An African-specific haplotype in MRGPRX4 is associated with menthol cigarette smoking

In the U.S., more than 80% of African-American smokers use mentholated cigarettes, compared to less than 30% of Caucasian smokers. The reasons for these differences are not well understood. To determine if genetic variation contributes to mentholated cigarette smoking, we performed an exome-wide association analysis in a multiethnic population-based sample from Dallas, TX (N = 561). Findings were replicated in an independent cohort of African Americans from Washington, DC (N = 741). We identified a haplotype of MRGPRX4 (composed of rs7102322[G], encoding N245S, and rs61733596[G], T43T), that was associated with a 5-to-8 fold increase in the odds of menthol cigarette smoking. The variants are present solely in persons of African ancestry. Functional studies indicated that the variant G protein-coupled receptor encoded by MRGPRX4 displays reduced agonism in both arrestin-based and G protein-based assays, and alteration of agonism by menthol. These data indicate that genetic variation in MRGPRX4 contributes to inter-individual and inter-ethnic differences in the preference for mentholated cigarettes, and that the existence of genetic factors predisposing vulnerable populations to mentholated cigarette smoking can inform tobacco control and public health policies

VEGAS as a Platform for Facile Directed Evolution in Mammalian Cells

Directed evolution, artificial selection toward designed objectives, is routinely used to develop new molecular tools and therapeutics. Successful directed molecular evolution campaigns repeatedly test diverse sequences with a designed selective pressure. Unicellular organisms and their viral pathogens are exceptional for this purpose and have been used for decades. However, many desirable targets of directed evolution perform poorly or unnaturally in unicellular backgrounds. Here, we present a system for facile directed evolution in mammalian cells. Using the RNA alphavirus Sindbis as a vector for heredity and diversity, we achieved 24-h selection cycles surpassing 10−3 mutations per base. Selection is achieved through genetically actuated sequences internal to the host cell, thus the system's name: viral evolution of genetically actuating sequences, or “VEGAS.” Using VEGAS, we evolve transcription factors, GPCRs, and allosteric nanobodies toward functional signaling endpoints each in less than 1 weeks’ time. © 2019 Elsevier Inc.The VEGAS system is a platform for directed evolution, a method for engineering DNA sequences, in mammalian cells. The system is highly mutagenic, facile, and self-contained, requiring no in vitro handling during evolution cycles. As a result, robust evolution campaigns can be run within the context of a mammalian cell signaling environment. We perform three such campaigns as a proof-of-concept: evolving a transcription factor, a G-protein coupled receptor, and llama-derived nanobodies toward specific in vivo activities. © 2019 Elsevier Inc

Erratum: VEGAS as a Platform for Facile Directed Evolution in Mammalian Cells (Cell (2019) 178(3) (748–761.e17), (S0092867419306221), (10.1016/j.cell.2019.05.051))

(Cell 178, 748–761.e1–e17; July 25, 2019) In our recent article reporting a platform for directed evolution in mammalian cells, we inadvertently failed to cite a paper that also reports a method for evolving biomolecules in mammalian cells (Berman et al., 2018). We have corrected the online version of our paper to cite this work, and we apologize for the omission. © 2019 Elsevier Inc

Crystal Structure of an LSD-Bound Human Serotonin Receptor

SummaryThe prototypical hallucinogen LSD acts via serotonin receptors, and here we describe the crystal structure of LSD in complex with the human serotonin receptor 5-HT2B. The complex reveals conformational rearrangements to accommodate LSD, providing a structural explanation for the conformational selectivity of LSD's key diethylamide moiety. LSD dissociates exceptionally slow from both 5-HT2BR and 5-HT2AR—a major target for its psychoactivity. Molecular dynamics (MD) simulations suggest that LSD's slow binding kinetics may be due to a "lid" formed by extracellular loop 2 (EL2) at the entrance to the binding pocket. A mutation predicted to increase the mobility of this lid greatly accelerates LSD's binding kinetics and selectively dampens LSD-mediated β-arrestin2 recruitment. This study thus reveals an unexpected binding mode of LSD; illuminates key features of its kinetics, stereochemistry, and signaling; and provides a molecular explanation for LSD's actions at human serotonin receptors.PaperCli

PRESTO-Tango as an open-source resource for interrogation of the druggable human GPCRome

