ESCC cells by inactivating PDH enzyme, and thus targeting GLS may be a novel therapeutic approach for ESCC patients.

Mito-LND and (E)-Akt inhibitor-IV: novel compounds inducing endoplasmic reticulum stress and ROS accumulation against hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality. Although multi-kinase inhibitors can prolong the overall survival of late-stage HCC patients, the emergence of drug resistance diminishes these benefits, ultimately resulting in treatment failure. Therefore, there is an urgent need for novel and effective drugs to impede the progression of liver cancer. METHODS: This study employed a concentration gradient increment method to establish acquired sorafenib or regorafenib-resistant SNU-449 cells. Cell viability was assessed using the cell counting kit-8 assay. A library of 793 bioactive small molecules related to metabolism screened compounds targeting both parental and drug-resistant cells. The screened compounds will be added to both the HCC parental cells and the drug-resistant cells, followed by a comprehensive assessment. Intracellular adenosine triphosphate (ATP) levels were quantified using kits. Flow cytometry was applied to assess cell apoptosis and reactive oxygen species (ROS). Real-time quantitative PCR studied relative gene expression, and western blot analysis assessed protein expression changes in HCC parental and drug-resistant cells. A xenograft model in vivo evaluated Mito-LND and (E)-Akt inhibitor-IV effects on liver tumors, with hematoxylin and eosin staining for tissue structure and immunohistochemistry staining for endoplasmic reticulum stress protein expression. RESULTS: From the compound library, we screened out two novel compounds, Mito-LND and (E)-Akt inhibitor-IV, which could potently kill both parental cells and drug-resistant cells. Mito-LND could significantly suppress proliferation and induce apoptosis in HCC parental and drug-resistant cells by upregulating glycolytic intermediates and downregulating those of the tricarboxylic acid (TCA) cycle, thereby decreasing ATP production and increasing ROS. (E)-Akt inhibitor-IV achieved comparable results by reducing glycolytic intermediates, increasing TCA cycle intermediates, and decreasing ATP synthesis and ROS levels. Both compounds trigger apoptosis in HCC cells through the interplay of the AMPK/MAPK pathway and the endoplasmic reticulum stress response. In vivo assays also showed that these two compounds could significantly inhibit the growth of HCC cells and induce endoplasmic reticulum stress. CONCLUSION: Through high throughput screening, we identified that Mito-LND and (E)-Akt inhibitor-IV are two novel compounds against both parental and drug-resistant HCC cells, which could offer new strategies for HCC patients.

Single-crystalline van der Waals layered dielectric with high dielectric constant.

The scaling of silicon-based transistors at sub-ten-nanometre technology nodes faces challenges such as interface imperfection and gate current leakage for an ultrathin silicon channel1,2. For next-generation nanoelectronics, high-mobility two-dimensional (2D) layered semiconductors with an atomic thickness and dangling-bond-free surfaces are expected as channel materials to achieve smaller channel sizes, less interfacial scattering and more efficient gate-field penetration1,2. However, further progress towards 2D electronics is hindered by factors such as the lack of a high dielectric constant (κ) dielectric with an atomically flat and dangling-bond-free surface3,4. Here, we report a facile synthesis of a single-crystalline high-κ (κ of roughly 16.5) van der Waals layered dielectric Bi2SeO5. The centimetre-scale single crystal of Bi2SeO5 can be efficiently exfoliated to an atomically flat nanosheet as large as 250 × 200 µm2 and as thin as monolayer. With these Bi2SeO5 nanosheets as dielectric and encapsulation layers, 2D materials such as Bi2O2Se, MoS2 and graphene show improved electronic performances. For example, in 2D Bi2O2Se, the quantum Hall effect is observed and the carrier mobility reaches 470,000 cm2 V-1 s-1 at 1.8 K. Our finding expands the realm of dielectric and opens up a new possibility for lowering the gate voltage and power consumption in 2D electronics and integrated circuits.

Light-Response Bric-A-Brack/Tramtrack/Broad proteins mediate cryptochrome 2 degradation in response to low ambient temperature.

