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Lysosomal transmembrane acetylation of heparan sulfates (HS) is catalyzed by HS acetyl-CoA:α-glucosaminide N-acetyltransferase (HGSNAT), whose dysfunction leads to lysosomal storage diseases. The mechanism by which HGSNAT, the sole non-hydrolase enzyme in HS degradation, brings cytosolic acetyl-coenzyme A (Ac-CoA) and lysosomal HS together for N-acyltransferase reactions remains unclear. Here, we present cryogenic-electron microscopy structures of HGSNAT alone, complexed with Ac-CoA and with acetylated products. These structures explain that Ac-CoA binding from the cytosolic side causes dimeric HGSNAT to form a transmembrane tunnel. Within this tunnel, catalytic histidine and asparagine approach the lumen and instigate the transfer of the acetyl group from Ac-CoA to the glucosamine group of HS. Our study unveils a transmembrane acetylation mechanism that may help advance therapeutic strategies targeting lysosomal storage diseases.
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http://dx.doi.org/10.1038/s41594-024-01315-5 | DOI Listing |
Cell Rep
September 2025
Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology Polish Academy of Sciences, Pasteur St. 3, Warsaw 02-093, Poland; Laboratory of Tumour Hypoxia and Epigenomics, Nencki Institute of Experimental Biology Polish Academy of Sciences, Pasteur St. 3, Warsaw 02-093, Poland. El
Hypoxia is a key histopathological feature of glioblastoma, associated with tumor aggressiveness and therapy resistance. Glioma-associated microglia and macrophages (GAMs) are key players in the tumor microenvironment of glioblastoma and acquire immunosuppressive properties during tumor progression. We show that hypoxia alters key GAM identity genes, as it upregulates the expression of monocytic marker lectin galactoside-binding doluble 3 (Lgals3) and downregulates the homeostatic microglial markers purinergic receptor P2Y G-protein coupled 12 (P2ry12) and transmembrane protein 119 (Tmem119) in GAMs co-cultured with glioma cells and in glioblastoma patients' samples.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
August 2025
Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA.
The epithelial sodium channel (ENaC) is a sodium channel expressed in renal tubules that by selectively allowing the transmembrane passage of sodium ions, plays a crucial role in maintaining extracellular fluid volume and regulating blood pressure. Recent data have indicated that ENaC also exists in the cells of the vascular wall and contributes to the direct regulation vascular function and blood pressure. The expression and activation of ENaC are both known to be regulated through mineralocorticoid receptor activation and serum glucocorticoid-regulated kinase 1.
View Article and Find Full Text PDFPLoS Pathog
August 2025
Center for Infection Biology, School of Basic Medical Sciences, Tsinghua University, Beijing, China.
Bacterial cell wall peptidoglycan (PG) consists of alternating β-(1,4) linked N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG). The C-6 hydroxyl group of NAM is acetylated by transmembrane O-acetyltransferases post PG biosynthesis in many pathogenic bacteria. This modification is important for bacterial resistance to lysozyme.
View Article and Find Full Text PDFInt J Biol Macromol
August 2025
Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian 116023, China; Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China; Liaoning Key Laboratory of
Integrin β2 subunit (CD18) also known as the β subunit of complement receptor 3 (CR3) participates in the innate immunity through regulating multiple immune processes. In the present study, a CD18 molecule containing a signal peptide, an INB domain, a VWA domain, an EGF2 domain, an integrin B tail domain, a transmembrane domain and an integrin B cyt domain was identified from Crassostrea gigas. Its mRNA expressions in hemocytes increased significantly after Vibrio splendidus stimulation.
View Article and Find Full Text PDFNat Commun
May 2025
Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
The human coronavirus HKU1 uses both sialoglycoconjugates and the protein transmembrane serine protease 2 (TMPRSS2) as receptors. Carbohydrate binding leads to the spike protein up conformation required for TMPRSS2 binding, an outcome suggesting a distinct mechanism for driving fusion of the viral and host cell membranes. Nevertheless, the conformational changes promoted by carbohydrate binding have not been fully elucidated and the basis for HKU1's carbohydrate binding specificity remains unknown.
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