title: Acute manipulation of diacylglycerol reveals roles in nuclear envelope assembly & endoplasmic reticulum morphology.
abstract: The functions and morphology of cellular membranes are intimately related and depend not only on their protein content but also on the repertoire of lipids that comprise them. In the absence of in vivo data on lipid asymmetry in endomembranes, it has been argued that motors, scaffolding proteins or integral membrane proteins rather than non-lamellar bilayer lipids such as diacylglycerol (DAG), are responsible for shaping of organelles, local membrane curvature and fusion. The effects of direct alteration of levels of such lipids remain predominantly uninvestigated. Diacylglycerol (DAG) is a well documented second messenger. Here we demonstrate two additional conserved functions of DAG: a structural role in organelle morphology, and a role in localised extreme membrane curvature required for fusion for which proteins alone are insufficient. Acute and inducible DAG depletion results in failure of the nuclear envelope (NE) to reform at mitosis and reorganisation of the ER into multi-lamellar sheets as revealed by correlative light and electron microscopy and 3D reconstructions. Remarkably, depleted cells divide without a complete NE, and unless rescued by 1,2 or 1,3 DAG soon die. Attenuation of DAG levels by enzyme microinjection into echinoderm eggs and embryos also results in alterations of ER morphology and nuclear membrane fusion. Our findings demonstrate that DAG is an in vivo modulator of organelle morphology in mammalian and echinoderm cells, indicating a fundamental role conserved across the deuterostome superphylum.
authors.affiliation: Cell Biophysics Laboratory, London Research Institute, Cancer Research United Kingdom, London, United Kingdom.
authors.forename: Marie-Charlotte
authors.initials: MC
authors.lastname: Domart
authors.forename: Tina M C
authors.initials: TM
authors.lastname: Hobday
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Peddie
authors.forename: Gary H C
authors.initials: GH
authors.lastname: Chung
authors.forename: Alan
authors.initials: A
authors.lastname: Wang
authors.forename: Karen
authors.initials: K
authors.lastname: Yeh
authors.forename: Nirmal
authors.initials: N
authors.lastname: Jethwa
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Zhang
authors.forename: Michael J O
authors.initials: MJ
authors.lastname: Wakelam
authors.forename: Rudiger
authors.initials: R
authors.lastname: Woscholski
authors.forename: Richard D
authors.initials: RD
authors.lastname: Byrne
authors.forename: Lucy M
authors.initials: LM
authors.lastname: Collinson
authors.forename: Dominic L
authors.initials: DL
authors.lastname: Poccia
authors.forename: Banafshé
authors.initials: B
authors.lastname: Larijani
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019852:Diacylglycerol Kinase / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008322:Mammals / Q000378:metabolism; D008561:Membrane Fusion / Q000187:drug effects; D008845:Microinjections; D008938:Mitosis / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000008:administration & dosage / Q000494:pharmacology; D009685:Nuclear Envelope / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D010641:Phenotype; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000008:administration & dosage / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D012617:Sea Urchins / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D000097682:Lamin B Receptor
chemical_list: D019852:Diacylglycerol Kinase; D004075:Diglycerides; D009419:Nerve Tissue Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D010744:Phosphoric Monoester Hydrolases; D018160:Receptors, Cytoplasmic and Nuclear; D000097682:Lamin B Receptor; C011439:1,2-diacylglycerol; C097702:synaptojanin