Cryptochromes (crys) are photolyase-like blue-light receptors first discovered in Arabidopsis thaliana and later identified in all major evolutionary lineages. Crys are involved in not only blue light responses but also in temperature responses; however, whether and how cry protein stability is regulated by temperature remains unknown. Here, we show that cry2 protein abundance is modulated by ambient temperature and cry2 protein is degraded under low ambient temperature via the 26S proteasome. Consistent with this, cry2 shows high levels of ubiquitination under low ambient temperatures. Interestingly, cry2 degradation at low ambient temperatures occurs only under blue light and not under red light or dark conditions, indicating blue-light-dependent degradation of cry2 at low ambient temperature. Furthermore, low ambient temperature promotes physical interaction of Light-Response Bric-a-Brack/Tramtrack/Broad (LRB) proteins with cry2 to modulate its ubiquitination and protein stability in response to ambient temperature. LRBs promote high-temperature-induced hypocotyl elongation by modulating the protein stability of cry2 protein. These results indicate that cry2 accumulation is regulated by not only blue light but also ambient temperature, and LRBs are responsible for cry2 degradation at low ambient temperature. The stabilization of cry2 by high temperature makes cry2 a better negative regulator of temperature responses.

The CRY2-COP1-HY5-BBX7/8 module regulates blue light-dependent cold acclimation in Arabidopsis.

Light and temperature are two key environmental factors that coordinately regulate plant growth and development. Although the mechanisms that integrate signaling mediated by cold and red light have been unraveled, the roles of the blue light photoreceptors cryptochromes in plant responses to cold remain unclear. In this study, we demonstrate that the CRYPTOCHROME2 (CRY2)-COP1-HY5-BBX7/8 module regulates blue light-dependent cold acclimation in Arabidopsis thaliana. We show that phosphorylated forms of CRY2 induced by blue light are stabilized by cold stress and that cold-stabilized CRY2 competes with the transcription factor HY5 to attenuate the HY5-COP1 interaction, thereby allowing HY5 to accumulate at cold temperatures. Furthermore, our data demonstrate that B-BOX DOMAIN PROTEIN7 (BBX7) and BBX8 function as direct HY5 targets that positively regulate freezing tolerance by modulating the expression of a set of cold-responsive genes, which mainly occurs independently of the C-repeat-binding factor pathway. Our study uncovers a mechanistic framework by which CRY2-mediated blue-light signaling enhances freezing tolerance, shedding light on the molecular mechanisms underlying the crosstalk between cold and light signaling pathways in plants.

Hybrid Membrane Composed of Nickel Diselenide Nanosheets with Carbon Nanotubes for Catalytic Conversion of Polysulfides in Lithium-Sulfur Batteries.

Lithium-sulfur batteries demonstrate enormous energy density are promising forms of energy storage. Unfortunately, the slow redox kinetics and polysulfides shuttle effect are some of the factors that prevent the its development. To address these issues, the hybrid membrane with combination of nickel diselenide nanosheets modified carbon nanotubes (NSN@CNTs) and utilized Li2 S6 catholyte for lithium sulfur battery. The conductive CNTs facilitates fast electronic/ionic transport, while the polarity of NSN as a strong affinity to lithium polysulfides, effectively anchoring them, facilitating the redox conversion of polysulfide species, and effectively diminishing reaction barriers. The cell with NSN@CNTs delivers the first discharge capacity of 1123.8 mAh g-1 and maintains 786.5 mAh g-1 after 300 cycles (0.2 C) at the sulfur loading 5.4 mg. Its rate capability is commendable, enabling it to sustain a capacity of 559.8 mAh g-1 even at a high discharge rate of 2 C. In addition, its initial discharge capacity can remain 8.33 mAh even at 10.8 mg for duration of 100 cycles. This research indicates the potential application of NSN@CNTs hybrid materials in lithium-sulfur batteries.

Identification of benzothiazoles as novel PCSK9 inhibitors.

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a clinically validated target on the treatment of cardiovascular disease (CVD). PCSK9 can regulate the hepatocyte surface low density lipoprotein receptor (LDLR) level by binding to LDLR and leading to their degradation in the lysosome. The clinical use of two monoclonal antibodies (alirocumab and evolocumab, approved in 2015) and one small interfering RNA (inclisiran, approved in 2020) which can inhibit PCSK9 function proved that they are very effective in lowering low density lipoprotein cholesterol (LDL-C). However, the high treatment costs and parenteral administration of these drugs prohibited widespread use and reduced their long-term advantage. Comparatively, small molecule drugs have many incomparable advantages of macromolecules, such as lower treatment cost, more drug administration options, superior pharmacokinetic properties, less adverse immunogenic responses and better affordable production. In this paper, we identified a series of benzothiazoles small molecule PCSK9 inhibitors through extensive screening. The structure and activity relationship (SAR) was summarized to facilitate further optimization. Moreover, the primary mechanism of action of the most potent compound was also investigated.

