Cholesterol is a critical component of cellular membranes, regulating assembly and function of membrane-based protein/lipid complexes. Many RNA viruses, including enteroviruses, remodel host membranes to generate organelles with unique lipid blueprints on which they assemble replication complexes and synthesize viral RNA. Here we find that clathrin-mediated endocytosis (CME) is harnessed by enteroviruses to traffic cholesterol from the plasma membrane (PM) and extracellular medium to replication organelles, where cholesterol then regulates viral polyprotein processing and facilitates genome synthesis. When CME is disrupted, cellular cholesterol pools are instead stored in lipid droplets, cholesterol cannot be trafficked to replication organelles, and replication is inhibited. In contrast, replication is stimulated in cholesterol-elevated cells like those lacking caveolins or those from Niemann-Pick disease patients. Our findings indicate cholesterol as a critical determinant for enteroviral replication and outline roles for the endocytic machinery in both the enteroviral life cycle and host cell cholesterol homeostasis.
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http://dx.doi.org/10.1016/j.chom.2013.08.002 | DOI Listing |
J Biol Chem
January 2025
The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada, M5G 1X8; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON, Canada, M5G 2M9. Electronic address:
The NUMB gene encodes a conserved adaptor protein with roles in asymmetric cell division and cell fate determination. First described as an inhibitor of Notch signaling, multi-functional NUMB proteins regulate multiple cellular pathways through protein complexes with ubiquitin ligases, polarity proteins and the endocytic machinery. The vertebrate NUMB protein isoforms were identified over two decades ago, yet the majority of functional studies exploring NUMB function in endocytosis, cell migration and adhesion, development and disease have largely neglected the potential for distinct isoform activity in design and interpretation.
View Article and Find Full Text PDFCells
December 2024
Molecular and Cellular Microbiology Laboratory, Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA.
Within mammalian cells, diverse endocytic mechanisms, including phagocytosis, pinocytosis, and receptor-mediated endocytosis, serve as gateways exploited by many bacterial pathogens and toxins. Among these, caveolae-mediated endocytosis is characterized by lipid-rich caveolae and dimeric caveolin proteins. Caveolae are specialized microdomains on cell surfaces that impact cell signaling.
View Article and Find Full Text PDFFEBS J
January 2025
Department of Drug Design and Pharmacology, University of Copenhagen, Denmark.
The glucagon-like peptide-1 receptor (GLP-1R) plays an important role in regulating insulin secretion and reducing body weight, making it a prominent target in the treatment of type 2 diabetes and obesity. Extensive research on GLP-1R signaling has provided insights into the connection between receptor function and physiological outcomes, such as the correlation between Gs signaling and insulin secretion, yet the exact mechanisms regulating signaling remain unclear. Here, we explore the internalization pathway of GLP-1R, which is crucial for controlling insulin release and maintaining pancreatic beta-cell function.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Institute of Infectious Disease and Biosecurity, School of Basic Medical Sciences, Fudan University, Shanghai, China.
Sodium taurocholate co-transporting polypeptide (NTCP) has been identified as an entry receptor for hepatitis B virus (HBV), but the molecular events of the viral post-endocytosis steps remain obscure. In this study, we discovered that manganese (Mn) could strongly inhibit HBV infection in NTCP-reconstituted HepG2 cells without affecting viral replication. We therefore profiled the antiviral effects of Mn2+ in an attempt to elucidate the regulatory mechanisms involved in early HBV infection.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Cell Biology, Harvard Medical School, Boston, MA 02115.
Plasma membrane protein degradation and recycling are regulated by the endolysosomal system, wherein endocytic vesicles bud from the plasma membrane into the cytoplasm and mature into endosomes and then degradative lysosomes. As such, the endolysosomal system plays a critical role in determining the abundance of proteins on the cell surface and influencing cellular identity and function. Highly polarized cells, like neurons, rely on the endolysosomal system for axonal and dendritic specialization and synaptic compartmentalization.
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