1
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Holzhütter HG. Dynamical modelling of lipid droplet formation suggests a key function of membrane phospholipids. FEBS J 2024. [PMID: 39132700 DOI: 10.1111/febs.17238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/10/2024] [Accepted: 07/23/2024] [Indexed: 08/13/2024]
Abstract
Cells store triacylglycerol (TAG) within lipid droplets (LDs). A dynamic model describing complete LD formation at the endoplasmic reticulum (ER) membrane does not yet exist. A biochemical-biophysical model of LD synthesis is proposed. It describes the time-dependent accumulation of TAG in the ER membrane as the formation of a potential LD (pLD) bounded by spherical caps of the inner and outer monolayers of the membrane. The expansion rate of the pLD depends on the TAG supply, the elastic properties of the ER membrane, and the recruitment of phospholipids (PLs) to the cap-covering monolayers. Model simulations provided the following insights: (a) Marginal differences in the surface tension of the cap monolayers are sufficient to fully drive the expansion of the pLD towards the cytosol or lumen. (b) Selective reduction of PL supply to the luminal monolayer ensures stable formation of cytosolic LDs, irrespective of variations in the elasto-mechanical properties of the ER membrane. (c) The rate of TAG supply to the cytosolic monolayer has a major effect on the size and maturation time of LDs but has no significant effect on the TAG export per individual LD. The recruitment of additional PLs to the cap monolayers of pLDs critically controls the budding direction, size, and maturation time of LDs. The ability of cells to acquire additional LD initiation sites appears to be key to coping with acutely high levels of potentially toxic free fatty acids.
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Affiliation(s)
- Hermann-Georg Holzhütter
- Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany
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2
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Wang CW, Chen RH, Chen YK. The lipid droplet assembly complex consists of seipin and four accessory factors in budding yeast. J Biol Chem 2024; 300:107534. [PMID: 38981533 PMCID: PMC11342095 DOI: 10.1016/j.jbc.2024.107534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 06/12/2024] [Accepted: 06/25/2024] [Indexed: 07/11/2024] Open
Abstract
Seipin, a crucial protein for cellular lipid droplet (LD) assembly, oligomerizes at the interface between the endoplasmic reticulum and LDs to facilitate neutral lipid packaging. Using proximity labeling, we identified four proteins-Ldo45, Ldo16, Tgl4, and Pln1-that are recruited to the vicinity of yeast seipin, the Sei1-Ldb16 complex, exclusively when seipin function is intact, hence termed seipin accessory factors. Localization studies identified Tgl4 at the endoplasmic reticulum-LD contact site, in contrast to Ldo45, Ldo16, and Pln1 at the LD surface. Cells with compromised seipin function resulted in uneven distribution of these proteins with aberrant LDs, supporting a central role of seipin in orchestrating their association with the LD. Overexpression of any seipin accessory factor causes LD aggregation and affects a subset of LD protein distribution, highlighting the importance of their stoichiometry. Although single factor mutations show minor LD morphology changes, the combined mutations have additive effects. Lastly, we present evidence that seipin accessory factors assemble and interact with seipin in the absence of neutral lipids and undergo dynamical rearrangements during LD formation induction, with Ldo45 acting as a central hub recruiting other factors to interact with the seipin complex.
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Affiliation(s)
- Chao-Wen Wang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
| | - Rey-Huei Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Kai Chen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
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3
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Mallick K, Paul S, Banerjee S, Banerjee S. Lipid Droplets and Neurodegeneration. Neuroscience 2024; 549:13-23. [PMID: 38718916 DOI: 10.1016/j.neuroscience.2024.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/19/2024] [Accepted: 04/25/2024] [Indexed: 05/15/2024]
Abstract
Energy metabolism in the brain has been considered one of the critical research areas of neuroscience for ages. One of the most vital parts of brain metabolism cascades is lipid metabolism, and fatty acid plays a crucial role in this process. The fatty acid breakdown process in mitochondria undergoes through a conserved pathway known as β-oxidation where acetyl-CoA and shorter fatty acid chains are produced along with a significant amount of energy molecule. Further, the complete breakdown of fatty acids occurs when they enter the mitochondrial oxidative phosphorylation. Cells store energy as neutral lipids in organelles known as Lipid Droplets (LDs) to prepare for variations in the availability of nutrients. Fatty acids are liberated by lipid droplets and are transported to various cellular compartments for membrane biogenesis or as an energy source. Current research shows that LDs are important in inflammation, metabolic illness, and cellular communication. Lipid droplet biology in peripheral organs like the liver and heart has been well investigated, while the brain's LDs have received less attention. Recently, there has been increased awareness of the existence and role of these dynamic organelles in the central nervous system, mainly connected to neurodegeneration. In this review, we discussed the role of beta-oxidation and lipid droplet formation in the oxidative phosphorylation process, which directly affects neurodegeneration through various pathways.
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Affiliation(s)
- Keya Mallick
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Kolkata, India.
| | - Shuchismita Paul
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Kolkata, India.
| | - Sayani Banerjee
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Kolkata, India.
| | - Sugato Banerjee
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Kolkata, India.
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4
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Chen H, de Boer R, Krikken AM, Wu F, van der Klei I. Hansenula polymorpha cells lacking the ER-localized peroxins Pex23 or Pex29 show defects in mitochondrial function and morphology. Biol Open 2024; 13:bio060271. [PMID: 38682287 PMCID: PMC11139031 DOI: 10.1242/bio.060271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/23/2024] [Indexed: 05/01/2024] Open
Abstract
Pex23 family proteins localize to the endoplasmic reticulum and play a role in peroxisome and lipid body formation. The yeast Hansenula polymorpha contains four members: Pex23, Pex24, Pex29 and Pex32. We previously showed that loss of Pex24 or Pex32 results in severe peroxisomal defects, caused by reduced peroxisome-endoplasmic reticulum contact sites. We now analyzed the effect of the absence of all four Pex23 family proteins on other cell organelles. Vacuoles were normal in all four deletion strains. The number of lipid droplets was reduced in pex23 and pex29, but not in pex24 and pex32 cells, indicating that peroxisome and lipid droplet formation require different Pex23 family proteins in H. polymorpha. In pex23 and pex29 cells mitochondria were fragmented and clustered accompanied by reduced levels of the fusion protein Fzo1. Deletion of DNM1 suppressed the morphological phenotype of pex23 and pex29 cells, suggesting that mitochondrial fusion is affected. pex23 and pex29 cells showed retarded growth and reduced mitochondrial activities. The growth defect was partially suppressed by DNM1 deletion as well as by an artificial mitochondrion-endoplasmic reticulum tether. Hence, the absence of Pex23 family proteins may influence mitochondrion-endoplasmic reticulum contact sites.
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Affiliation(s)
- Haiqiong Chen
- Molecular Cell Biology — Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Rinse de Boer
- Molecular Cell Biology — Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Arjen M. Krikken
- Molecular Cell Biology — Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Fei Wu
- Molecular Cell Biology — Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Ida van der Klei
- Molecular Cell Biology — Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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5
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Cui W, Chen H, Lei L, Wang W, Lim KL, Zhang C, Lu L. Seipin Deficiency Leads to Energy Dyshomeostasis via Inducing Hypothalamic Neuroinflammation and Aberrant Expression of Neuropeptides. Neuromolecular Med 2024; 26:18. [PMID: 38691185 DOI: 10.1007/s12017-024-08788-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/10/2024] [Indexed: 05/03/2024]
Abstract
Seipin is a key regulator of lipid metabolism, the deficiency of which leads to severe lipodystrophy. Hypothalamus is the pivotal center of brain that modulates appetite and energy homeostasis, where Seipin is abundantly expressed. Whether and how Seipin deficiency leads to systemic metabolic disorders via hypothalamus-involved energy metabolism dysregulation remains to be elucidated. In the present study, we demonstrated that Seipin-deficiency induced hypothalamic inflammation, reduction of anorexigenic pro-opiomelanocortin (POMC), and elevation of orexigenic agonist-related peptide (AgRP). Importantly, administration of rosiglitazone, a thiazolidinedione antidiabetic agent, rescued POMC and AgRP expression, suppressed hypothalamic inflammation, and restored energy homeostasis in Seipin knockout mice. Our findings offer crucial insights into the mechanism of Seipin deficiency-associated energy imbalance and indicates that rosiglitazone could serve as potential intervening agent towards metabolic disorders linked to Seipin.
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Affiliation(s)
- Wenli Cui
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology of Chinese Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Hong Chen
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology of Chinese Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Lingfeng Lei
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology of Chinese Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Wenru Wang
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology of Chinese Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Kah-Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Novena, 308232, Singapore
| | - Chengwu Zhang
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
- Key Laboratory of Cellular Physiology of Chinese Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
| | - Li Lu
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
- Key Laboratory of Cellular Physiology of Chinese Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
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6
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Klug YA, Ferreira JV, Carvalho P. A unifying mechanism for seipin-mediated lipid droplet formation. FEBS Lett 2024; 598:1116-1126. [PMID: 38785192 DOI: 10.1002/1873-3468.14825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/13/2024] [Accepted: 01/23/2024] [Indexed: 05/25/2024]
Abstract
Lipid droplets (LDs) are dynamic organelles essential for cellular lipid homeostasis. Assembly of LDs occurs in the endoplasmic reticulum (ER), and the conserved ER membrane protein seipin emerged as a key player in this process. Here, we review recent advances provided by structural, biochemical, and in silico analysis that revealed mechanistic insights into the molecular role of the seipin complexes and led to an updated model for LD biogenesis. We further discuss how other ER components cooperate with seipin during LD biogenesis. Understanding the molecular mechanisms underlying seipin-mediated LD assembly is important to uncover the fundamental aspects of lipid homeostasis and organelle biogenesis and to provide hints on the pathogenesis of lipid storage disorders.
