β-Arrestins 1 and 2 are multifunctional adaptor proteins1 that regulate the signalling of G-protein-coupled receptors (GPCRs), the largest class of receptors, which impact nearly all aspects of physiology and are one of the most common drug targets2. Although β-arrestins interact with a wide array of signalling effectors at many GPCRs, it is unclear how β-arrestins promote such varied functions. Here we show that β-arrestins undergo liquid-liquid phase separation, forming condensates that regulate GPCR function. We show that condensation is specific to visual arrestins and β-arrestins, and demonstrate that β-arrestin oligomerization occurs in proximity to the GPCR to regulate GPCR functions such as internalization and signalling. Our work provides a paradigm for β-arrestin condensates as regulators of GPCR function, with liquid-liquid phase separation serving as an important promoter of signalling compartmentalization at GPCRs.

Dehydroepiandrosterone (DHEA), a steroid hormone critical to reproductive health, is widely used to improve outcomes in assisted reproductive technologies, though its molecular targets and mechanisms remain incompletely defined. In our previous studies, we identified DHEA as a ligand for the male reproductive-related receptor ADGRG2 and elucidated the recognition mechanism between DHEA and ADGRG2 using Cryo-EM structure of ADGRG2 in complex with DHEA and Gs. However, it remains unclear whether DHEA acts as a physiological ligand for ADGRG2 to regulate its functions. Using ADGRG2-deficient mice and in vitro reconstitution assays, we demonstrated that DHEA activated the Gs signaling pathways of ADGRG2 in efferent ductal cells, which facilitated synergistic coupling with cystic fibrosis transmembrane conduction regulator (CFTR) to regulate chlorine homeostasis. Strikingly, ADGRG2 is selectively expressed in X chromosome-bearing (X) sperm, where DHEA enhances motility via a Gs-cAMP signaling axis. This functional bias enables efficient enrichment of X sperm through DHEA-induced motility enhancement, achieving 80.5% XX embryos in in vitro fertilization (IVF). These findings reveal ADGRG2-dependent mechanisms underlying male reproductive physiology and position DHEA-ADGRG2 axis as a promising therapeutic target for precision management of infertility and sex-controlled reproductive technologies.

Traumatic spinal cord injury (SCI) is a debilitating condition characterized by the impairment of neural circuits, leading to the loss of motor and sensory functions and accompanied by severe complications. Substantial research has reported the therapeutic potential of Omega-3 fatty acids for the central nervous system, particularly after traumatic SCI. Omega-3 fatty acids may contribute to improving SCI recovery through their anti-inflammatory, anti-oxidative, neurotrophic, and membrane integrity-preserving properties. These functions of Omega-3 fatty acids are primarily mediated via the activation of G protein-coupled receptor 120 (GPR120), commonly known as the fish oil-specific receptor. Advancements in understanding of the molecular mechanisms of GPR120’s recognition of Omega-3 fatty acids and its downstream signaling mechanisms has significantly promoted research on the pharmacological potential of Omega-3 fatty acids and the development of highly selective and high-affinity alternatives. This review aims to provide in-depth analysis of the comprehensive therapeutic potential of Omega-3 fatty acids for SCI and its accompanying complications, and the prospects for developing novel drugs based on the recognition of Omega-3 fatty acids by GPR120.

Blockade of signaling through the angiotensin II type 1 receptor (AT1R), a prototypical G protein-coupled receptor (GPCR), by angiotensin receptor blockers (ARBs) is a major therapeutic approach to treating a wide variety of cardiovascular and renal diseases 1 . Like most GPCRs, the AT1R signals through two transducers, G proteins and β-arrestins 2,3 . Previous reports have described β-arrestin-biased peptide orthosteric agonists for the AT1R with potential therapeutic advantages over currently available unbiased ARBs 4-6 . Here we report the DNA- encoded library screening-guided isolation and pharmacological characterization of the first small molecule AT1R allosteric ligands. We use cryo-electron microscopy, double electron- electron resonance spectroscopy, molecular dynamics simulations, and targeted mutagenesis to determine their binding sites, binding modes and conformational mechanisms driving their unique and divergent modulatory effects on G protein and β-arrestin pathways. Our findings uncover new mechanisms for precisely controlling the dynamic behavior of the AT1R with implications for drug development targeting this pathophysiologically important receptor family.

