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Li Y, Usman M, Sapp E, Ke Y, Wang Z, Boudi A, DiFiglia M, Li X. Chronic pharmacologic manipulation of dopamine transmission ameliorates metabolic disturbance in Trappc9-linked brain developmental syndrome. JCI Insight 2024; 9:e181339. [PMID: 38889014 DOI: 10.1172/jci.insight.181339] [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: 03/25/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024] Open
Abstract
Loss-of-function mutations of the gene encoding the trafficking protein particle complex subunit 9 (Trappc9) cause autosomal recessive intellectual disability and obesity by unknown mechanisms. Genome-wide analysis links Trappc9 to nonalcoholic fatty liver disease (NAFLD). Trappc9-deficient mice have been shown to appear overweight shortly after weaning. Here, we analyzed serum biochemistry and histology of adipose and liver tissues to determine the incidence of obesity and NAFLD in Trappc9-deficient mice and combined transcriptomic and proteomic analyses, pharmacological studies, and biochemical and histological examinations of postmortem mouse brains to unveil mechanisms involved. We found that Trappc9-deficient mice presented with systemic glucose homeostatic disturbance, obesity, and NAFLD, which were relieved upon chronic treatment combining dopamine receptor D2 (DRD2) agonist quinpirole and DRD1 antagonist SCH23390. Blood glucose homeostasis in Trappc9-deficient mice was restored upon administering quinpirole alone. RNA-sequencing analysis of DRD2-containing neurons and proteomic study of brain synaptosomes revealed signs of impaired neurotransmitter secretion in Trappc9-deficient mice. Biochemical and histological studies of mouse brains showed that Trappc9-deficient mice synthesized dopamine normally, but their dopamine-secreting neurons had a lower abundance of structures for releasing dopamine in the striatum. Our study suggests that Trappc9 loss of function causes obesity and NAFLD by constraining dopamine synapse formation.
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Affiliation(s)
- Yan Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Muhammad Usman
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Yuting Ke
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Zejian Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Adel Boudi
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Xueyi Li
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
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2
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Liu J, Li L, Xu D, Li Y, Chen T, Liu Y, Bao Y, Wang Y, Yang L, Li P, Xu L. Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders. SCIENCE CHINA. LIFE SCIENCES 2024; 67:1170-1182. [PMID: 38523235 DOI: 10.1007/s11427-023-2367-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/15/2023] [Indexed: 03/26/2024]
Abstract
Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders. These people store fat in subcutaneous adipose tissue (SAT) rather than in visceral adipose tissue (VAT). However, the molecules participating in this specific scenario remain elusive. Rab18, a lipid droplet (LD)-associated protein, mediates the contact between the endoplasmic reticulum (ER) and LDs to facilitate LD growth and maturation. In the present study, we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice. Rab18 adipocyte-specific knockout (Rab18 AKO) mice had a decreased volume ratio of SAT to VAT compared with wildtype mice. When subjected to high-fat diet (HFD), Rab18 AKO mice had increased ER stress and inflammation, reduced adiponectin, and decreased triacylglycerol (TAG) accumulation in SAT. In contrast, TAG accumulation in VAT, brown adipose tissue (BAT) or liver of Rab18 AKO mice had a moderate increase without ER stress stimulation. Rab18 AKO mice developed insulin resistance and systematic inflammation. Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT, similar to the counterpart mice. Furthermore, Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress, indicating the involvement of Rab18 in alleviating lipid toxicity. Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT. In conclusion, our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.
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Affiliation(s)
- Jiaming Liu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Shanghai Qi Zhi Institute, Shanghai, 200232, China
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, 200438, China
| | - Liangkui Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tianjian Laboratory of Advanced Biomedical Sciences, Zhengzhou University, Zhengzhou, 450001, China
| | - Dijin Xu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yuqi Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Tao Chen
- Department of Physiology, School of Basic Medical Sciences, Gannan Medical University, Ganzhou, 341000, China
| | - Yeyang Liu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yuqian Bao
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, Shanghai, 200025, China
| | - Yan Wang
- Center for Endocrine Metabolism and Immune Diseases, Beijing Luhe Hospital, Capital Medical University, Beijing, 101149, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing, 101149, China
| | - Longyan Yang
- Center for Endocrine Metabolism and Immune Diseases, Beijing Luhe Hospital, Capital Medical University, Beijing, 101149, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing, 101149, China
| | - Peng Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Shanghai Qi Zhi Institute, Shanghai, 200232, China.
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, 200438, China.
- Tianjian Laboratory of Advanced Biomedical Sciences, Zhengzhou University, Zhengzhou, 450001, China.
| | - Li Xu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Shanghai Qi Zhi Institute, Shanghai, 200232, China.