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Affiliation(s)
- Yoel A Klug
- Sir William Dunn School of Pathology, University of Oxford, UK
| | | | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, UK
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7
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Song YF, Bai ZY, Lai XH, Luo Z, Hogstrand C. Ip3r-Grp75-Vdac and Relevant Ca 2+ Signaling Regulate Dietary Palmitic Acid-Induced De Novo Lipogenesis by Mitochondria-Associated ER Membrane (MAM) Recruiting Seipin in Yellow Catfish. J Nutr 2024:S0022-3166(24)00224-4. [PMID: 38641205 DOI: 10.1016/j.tjnut.2024.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 04/10/2024] [Accepted: 04/13/2024] [Indexed: 04/21/2024] Open
Abstract
BACKGROUND The mitochondria-associated endoplasmic reticulum membrane (MAM) is the central hub for endoplasmic reticulum and mitochondria functional communication. It plays a crucial role in hepatic lipid homeostasis. However, even though MAM has been acknowledged to be rich in enzymes that contribute to lipid biosynthesis, no study has yet investigated the exact role of MAM on hepatic neutral lipid synthesis. OBJECTIVES To address these gaps, this study investigated the systemic control mechanisms of MAM on neutral lipids synthesis by recruiting seipin, focusing on the role of the inositol trisphosphate receptor-1,4,5(Ip3r)-75 kDa glucose-regulated protein (Grp75)-voltage-dependent anion channel (Vdac) complex and their relevant Ca2+ signaling in this process. METHODS To this end, a model animal for lipid metabolism, yellow catfish (Pelteobagrus fulvidraco), were fed 6 different diets containing a range of palmitic acid (PA) concentrations from 0-150 g/kg in vivo for 10 wk. In vitro, experiments were also conducted to intercept the MAM-mediated Ca2+ signaling in isolated hepatocytes by transfecting them with si-mitochondrial calcium uniporter (mcu). Because mcu was placed in the inner mitochondrial membrane (IMM), si-mcu cannot disrupt MAM's structural integrity. RESULTS 1. Hepatocellular MAM subproteome analysis indicated excessive dietary PA intake enhanced hepatic MAM structure joined by activating Ip3r-Grp75-Vdac complexes. 2. Dietary PA intake induced hepatic neutral lipid accumulation through MAM recruiting Seipin, which activated lipid droplet biogenesis. Our findings also revealed a previously unidentified mechanism whereby MAM-recruited seipin and controlled hepatic lipid homeostasis, depending on Ip3r-Grp75-Vdac-controlled Ca2+ signaling and not only MAM's structural integrity. CONCLUSIONS These results offer a novel insight into the MAM-recruited seipin in controlling hepatic lipid synthesis in a MAM structural integrity-dependent and Ca2+ signaling-dependent manner, highlighting the critical contribution of MAM in maintaining hepatic neutral lipid homeostasis.
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Affiliation(s)
- Yu-Feng Song
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan, China.
| | - Zhen-Yu Bai
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan, China
| | - Xiao-Hong Lai
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan, China
| | - Zhi Luo
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Christer Hogstrand
- Diabetes and Nutritional Sciences Division, School of Medicine, King's College London, Franklin-Wilkins Building, London, United Kingdom
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8
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Bittner E, Stehlik T, Lam J, Dimitrov L, Heimerl T, Schöck I, Harberding J, Dornes A, Heymons N, Bange G, Schuldiner M, Zalckvar E, Bölker M, Schekman R, Freitag J. Proteins that carry dual targeting signals can act as tethers between peroxisomes and partner organelles. PLoS Biol 2024; 22:e3002508. [PMID: 38377076 PMCID: PMC10906886 DOI: 10.1371/journal.pbio.3002508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 03/01/2024] [Accepted: 01/19/2024] [Indexed: 02/22/2024] Open
Abstract
Peroxisomes are organelles with crucial functions in oxidative metabolism. To correctly target to peroxisomes, proteins require specialized targeting signals. A mystery in the field is the sorting of proteins that carry a targeting signal for peroxisomes and as well as for other organelles, such as mitochondria or the endoplasmic reticulum (ER). Exploring several of these proteins in fungal model systems, we observed that they can act as tethers bridging organelles together to create contact sites. We show that in Saccharomyces cerevisiae this mode of tethering involves the peroxisome import machinery, the ER-mitochondria encounter structure (ERMES) at mitochondria and the guided entry of tail-anchored proteins (GET) pathway at the ER. Our findings introduce a previously unexplored concept of how dual affinity proteins can regulate organelle attachment and communication.
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Affiliation(s)
- Elena Bittner
- Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Thorsten Stehlik
- Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Jason Lam
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, California, United States of America
| | - Lazar Dimitrov
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, California, United States of America
| | - Thomas Heimerl
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
| | - Isabelle Schöck
- Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Jannik Harberding
- Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Anita Dornes
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
| | - Nikola Heymons
- Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Bölker
- Department of Biology, Philipps-University Marburg, Marburg, Germany
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
| | - Randy Schekman
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, California, United States of America
| | - Johannes Freitag
- Department of Biology, Philipps-University Marburg, Marburg, Germany
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, California, United States of America
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9
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Kumari RM, Khatri A, Chaudhary R, Choudhary V. Concept of lipid droplet biogenesis. Eur J Cell Biol 2023; 102:151362. [PMID: 37742390 PMCID: PMC7615795 DOI: 10.1016/j.ejcb.2023.151362] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023] Open
Abstract
Lipid droplets (LD) are functionally conserved fat storage organelles found in all cell types. LDs have a unique structure comprising of a hydrophobic core of neutral lipids (fat), triacylglycerol (TAG) and cholesterol esters (CE) surrounded by a phospholipid monolayer. LD surface is decorated by a multitude of proteins and enzymes rendering this compartment functional. Accumulating evidence suggests that LDs originate from discrete ER-subdomains, demarcated by the lipodystrophy protein seipin, however, the mechanisms of which are not well understood. LD biogenesis factors together with biophysical properties of the ER membrane orchestrate spatiotemporal regulation of LD nucleation and growth at specific ER subdomains in response to metabolic cues. Defects in LD formation manifests in several human pathologies, including obesity, lipodystrophy, ectopic fat accumulation, and insulin resistance. Here, we review recent advances in understanding the molecular events during initial stages of eukaryotic LD assembly and discuss the critical role of factors that ensure fidelity of this process.
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Affiliation(s)
- R Mankamna Kumari
- Lipid Metabolism Laboratory, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Amit Khatri
- Lipid Metabolism Laboratory, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Ritika Chaudhary
- Lipid Metabolism Laboratory, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Vineet Choudhary
- Lipid Metabolism Laboratory, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India.
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10
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Cobelo-Gómez S, Sánchez-Iglesias S, Rábano A, Senra A, Aguiar P, Gómez-Lado N, García-Varela L, Burgueño-García I, Lampón-Fernández L, Fernández-Pombo A, Díaz-López EJ, Prado-Moraña T, San Millán B, Araújo-Vilar D. A murine model of BSCL2-associated Celia's encephalopathy. Neurobiol Dis 2023; 187:106300. [PMID: 37717662 DOI: 10.1016/j.nbd.2023.106300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 09/19/2023] Open
Abstract
Celia's encephalopathy or progressive encephalopathy with/without lipodystrophy is a neurodegenerative disease with a fatal prognosis in childhood. It is generally caused by the c.985C > T variant in the BSCL2 gene, leading to the skipping of exon 7 and resulting in an aberrant seipin protein (Celia-seipin). To precisely define the temporal evolution and the mechanisms involved in neurodegeneration, lipodystrophy and fatty liver in Celia's encephalopathy, our group has generated the first global knock-in murine model for the aberrant human transcript of BSCL2 (Bscl2Celia/Celia) using a strategy based on the Cre/loxP recombination system. In order to carry out a characterization at the neurological, adipose tissue and hepatic level, behavioral studies, brain PET, metabolic, histological and molecular studies were performed. Around 12% of homozygous and 5.4% of heterozygous knock-in mice showed severe neurological symptoms early in life, and their life expectancy was dramatically reduced. Severe generalized lipodystrophy and mild hepatic steatosis were present in these affected animals, while serum triglycerides and glucose metabolism were normal, with no insulin resistance. Furthermore, the study revealed a reduction in brain glucose uptake, along with patchy loss of Purkinje cells and the presence of intranuclear inclusions in cerebellar cortex cells. Homozygous, non-severely-affected knock-in mice showed a decrease in locomotor activity and greater anxiety compared with their wild type littermates. Bscl2Celia/Celia is the first murine model of Celia's encephalopathy which partially recapitulates the phenotype and severe neurodegenerative picture suffered by these patients. This model will provide a helpful tool to investigate both the progressive encephalopathy with/without lipodystrophy and congenital generalized lipodystrophy.
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Affiliation(s)
- Silvia Cobelo-Gómez
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain
| | - Sofía Sánchez-Iglesias
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain
| | - Alberto Rábano
- Alzheimer's Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center, Madrid, Spain
| | - Ana Senra
- Department of Physiology, CIMUS, University of Santiago de Compostela, Spain
| | - Pablo Aguiar
- Molecular Imaging and Medical Physics, University of Santiago de Compostela-IDIS, Spain; Nuclear Medicine and Molecular Imaging Group, IDIS, University Clinical Hospital of Santiago de Compostela, Spain
| | - Noemí Gómez-Lado
- Molecular Imaging and Medical Physics, University of Santiago de Compostela-IDIS, Spain; Nuclear Medicine and Molecular Imaging Group, IDIS, University Clinical Hospital of Santiago de Compostela, Spain
| | - Lara García-Varela
- Molecular Imaging and Medical Physics, University of Santiago de Compostela-IDIS, Spain; Nuclear Medicine and Molecular Imaging Group, IDIS, University Clinical Hospital of Santiago de Compostela, Spain
| | - Iván Burgueño-García
- Alzheimer's Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center, Madrid, Spain
| | - Laura Lampón-Fernández
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain
| | - Antía Fernández-Pombo
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain
| | - Everardo Josué Díaz-López
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain
| | - Teresa Prado-Moraña
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain
| | - Beatriz San Millán
- Grupo de Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IISGS), Vigo, Spain; Pathology Department, Alvaro Cunqueiro Hospital, Vigo, Spain
| | - David Araújo-Vilar
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain.
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11
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Sun X, Shen J, Perrimon N, Kong X, Wang D. The endoribonuclease Arlr is required to maintain lipid homeostasis by downregulating lipolytic genes during aging. Nat Commun 2023; 14:6254. [PMID: 37803019 PMCID: PMC10558556 DOI: 10.1038/s41467-023-42042-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/28/2023] [Indexed: 10/08/2023] Open
Abstract
While disorders in lipid metabolism have been associated with aging and age-related diseases, how lipid metabolism is regulated during aging is poorly understood. Here, we characterize the Drosophila endoribonuclease CG2145, an ortholog of mammalian EndoU that we named Age-related lipid regulator (Arlr), as a regulator of lipid homeostasis during aging. In adult adipose tissues, Arlr is necessary for maintenance of lipid storage in lipid droplets (LDs) as flies age, a phenotype that can be rescued by either high-fat or high-glucose diet. Interestingly, RNA-seq of arlr mutant adipose tissues and RIP-seq suggest that Arlr affects lipid metabolism through the degradation of the mRNAs of lipolysis genes - a model further supported by the observation that knockdown of Lsd-1, regucalcin, yip2 or CG5162, which encode genes involved in lipolysis, rescue the LD defects of arlr mutants. In addition, we characterize DendoU as a functional paralog of Arlr and show that human ENDOU can rescue arlr mutants. Altogether, our study reveals a role of ENDOU-like endonucleases as negative regulator of lipolysis.
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Affiliation(s)
- Xiaowei Sun
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Howard Hughes Medical Institute, Boston, MA, USA
| | - Xue Kong
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Dan Wang
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China.
