Search

Abstract The HIV-1 entry inhibitor temsavir prevents the viral receptor CD4 (cluster of differentiation 4) from interacting with the envelope glycoprotein (Env) and blocks its conformational changes. To do this, temsavir relies on the presence of a residue with small side chain at position 375 in Env and is unable to neutralize viral strains like CRF01_AE carrying His375. Here we investigate the mechanism of temsavir resistance and show that residue 375 is not the sole determinant of resistance. At least six additional residues within the gp120 inner domain layers, including five distant from the drug-binding pocket, contribute to resistance. A detailed structure-function analysis using engineered viruses and soluble trimer variants reveals that the molecular basis of resistance is mediated by crosstalk between His375 and the inner domain layers. Furthermore, our data confirm that temsavir can adjust its binding mode to accommodate changes in Env conformation, a property that likely contributes to its broad antiviral activity.

The human GABAB receptor-a member of the class C family of G-protein-coupled receptors (GPCRs)-mediates inhibitory neurotransmission and has been implicated in epilepsy, pain and addiction1. A unique GPCR that is known to require heterodimerization for function2-6, the GABAB receptor has two subunits, GABAB1 and GABAB2, that are structurally homologous but perform distinct and complementary functions. GABAB1 recognizes orthosteric ligands7,8, while GABAB2 couples with G proteins9-14. Each subunit is characterized by an extracellular Venus flytrap (VFT) module, a descending peptide linker, a seven-helix transmembrane domain and a cytoplasmic tail15. Although the VFT heterodimer structure has been resolved16, the structure of the full-length receptor and its transmembrane signalling mechanism remain unknown. Here we present a near full-length structure of the GABAB receptor, captured in an inactive state by cryo-electron microscopy. Our structure reveals several ligands that preassociate with the receptor, including two large endogenous phospholipids that are embedded within the transmembrane domains to maintain receptor integrity and modulate receptor function. We also identify a previously unknown heterodimer interface between transmembrane helices 3 and 5 of both subunits, which serves as a signature of the inactive conformation. A unique 'intersubunit latch' within this transmembrane interface maintains the inactive state, and its disruption leads to constitutive receptor activity.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Mutations in the retinal protein retinoschisin (RS1) cause progressive loss of vision in young males, a form of macular degeneration called X-linked retinoschisis (XLRS). We previously solved the structure of RS1, a 16-mer composed of paired back-to-back octameric rings. Here, we show by cryo-electron microscopy that RS1 16-mers can assemble into extensive branched networks. We classified the different configurations, finding four types of interaction between the RS1 molecules. The predominant configuration is a linear strand with a wavy appearance. Three less frequent types constitute the branch points of the network. In all cases, the "spikes" around the periphery of the double rings are involved in these interactions. In the linear strand, a loop (usually referred to as spike 1) occurs on both sides of the interface between neighboring molecules. Mutations in this loop suppress secretion, indicating the possibility of intracellular higher-order assembly. These observations suggest that branched networks of RS1 may play a stabilizing role in maintaining the integrity of the retina.

Summary: Neutralizing antibodies (NAbs) hold great promise for clinical interventions against SARS-CoV-2 variants of concern (VOCs). Understanding NAb epitope-dependent antiviral mechanisms is crucial for developing vaccines and therapeutics against VOCs. Here we characterized two potent NAbs, EH3 and EH8, isolated from an unvaccinated pediatric patient with exceptional plasma neutralization activity. EH3 and EH8 cross-neutralize the early VOCs and mediate strong Fc-dependent effector activity in vitro. Structural analyses of EH3 and EH8 in complex with the receptor-binding domain (RBD) revealed the molecular determinants of the epitope-driven protection and VOC evasion. While EH3 represents the prevalent IGHV3-53 NAb whose epitope substantially overlaps with the ACE2 binding site, EH8 recognizes a narrow epitope exposed in both RBD-up and RBD-down conformations. When tested in vivo, a single-dose prophylactic administration of EH3 fully protected stringent K18-hACE2 mice from lethal challenge with Delta VOC. Our study demonstrates that protective NAbs responses converge in pediatric and adult SARS-CoV-2 patients.

Renewable energy production is necessary to mitigate climate change, however, generating the required technologies and infrastructure will demand huge production increases of many metals. Here, the authors map mining areas and assess spatial coincidence with biodiversity conservation sites, and show that new mining threats to biodiversity may surpass those averted by climate change mitigation.

As low-carbon energy technologies advance, markets are driving demand for energy transition metals, increasing the stress placed on people and the environment in extractive locations. Here, the authors quantify this stress by developing a set of global composite environmental, social and governance risk indicators, and find that 84% of platinum resources and 70% of cobalt resources are located in high-risk contexts.