Adhesion G protein-coupled receptor GPR133 participates extensively in bone development, skeletal muscle function regulation, and the malignant progression of glioma. This receptor is activated through a Stachel sequence-dependent mechanism and mediates downstream Gs signaling. However, the evolutionary conservation of this activation mechanism and its structural basis remain unclear, particularly in basal organisms. Here, we show that GPR133 from the cephalochordate Branchiostoma lanceolatum and the mollusk Mytilus coruscus exhibits constitutive Gs signaling activity. We further determined the cryo-EM structures of Branchiostoma lanceolatum GPR133-Gs complex and Mytilus coruscus GPR133-Gs complexes at resolutions of 2.92 Å and 2.71 Å, respectively. Cross-species structural comparisons reveal differences in the Stachel binding pocket, overall conformation and Gs coupling interface, providing structural insights into the evolutionary conservation and diversification of Stachel-dependent activation in aGPCRs.

Adhesion G-protein-coupled receptors (aGPCRs) are essential membrane proteins that contribute to diverse human pathologies, including cancer, psychiatric disorders and autoimmune diseases. A defining feature of these receptors is the large N terminus including the GPCR autoproteolysis-inducing domain, which mediates autoproteolysis and enables complex modes of activation through both cis and trans signalling. Recent breakthroughs in structural biology, in particular, cryogenic electron microscopy structures of aGPCRs, have transformed our understanding of receptor activation and facilitated development of small-molecule agonists and antibody-based strategies, which hold considerable promise for therapeutic intervention. In this Review, we summarize the roles of aGPCRs in human disease and in phenotypes characterized in animal models. We consolidate current insights into aGPCR structure-function relationships, highlight how distinct activation mechanisms are already being harnessed to modulate receptor activity in vitro and in vivo, and discuss how these principles could be leveraged for future therapeutic targeting.

Photodynamic therapy (PDT) is a minimally invasive cancer treatment modality with high spatial selectivity, whose therapeutic efficacy is largely governed by the photosensitizer's tissue penetration, singlet oxygen generation, and target specificity. In recent years, RNA has emerged as an attractive alternative target for PDT owing to its distinctive structural and biological features. In many cancers, ribosome biogenesis and nucleolar activity are markedly upregulated, leading to the accumulation of RNA species that are structurally exposed, highly abundant, and intrinsically susceptible to oxidative damage, thereby rendering RNA an efficient and accessible photodynamic target. RNA-targeted PDT enables selective photodamage without inducing permanent genomic lesions, reducing mutagenic risk while allowing light-triggered RNA degradation and precise spatiotemporal control of protein translation and cellular function. Moreover, unlike DNA damage, which can be partially repaired, oxidatively damaged RNA is typically eliminated through degradation rather than repair, enabling RNA-targeted PDT to circumvent repair-mediated resistance and achieve sustained cytotoxic effects. This Review summarizes recent advances in the molecular design of RNA-targeted photosensitizers, highlights their photophysical and biological mechanisms of action, and discusses the challenges and future opportunities for translating RNA-targeted PDT into clinical cancer therapy.

BACKGROUND:The causal relationship between PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm) and common mental disorders, along with its neuropathological mechanisms, remains unclear. METHODS:We used genome-wide association study datasets from the UK Biobank and Psychiatric Genomics Consortium to systematically investigate the causal relationship between PM2.5 and nine common psychiatric disorders using two-sample Mendelian randomization (TSMR) methods. Subsequently, we used two-step MR to investigate the mediating effect of 108 potential mediators in the association between PM2.5 and mental disorders. RESULTS:Our findings indicated that PM2.5 was positively associated with major depressive disorder (odds ratio (OR): 1.33, 95 % confidence interval (CI): 1.11-1.55), anxiety disorder (OR: 2.96, 95 % CI: 2.13-3.79), schizophrenia (OR: 1.55, 95 % CI: 1.29-1.81), and attention deficit hyperactivity disorder (ADHD) (OR: 1.95, 95 % CI: 1.66-2.24). Unexpectedly, PM2.5 was inversely associated with bipolar disorder (OR: 0.65, 95 % CI: 0.37-0.93). Additionally, PM2.5 was not significantly associated with autism spectrum disorders (OR: 1.24, 95 % CI: 0.83-1.65), post-traumatic stress disorder (OR: 1.51, 95 % CI: 1.11-1.91), obsessive-compulsive disorder (OR: 0.81, 95 % CI: -0.07-1.69), or anorexia nervosa (OR: 1.42, 95 % CI: 0.86-1.98). Further analysis using two-step MR revealed that Neurotrophin-3 mediated 9.86 % of the PM2.5-ADHD association and 5.88 % of the PM2.5-schizophrenia association. Sensitivity analyses supported these findings. CONCLUSIONS:This TSMR analysis provides a comprehensive examination of the causal relationship between PM2.5 exposure and nine common psychiatric disorders, with mediation analysis offering insight into the underlying mechanisms. This study aims to raise public awareness of how air quality affects mental health through empirical evidence.