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12
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Banerjee S, Prinz WA. Early steps in the birth of four membrane-bound organelles-Peroxisomes, lipid droplets, lipoproteins, and autophagosomes. Curr Opin Cell Biol 2023; 84:102210. [PMID: 37531895 PMCID: PMC10926090 DOI: 10.1016/j.ceb.2023.102210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 08/04/2023]
Abstract
Membrane-bound organelles allow cells to traffic cargo and separate and regulate metabolic pathways. While many organelles are generated by the growth and division of existing organelles, some can also be produced de novo, often in response to metabolic cues. This review will discuss recent advances in our understanding of the early steps in the de novo biogenesis of peroxisomes, lipid droplets, lipoproteins, and autophagosomes. These organelles play critical roles in cellular lipid metabolism and other processes, and their dysfunction causes or is linked to several human diseases. The de novo biogenesis of these organelles occurs in or near the endoplasmic reticulum membrane. This review summarizes recent progress and highlights open questions.
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Affiliation(s)
- Subhrajit Banerjee
- Dept of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - William A Prinz
- Dept of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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13
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Khaddaj R, Stribny J, Cottier S, Schneiter R. Perilipin 3 promotes the formation of membrane domains enriched in diacylglycerol and lipid droplet biogenesis proteins. Front Cell Dev Biol 2023; 11:1116491. [PMID: 37465010 PMCID: PMC10350540 DOI: 10.3389/fcell.2023.1116491] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 06/14/2023] [Indexed: 07/20/2023] Open
Abstract
Lipid droplets (LDs) serve as intracellular stores of energy-rich neutral lipids. LDs form at discrete sites in the endoplasmic reticulum (ER) and they remain closely associated with the ER during lipogenic growth and lipolytic consumption. Their hydrophobic neutral lipid core is covered by a monolayer of phospholipids, which harbors a specific set of proteins. This LD surface is coated and stabilized by perilipins, a family of soluble proteins that specifically target LDs from the cytosol. We have previously used chimeric fusion proteins between perilipins and integral ER membrane proteins to test whether proteins that are anchored to the ER bilayer could be dragged onto the LD monolayer. Expression of these chimeric proteins induces repositioning of the ER membrane around LDs. Here, we test the properties of membrane-anchored perilipins in cells that lack LDs. Unexpectedly, membrane-anchored perilipins induce expansion and vesiculation of the perinuclear membrane resulting in the formation of crescent-shaped membrane domains that harbor LD-like properties. These domains are stained by LD-specific lipophilic dyes, harbor LD marker proteins, and they transform into nascent LDs upon induction of neutral lipid synthesis. These ER domains are enriched in diacylglycerol (DAG) and in ER proteins that are important for early steps of LD biogenesis, including seipin and Pex30. Formation of the domains in vivo depends on DAG levels, and we show that perilipin 3 (PLIN3) binds to liposomes containing DAG in vitro. Taken together, these observations indicate that perilipin not only serve to stabilize the surface of mature LDs but that they are likely to exert a more active role in early steps of LD biogenesis at ER subdomains enriched in DAG, seipin, and neutral lipid biosynthetic enzymes.
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Affiliation(s)
- Rasha Khaddaj
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jiri Stribny
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Stéphanie Cottier
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Roger Schneiter
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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14
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Walther TC, Kim S, Arlt H, Voth GA, Farese RV. Structure and function of lipid droplet assembly complexes. Curr Opin Struct Biol 2023; 80:102606. [PMID: 37150040 PMCID: PMC10853036 DOI: 10.1016/j.sbi.2023.102606] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/03/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023]
Abstract
Cells store lipids as a reservoir of metabolic energy and membrane component precursors in organelles called lipid droplets (LDs). LD formation occurs in the endoplasmic reticulum (ER) at LD assembly complexes (LDAC), consisting of an oligomeric core of seipin and accessory proteins. LDACs determine the sites of LD formation and are required for this process to occur normally. Seipin oligomers form a cage-like structure in the membrane that may serve to facilitate the phase transition of neutral lipids in the membrane to form an oil droplet within the LDAC. Modeling suggests that, as the LD grows, seipin anchors it to the ER bilayer and conformational shifts of seipin transmembrane segments open the LDAC dome toward the cytoplasm, enabling the emerging LD to egress from the ER.
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Affiliation(s)
- Tobias C Walther
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA; Howard Hughes Medical Institute, New York, NY 10065, USA.
| | - Siyoung Kim
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA
| | - Henning Arlt
- Howard Hughes Medical Institute, New York, NY 10065, USA
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Robert V Farese
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
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15
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Zadoorian A, Du X, Yang H. Lipid droplet biogenesis and functions in health and disease. Nat Rev Endocrinol 2023:10.1038/s41574-023-00845-0. [PMID: 37221402 DOI: 10.1038/s41574-023-00845-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/25/2023] [Indexed: 05/25/2023]
Abstract
Ubiquitous yet unique, lipid droplets are intracellular organelles that are increasingly being recognized for their versatility beyond energy storage. Advances uncovering the intricacies of their biogenesis and the diversity of their physiological and pathological roles have yielded new insights into lipid droplet biology. Despite these insights, the mechanisms governing the biogenesis and functions of lipid droplets remain incompletely understood. Moreover, the causal relationship between the biogenesis and function of lipid droplets and human diseases is poorly resolved. Here, we provide an update on the current understanding of the biogenesis and functions of lipid droplets in health and disease, highlighting a key role for lipid droplet biogenesis in alleviating cellular stresses. We also discuss therapeutic strategies of targeting lipid droplet biogenesis, growth or degradation that could be applied in the future to common diseases, such as cancer, hepatic steatosis and viral infection.
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Affiliation(s)
- Armella Zadoorian
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia.
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16
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Farese RV, Walther TC. Glycerolipid Synthesis and Lipid Droplet Formation in the Endoplasmic Reticulum. Cold Spring Harb Perspect Biol 2023; 15:a041246. [PMID: 36096640 PMCID: PMC10153804 DOI: 10.1101/cshperspect.a041246] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
More than 60 years ago, Eugene Kennedy and coworkers elucidated the endoplasmic reticulum (ER)-based pathways of glycerolipid synthesis, including the synthesis of phospholipids and triacylglycerols (TGs). The reactions of the Kennedy pathway were identified by studying the conversion of lipid intermediates and the isolation of biochemical enzymatic activities, but the molecular basis for most of these reactions was unknown. With recent progress in the cell biology, biochemistry, and structural biology in this area, we have a much more mechanistic understanding of this pathway and its reactions. In this review, we provide an overview of molecular aspects of glycerolipid synthesis, focusing on recent insights into the synthesis of TGs. Further, we go beyond the Kennedy pathway to describe the mechanisms for storage of TG in cytosolic lipid droplets and discuss how overwhelming these pathways leads to ER stress and cellular toxicity, as seen in diseases linked to lipid overload and obesity.
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Affiliation(s)
- Robert V Farese
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
- Center for Causes and Prevention of Cardiovascular Disease (CAP-CVD), Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Tobias C Walther
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
- Center for Causes and Prevention of Cardiovascular Disease (CAP-CVD), Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA
- Howard Hughes Medical Institute Boston, Boston, Massachusetts 02115, USA
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17
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Choudhary V, Goodman JM. Editorial: The evolving role of lipid droplets: Advancements and future directions. Front Cell Dev Biol 2023; 11:1175083. [PMID: 37025181 PMCID: PMC10070960 DOI: 10.3389/fcell.2023.1175083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/13/2023] [Indexed: 04/08/2023] Open
Affiliation(s)
- Vineet Choudhary
- All India Institute of Medical Sciences (AIIMS), Department of Biotechnology, New Delhi, India
| | - Joel M. Goodman
- Department of Pharmacology, University of Texas Southwestern Medical School, Dallas, TX, United States
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18
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Deori NM, Infant T, Thummer RP, Nagotu S. Characterization of the Multiple Domains of Pex30 Involved in Subcellular Localization of the Protein and Regulation of Peroxisome Number. Cell Biochem Biophys 2023; 81:39-47. [PMID: 36462131 DOI: 10.1007/s12013-022-01122-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022]
Abstract
Pex30 is a peroxisomal protein whose role in peroxisome biogenesis via the endoplasmic reticulum has been established. It is a 58 KDa multi-domain protein that facilitates contact site formation between various organelles. The present study aimed to investigate the role of various domains of the protein in its sub-cellular localization and regulation of peroxisome number. For this, we created six truncations of the protein (1-87, 1-250, 1-352, 88-523, 251-523 and 353-523) and tagged GFP at the C-terminus. Biochemical methods and fluorescence microscopy were used to characterize the effect of truncation on expression and localization of the protein. Quantitative analysis was performed to determine the effect of truncation on peroxisome number in these cells. Expression of the truncated variants in cells lacking PEX30 did not cause any effect on cell growth. Interestingly, variable expression and localization of the truncated variants in both peroxisome-inducing and non-inducing medium was observed. Truncated variants depicted different distribution patterns such as punctate, reticulate and cytosolic fluorescence. Interestingly, lack of the complete dysferlin domain or C-Dysf resulted in increased peroxisome number similar to as reported for cells lacking Pex30. No contribution of this domain in the reticulate distribution of the proteins was also observed. Our results show an interesting role for the various domains of Pex30 in localization and regulation of peroxisome number.
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Affiliation(s)
- Nayan Moni Deori
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Terence Infant
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Rajkumar P Thummer
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
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19
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Salo VT. Seipin-still a mysterious protein? Front Cell Dev Biol 2023; 11:1112954. [PMID: 36819093 PMCID: PMC9935593 DOI: 10.3389/fcell.2023.1112954] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Cells store excess energy in the form of lipid droplets (LDs), a specialized sub-compartment of the endoplasmic reticulum (ER) network. The lipodystrophy protein seipin is a key player in LD biogenesis and ER-LD contact site maintenance. Recent structural and in silico studies have started to shed light on the molecular function of seipin as a LD nucleator in early LD biogenesis, whilst new cell biological work implies a role for seipin in ER-mitochondria contact sites and calcium metabolism. In this minireview, I discuss recent insights into the molecular function of seipin.
