title: HS1BP3 negatively regulates autophagy by modulation of phosphatidic acid levels.
abstract: A fundamental question is how autophagosome formation is regulated. Here we show that the PX domain protein HS1BP3 is a negative regulator of autophagosome formation. HS1BP3 depletion increased the formation of LC3-positive autophagosomes and degradation of cargo both in human cell culture and in zebrafish. HS1BP3 is localized to ATG16L1- and ATG9-positive autophagosome precursors and we show that HS1BP3 binds phosphatidic acid (PA) through its PX domain. Furthermore, we find the total PA content of cells to be significantly upregulated in the absence of HS1BP3, as a result of increased activity of the PA-producing enzyme phospholipase D (PLD) and increased localization of PLD1 to ATG16L1-positive membranes. We propose that HS1BP3 regulates autophagy by modulating the PA content of the ATG16L1-positive autophagosome precursor membranes through PLD1 activity and localization. Our findings provide key insights into how autophagosome formation is regulated by a novel negative-feedback mechanism on membrane lipids.
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Petter
authors.initials: P
authors.lastname: Holland
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Helene
authors.initials: H
authors.lastname: Knævelsrud
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Kristiane
authors.initials: K
authors.lastname: Søreng
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Benan J
authors.initials: BJ
authors.lastname: Mathai
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Alf Håkon
authors.initials: AH
authors.lastname: Lystad
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Serhiy
authors.initials: S
authors.lastname: Pankiv
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Gunnveig T
authors.initials: GT
authors.lastname: Bjørndal
authors.affiliation: Centre for Cancer Biomedicine, Faculty of Medicine and Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, 0379 Oslo, Norway.
authors.forename: Sebastian W
authors.initials: SW
authors.lastname: Schultz
authors.affiliation: Centre for Cancer Biomedicine, Faculty of Medicine and Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, 0379 Oslo, Norway.
authors.forename: Viola H
authors.initials: VH
authors.lastname: Lobert
authors.affiliation: Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, New York 10032, USA.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Chan
authors.affiliation: Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, New York 10032, USA.
authors.forename: Bowen
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway.
authors.forename: Knut
authors.initials: K
authors.lastname: Liestøl
authors.forename: Sven R
authors.initials: SR
authors.lastname: Carlsson
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, PO Box 208002, 333 Cedar Street, New Haven, Connecticut 06520-800210032, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Melia
authors.affiliation: Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, New York 10032, USA.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Di Paolo
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, 0317 Oslo, Norway.
authors.forename: Anne
authors.identifier: http://orcid.org/0000-0003-4711-7057
authors.initials: A
authors.lastname: Simonsen
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000071182:Autophagosomes / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D000071183:Autophagy-Related Proteins / Q000378:metabolism; D002460:Cell Line; D051356:Cortactin / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008563:Membrane Lipids / Q000378:metabolism; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism; D000072417:Protein Domains; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: C518959:ATG16L1 protein, human; D000071183:Autophagy-Related Proteins; C495868:CTTN protein, human; D051356:Cortactin; C503777:HS1BP3 protein, human; D008563:Membrane Lipids; D009419:Nerve Tissue Proteins; D010712:Phosphatidic Acids; D029961:Zebrafish Proteins; D010739:Phospholipase D; C106801:phospholipase D1