OSBP-related protein-2 (ORP2) : a novel Akt effector that controls cellular energy metabolism
| Autor: | Henriikka Kentala, Robert Andrews, Zoltán Pataj, Vesa M. Olkkonen, Eija Jokitalo, Juho Pirhonen, Silke Matysik, Leena Karhinen, Eeva Jääskeläinen, Leena Meriläinen, Shiqian Li, Annika Koponen, Helena Vihinen, You Zhou, Elina Ikonen, Annukka M. Kivelä, Gerhard Liebisch |
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| Přispěvatelé: | Institute of Biotechnology, Electron Microscopy, University of Helsinki, Medicum, Department of Anatomy, Faculty of Medicine, Research Services, Lipid Trafficking Lab |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Receptors Steroid OSBP-related protein Chaperonins Cell Cycle Proteins STEROL Gene Knockout Techniques GSK-3 Cell Movement MAMMALIAN-CELLS Lipid droplet Akt signaling CHOLESTEROL-METABOLISM biology Chemistry Hsp90 Cell biology Actin Cytoskeleton OSBPL2 Molecular Medicine LIPID DROPLETS CRISPR-Cas9 Glycolysis Signal Transduction Triacylglycerol Cell Line 03 medical and health sciences Cellular and Molecular Neuroscience Humans HSP90 Heat-Shock Proteins RNA Messenger Glycogen synthase Molecular Biology OSBP Protein kinase B Cell Proliferation Pharmacology Organelles 030102 biochemistry & molecular biology Endoplasmic reticulum GLUCOSE-UPTAKE Lipid metabolism Biological Transport TRIACYLGLYCEROL SYNTHESIS Cell Biology PHOSPHATIDYLSERINE TRANSPORT Lipid Metabolism 030104 developmental biology ER PLASMA-MEMBRANE biology.protein 1182 Biochemistry cell and molecular biology 3111 Biomedicine Energy Metabolism Proto-Oncogene Proteins c-akt OXYSTEROL-BINDING PROTEINS |
| Popis: | ORP2 is a ubiquitously expressed OSBP-related protein previously implicated in endoplasmic reticulum (ER)lipid droplet (LD) contacts, triacylglycerol (TG) metabolism, cholesterol transport, adrenocortical steroidogenesis, and actin-dependent cell dynamics. Here, we characterize the role of ORP2 in carbohydrate and lipid metabolism by employing ORP2-knockout (KO) hepatoma cells (HuH7) generated by CRISPR-Cas9 gene editing. The ORP2-KO and control HuH7 cells were subjected to RNA sequencing, analyses of Akt signaling, carbohydrate and TG metabolism, the extracellular acidification rate, and the lipidome, as well as to transmission electron microscopy. The loss of ORP2 resulted in a marked reduction of active phosphorylated Akt(Ser473) and its target Glycogen synthase kinase 3(Ser9), consistent with defective Akt signaling. ORP2 was found to form a physical complex with the key controllers of Akt activity, Cdc37, and Hsp90, and to co-localize with Cdc37 and active Akt(Ser473) at lamellipodial plasma membrane regions, in addition to the previously reported ER-LD localization. ORP2-KO reduced glucose uptake, glycogen synthesis, glycolysis, mRNA-encoding glycolytic enzymes, and SREBP-1 target gene expression, and led to defective TG synthesis and storage. ORP2-KO did not reduce but rather increased ER-LD contacts under basal culture conditions and interfered with their expansion upon fatty acid loading. Together with our recently published work (Kentala et al. in FASEB J 32:1281-1295, 2018), this study identifies ORP2 as a new regulatory nexus of Akt signaling, cellular energy metabolism, actin cytoskeletal function, cell migration, and proliferation. |
| Databáze: | OpenAIRE |
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