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20
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Castro IG, Shortill SP, Dziurdzik SK, Cadou A, Ganesan S, Valenti R, David Y, Davey M, Mattes C, Thomas FB, Avraham RE, Meyer H, Fadel A, Fenech EJ, Ernst R, Zaremberg V, Levine TP, Stefan C, Conibear E, Schuldiner M. Systematic analysis of membrane contact sites in Saccharomyces cerevisiae uncovers modulators of cellular lipid distribution. eLife 2022; 11:74602. [DOI: 10.7554/elife.74602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
Actively maintained close appositions between organelle membranes, also known as contact sites, enable the efficient transfer of biomolecules between cellular compartments. Several such sites have been described as well as their tethering machineries. Despite these advances we are still far from a comprehensive understanding of the function and regulation of most contact sites. To systematically characterize contact site proteomes, we established a high-throughput screening approach in Saccharomyces cerevisiae based on co-localization imaging. We imaged split fluorescence reporters for six different contact sites, several of which are poorly characterized, on the background of 1165 strains expressing a mCherry-tagged yeast protein that has a cellular punctate distribution (a hallmark of contact sites), under regulation of the strong TEF2 promoter. By scoring both co-localization events and effects on reporter size and abundance, we discovered over 100 new potential contact site residents and effectors in yeast. Focusing on several of the newly identified residents, we identified three homologs of Vps13 and Atg2 that are residents of multiple contact sites. These proteins share their lipid transport domain, thus expanding this family of lipid transporters. Analysis of another candidate, Ypr097w, which we now call Lec1 (Lipid-droplet Ergosterol Cortex 1), revealed that this previously uncharacterized protein dynamically shifts between lipid droplets and the cell cortex, and plays a role in regulation of ergosterol distribution in the cell. Overall, our analysis expands the universe of contact site residents and effectors and creates a rich database to mine for new functions, tethers, and regulators.
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Affiliation(s)
| | - Shawn P Shortill
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
- Department of Medical Genetics, University of British Columbia
| | - Samantha Katarzyna Dziurdzik
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
- Department of Medical Genetics, University of British Columbia
| | - Angela Cadou
- Laboratory for Molecular Cell Biology, University College London
| | | | - Rosario Valenti
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Yotam David
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
| | - Carsten Mattes
- Medical Biochemistry and Molecular Biology, PZMS, Medical Faculty, Saarland University
| | - Ffion B Thomas
- Laboratory for Molecular Cell Biology, University College London
| | | | - Hadar Meyer
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Amir Fadel
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Emma J Fenech
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Robert Ernst
- Medical Biochemistry and Molecular Biology, PZMS, Medical Faculty, Saarland University
| | | | - Tim P Levine
- UCL Institute of Ophthalmology, University College London
| | | | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
- Department of Medical Genetics, University of British Columbia
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science
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21
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Deori NM, Nagotu S. Peroxisome biogenesis and inter-organelle communication: an indispensable role for Pex11 and Pex30 family proteins in yeast. Curr Genet 2022; 68:537-550. [PMID: 36242632 DOI: 10.1007/s00294-022-01254-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/26/2022]
Abstract
Peroxisomes are highly dynamic organelles present in most eukaryotic cells. They also play an important role in human health and the optimum functioning of cells. An extensive repertoire of proteins is associated with the biogenesis and function of these organelles. Two protein families that are involved in regulating peroxisome number in a cell directly or indirectly are Pex11 and Pex30. Interestingly, these proteins are also reported to regulate the contact sites between peroxisomes and other cell organelles such as mitochondria, endoplasmic reticulum and lipid droplets. In this manuscript, we review our current knowledge of the role of these proteins in peroxisome biogenesis in various yeast species. Further, we also discuss in detail the role of these protein families in the regulation of inter-organelle contacts in yeast.
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Affiliation(s)
- Nayan Moni Deori
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
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22
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Bittner E, Stehlik T, Freitag J. Sharing the wealth: The versatility of proteins targeted to peroxisomes and other organelles. Front Cell Dev Biol 2022; 10:934331. [PMID: 36225313 PMCID: PMC9549241 DOI: 10.3389/fcell.2022.934331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Peroxisomes are eukaryotic organelles with critical functions in cellular energy and lipid metabolism. Depending on the organism, cell type, and developmental stage, they are involved in numerous other metabolic and regulatory pathways. Many peroxisomal functions require factors also relevant to other cellular compartments. Here, we review proteins shared by peroxisomes and at least one different site within the cell. We discuss the mechanisms to achieve dual targeting, their regulation, and functional consequences. Characterization of dual targeting is fundamental to understand how peroxisomes are integrated into the metabolic and regulatory circuits of eukaryotic cells.
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Affiliation(s)
| | | | - Johannes Freitag
- Department of Biology, Philipps-University Marburg, Marburg, Germany
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23
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Guyard V, Monteiro-Cardoso VF, Omrane M, Sauvanet C, Houcine A, Boulogne C, Ben Mbarek K, Vitale N, Faklaris O, El Khallouki N, Thiam AR, Giordano F. ORP5 and ORP8 orchestrate lipid droplet biogenesis and maintenance at ER-mitochondria contact sites. J Cell Biol 2022; 221:e202112107. [PMID: 35969857 PMCID: PMC9375143 DOI: 10.1083/jcb.202112107] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/30/2022] [Accepted: 07/05/2022] [Indexed: 12/29/2022] Open
Abstract
Lipid droplets (LDs) are the primary organelles of lipid storage, buffering energy fluctuations of the cell. They store neutral lipids in their core that is surrounded by a protein-decorated phospholipid monolayer. LDs arise from the endoplasmic reticulum (ER). The ER protein seipin, localizing at ER-LD junctions, controls LD nucleation and growth. However, how LD biogenesis is spatially and temporally coordinated remains elusive. Here, we show that the lipid transfer proteins ORP5 and ORP8 control LD biogenesis at mitochondria-associated ER membrane (MAM) subdomains, enriched in phosphatidic acid. We found that ORP5/8 regulates seipin recruitment to these MAM-LD contacts, and their loss impairs LD biogenesis. Importantly, the integrity of ER-mitochondria contact sites is crucial for ORP5/8 function in regulating seipin-mediated LD biogenesis. Our study uncovers an unprecedented ORP5/8 role in orchestrating LD biogenesis and maturation at MAMs and brings novel insights into the metabolic crosstalk between mitochondria, ER, and LDs at the membrane contact sites.
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Affiliation(s)
- Valentin Guyard
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Vera Filipa Monteiro-Cardoso
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Mohyeddine Omrane
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Cécile Sauvanet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Audrey Houcine
- Institut Jacques Monod, CNRS, UMR7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Claire Boulogne
- Imagerie-Gif, Electron Microscopy Facility, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Kalthoum Ben Mbarek
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, UPR-321267000 Strasbourg, France
| | - Orestis Faklaris
- MRI, BioCampus Montpellier, CRBM, Univ. Montpellier, CNRS, Montpellier, France
| | - Naima El Khallouki
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Francesca Giordano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
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24
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Renne MF, Corey RA, Ferreira JV, Stansfeld PJ, Carvalho P. Seipin concentrates distinct neutral lipids via interactions with their acyl chain carboxyl esters. J Cell Biol 2022; 221:e202112068. [PMID: 35938957 PMCID: PMC9365673 DOI: 10.1083/jcb.202112068] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 05/28/2022] [Accepted: 07/12/2022] [Indexed: 11/22/2022] Open
Abstract
Lipid droplets (LDs) are essential for cellular lipid homeostasis by storing diverse neutral lipids (NLs), such as triacylglycerol (TAG), steryl esters (SE), and retinyl esters (RE). A proper assembly of TAG-containing LDs at the ER requires Seipin, a conserved protein often mutated in lipodystrophies. Here, we show that the yeast Seipin Sei1 and its partner Ldb16 also promote the storage of other NL in LDs. Importantly, this role of Sei1/Ldb16 is evolutionarily conserved as expression of human-Seipin restored normal SE-containing LDs in yeast Seipin mutants. As in the case of TAG, the formation of SE-containing LDs requires interactions between hydroxyl-residues in human Seipin or yeast Ldb16 with NL carboxyl esters. These findings provide a universal mechanism for Seipin-mediated LD formation and suggest a model for how Seipin distinguishes NLs from aliphatic phospholipid acyl chains in the center of the membrane bilayer.
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Affiliation(s)
- Mike F. Renne
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Robin A. Corey
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Phillip J. Stansfeld
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences and Department of Chemistry, University of Warwick, Coventry, UK
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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25
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Wu F, van der Klei IJ. Structure–function analysis of the ER-peroxisome contact site protein Pex32. Front Cell Dev Biol 2022; 10:957871. [PMID: 36016650 PMCID: PMC9395739 DOI: 10.3389/fcell.2022.957871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
In the yeast Hansenula polymorpha, the ER protein Pex32 is required for associating peroxisomes to the ER. Here, we report on a structure–function analysis of Pex32. Localization studies of various Pex32 truncations showed that the N-terminal transmembrane domain of Pex32 is responsible for sorting. Moreover, this part of the protein is sufficient for the function of Pex32 in peroxisome biogenesis. The C-terminal DysF domain is required for concentrating Pex32 at ER-peroxisome contact sites and has the ability to bind to peroxisomes. In order to better understand the role of Pex32 in peroxisome biogenesis, we analyzed various peroxisomal proteins in pex32 cells. This revealed that Pex11 levels are strongly reduced in pex32 cells. This may explain the strong reduction in peroxisome numbers in pex32 cells, which also occurs in cells lacking Pex11.
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Wang Y, Li C, Zhang J, Xu X, Fu L, Xu J, Zhu H, Hu Y, Li C, Wang M, Wu Y, Zou X, Liang B. Polyunsaturated fatty acids promote the rapid fusion of lipid droplets in Caenorhabditis elegans. J Biol Chem 2022; 298:102179. [PMID: 35752365 PMCID: PMC9352923 DOI: 10.1016/j.jbc.2022.102179] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/27/2022] Open
Abstract
Lipid droplets (LDs) are intracellular organelles that dynamically regulate lipids and energy homeostasis in the cell. LDs can grow through either local lipid synthesis or LD fusion. However, how lipids involving in LD fusion for LD growth is largely unknown. Here, we show that genetic mutation of acox-3 (acyl-CoA oxidase), maoc-1 (enoyl-CoA hydratase), dhs-28 (3-hydroxylacyl-CoA dehydrogenase), and daf-22 (3-ketoacyl-CoA thiolase), all involved in the peroxisomal β-oxidation pathway in Caenorhabditis elegans, led to rapid fusion of adjacent LDs to form giant LDs (gLDs). Mechanistically, we show that dysfunction of peroxisomal β-oxidation results in the accumulation of long-chain fatty acid-CoA and phosphocholine, which may activate the sterol-binding protein 1/sterol regulatory element-binding protein to promote gLD formation. Furthermore, we found that inactivation of either FAT-2 (delta-12 desaturase) or FAT-3 and FAT-1 (delta-15 desaturase and delta-6 desaturase, respectively) to block the biosynthesis of polyunsaturated fatty acids (PUFAs) with three or more double bonds (n≥3-PUFAs) fully repressed the formation of gLDs; in contrast, dietary supplementation of n≥3-PUFAs or phosphocholine bearing these PUFAs led to recovery of the formation of gLDs in peroxisomal β-oxidation-defective worms lacking PUFA biosynthesis. Thus, we conclude that n≥3-PUFAs, distinct from other well-known lipids and proteins, promote rapid LD fusion leading to LD growth.
