Sterols lower energetic barriers of membrane bending and fission necessary for efficient clathrin-mediated endocytosis
Ruthellen H. Anderson,
Kem A. Sochacki,
Harika Vuppula,
Brandon L. Scott,
Elizabeth M. Bailey,
Maycie M. Schultz,
Jason G. Kerkvliet,
Justin W. Taraska,
Adam D. Hoppe,
Kevin R. Francis
Affiliations
Ruthellen H. Anderson
Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA; Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
Kem A. Sochacki
Laboratory of Molecular Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20814, USA
Harika Vuppula
Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA
Brandon L. Scott
Nanoscience and Nanoengineering, South Dakota School of Mines & Technology, Rapid City, SD 57701, USA
Elizabeth M. Bailey
Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA
Maycie M. Schultz
Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
Jason G. Kerkvliet
Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA
Justin W. Taraska
Laboratory of Molecular Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20814, USA
Adam D. Hoppe
Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA; Corresponding author
Kevin R. Francis
Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA; Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA; Corresponding author
Summary: Clathrin-mediated endocytosis (CME) is critical for cellular signal transduction, receptor recycling, and membrane homeostasis in mammalian cells. Acute depletion of cholesterol disrupts CME, motivating analysis of CME dynamics in the context of human disorders of cholesterol metabolism. We report that inhibition of post-squalene cholesterol biosynthesis impairs CME. Imaging of membrane bending dynamics and the CME pit ultrastructure reveals prolonged clathrin pit lifetimes and shallow clathrin-coated structures, suggesting progressive impairment of curvature generation correlates with diminishing sterol abundance. Sterol structural requirements for efficient CME include 3′ polar head group and B-ring conformation, resembling the sterol structural prerequisites for tight lipid packing and polarity. Furthermore, Smith-Lemli-Opitz fibroblasts with low cholesterol abundance exhibit deficits in CME-mediated transferrin internalization. We conclude that sterols lower the energetic costs of membrane bending during pit formation and vesicular scission during CME and suggest that reduced CME activity may contribute to cellular phenotypes observed within disorders of cholesterol metabolism.
