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Bitter taste receptors (TAS2Rs), a subfamily of G-protein coupled receptors (GPCRs) expressed orally and extraorally, elicit signaling in response to a large set of tastants. Among 25 functional TAS2Rs encoded in the human genome, TAS2R14 is the most promiscuous, and responds to hundreds of chemically diverse ligands. Here we present the cryo-electron microscopy (cryo-EM) structure of the human TAS2R14 in complex with its signaling partner gustducin, and bound to flufenamic acid (FFA), a clinically approved nonsteroidal anti-inflammatory drug. The structure reveals an unusual binding mode, where two copies of FFA are bound at distinct pockets: one at the canonical receptor site within the trans-membrane bundle, and the other in the intracellular facet, bridging the receptor with gustducin. Together with a pocket-specific BRET-based ligand binding assay, these results illuminate bitter taste signaling and provide tools for a site-targeted compound design., Competing Interests: Competing interests The authors declare no competing interests, (© 2024. The Author(s).)

The term supramolecular polymer has been applied to polymeric materials in which the individual units, i.e., building blocks-are bound to each other via noncovalent interactions, including electrostatic or hydrogen bonding, as well as metal-ligand conjugation. The building blocks are generally low molecular weight amphiphiles. Methods for preparing biopolymers based on non-toxic, metal-ligand conjugation have been little studied; however, they offer significant potential for tuning the response of biologically relevant macromolecules. In this communication, we characterize the assembly and morphology of supramolecular biopolymers in which the building blocks are low- or medium-molecular weight globular proteins-ubiquitin and Cas9-interacting via metal-ligand conjugation. In each case, the protein gene was expressed in cell culture with the addition of hexa-His/linkers at both the N and C termini. Divalent cations investigated were Zn 2+ and Ni 2+ . We observe in cryo-TEM imaging an absolute requirement for divalent cations for the formation of supramolecular biopolymers. In the presence of Ni 2+ , 1D assembled fibers are predominant, while with Zn 2+ , the more frequently detected structures are sheet-like. We use gel electrophoresis and CD spectroscopy to monitor possible secondary and tertiary structural changes in the protein building blocks during conjugation., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Long-term outcomes of rituximab-treated adult patients with podocytopathies (either minimal change disease or focal segmental glomerulosclerosis) are largely unknown., Methods: A retrospective study at 30 nephrology departments from 15 countries worldwide included rituximab-treated adults with primary podocytopathies and a minimum clinical follow-up of 36 months. The primary outcome was relapse-free survival at 36 months., Results: 183 adult patients (n=64 with focal segmental glomerulosclerosis and n=119 with minimal change disease) with difficult-to-treat nephrotic syndrome (68% steroid-dependent/frequently relapsing, 22% steroid-resistant, 85% previously treated with two or more lines of immunosuppressive therapy) were treated with rituximab as part of a remission induction regimen. Complete or partial remission at 6 months after rituximab treatment was achieved in 82%. Eighty-three of 151 (55%) initial responders achieved long-term relapse-free survival over three years. Maintenance therapy with rituximab was associated with a better relapse-free survival (HR 2.05, 95% CI: 1.07-3.91), irrespective of the dosing regimen. At 36 months, 61% of initial responders receiving maintenance therapy with rituximab achieved long-term relapse-free survival and withdrawal of all concomitant immunosuppressive medication compared to 36% of patients without maintenance treatment (OR 2.69, 95% CI: 1.27-5.73). Relapses per year were reduced from an annual relapse rate of 1.0 (95% CI: 1.0-1.7) before to 0.17 (95% CI: 0.00-0.24) relapses/year after rituximab initiation. Over the 36 months of follow-up, a stable course of estimated glomerular filtration rate (eGFR) was observed in those who initially responded with either complete or partial remission, whereas non-responders experienced a reduction in eGFR reaching -11 (95% CI: -18 to -8) mL/min/1.73m2 ., Conclusions: Rituximab facilitated achievement of initial and long-term response in a majority of adult patients with difficult-to-treat podocytopathies. Maintenance treatment with rituximab further associated with long-term relapse-free survival over three years. Non-response to initial rituximab treatment was associated with poor kidney prognosis., (Copyright © 2024 by the American Society of Nephrology.)