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Affiliation(s)
- Yanli Wang
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Chunxia Li
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Jingjing Zhang
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Xiumei Xu
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Lin Fu
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Jie Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan province, Kunming Institute of Zoology, CAS, Kunming, Yunnan, China
| | - Hong Zhu
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Ying Hu
- College of Chinese Materia Medica and Yunnan Key Laboratory of Southern Medicinal Utilization, Yunnan University of Chinese Medicine, Kunming, Yunnan, China
| | - Chengbin Li
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Mengjie Wang
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Yingjie Wu
- Shandong Provincial Hospital, School of Laboratory Animal & Shandong Laboratory Animal Center, Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China; Institute for Genome Engineered Animal Models of Human Diseases, National Center of Genetically Engineered Animal Models for International Research, Liaoning Provence Key Lab of Genome Engineered Animal Models Dalian Medical University, Dalian, Liaoning, China.
| | - Xiaoju Zou
- College of Chinese Materia Medica and Yunnan Key Laboratory of Southern Medicinal Utilization, Yunnan University of Chinese Medicine, Kunming, Yunnan, China.
| | - Bin Liang
- Center for Life Sciences, School of Life Sciences, State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China.
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Li Y, Yang X, Peng L, Xia Q, Zhang Y, Huang W, Liu T, Jia D. Role of Seipin in Human Diseases and Experimental Animal Models. Biomolecules 2022; 12:biom12060840. [PMID: 35740965 PMCID: PMC9221541 DOI: 10.3390/biom12060840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 02/05/2023] Open
Abstract
Seipin, a protein encoded by the Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) gene, is famous for its key role in the biogenesis of lipid droplets and type 2 congenital generalised lipodystrophy (CGL2). BSCL2 gene mutations result in genetic diseases including CGL2, progressive encephalopathy with or without lipodystrophy (also called Celia’s encephalopathy), and BSCL2-associated motor neuron diseases. Abnormal expression of seipin has also been found in hepatic steatosis, neurodegenerative diseases, glioblastoma stroke, cardiac hypertrophy, and other diseases. In the current study, we comprehensively summarise phenotypes, underlying mechanisms, and treatment of human diseases caused by BSCL2 gene mutations, paralleled by animal studies including systemic or specific Bscl2 gene knockout, or Bscl2 gene overexpression. In various animal models representing diseases that are not related to Bscl2 mutations, differential expression patterns and functional roles of seipin are also described. Furthermore, we highlight the potential therapeutic approaches by targeting seipin or its upstream and downstream signalling pathways. Taken together, restoring adipose tissue function and targeting seipin-related pathways are effective strategies for CGL2 treatment. Meanwhile, seipin-related pathways are also considered to have potential therapeutic value in diseases that are not caused by BSCL2 gene mutations.
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Affiliation(s)
- Yuying Li
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Xinmin Yang
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Linrui Peng
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China; (L.P.); (Y.Z.)
| | - Qing Xia
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Yuwei Zhang
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China; (L.P.); (Y.Z.)
| | - Wei Huang
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
- Institutes for Systems Genetics & Immunology and Inflammation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (W.H.); (T.L.)
| | - Tingting Liu
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
- Correspondence: (W.H.); (T.L.)
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu 610041, China;
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28
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Gong J, Peng Y, Yu J, Pei W, Zhang Z, Fan D, Liu L, Xiao X, Liu R, Lu Q, Li P, Shang H, Shi Y, Li J, Ge Q, Liu A, Deng X, Fan S, Pan J, Chen Q, Yuan Y, Gong W. Linkage and association analyses reveal that hub genes in energy-flow and lipid biosynthesis pathways form a cluster in upland cotton. Comput Struct Biotechnol J 2022; 20:1841-1859. [PMID: 35521543 PMCID: PMC9046884 DOI: 10.1016/j.csbj.2022.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 11/25/2022] Open
Abstract
Upland cotton is an important allotetraploid crop that provides both natural fiber for the textile industry and edible vegetable oil for the food or feed industry. To better understand the genetic mechanism that regulates the biosynthesis of storage oil in cottonseed, we identified the genes harbored in the major quantitative trait loci/nucleotides (QTLs/QTNs) of kernel oil content (KOC) in cottonseed via both multiple linkage analyses and genome-wide association studies (GWAS). In ‘CCRI70′ RILs, six stable QTLs were simultaneously identified by linkage analysis of CHIP and SLAF-seq strategies. In ‘0-153′ RILs, eight stable QTLs were detected by consensus linkage analysis integrating multiple strategies. In the natural panel, thirteen and eight loci were associated across multiple environments with two algorithms of GWAS. Within the confidence interval of a major common QTL on chromosome 3, six genes were identified as participating in the interaction network highly correlated with cottonseed KOC. Further observations of gene differential expression showed that four of the genes, LtnD, PGK, LPLAT1, and PAH2, formed hub genes and two of them, FER and RAV1, formed the key genes in the interaction network. Sequence variations in the coding regions of LtnD, FER, PGK, LPLAT1, and PAH2 genes may support their regulatory effects on oil accumulation in mature cottonseed. Taken together, clustering of the hub genes in the lipid biosynthesis interaction network provides new insights to understanding the mechanism of fatty acid biosynthesis and TAG assembly and to further genetic improvement projects for the KOC in cottonseeds.
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Affiliation(s)
- Juwu Gong
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- Engineering Research Centre of Cotton, Ministry of Education, College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830052, Xinjiang, China
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Yan Peng
- Third Division of the Xinjiang Production and Construction Corps Agricultural Research Institute, Tumushuke, Xijiang 843900, China
| | - Jiwen Yu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Wenfeng Pei
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Zhen Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Daoran Fan
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Linjie Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- Engineering Research Centre of Cotton, Ministry of Education, College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830052, Xinjiang, China
| | - Xianghui Xiao
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- Engineering Research Centre of Cotton, Ministry of Education, College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830052, Xinjiang, China
| | - Ruixian Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- Engineering Research Centre of Cotton, Ministry of Education, College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830052, Xinjiang, China
| | - Quanwei Lu
- College of Biotechnology and Food Engineering, Anyang Institute of Technology, Anyang, China
| | - Pengtao Li
- College of Biotechnology and Food Engineering, Anyang Institute of Technology, Anyang, China
| | - Haihong Shang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Yuzhen Shi
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Junwen Li
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Qun Ge
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Aiying Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Xiaoying Deng
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Senmiao Fan
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Jingtao Pan
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
| | - Quanjia Chen
- Engineering Research Centre of Cotton, Ministry of Education, College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830052, Xinjiang, China
| | - Youlu Yuan
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
- Engineering Research Centre of Cotton, Ministry of Education, College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830052, Xinjiang, China
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Wankui Gong
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China
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29
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Schneiter R, Choudhary V. Seipin collaborates with the ER membrane to control the sites of lipid droplet formation. Curr Opin Cell Biol 2022; 75:102070. [PMID: 35306312 PMCID: PMC7615794 DOI: 10.1016/j.ceb.2022.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 12/24/2022]
Abstract
Most cells store metabolic energy in lipid droplets (LDs). LDs are composed of a hydrophobic core, covered by a phospholipid monolayer, and functionalized by a specific set of proteins. Formation of LDs takes place in the endoplasmic reticulum (ER), where neutral lipid biosynthetic enzymes are located. Recent evidence indicate that this process is confined to specific ER subdomains, where proteins meet to initiate LD assembly. The lipodystrophy protein Seipin, is emerging as a major coordinator of LD biogenesis. Seipin forms a large oligomeric toroidal structure, which traps neutral lipids to promote LD nucleation. Here, we discuss the role of LD biogenesis factors that associate with Seipin to assemble functional LDs.
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Affiliation(s)
- Roger Schneiter
- University of Fribourg, Department of Biology, 1700, Fribourg, Switzerland.
| | - Vineet Choudhary
- All India Institute of Medical Sciences (AIIMS), Department of Biotechnology, New Delhi, 110029, India.
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30
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Pressly JD, Gurumani MZ, Varona Santos JT, Fornoni A, Merscher S, Al-Ali H. Adaptive and maladaptive roles of lipid droplets in health and disease. Am J Physiol Cell Physiol 2022; 322:C468-C481. [PMID: 35108119 PMCID: PMC8917915 DOI: 10.1152/ajpcell.00239.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Advances in the understanding of lipid droplet biology have revealed essential roles for these organelles in mediating proper cellular homeostasis and stress response. Lipid droplets were initially thought to play a passive role in energy storage. However, recent studies demonstrate that they have substantially broader functions, including protection from reactive oxygen species, endoplasmic reticulum stress, and lipotoxicity. Dysregulation of lipid droplet homeostasis is associated with various pathologies spanning neurological, metabolic, cardiovascular, oncological, and renal diseases. This review provides an overview of the current understanding of lipid droplet biology in both health and disease.
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Affiliation(s)
- Jeffrey D. Pressly
- 1Katz Division of Nephrology and Hypertension and Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, Florida,2Department of Medicine, University of Miami, Miller School of Medicine, Miami, Florida
| | - Margaret Z. Gurumani
- 1Katz Division of Nephrology and Hypertension and Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, Florida,2Department of Medicine, University of Miami, Miller School of Medicine, Miami, Florida
| | - Javier T. Varona Santos
- 1Katz Division of Nephrology and Hypertension and Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, Florida,2Department of Medicine, University of Miami, Miller School of Medicine, Miami, Florida
| | - Alessia Fornoni
- 1Katz Division of Nephrology and Hypertension and Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, Florida,2Department of Medicine, University of Miami, Miller School of Medicine, Miami, Florida
| | - Sandra Merscher
- 1Katz Division of Nephrology and Hypertension and Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, Florida,2Department of Medicine, University of Miami, Miller School of Medicine, Miami, Florida
| | - Hassan Al-Ali
- 1Katz Division of Nephrology and Hypertension and Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, Florida,2Department of Medicine, University of Miami, Miller School of Medicine, Miami, Florida,3Department of Neurological Surgery, University of Miami, Miller School of Medicine, Miami, Florida,4The Miami Project to Cure Paralysis, University of Miami, Miller School of Medicine, Miami, Florida,5Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, Miami, Florida
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31
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Deori NM, Infant T, Sundaravadivelu PK, Thummer RP, Nagotu S. Pex30 undergoes phosphorylation and regulates peroxisome number in Saccharomyces cerevisiae. Mol Genet Genomics 2022; 297:573-590. [PMID: 35218395 DOI: 10.1007/s00438-022-01872-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/08/2022] [Indexed: 10/19/2022]
Abstract
Pex30 is a dysferlin domain-containing protein whose role in peroxisome biogenesis has been studied by several research groups. Notably, recent studies have linked this protein to peroxisomes, endoplasmic reticulum and lipid bodies in Saccharomyces cerevisiae. Phosphoproteome studies of S. cerevisiae have identified several phosphorylation sites in Pex30. In this study we expressed and purified Pex30 from its native host. Analysis of the purified protein by circular dichroism spectroscopy showed that it retained its secondary structure and revealed primarily a helical structure. Further phosphorylation of Pex30 at three residues, Threonine 60, Serine 61 and Serine 511 was identified by mass spectrometry in this study. To understand the importance of this post-translational modification in peroxisome biogenesis, the identified residues were mutated to both non-phosphorylatable (alanine) and phosphomimetic (aspartic acid) variants. Upon analysis of the mutant variants by fluorescence microscopy, no alteration in the localization of the protein to ER and peroxisomes was observed. Interestingly, reduced number of peroxisomes were observed in cells expressing phosphomimetic mutations when cultured in peroxisome-inducing conditions. Our data suggest that phosphorylation and dephosphorylation of Pex30 may promote distinct interactions essential in regulating peroxisome number in a cell.
