98%
921
2 minutes
20
Biogenesis of lysosome-related organelle complex-3 (BLOC-3) is pivotal in vesicle trafficking and has been linked to Hermansky-Pudlak syndrome (HPS). Despite its importance, the structure and molecular function of BLOC-3 remains elusive. Here, we report the Cryo-EM structure of human BLOC-3 at 3.2 Å resolution. The BLOC-3 complex consists of one copy of HPS1 and HPS4, which tightly associate with each other via their longin domains (LD1 and LD3). The unique four-helical bundle (4HB) domain of HPS1 is involved in stabilizing its LD1 and LD2 domains. Moreover, we identify interactions between BLOC-3 and the small GTPases RAB32/38 and RAB9A, which are essential for lysosome-related organelle biogenesis. Functional assays using zebrafish models confirm the significance of BLOC-3 assembly and its interaction with RAB9A during melanosome biogenesis. Most importantly, our structural information provides an accurate prediction for clinical variants associated with HPS. In summary, our study provides a comprehensive understanding of the molecular architecture and functional roles of BLOC-3, shedding light on HPS pathogenesis.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11947305 | PMC |
http://dx.doi.org/10.1038/s41467-025-58235-1 | DOI Listing |
Handb Exp Pharmacol
September 2025
Tsinghua University, Beijing, China.
The μ-opioid receptor (μOR) is the primary drug target of opioid analgesics such as morphine and fentanyl. Activation of μORs in the central nervous system inhibits ascending pain signaling to the cortex, thereby producing analgesic effects. However, the clinical use of opioid analgesics is severely limited by adverse side effects, including respiratory depression, constipation, addiction, and the development of tolerance.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Martin A. Fisher School of Physics, Brandeis University, Waltham, MA 02453.
Programmable self-assembly has recently enabled the creation of complex structures through precise control of the interparticle interactions and the particle geometries. Targeting ever more structurally complex, dynamic, and functional assemblies necessitates going beyond the design of the structure itself, to the measurement and control of the local flexibility of the intersubunit connections and its impact on the collective mechanics of the entire assembly. In this study, we demonstrate a method to infer the mechanical properties of multisubunit assemblies using cryogenic electron microscopy (cryo-EM) and RELION's multi-body refinement.
View Article and Find Full Text PDFmBio
September 2025
Department of Biology, Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Flanders, Belgium.
Echinocandins, which target the fungal β-1,3-glucan synthase (Fks), are essential for treating invasive fungal infections, yet resistance is increasingly reported. While resistance typically arises through mutations in Fks hotspots, emerging evidence suggests a contributing role of changes in membrane sterol composition due to mutations. Here, we present a clinical case of () in which combined mutations in and , but not alone, appear to confer echinocandin resistance.
View Article and Find Full Text PDFActa Crystallogr D Struct Biol
October 2025
Centro Nacional de Biotecnologia-CSIC, Calle Darwin 3, 28049 Cantoblanco, Madrid, Spain.
Heterogeneity in cryoEM is essential for capturing the structural variability of macromolecules, reflecting their functional states and biological significance. However, estimating heterogeneity remains challenging due to particle misclassification and algorithmic biases, which can lead to reconstructions that blend distinct conformations or fail to resolve subtle differences. Furthermore, the low signal-to-noise ratio inherent in cryo-EM data makes it nearly impossible to detect minute structural changes, as noise often obscures subtle variations in macromolecular projections.
View Article and Find Full Text PDFEMBO J
September 2025
Department of Surgery & Cancer, Imperial, London, UK.
CDK7 has emerged as a cancer target because of its pivotal roles in cell cycle progression and transcription. Several CDK7 inhibitors (CDK7i) are now in clinical evaluation. Identifying patients most likely to respond to treatment and early detection of tumour evolution towards resistance are necessary for optimal implementation of cancer therapies.
View Article and Find Full Text PDF