Objective: To synthesize evidence for the effectiveness of self-management interventions for chronic health conditions that have symptom overlap with traumatic brain injury (TBI) in order to extract recommendations for self-management intervention in persons with TBI. Design: An umbrella review of existing systematic reviews and/or meta-analyses of randomized controlled trials or nonrandomized studies targeting self-management of chronic conditions and specific outcomes relevant to persons with TBI. Method: A comprehensive literature search of 5 databases was conducted using PRISMA guidelines. Two independent reviewers conducted screening and data extraction using the Covidence web-based review platform. Qpality assessment was conducted using criteria adapted from the Assessing the Methodological Qpality of Systematic Reviews-2 (AMSTAR-2). Results: A total of26 reviews met the inclusion criteria, covering a range of chronic conditions and a range of outcomes. Seven reviews were of moderate or high quality and focused on self-management in persons with stroke, chronic pain, and psychiatric disorders with psychotic features. Self-management interventions were found to have positive effects on quality of life, self-efficacy, hope, reduction of disability, pain, relapse and rehospitalization rates, psychiatric symptoms, and occupational and social functioning. Conclusions: Findings are encouraging with regard to the effectiveness of sel fmanagement interventions in patients with symptoms similar to those of TBI. However, reviews did not address adaptation of self-management interventions for those with cognitive deficits or for populations with greater vulnerabilities, such as low education and older adults. Adaptations for TBI and its intersection with these special groups may be needed. [ABSTRACT FROM AUTHOR]

Objective: To conduct a scoping review of models of care for chronic disease management to identify potentially effective components for management of chronic traumatic brain injury (TBI). Methods: Information sources: Systematic searches of three databases (Ovid MEDLINE, Embase, and Cochrane Database of Systematic Reviews) from January 2010 to May 2021. Eligibility criteria: Systematic reviews and meta‐analyses reporting on the effectiveness of the Chronic Care Model (CCM), collaborative/integrated care, and other chronic disease management models. Data: Target diseases, model components used (n = 11), and six outcomes (disease‐specific, generic health‐related quality of life and functioning, adherence, health knowledge, patient satisfaction, and cost/health care use). Synthesis: Narrative synthesis, including proportion of reviews documenting outcome benefits. Results: More than half (55%) of the 186 eligible reviews focused on collaborative/integrated care models, with 25% focusing on CCM and 20% focusing on other chronic disease management models. The most common health conditions were diabetes (n = 22), depression (n = 16), heart disease (n = 12), aging (n = 11), and kidney disease (n = 8). Other single medical conditions were the focus of 22 reviews, multiple medical conditions of 59 reviews, and other or mixed mental health/behavioral conditions of 20 reviews. Some type of quality rating for individual studies was conducted in 126 (68%) of the reviews. Of reviews that assessed particular outcomes, 80% reported disease‐specific benefits, and 57% to 72% reported benefits for the other five types of outcomes. Outcomes did not differ by the model category, number or type of components, or target disease. Conclusions: Although there is a paucity of evidence for TBI per se, care model components proven effective for other chronic diseases may be adaptable for chronic TBI care. [ABSTRACT FROM AUTHOR]

Plasmodium vivax is the most widely distributed malaria parasite that infects humans.sup.1. P. vivax invades reticulocytes exclusively, and successful entry depends on specific interactions between the P. vivax reticulocyte-binding protein 2b (PvRBP2b) and transferrin receptor 1 (TfR1).sup.2. TfR1-deficient erythroid cells are refractory to invasion by P. vivax, and anti-PvRBP2b monoclonal antibodies inhibit reticulocyte binding and block P. vivax invasion in field isolates.sup.2. Here we report a high-resolution cryo-electron microscopy structure of a ternary complex of PvRBP2b bound to human TfR1 and transferrin, at 3.7 Å resolution. Mutational analyses show that PvRBP2b residues involved in complex formation are conserved; this suggests that antigens could be designed that act across P. vivax strains. Functional analyses of TfR1 highlight how P. vivax hijacks TfR1, an essential housekeeping protein, by binding to sites that govern host specificity, without affecting its cellular function of transporting iron. Crystal and solution structures of PvRBP2b in complex with antibody fragments characterize the inhibitory epitopes. Our results establish a structural framework for understanding how P. vivax reticulocyte-binding protein engages its receptor and the molecular mechanism of inhibitory monoclonal antibodies, providing important information for the design of novel vaccine candidates. Structural studies show that conserved residues in Plasmodium vivax reticulocyte-binding protein 2b determine interactions with transferrin receptor 1 that are essential for host invasion, suggesting avenues for designing vaccines that work across P. vivax strains., Author(s): Jakub Gruszczyk [sup.1] , Rick K. Huang [sup.2] , Li-Jin Chan [sup.1] [sup.3] , Sébastien Menant [sup.1] , Chuan Hong [sup.2] , James M. Murphy [sup.1] [sup.3] , Yee-Foong [...]