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Affiliation(s)
- Nayan Moni Deori
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | - Terence Infant
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | - Pradeep Kumar Sundaravadivelu
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | - Rajkumar P Thummer
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India.
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32
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Liao PC, Yang EJ, Borgman T, Boldogh IR, Sing CN, Swayne TC, Pon LA. Touch and Go: Membrane Contact Sites Between Lipid Droplets and Other Organelles. Front Cell Dev Biol 2022; 10:852021. [PMID: 35281095 PMCID: PMC8908909 DOI: 10.3389/fcell.2022.852021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/03/2022] [Indexed: 12/26/2022] Open
Abstract
Lipid droplets (LDs) have emerged not just as storage sites for lipids but as central regulators of metabolism and organelle quality control. These critical functions are achieved, in part, at membrane contact sites (MCS) between LDs and other organelles. MCS are sites of transfer of cellular constituents to or from LDs for energy mobilization in response to nutrient limitations, as well as LD biogenesis, expansion and autophagy. Here, we describe recent findings on the mechanisms underlying the formation and function of MCS between LDs and mitochondria, ER and lysosomes/vacuoles and the role of the cytoskeleton in promoting LD MCS through its function in LD movement and distribution in response to environmental cues.
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Affiliation(s)
- Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Emily J. Yang
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
| | - Taylor Borgman
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Istvan R. Boldogh
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, United States
| | - Cierra N. Sing
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Theresa C. Swayne
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, United States
| | - Liza A. Pon
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
- *Correspondence: Liza A. Pon,
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33
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Yuan W, Akşit A, de Boer R, Krikken AM, van der Klei IJ. Yeast Vps13 is Crucial for Peroxisome Expansion in Cells With Reduced Peroxisome-ER Contact Sites. Front Cell Dev Biol 2022; 10:842285. [PMID: 35252206 PMCID: PMC8891532 DOI: 10.3389/fcell.2022.842285] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/28/2022] [Indexed: 12/22/2022] Open
Abstract
In the yeast Hansenula polymorpha the peroxisomal membrane protein Pex11 and three endoplasmic reticulum localized proteins of the Pex23 family (Pex23, Pex24 and Pex32) are involved in the formation of peroxisome-ER contact sites. Previous studies suggested that these contacts are involved in non-vesicular lipid transfer and important for expansion of the peroxisomal membrane. The absence of Pex32 results in a severe peroxisomal phenotype, while cells lacking Pex11, Pex23 or Pex24 show milder defects and still are capable to form peroxisomes and grow on methanol. We performed transposon mutagenesis on H. polymorpha pex11 cells and selected mutants that lost the capacity to grow on methanol and are severely blocked in peroxisome formation. This strategy resulted in the identification of Vps13, a highly conserved contact site protein involved in bulk lipid transfer. Our data show that peroxisome formation and function is normal in cells of a vps13 single deletion strain. However, Vps13 is essential for peroxisome biogenesis in pex11. Notably, Vps13 is also required for peroxisome formation in pex23 and pex24 cells. These data suggest that Vps13 is crucial for peroxisome formation in cells with reduced peroxisome-endoplasmic reticulum contact sites and plays a redundant function in lipid transfer from the ER to peroxisomes.
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34
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Magré J, Prieur X. Seipin Deficiency as a Model of Severe Adipocyte Dysfunction: Lessons from Rodent Models and Teaching for Human Disease. Int J Mol Sci 2022; 23:740. [PMID: 35054926 PMCID: PMC8775404 DOI: 10.3390/ijms23020740] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 02/05/2023] Open
Abstract
Obesity prevalence is increasing worldwide, leading to cardiometabolic morbidities. Adipocyte dysfunction, impairing white adipose tissue (WAT) expandability and metabolic flexibility, is central in the development of obesity-related metabolic complications. Rare syndromes of lipodystrophy characterized by an extreme paucity of functional adipose tissue should be considered as primary adipocyte dysfunction diseases. Berardinelli-Seip congenital lipodystrophy (BSCL) is the most severe form with a near absence of WAT associated with cardiometabolic complications such as insulin resistance, liver steatosis, dyslipidemia, and cardiomyopathy. Twenty years ago, mutations in the BSCL2 gene have been identified as the cause of BSCL in human. BSCL2 encodes seipin, an endoplasmic reticulum (ER) anchored protein whose function was unknown back then. Studies of seipin knockout mice or rats demonstrated how seipin deficiency leads to severe lipodystrophy and to cardiometabolic complications. At the cellular levels, seipin is organized in multimers that are particularly enriched at ER/lipid droplet and ER/mitochondria contact sites. Seipin deficiency impairs both adipocyte differentiation and mature adipocyte maintenance. Experiments using adipose tissue transplantation in seipin knockout mice and tissue-specific deletion of seipin have provided a large body of evidence that liver steatosis, cardiomyopathy, and renal injury, classical diabetic complications, are all consequences of lipodystrophy. Rare adipocyte dysfunctions such as in BSCL are the key paradigm to unravel the pathways that control adipocyte homeostasis. The knowledge gathered through the study of these pathologies may bring new strategies to maintain and improve adipose tissue expandability.
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Affiliation(s)
| | - Xavier Prieur
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, L’institut du Thorax, Université de Nantes, F-44000 Nantes, France;
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Lipid Droplet-a New Target in Ischemic Heart Disease. J Cardiovasc Transl Res 2022; 15:730-739. [PMID: 34984637 DOI: 10.1007/s12265-021-10204-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/22/2021] [Indexed: 10/19/2022]
Abstract
Lipid droplet (LD) is a kind of subcellular organelle, which originates from the endoplasmic reticulum (ER). LDs can move flexibly between other organelles and store energy in the cells. In recent years, LDs and lipid droplet-associated proteins have attracted added attention at home and abroad, especially in cardiovascular diseases. Cardiovascular diseases, especially ischemic heart disease (IHD), have always been the focus of attention because of their high morbidity and mortality. Atherosclerosis and myocardial remodeling are two important pathologic processes of IHD, and LDs and other organelles are involved in the development of the disease. The interaction between LDs and ER is involved in the formation of foam cells in atherosclerosis. And LDs, mitochondria, and lysosomes also affect the remodeling of cardiomyocytes by affecting ROS production and regulating PI3K/AKT pathways. In this article, we will review the role of LDs in IHD.
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36
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Joshi AS. Peroxisomal Membrane Contact Sites in Yeasts. Front Cell Dev Biol 2021; 9:735031. [PMID: 34869317 PMCID: PMC8640217 DOI: 10.3389/fcell.2021.735031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Peroxisomes are ubiquitous, single membrane-bound organelles that play a crucial role in lipid metabolism and human health. While peroxisome number is maintained by the division of existing peroxisomes, nascent peroxisomes can be generated from the endoplasmic reticulum (ER) membrane in yeasts. During formation and proliferation, peroxisomes maintain membrane contacts with the ER. In addition to the ER, contacts between peroxisomes and other organelles such as lipid droplets, mitochondria, vacuole, and plasma membrane have been reported. These membrane contact sites (MCS) are dynamic and important for cellular function. This review focuses on the recent developments in peroxisome biogenesis and the functional importance of peroxisomal MCS in yeasts.
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Affiliation(s)
- Amit S Joshi
- Department of Biochemistry and Cell and Molecular Biology, University of Tennessee, Knoxville, TN, United States
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37
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Hello from the other side: Membrane contact of lipid droplets with other organelles and subsequent functional implications. Prog Lipid Res 2021; 85:101141. [PMID: 34793861 DOI: 10.1016/j.plipres.2021.101141] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 02/06/2023]
Abstract
Lipid droplets (LDs) are ubiquitous organelles that play crucial roles in response to physiological and environmental cues. The identification of several neutral lipid synthesizing and regulatory protein complexes have propelled significant advance on the mechanisms of LD biogenesis in the endoplasmic reticulum (ER). Increasing evidence suggests that distinct proteins and regulatory factors, which localize to membrane contact sites (MCS), are involved not only in interorganellar lipid exchange and transport, but also function in other important cellular processes, including autophagy, mitochondrial dynamics and inheritance, ion signaling and inter-regulation of these MCS. More and more tethers and molecular determinants are associated to MCS and to a diversity of cellular and pathophysiological processes, demonstrating the dynamics and importance of these junctions in health and disease. The conjugation of lipids with proteins in supramolecular complexes is known to be paramount for many biological processes, namely membrane biosynthesis, cell homeostasis, regulation of organelle division and biogenesis, and cell growth. Ultimately, this physical organization allows the contact sites to function as crucial metabolic hubs that control the occurrence of chemical reactions. This leads to biochemical and metabolite compartmentalization for the purposes of energetic efficiency and cellular homeostasis. In this review, we will focus on the structural and functional aspects of LD-organelle interactions and how they ensure signaling exchange and metabolites transfer between organelles.
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38
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Ajjaji D, Ben M'barek K, Boson B, Omrane M, Gassama-Diagne A, Blaud M, Penin F, Diaz E, Ducos B, Cosset FL, Thiam AR. Hepatitis C virus core protein uses triacylglycerols to fold onto the endoplasmic reticulum membrane. Traffic 2021; 23:63-80. [PMID: 34729868 DOI: 10.1111/tra.12825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/16/2021] [Accepted: 11/01/2021] [Indexed: 12/12/2022]
Abstract
Lipid droplets (LDs) are involved in viral infections, but exactly how remains unclear. Here, we study the hepatitis C virus (HCV) whose core capsid protein binds to LDs but is also involved in the assembly of virions at the endoplasmic reticulum (ER) bilayer. We found that the amphipathic helix-containing domain of core, D2, senses triglycerides (TGs) rather than LDs per se. In the absence of LDs, D2 can bind to the ER membrane but only if TG molecules are present in the bilayer. Accordingly, the pharmacological inhibition of the diacylglycerol O-acyltransferase enzymes, mediating TG synthesis in the ER, inhibits D2 association with the bilayer. We found that TG molecules enable D2 to fold into alpha helices. Sequence analysis reveals that D2 resembles the apoE lipid-binding region. Our data support that TG in LDs promotes the folding of core, which subsequently relocalizes to contiguous ER regions. During this motion, core may carry TG molecules to these regions where HCV lipoviroparticles likely assemble. Consistent with this model, the inhibition of Arf1/COPI, which decreases LD surface accessibility to proteins and ER-LD material exchange, severely impedes the assembly of virions. Altogether, our data uncover a critical function of TG in the folding of core and HCV replication and reveals, more broadly, how TG accumulation in the ER may provoke the binding of soluble amphipathic helix-containing proteins to the ER bilayer.