MicroRNA sequencing analysis reveals immune responses in hepatopancreas of Fenneropenaeus penicillatus under white spot syndrome virus infection.

White Spot Disease is one of the most harmful diseases of the red tail shrimp, which can cause devastating economic losses due to the highest mortality up to 100% within a few days. MicroRNAs (miRNAs) are large class of small noncoding RNAs with the ability to post-transcriptionally repress the translation of target mRNAs. MiRNAs are considered to have a significant role in the innate immune response of crustaceans, particularly in relation to antiviral defense mechanisms. Numerous crustacean miRNAs have been verified to be required in host immune defense against viral infection, however, till present, the miRNAs functions of F. penicillatus defense WSSV infection have not been studied yet. Here in this study, for the first time, miRNAs involved in the F. penicillatus immune defense against WSSV infection were identified using high-throughput sequencing platform. A total of 432 miRNAs were obtained including 402 conserved miRNAs and 30 novel predicted miRNAs. Comparative analysis between the WSSV-challenged group and the control group revealed differential expression of 159 microRNAs in response to WSSV infection. Among these, 48 were up-regulated and 111 were down-regulated. Ten candidate MicroRNAs associated with immune activities were randomly selected for qRT-PCR analysis, which confirming the expression profiling observed in the MicroRNA sequencing data. As a result, most differentially expressed miRNAs were down-regulated lead to increase the expression of various target genes that mediated immune reaction defense WSSV infection, including genes related to signal transduction, Complement and coagulation cascade, Phagocytosis, and Apoptosis. Furthermore, the genes expression of the key members in Toll and Imd signaling pathways and apoptotic signaling were mediated by microRNAs to activate host immune responses including apoptosis against WSSV infection. These results will help to understand molecular defense mechanism against WSSV infection in F. penicillatus and to develop an effective WSSV defensive strategy in shrimp farming.

PM2.5 regulates the progression of lung adenocarcinoma through the axis of HCG18, miR-195 and ATG14.

Relevant studies have indicated the association of HCG18 with tumour occurrence and progression. In this study, we observed that PM2.5 can enhance the growth of lung adenocarcinoma cells by modulating the expression of HCG18. Further investigations, including overexpression and knockout experiments, elucidated that HCG18 suppresses miR-195, which in turn upregulates the expression of ATG14, resulting in the upregulation of autophagy. Consequently, exposure to PM2.5 leads to elevated HCG18 expression in lung tissues, which in turn increases Atg14 expression and activates autophagy pathways through inhibition of miR-195, thereby contributing to oncogenesis.

Butyrate enhances erastin-induced ferroptosis of lung cancer cells via modulating the ATF3/SLC7A11 pathway.

Ferroptosis is a novel form of programmed cell death triggered by iron-dependent lipid peroxidation and has been associated with various diseases, including cancer. Erastin, an inhibitor of system Xc-, which plays a critical role in regulating ferroptosis, has been identified as an inducer of ferroptosis in cancer cells. In this study, we investigated the impact of butyrate, a short-chain fatty acid produced by gut microbiota, on erastin-induced ferroptosis in lung cancer cells. Our results demonstrated that butyrate significantly enhanced erastin-induced ferroptosis in lung cancer cells, as evidenced by increased lipid peroxidation and reduced expression of glutathione peroxidase 4 (GPX4). Mechanistically, we found that butyrate modulated the pathway involving activating transcription factor 3 (ATF3) and solute carrier family 7 member 11 (SLC7A11), leading to enhanced erastin-induced ferroptosis. Furthermore, partial reversal of the effect of butyrate on ferroptosis was observed upon knockdown of ATF3 or SLC7A11. Collectively, our findings indicate that butyrate enhances erastin-induced ferroptosis in lung cancer cells by modulating the ATF3/SLC7A11 pathway, suggesting its potential as a therapeutic agent for cancer treatment.