In both cancer and infections, diseased cells are presented to human Vγ9Vδ2 T cells through an ‘inside out’ signalling process whereby structurally diverse phosphoantigen (pAg) molecules are sensed by the intracellular domain of butyrophilin BTN3A1^1–4. Here we show how—in both humans and alpaca—multiple pAgs function as ‘molecular glues’ to promote heteromeric association between the intracellular domains of BTN3A1 and the structurally similar butyrophilin BTN2A1. X-ray crystallography studies visualized that engagement of BTN3A1 with pAgs forms a composite interface for direct binding to BTN2A1, with various pAg molecules each positioned at the centre of the interface and gluing the butyrophilins with distinct affinities. Our structural insights guided mutagenesis experiments that led to disruption of the intracellular BTN3A1–BTN2A1 association, abolishing pAg-mediated Vγ9Vδ2 T cell activation. Analyses using structure-based molecular-dynamics simulations, ¹⁹F-NMR investigations, chimeric receptor engineering and direct measurement of intercellular binding force revealed how pAg-mediated BTN2A1 association drives BTN3A1 intracellular fluctuations outwards in a thermodynamically favourable manner, thereby enabling BTN3A1 to push off from the BTN2A1 ectodomain to initiate T cell receptor–mediated γδ T cell activation. Practically, we harnessed the molecular-glue model for immunotherapeutics design, demonstrating chemical principles for developing both small-molecule activators and inhibitors of human γδ T cell function.

Toll-like receptors (TLRs) are a class of proteins that play critical roles in recognizing pathogens and initiating innate immune responses. TASL, a recently identified innate immune adaptor protein for endolysosomal TLR7/8/9 signaling, is recruited by the lysosomal proton-coupled amino-acid transporter SLC15A4, and then activates IRF5, which in turn triggers the transcription of type I interferons and cytokines. Here, we report three cryo-electron microscopy (cryo-EM) structures of human SLC15A4 in the apo monomeric and dimeric state and as a TASL-bound complex. The apo forms are in an outward-facing conformation, with the dimeric form showing an extensive interface involving four cholesterol molecules. The structure of the TASL-bound complex reveals an unprecedented interaction mode with solute carriers. During the recruitment of TASL, SLC15A4 undergoes a conformational change from an outward-facing, lysosomal lumen-exposed state to an inward-facing state to form a binding pocket, allowing the N-terminal helix of TASL to be inserted into. Our findings provide insights into the molecular basis of regulatory switch involving a human solute carrier and offers an important framework for structure-guided drug discovery targeting SLC15A4-TASL-related human autoimmune diseases.

Soft tissue myoepithelial neoplasms are a rare yet diverse group of tumors, ranging from benign to malignant lesions. Their presentation in the head and neck region is uncommon and represents a challenging diagnosis. Early identification of myoepithelial carcinoma is crucial given its more aggressive course compared to its benign counterpart, although the histopathological distinction between the two can be difficult. EWSR1 gene rearrangement is found in half the cases and has a speculative role in pathogenesis. Complete excision remains the treatment of choice. The roles of chemotherapy and radiation are unclear. We report the hospital course of a 33-year-old female who presented to our institution with a posterior neck mass with spinal invasion, diagnosed as myoepithelial cancer. A literature review of these rare tumors is discussed here.

Background: As essential biomolecules composed of proteins and carbohydrate moieties, glycoproteins play pivotal roles in numerous biological processes. The glycosylation level plays a crucial role in determining the functionality of glycoproteins. Therefore, the precise quantification of glycan components in proteins holds significant importance for research on and development of polysaccharide–protein-conjugated vaccines. Methods: In this study, a novel glycan quantification approach was developed, leveraging analytical ultracentrifugation (AUC) technology that synergistically utilizes ultraviolet wavelength absorption and interference data to directly determine glycan mass fractions in glycoproteins. Results: This methodology expands the analytical framework for glycoproteins while retaining the intrinsic advantages of AUC, enabling analysis in native states with high reproducibility as indicated by low standard deviation across replicates. Conclusions: The approach was implemented in our proprietary AUC data analysis software called AUCAgent (v1.8.8), providing a new method for glycoprotein quantification and polysaccharide ratio determination in polysaccharide-protein-conjugate vaccines.

Modern biotechnology has rapidly developed, and biotechnological drugs have become the center of global drug research and development as an important aspect of clinical treatment. These drugs have unique advantages, such as strong species specificity and prominent targeting, and they are widely used in the treatment of various intractable diseases. However, their complex molecular structure, poor stability, and significant heterogeneity make quality control much more difficult than that of traditional small-molecule drugs that require high-precision analytical methods. Analytical ultracentrifugation (AUC) technology was pioneered by Theodor Svedberg during the early 20th century, and it has become an indispensable biophysical tool through technological innovation. This technology has unique advantages for the quality control of biotechnological drugs, including non-destructive detection, high resolution, and wide applicability. Therefore, AUC has been extensively adopted for the characterization of various biological products. This review systematically summarizes AUC technology applications in major categories of biotechnological drugs, with the aim to provide technical guidance and promote the standardized application of AUC.