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Affiliation(s)
- Dalila Ajjaji
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, Paris, 75005, France
| | - Kalthoum Ben M'barek
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, Paris, 75005, France
| | - Bertrand Boson
- CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Mohyeddine Omrane
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, Paris, 75005, France
| | - Ama Gassama-Diagne
- INSERM, Unité 1193, Villejuif, France.,Université Paris-Sud, UMR-S 1193, Villejuif, France
| | - Magali Blaud
- Université de Paris, CiTCoM, CNRS, Paris, France
| | - François Penin
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, UMR 5086, CNRS, Labex Ecofect, University of Lyon, Lyon, France
| | - Elise Diaz
- High Throughput qPCR Core Facility of the ENS, IBENS, PSL Research University, Paris, France
| | - Bertrand Ducos
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, Paris, 75005, France.,High Throughput qPCR Core Facility of the ENS, IBENS, PSL Research University, Paris, France
| | - François-Loïc Cosset
- CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, Paris, 75005, France
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Lalioti V, Beznoussenko GV, Mironov AA, Sandoval IV. The E-Syt3 cleavage and traffic uncovers the primordial cisterna, a new organelle that mothers the lipid droplets in the adipocyte. Traffic 2021; 23:21-41. [PMID: 34693607 DOI: 10.1111/tra.12823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/21/2021] [Indexed: 12/27/2022]
Abstract
Extended synaptotagmins are endoplasmic reticulum proteins consisting of an SMP domain and multiple C2 domains that bind phospholipids and Ca2+ . E-Syts create contact junctions between the ER and plasma membrane (PM) to facilitate the exchange of glycerophospholipids between the apposed membranes. We find in the differentiating adipocyte that the E-Syt3 carboxyl domain is cleaved by a multi-step mechanism that includes removing the C2C domain. Confocal and live-cell time-lapse studies show that truncated E-Syt3ΔC2C, as well as endogenous E-Syt3 and the coat protein PLIN1, target the LDs from an annular, single giant ER cisterna. Inhibition of the proteasome blocks the proteolytic cleavage of Esyt3 and E-Syt3ΔC2C and causes the E-Syt3ΔC2C retention in the giant cisterna. The Esyt3 and PLIN1 distributions and LDs biogenesis show that the primordial cisterna, as we call it, is the birth and nurturing site of LDs in the adipocyte. Isoproterenol-induced lipolysis results in loss of cytoplasmic LDs and reappearance of the primordial cisterna. Electron microscopy and 3D-electron tomography studies show that the primordial cisterna consists of a tightly packed network of varicose tubules with extensively blistered membranes. Rounds of homotypic fusions from nascent to mature LDs play a central role in LD growth. The knockdown of E-Syt3 inhibits LD biogenesis. The identification of the primordial cisterna, an organelle that substitutes the randomly scattered ER foci that mother the LDs in non-adipose cells, sets the stage for a better understanding of LD biogenesis in the adipocyte.
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Affiliation(s)
- Vasiliki Lalioti
- Centro de Biología Molecular Severo Ochoa, Department of Cell Biology and Immunology, Physiological and Pathological Processes, Madrid, Spain
| | - Galina V Beznoussenko
- Laboratory of Electron Microscopy, The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Alexander A Mironov
- Laboratory of Electron Microscopy, The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Ignacio V Sandoval
- Centro de Biología Molecular Severo Ochoa, Department of Cell Biology and Immunology, Physiological and Pathological Processes, Madrid, Spain
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40
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Ferreira JV, Carvalho P. Pex30-like proteins function as adaptors at distinct ER membrane contact sites. J Cell Biol 2021; 220:212563. [PMID: 34402813 PMCID: PMC8374871 DOI: 10.1083/jcb.202103176] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/19/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022] Open
Abstract
Membrane lipids and proteins synthesized in the ER are used for de novo assembly of organelles, such as lipid droplets and peroxisomes. After assembly, the growth of these organelles is supported by ER-derived lipids transferred at membrane contact sites (MCSs). How ER sites for organelle biogenesis and lipid transfer are established and regulated is unclear. Here, we investigate how the ER membrane protein Pex30 and its family members Pex28, Pex29, Pex31, and Pex32 target and function at multiple MCSs. We show that different Pex30 complexes function at distinct ER domains and MCSs. Pex30 targets ER–peroxisome MCSs when bound to Pex28 and Pex32, organizes the nuclear–vacuolar junction when bound to Pex29, and promotes the biogenesis of lipid droplets independently of other family members. Importantly, the reticulon homology domain (RHD) mediates the assembly of the various Pex30 complexes. Given the role of RHD in membrane shaping, our findings offer a mechanistic link between MCS and regulation of membrane curvature.
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Affiliation(s)
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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41
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Renne MF, Hariri H. Lipid Droplet-Organelle Contact Sites as Hubs for Fatty Acid Metabolism, Trafficking, and Metabolic Channeling. Front Cell Dev Biol 2021; 9:726261. [PMID: 34595176 PMCID: PMC8477659 DOI: 10.3389/fcell.2021.726261] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/12/2021] [Indexed: 01/21/2023] Open
Abstract
Cells prepare for fluctuations in nutrient availability by storing energy in the form of neutral lipids in organelles called Lipid Droplets (LDs). Upon starvation, fatty acids (FAs) released from LDs are trafficked to different cellular compartments to be utilized for membrane biogenesis or as a source of energy. Despite the biochemical pathways being known in detail, the spatio-temporal regulation of FA synthesis, storage, release, and breakdown is not completely understood. Recent studies suggest that FA trafficking and metabolism are facilitated by inter-organelle contact sites that form between LDs and other cellular compartments such as the Endoplasmic Reticulum (ER), mitochondria, peroxisomes, and lysosomes. LD-LD contact sites are also sites where FAs are transferred in a directional manner to support LD growth and expansion. As the storage site of neutral lipids, LDs play a central role in FA homeostasis. In this mini review, we highlight the role of LD contact sites with other organelles in FA trafficking, channeling, and metabolism and discuss the implications for these pathways on cellular lipid and energy homeostasis.
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Affiliation(s)
- Mike F. Renne
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
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42
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Rao MJ, Goodman JM. Seipin: harvesting fat and keeping adipocytes healthy. Trends Cell Biol 2021; 31:912-923. [PMID: 34215489 DOI: 10.1016/j.tcb.2021.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 01/17/2023]
Abstract
Seipin is a key protein in the assembly of cytoplasmic lipid droplets (cLDs) and their maintenance at endoplasmic reticulum (ER)-LD junctions; the absence of seipin results in generalized lipodystrophy. How seipin mediates LD dynamics and prevents lipodystrophy are not well understood. New evidence suggests that seipin attracts triglyceride monomers from the ER to sites of droplet formation. By contrast, seipin may not be directly involved in the assembly of nuclear LDs and may actually suppress their formation at a distance. Seipin promotes adipogenesis, but lipodystrophy may also involve postadipogenic effects. We hypothesize that among these are a cycle of runaway lipolysis and lipotoxicity caused by aberrant LDs, resulting in a depletion of fat stores and a failure of adipose and other cells to thrive.
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Affiliation(s)
- Monala Jayaprakash Rao
- Department of Pharmacology, University of Texas Southwestern Medical School, Dallas, TX 75390-9041, USA
| | - Joel M Goodman
- Department of Pharmacology, University of Texas Southwestern Medical School, Dallas, TX 75390-9041, USA.
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43
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Sanya DRA, Onésime D, Passoth V, Maiti MK, Chattopadhyay A, Khot MB. Yeasts of the Blastobotrys genus are promising platform for lipid-based fuels and oleochemicals production. Appl Microbiol Biotechnol 2021; 105:4879-4897. [PMID: 34110474 DOI: 10.1007/s00253-021-11354-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/29/2021] [Accepted: 05/16/2021] [Indexed: 12/31/2022]
Abstract
Strains of the yeast genus Blastobotrys (subphylum Saccharomycotina) represent a valuable biotechnological resource for basic biochemistry research, single-cell protein, and heterologous protein production processes. Species of this genus are dimorphic, non-pathogenic, thermotolerant, and can assimilate a variety of hydrophilic and hydrophobic substrates. These can constitute a single-cell oil platform in an emerging bio-based economy as oleaginous traits have been discovered recently. However, the regulatory network of lipogenesis in these yeasts is poorly understood. To keep pace with the growing market demands for lipid-derived products, it is critical to understand the lipid biosynthesis in these unconventional yeasts to pinpoint what governs the preferential channelling of carbon flux into lipids instead of the competing pathways. This review summarizes information relevant to the regulation of lipid metabolic pathways and prospects of metabolic engineering in Blastobotrys yeasts for their application in food, feed, and beyond, particularly for fatty acid-based fuels and oleochemicals. KEY POINTS: • The production of biolipids by heterotrophic yeasts is reviewed. • Summary of information concerning lipid metabolism regulation is highlighted. • Special focus on the importance of diacylglycerol acyltransferases encoding genes in improving lipid production is made.