Expressed in the entorhinal cortex (EC), the cholecystokinin (CCK) B receptor (CCKBR) plays an important role in memory and learning. Here, we identify that CCKBR-Gs and -Gq signaling, rather than CCKBR-Gi signaling, are beneficial for Alzheimer's disease (AD) treatment. Clinically, patients with more severe AD associated with lower CCKBR-Gq activity. The cryo-electron microscopy (cryo-EM) structures of CCKBR in complex with the endogenous agonist sulfated CCK8 (CCK8s) and 3 different G protein subtypes revealed that distinct receptor conformations contribute to selective G protein bias. Leveraging these structural insights, we rationally develop synthetic CCKBR agonists, including a Gi-biased agonist (z-44) and a Gq-biased agonist (3r1). Notably, 3r1 demonstrates therapeutic potential by ameliorating cognitive decline in 5×FAD mice, reducing the number of amyloid-β plaques, and promoting long-term potentiation (LTP) via upregulation of the α-secretase (ADAM10) and the calcium signaling molecule PLCB4. Our findings suggest that synthetic biased agonists targeting CCKBR-Gq signaling have therapeutic potential for AD.

GPR133 is an adhesion-class G protein-coupled receptor (GPCR) that has recently been de-orphanized. Its functions are complex and multifaceted. While GPR133 is primarily recognized for coupling with the Gs subunit to mediate elevated intracellular cAMP levels, its potential engagement with alternative signaling pathways remains poorly characterized. In our experiments, we demonstrated that GPR133 exhibits constitutive self-activation via its Stachel sequence as an adhesion GPCR, enabling activation of downstream G13 signaling. We reconstituted the GPR133-GAIN-miniGα13 complex in vitro and resolved its cryo-electron microscopy structure at a resolution of 3.51 Å. Detailed structural comparisons between the GPR133-GAIN-miniGα13 complex and the previously resolved GPR133-CTF-Gs structure highlighted both conserved and different features. These findings provide critical insights into the signal transduction mechanisms of GPR133 and lay a foundation for targeted therapeutic strategies.

As a critical subfamily of G protein-coupled receptors (GPCRs), chemokine receptors (CCRs) play pivotal regulatory roles in immune cell migration, inflammatory modulation, tissue regeneration, and tumor microenvironment (TME) remodeling. By specifically recognizing chemokine ligands, CCRs orchestrate immune cell trafficking and tissue positioning, with functional dysregulation implicated in infectious diseases, autoimmune disorders, neurodegenerative pathologies, and cancer. These receptors thus represent promising therapeutic targets. Recent breakthroughs in cryo-electron microscopy (cryo-EM) and computational chemistry have enabled high-resolution structural analysis and dynamic conformational modeling of CCRs, establishing a robust foundation for structure-based drug design (SBDD). This review synthesizes current advances in CCR biology, structural mechanisms, disease involvement, and targeted drug development, providing theoretical insights and technical frameworks for future research.

Allosteric modulation of receptor responses to endogenous agonists has therapeutic value, maintaining ligand profiles, reducing side effects and restoring mutant responses. Adhesion G-protein-coupled receptors (aGPCRs), with large N termini, are ideal for allosteric modulator development. We designed a nanobody strategy targeting ADGRG2 N-terminal fragments and got a specific nanobody Nb23-bi, which promoted dehydroepiandrosterone (DHEA)-induced ADGRG2 activation and reversed mutant-induced dysfunctions. By combining structural characterization, crosslinking mass spectrometry, mutational analysis and molecular dynamics simulations, we clarified the allosteric mechanism of how the Nb23-bi modulates conformational changes in the DHEA-binding pocket. Animal studies showed that Nb23-bi promoted the response of DHEA in alleviating testicular inflammation and reversing mutant defects. In summary, we developed an allosteric nanobody of ADGRG2 and gained insights into its functions in reversing disease-associated dysfunctions. Our study may serve as a template for developing allosteric modulators of other aGPCRs for biological and therapeutic purposes.

