title: LDL cholesterol recycles to the plasma membrane via a Rab8a-Myosin5b-actin-dependent membrane transport route.
abstract: Mammalian cells acquire cholesterol, a major membrane constituent, via low-density lipoprotein (LDL) uptake. However, the mechanisms by which LDL cholesterol reaches the plasma membrane (PM) have remained obscure. Here, we applied LDL labeled with BODIPY cholesteryl linoleate to identify this pathway in living cells. The egress of BODIPY cholesterol (BC) from late endosomal (LE) organelles was dependent on acid lipase and Niemann-Pick C1 (NPC1) protein, as for natural cholesterol. We show that NPC1 was needed to recruit Rab8a to BC-containing LEs, and Rab8a enhanced the motility and segregation of BC- and CD63-positive organelles from lysosomes. The BC carriers docked to the cortical actin by a Rab8a- and Myosin5b (Myo5b)-dependent mechanism, typically in the proximity of focal adhesions (FAs). LDL increased the number and dynamics of FAs and stimulated cell migration in an acid lipase, NPC1, and Rab8a-dependent fashion, providing evidence that this cholesterol delivery route to the PM is important for cell movement.
authors.affiliation: Institute of Biomedicine, Anatomy, University of Helsinki, FI-00014 Helsinki, Finland; Minerva Foundation Institute for Medical Research, FI-00290 Helsinki, Finland.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Kanerva
authors.forename: Riikka-Liisa
authors.initials: RL
authors.lastname: Uronen
authors.forename: Tomas
authors.initials: T
authors.lastname: Blom
authors.forename: Shiqian
authors.initials: S
authors.lastname: Li
authors.forename: Robert
authors.initials: R
authors.lastname: Bittman
authors.forename: Pekka
authors.initials: P
authors.lastname: Lappalainen
authors.forename: Johan
authors.initials: J
authors.lastname: Peränen
authors.forename: Graça
authors.initials: G
authors.lastname: Raposo
authors.forename: Elina
authors.initials: E
authors.lastname: Ikonen
mesh_terms: D000199:Actins / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D008078:Cholesterol, LDL / Q000378:metabolism*; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D022001:Focal Adhesions / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D009218:Myosins / Q000378:metabolism*; D000077296:Niemann-Pick C1 Protein; D011162:Porphobilinogen / Q000031:analogs & derivatives / Q000494:pharmacology; D060149:Tetraspanin 30 / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
chemical_list: C538930:3-anilino difluoroboron dipyrromethene; D000199:Actins; D002352:Carrier Proteins; D008078:Cholesterol, LDL; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; C106881:NPC1 protein, human; D000077296:Niemann-Pick C1 Protein; D060149:Tetraspanin 30; D011162:Porphobilinogen; C082377:RAB8A protein, human; D009218:Myosins; D020691:rab GTP-Binding Proteins