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Affiliation(s)
- Daniel Ruben Akiola Sanya
- Université Paris-Saclay, Institut Micalis, Diversité génomique et fonctionnelle des levures, domaine de Vilvert, 78350, Jouy-en-Josas, France.
| | - Djamila Onésime
- Université Paris-Saclay, Institut Micalis, Diversité génomique et fonctionnelle des levures, domaine de Vilvert, 78350, Jouy-en-Josas, France
| | - Volkmar Passoth
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07, Uppsala, Sweden
| | - Mrinal K Maiti
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Atrayee Chattopadhyay
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Mahesh B Khot
- Laboratorio de Recursos Renovables, Centro de Biotecnologia, Universidad de Concepcion, Barrio Universitario s/n, Concepcion, Chile
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44
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Gao M, Liu L, Wang X, Mak HY, Liu G, Yang H. GPAT3 deficiency alleviates insulin resistance and hepatic steatosis in a mouse model of severe congenital generalized lipodystrophy. Hum Mol Genet 2021; 29:432-443. [PMID: 31873720 DOI: 10.1093/hmg/ddz300] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/12/2019] [Accepted: 12/05/2019] [Indexed: 12/17/2022] Open
Abstract
Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) is the most severe form of human lipodystrophy and is caused by loss-of-function mutations in the BSCL2/seipin gene. Exactly how seipin may regulate adipogenesis remains unclear. A recent study in vitro suggested that seipin may function to inhibit the activity of glycerol-3-phosphate acyltransferases (GPATs), and increased GPAT activity may be responsible for the defective adipogenesis under seipin deficiency. Here we generated Seipin-/-Gpat3-/- mice, which had mild but significant recovery of white adipose tissue mass over Seipin-/- mice. The mass of brown adipose tissue (BAT) of the Seipin-/-Gpat3-/- mice was almost completely restored to normal level. Importantly, the Seipin-/-Gpat3-/- mice showed significant improvement in liver steatosis and insulin sensitivity over Seipin-/- mice, which is attributable to the increased BAT mass and to the enhanced browning of the subcutaneous fat of the Seipin-/-Gpat3-/- mice. Together, our results establish a functional link between seipin and GPAT3 in vivo and suggest that GPAT inhibitors may have beneficial effects on BSCL2 patients.
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Affiliation(s)
- Mingming Gao
- Laboratory of Lipid Metabolism, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Lin Liu
- Laboratory of Lipid Metabolism, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Xiaowei Wang
- Laboratory of Lipid Metabolism, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Hoi Yin Mak
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - George Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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45
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Joshi AS, Ragusa JV, Prinz WA, Cohen S. Multiple C2 domain-containing transmembrane proteins promote lipid droplet biogenesis and growth at specialized endoplasmic reticulum subdomains. Mol Biol Cell 2021; 32:1147-1157. [PMID: 33826368 PMCID: PMC8351558 DOI: 10.1091/mbc.e20-09-0590] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022] Open
Abstract
Lipid droplets (LDs) are neutral lipid-containing organelles enclosed in a single monolayer of phospholipids. LD formation begins with the accumulation of neutral lipids within the bilayer of the endoplasmic reticulum (ER) membrane. It is not known how the sites of formation of nascent LDs in the ER membrane are determined. Here we show that multiple C2 domain-containing transmembrane proteins, MCTP1 and MCTP2, are at sites of LD formation in specialized ER subdomains. We show that the transmembrane domain (TMD) of these proteins is similar to a reticulon homology domain. Like reticulons, these proteins tubulate the ER membrane and favor highly curved regions of the ER. Our data indicate that the MCTP TMDs promote LD biogenesis, increasing LD number. MCTPs colocalize with seipin, a protein involved in LD biogenesis, but form more stable microdomains in the ER. The MCTP C2 domains bind charged lipids and regulate LD size, likely by mediating ER-LD contact sites. Together, our data indicate that MCTPs form microdomains within ER tubules that regulate LD biogenesis, size, and ER-LD contacts. Interestingly, MCTP punctae colocalized with other organelles as well, suggesting that these proteins may play a general role in linking tubular ER to organelle contact sites.
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Affiliation(s)
- Amit S. Joshi
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Biochemistry, Cell and Molecular Biology, University of Tennessee, Knoxville, TN 37916
| | - Joey V. Ragusa
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - William A. Prinz
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20814
| | - Sarah Cohen
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Khaddaj R, Mari M, Cottier S, Reggiori F, Schneiter R. The surface of lipid droplets constitutes a barrier for endoplasmic reticulum-resident integral membrane proteins. J Cell Sci 2021; 135:268334. [PMID: 34028531 DOI: 10.1242/jcs.256206] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 04/14/2021] [Indexed: 12/12/2022] Open
Abstract
Lipid droplets (LDs) are globular subcellular structures that store neutral lipids. LDs are closely associated with the endoplasmic reticulum (ER) and are limited by a phospholipid monolayer harboring a specific set of proteins. Most of these proteins associate with LDs through either an amphipathic helix or a membrane-embedded hairpin motif. Here, we address the question of whether integral membrane proteins can localize to the surface of LDs. To test this, we fused perilipin 3 (PLIN3), a mammalian LD-targeted protein, to ER-resident proteins. The resulting fusion proteins localized to the periphery of LDs in both yeast and mammalian cells. This peripheral LD localization of the fusion proteins, however, was due to a redistribution of the ER around LDs, as revealed by bimolecular fluorescence complementation between ER- and LD-localized partners. A LD-tethering function of PLIN3-containing membrane proteins was confirmed by fusing PLIN3 to the cytoplasmic domain of an outer mitochondrial membrane protein, OM14. Expression of OM14-PLIN3 induced a close apposition between LDs and mitochondria. These data indicate that the ER-LD junction constitutes a barrier for ER-resident integral membrane proteins.
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Affiliation(s)
- Rasha Khaddaj
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Stéphanie Cottier
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Roger Schneiter
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
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47
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Jansen RLM, Santana-Molina C, van den Noort M, Devos DP, van der Klei IJ. Comparative Genomics of Peroxisome Biogenesis Proteins: Making Sense of the PEX Proteins. Front Cell Dev Biol 2021; 9:654163. [PMID: 34095119 PMCID: PMC8172628 DOI: 10.3389/fcell.2021.654163] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/21/2021] [Indexed: 11/29/2022] Open
Abstract
PEX genes encode proteins involved in peroxisome biogenesis and proliferation. Using a comparative genomics approach, we clarify the evolutionary relationships between the 37 known PEX proteins in a representative set of eukaryotes, including all common model organisms, pathogenic unicellular eukaryotes and human. A large number of previously unknown PEX orthologs were identified. We analyzed all PEX proteins, their conservation and domain architecture and defined the core set of PEX proteins that is required to make a peroxisome. The molecular processes in peroxisome biogenesis in different organisms were put into context, showing that peroxisomes are not static organelles in eukaryotic evolution. Organisms that lack peroxisomes still contain a few PEX proteins, which probably play a role in alternative processes. Finally, the relationships between PEX proteins of two large families, the Pex11 and Pex23 families, were analyzed, thereby contributing to the understanding of their complicated and sometimes incorrect nomenclature. We provide an exhaustive overview of this important eukaryotic organelle.
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Affiliation(s)
- Renate L M Jansen
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Carlos Santana-Molina
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide, Seville, Spain
| | - Marco van den Noort
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Damien P Devos
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide, Seville, Spain
| | - Ida J van der Klei
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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Roberts MA, Segura-Roman A, Olzmann JA. Organelle Biogenesis: ER Shape Influences Lipid Droplet Nucleation. Curr Biol 2021; 30:R770-R773. [PMID: 32634419 DOI: 10.1016/j.cub.2020.05.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipid droplets (LDs) are neutral lipid storage organelles assembled at the endoplasmic reticulum (ER). A new study reveals that the high membrane curvature of ER tubules catalyzes the nucleation of a neutral lipid lens, an early step in LD biogenesis.
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Affiliation(s)
- Melissa A Roberts
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ashley Segura-Roman
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - James A Olzmann
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, CA 94720, USA.
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49
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Guéguen N, Le Moigne D, Amato A, Salvaing J, Maréchal E. Lipid Droplets in Unicellular Photosynthetic Stramenopiles. FRONTIERS IN PLANT SCIENCE 2021; 12:639276. [PMID: 33968100 PMCID: PMC8100218 DOI: 10.3389/fpls.2021.639276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The Heterokonta or Stramenopile phylum comprises clades of unicellular photosynthetic species, which are promising for a broad range of biotechnological applications, based on their capacity to capture atmospheric CO2 via photosynthesis and produce biomolecules of interest. These molecules include triacylglycerol (TAG) loaded inside specific cytosolic bodies, called the lipid droplets (LDs). Understanding TAG production and LD biogenesis and function in photosynthetic stramenopiles is therefore essential, and is mostly based on the study of a few emerging models, such as the pennate diatom Phaeodactylum tricornutum and eustigmatophytes, such as Nannochloropsis and Microchloropsis species. The biogenesis of cytosolic LD usually occurs at the level of the endoplasmic reticulum. However, stramenopile cells contain a complex plastid deriving from a secondary endosymbiosis, limited by four membranes, the outermost one being connected to the endomembrane system. Recent cell imaging and proteomic studies suggest that at least some cytosolic LDs might be associated to the surface of the complex plastid, via still uncharacterized contact sites. The carbon length and number of double bonds of the acyl groups contained in the TAG molecules depend on their origin. De novo synthesis produces long-chain saturated or monounsaturated fatty acids (SFA, MUFA), whereas subsequent maturation processes lead to very long-chain polyunsaturated FA (VLC-PUFA). TAG composition in SFA, MUFA, and VLC-PUFA reflects therefore the metabolic context that gave rise to the formation of the LD, either via an early partitioning of carbon following FA de novo synthesis and/or a recycling of FA from membrane lipids, e.g., plastid galactolipids or endomembrane phosphor- or betaine lipids. In this review, we address the relationship between cytosolic LDs and the complex membrane compartmentalization within stramenopile cells, the metabolic routes leading to TAG accumulation, and the physiological conditions that trigger LD production, in response to various environmental factors.
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Choudhary V, Schneiter R. A Unique Junctional Interface at Contact Sites Between the Endoplasmic Reticulum and Lipid Droplets. Front Cell Dev Biol 2021; 9:650186. [PMID: 33898445 PMCID: PMC8060488 DOI: 10.3389/fcell.2021.650186] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/09/2021] [Indexed: 12/19/2022] Open
Abstract
Lipid droplets (LDs) constitute compartments dedicated to the storage of metabolic energy in the form of neutral lipids. LDs originate from the endoplasmic reticulum (ER) with which they maintain close contact throughout their life cycle. These ER-LD junctions facilitate the exchange of both proteins and lipids between these two compartments. In recent years, proteins that are important for the proper formation of LDs and localize to ER-LD junctions have been identified. This junction is unique as it is generally believed to invoke a transition from the ER bilayer membrane to a lipid monolayer that delineates LDs. Proper formation of this junction requires the ordered assembly of proteins and lipids at specialized ER subdomains. Without such a well-ordered assembly of LD biogenesis factors, neutral lipids are synthesized throughout the ER membrane, resulting in the formation of aberrant LDs. Such ectopically formed LDs impact ER and lipid homeostasis, resulting in different types of lipid storage diseases. In response to starvation, the ER-LD junction recruits factors that tether the vacuole to these junctions to facilitate LD degradation. In addition, LDs maintain close contacts with peroxisomes and mitochondria for metabolic channeling of the released fatty acids toward beta-oxidation. In this review, we discuss the function of different components that ensure proper functioning of LD contact sites, their role in lipogenesis and lipolysis, and their relation to lipid storage diseases.
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Affiliation(s)
- Vineet Choudhary
- Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Roger Schneiter
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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