G protein-coupled receptors (GPCRs) are the largest class of receptors in the genome and control many signaling cascades essential for survival. GPCR signaling is regulated by β-arrestins, multifunctional adapter proteins that direct receptor desensitization, internalization, and signaling. While at many GPCRs, β-arrestins interact with a wide array of signaling effectors, it is unclear how β-arrestins promote such varied functions. Here we show that β-arrestins undergo liquid-liquid phase separation (LLPS) to form condensates that regulate GPCR function. We demonstrate that β-arrestin oligomerization occurs in proximity to the GPCR and regulates GPCR functions such as internalization and signaling. This model is supported by a cryoEM structure of the adhesion receptor ADGRE1 in a 2:2 complex with β-arrestin 1, with a β-arrestin orientation that can promote oligomerization. Our work provides a paradigm for β-arrestin condensates as regulators of GPCR function, with LLPS serving as an important promoter of signaling compartmentalization at GPCRs.

Malaria caused by Plasmodium falciparum remains a public health issue, yet direct targets of antimalarial drugs remain elusive. Membrane proteins in Plasmodium are potential drug targets and may contribute to pathophysiological processes in malaria. Recent studies show that the serpentine receptor SR10 is essential for coordinating host rhythms during parasite development. In this study, we found that antimalarial drugs including chloroquine (CQ), dihydroartemisinin (DHA), piperaquine-tetraphosphatetetrahydrate (PIP-TT), and primaquine diphosphate (PQ) are PfSR10 agonists that induce coupling with human Gi/Gq proteins, confirmed through biochemical reconstitution and cryo-EM analysis. Using proteomic profiling, we also identified bradykinin as an endogenous agonist activating PfSR10. Ligand binding and conformational changes were characterized via mutagenesis and FlAsH-BRET assays. These results establish PfSR10 as a receptor for both antimalarials and host peptides, highlighting its dual role in drug action and host-parasite communication, with broad implications in understanding malaria pathogenesis and developing new therapeutics.

Androgens, such as 5α-dihydrotestosterone (5α-DHT), regulate numerous functions by binding to nuclear androgen receptors (ARs) and potential unknown membrane receptors. Here, we report that the androgen 5α-DHT activates membrane receptor GPR133 in muscle cells, thereby increasing intracellular cyclic AMP (cAMP) levels and enhancing muscle strength. Further cryoelectron microscopy (cryo-EM) structural analysis of GPR133-Gs in complex with 5α-DHT or its derivative methenolone (MET) reveals the structural basis for androgen recognition. Notably, the presence of the “Φ(F/L)2.64-F3.40-W6.53” and the “F7.42××N/D7.46” motifs, which recognize the hydrophobic steroid core and polar groups, respectively, are common in adhesion GPCRs (aGPCRs), suggesting that many aGPCRs may recognize different steroid hormones. Finally, we exploited in silico screening methods to identify a small molecule, AP503, which activates GPR133 and separates the beneficial muscle-strengthening effects from side effects mediated by AR. Thus, GPR133 represents an androgen membrane receptor that contributes to normal androgen physiology and has important therapeutic potentials.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with few effective targeted therapies. Taxanes and other microtubule-targeting agents (MTA) are first-line chemotherapies for TNBC; however, the molecular mechanisms that underlie TNBC taxane sensitivity are largely unknown, preventing selection of taxane-responsive patients and development of more selective therapeutic strategies. In this study, we identified tumor-selective vulnerabilities in TNBC harboring inactivation of the tumor suppressor PTPN12 by integrating proteogenomic characterization and synthetic lethality screening. We discovered that PTPN12 inactivation drives mitotic defects through aberrant hyperactivation of the ubiquitin ligase complex APCFZR1, a critical regulator of the cell cycle. Consistent with the mitotic stress caused by PTPN12 inactivation in TNBC cell lines, tumors harboring loss of PTPN12 exhibit heightened sensitivity to taxane chemotherapy. Collectively, these data suggests that PTPN12 inactivation may drive chromosomal instability and favorable MTA response in TNBC-two prominent features of the disease with unclear mechanistic etiology. SIGNIFICANCE:Many TNBCs respond to MTAs, but the underlying cause(s) of this sensitivity remain poorly understood. Herein, we discover that the tumor suppressor PTPN12 regulates mitotic fidelity and MTA sensitivity in a large subset of patients with TNBC, which has significant implications for the use of MTAs in breast cancer.