G protein-coupled receptors (GPCRs) are essential mediators of cellular signaling and important targets of drug action. Of the approximately 350 non-olfactory human GPCRs, more than 100 are still considered “orphans” as their endogenous ligand(s) remain unknown. Here, we describe a unique open-source resource that provides the capacity to interrogate the druggable human GPCR-ome via a G protein-independent β-arrestin recruitment assay. We validate this unique platform at more than 120 non-orphan human GPCR targets, demonstrate its utility for discovering new ligands for orphan human GPCRs, and describe a method (PRESTO-TANGO; Parallel Receptor-ome Expression and Screening via Transcriptional Output - TANGO) for the simultaneous and parallel interrogation of the entire human GPCR-ome

In silico design of novel probes for the atypical opioid receptor MRGPRX2

The primate-exclusive MRGPRX2 G protein-coupled receptor (GPCR) has been suggested to modulate pain and itch. Despite putative peptide and small molecule MRGPRX2 agonists, selective nanomolar potency probes have not yet been reported. To identify a MRGPRX2 probe, we first screened 5,695 small molecules and found many opioid compounds activated MRGPRX2, including (−)- and (+)-morphine, hydrocodone, sinomenine, dextromethorphan and the prodynorphin-derived peptides, dynorphin A, dynorphin B, and α- and β-neoendorphin. We used these to select for mutagenesis-validated homology models and docked almost 4 million small molecules. From this docking, we predicted ZINC-3573, which represents a potent MRGPRX2-selective agonist, showing little activity against 315 other GPCRs and 97 representative kinases, and an essentially inactive enantiomer. ZINC-3573 activates endogenous MRGPRX2 in a human mast cell line inducing degranulation and calcium release. MRGPRX2 is a unique atypical opioid-like receptor important for modulating mast cell degranulation, which can now be specifically modulated with ZINC-3573

Teacher Perspectives on Whole-Task Information Literacy Instruction

This paper presents results of an explorative study on perceived merits of contemporary holistic approaches to designing information literacy instruction in a university setting. Seven teachers in educational sciences evaluated their premaster’s course on conducting a literature review designed according to a modern design approach, named Four-Component Instructional Design (4C/ID). They noted their perceptions on course quality by means of a standardized course evaluation questionnaire and a SWOT analysis. Results of the questionnaire showed that teachers were positive on whole-task information literacy instruction, confirming the results of an earlier study on 4C/ID-caused instructional effects. The SWOT analysis indicated that teachers recognized the value of applied 4C/ID principles like whole-task-centeredness, structured guidance, and scaffolding. We added suggestions on enhancing the positive effects of whole-task instructional design based on identified educational weaknesses such as relatively poor constructive alignment and threats such as imperfect curriculum coherence

Emerging Themes and Future Directions of Multi-Sector Nexus Research and Implementation

Water, energy, and food are all essential components of human societies. Collectively, their respective resource systems are interconnected in what is called the “nexus”. There is growing consensus that a holistic understanding of the interdependencies and trade-offs between these sectors and other related systems is critical to solving many of the global challenges they present. While nexus research has grown exponentially since 2011, there is no unified, overarching approach, and the implementation of concepts remains hampered by the lack of clear case studies. Here, we present the results of a collaborative thought exercise involving 75 scientists and summarize them into 10 key recommendations covering: the most critical nexus issues of today, emerging themes, and where future efforts should be directed. We conclude that a nexus community of practice to promote open communication among researchers, to maintain and share standardized datasets, and to develop applied case studies will facilitate transparent comparisons of models and encourage the adoption of nexus approaches in practice

Eye gaze and visual attention as a window into leadership and followership: A review of empirical insights and future directions

Illuminating the nature of leadership and followership requires insights into not only how leaders and followers behave, but also the different cognitions that underpin these social relationships. We argue that the roots of leader and follower roles and status asymmetries often lie in basic mental processes such as attention and visual perception. To understand not only how but also why leaders' and followers’ behavioral patterns vary, we focus here on underpinning attentional processes that often drive rank-based behaviors. Methodologically, this focus on basic attentional and perceptual processes lessens the reliance on self-report and questionnaire-based data, and expands our scientific understanding to actual, real-world leadership dynamics. Here, we review the available evidence indicating that leaders and followers differ in whether and how they receive, direct, and pay visual attention. Our review brings together diverse empirical evidence from organization science, primatology, and social, developmental, and cognitive psychology on eye gaze, attention, and status in adults, children, and non-human primates. Based on this review of the cross-disciplinary literature, we propose future directions and research questions that this attention-based approach can generate for illuminating the puzzle of leadership and followership