The efficacy of photodynamic therapy (PDT) critically depends on the intrinsic properties of the employed photosensitizer (PS). Conventional PSs often suffer from an "always-on" characteristic, which leads to poor selectivity and undesirable phototoxicity in nontarget tissues. To address this limitation, activatable photosensitizers (aPSs) that respond selectively to disease-associated stimuli are highly desirable. Herein, we report a universal near-infrared (NIR) photosensitizing scaffold, Rho-I, for the construction of stimulus-responsive aPSs. Rho-I exhibits strong NIR absorption and high phototoxicity upon illumination, enabling efficient tumor ablation. Notably, its photodynamic activity can be effectively suppressed through phenolate donor caging. Leveraging this feature, we developed two aPSs, Rho-I-H 2 O 2 and Rho-I-ALP, which are specifically activated by hydrogen peroxide (H2O2) and alkaline phosphatase (ALP), respectively. These aPSs demonstrated selective activation and efficient photoablation of tumor cells in response to their respective stimuli. This work establishes Rho-I as a versatile scaffold for the development of precision aPSs, offering a promising strategy for targeted and safe PDT applications.

Equilibrioception (sensing of balance) is essential for mammals to perceive and navigate the three-dimensional world. A rapid mechanoelectrical transduction (MET) response in vestibular hair cells is crucial for detecting position and motion. Here, we identify the G protein-coupled receptor (GPCR) LPHN2/ADGRL2, expressed on the apical membrane of utricular hair cells, as essential for maintaining normal balance. Loss of LPHN2 specifically in hair cells impaired both balance behavior and the MET response in mice. Functional analyses using hair-cell-specific Lphn2-knockout mice and an LPHN2-specific inhibitor suggest that LPHN2 regulates tip-link-independent MET currents at the apical surface of utricular hair cells. Mechanistic studies in a heterologous system show that LPHN2 converts force stimuli into increased open probability of transmembrane channel-like protein 1 (TMC1). LPHN2-mediated force sensation triggers glutamate release and calcium signaling in utricular hair cells. Importantly, reintroducing LPHN2 into the hair cells of Lphn2-deficient mice restores vestibular function and MET response. Our data reveal that a mechanosensitive GPCR is required for equilibrioception.

Objectives:This study aimed to investigate the impact of foam macrophages (FMs) on the intracellular survival of Mycobacterium tuberculosis (MTB) and identify the molecular mechanisms influencing MTB survival. Methods:An in vitro FM model was established using oleic acid induction. Transcriptomic and metabolomic analyses were conducted to identify the key molecular pathways involved in FM-mediated MTB survival. Results:Induced FMs effectively restricted MTB survival. Transcriptomic and metabolomic profiling revealed distinct changes in gene and metabolite expression in FMs during MTB infection compared with normal macrophages. Integrated analyses identified significant alterations in the cyclic adenosine monophosphate (cAMP) signaling pathway, indicating that its activation contributes to the FM-mediated restriction of MTB survival. Conclusions:FMs inhibit MTB survival. The cAMP signaling pathway is a key contributor. These findings enhance the understanding of the role of FMs in tuberculosis progression, suggest potential targets for host-directed therapies, and offer new directions for developing diagnostic and therapeutic strategies against tuberculosis.

Recent advancements in the study of mushroom-derived tryptamines, particularly psilocybin and its metabolite psilocin, highlight their unique psychedelic properties and potential therapeutic applications, especially for mental health conditions like depression. This study examines how the position of the hydroxyl group on the indole ring affects the 5-HT2A receptor activity and psychedelic-like effects of psilocin analogs. Chemically synthesized psilocin (1) and its analogs bufotenine (2), 6-OH-DMT (3), and 7-OH-DMT (4) were assessed for 5-HT2A receptor agonistic activity using the Gαq-Gγ dissociation bioluminescence resonance energy transfer (BRET) assay and for psychedelic-like effects through the head-twitch response assay. Results show that compounds with hydroxyl group at the 4th and 5th positions exhibit significantly higher 5-HT2A agonistic and psychedelic-like activities than those with hydroxyl group at the 6th and 7th positions. Funnel metadynamics simulations revealed that psilocin (1) and bufotenine (2) have lower binding free energies, correlating with experimental data. Analysis of the simulation trajectories reveals that the formation of a hydrogen bond with residue L229 is crucial for guiding psilocin (1) and bufotenine (2) into the 5-HT2AR binding site. In contrast, analogs 3 and 4, which lack this interaction, fail to be directed into the orthosteric site. Furthermore, psilocin (1) and bufotenine (2) establish a stable salt bridge and hydrogen bond with residue D155. These interactions are more stable compared to those formed by ligands 3 and 4, contributing to the latter's poor 5-HT2AR activities. These findings underscore the critical role of the hydroxyl group position on the indole ring in modulating 5-HT2A receptor activity and the corresponding psychedelic-like effects, offering valuable insights for the development of targeted therapeutics.