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3
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Malis Y, Armoza-Eilat S, Nevo-Yassaf I, Dukhovny A, Sklan EH, Hirschberg K. Rab1b facilitates lipid droplet growth by ER-to-lipid droplet targeting of DGAT2. SCIENCE ADVANCES 2024; 10:eade7753. [PMID: 38809969 PMCID: PMC11135398 DOI: 10.1126/sciadv.ade7753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 04/16/2024] [Indexed: 05/31/2024]
Abstract
Lipid droplets (LDs) comprise a triglyceride core surrounded by a lipid monolayer enriched with proteins, many of which function in LD homeostasis. How proteins are targeted to the growing LD is still unclear. Rab1b, a GTPase regulating secretory transport, was recently associated with targeting proteins to LDs in a Drosophila RNAi screen. LD formation was prevented in human hepatoma cells overexpressing dominant-negative Rab1b. We thus hypothesized that Rab1b recruits lipid-synthesizing enzymes, facilitating LD growth. Here, FRET between diacylglycerol acyltransferase 2 (DGAT2) and Rab1b and activity mutants of the latter demonstrated that Rab1b promotes DGAT2 ER to the LD surface redistribution. Last, alterations in LD metabolism and DGAT2 redistribution, consistent with Rab1b activity, were caused by mutations in the Rab1b-GTPase activating protein TBC1D20 in Warburg Micro syndrome (WARBM) model mice fibroblasts. These data contribute to our understanding of the mechanism of Rab1b in LD homeostasis and WARBM, a devastating autosomal-recessive disorder caused by mutations in TBC1D20.
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Affiliation(s)
- Yehonathan Malis
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shir Armoza-Eilat
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Inbar Nevo-Yassaf
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anna Dukhovny
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ella H. Sklan
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Koret Hirschberg
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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4
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Feiner N, Yang W, Bunikis I, While GM, Uller T. Adaptive introgression reveals the genetic basis of a sexually selected syndrome in wall lizards. SCIENCE ADVANCES 2024; 10:eadk9315. [PMID: 38569035 PMCID: PMC10990284 DOI: 10.1126/sciadv.adk9315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 02/28/2024] [Indexed: 04/05/2024]
Abstract
The joint expression of particular colors, morphologies, and behaviors is a common feature of adaptation, but the genetic basis for such "phenotypic syndromes" remains poorly understood. Here, we identified a complex genetic architecture associated with a sexually selected syndrome in common wall lizards, by capitalizing on the adaptive introgression of coloration and morphology into a distantly related lineage. Consistent with the hypothesis that the evolution of phenotypic syndromes in vertebrates is facilitated by developmental linkage through neural crest cells, most of the genes associated with the syndrome are involved in neural crest cell regulation. A major locus was a ~400-kb region, characterized by standing structural genetic variation and previously implied in the evolutionary innovation of coloration and beak size in birds. We conclude that features of the developmental and genetic architecture contribute to maintaining trait integration, facilitating the extensive and rapid introgressive spread of suites of sexually selected characters.
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Affiliation(s)
| | - Weizhao Yang
- Department of Biology, Lund University, Lund, Sweden
| | - Ignas Bunikis
- Uppsala Genome Center, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Geoffrey M. While
- School of Natural Sciences, University of Tasmania, Sandy Bay, Tasmania, Australia
| | - Tobias Uller
- Department of Biology, Lund University, Lund, Sweden
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5
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Aljuraysi S, Platt M, Pulix M, Poptani H, Plagge A. Microcephaly with a disproportionate hippocampal reduction, stem cell loss and neuronal lipid droplet symptoms in Trappc9 KO mice. Neurobiol Dis 2024; 192:106431. [PMID: 38331351 DOI: 10.1016/j.nbd.2024.106431] [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: 12/04/2023] [Revised: 01/23/2024] [Accepted: 02/04/2024] [Indexed: 02/10/2024] Open
Abstract
Mutations of the human TRAFFICKING PROTEIN PARTICLE COMPLEX SUBUNIT 9 (TRAPPC9) cause a neurodevelopmental disorder characterised by microcephaly and intellectual disability. Trappc9 constitutes a subunit specific to the intracellular membrane-associated TrappII complex. The TrappII complex interacts with Rab11 and Rab18, the latter being specifically associated with lipid droplets (LDs). Here we used non-invasive imaging to characterise Trappc9 knock-out (KO) mice as a model of the human hereditary disorder. KOs developed postnatal microcephaly with many grey and white matter regions being affected. In vivo magnetic resonance imaging (MRI) identified a disproportionately stronger volume reduction in the hippocampus, which was associated with a significant loss of Sox2-positive neural stem and progenitor cells. Diffusion tensor imaging indicated a reduced organisation or integrity of white matter areas. Trappc9 KOs displayed behavioural abnormalities in several tests related to exploration, learning and memory. Trappc9-deficient primary hippocampal neurons accumulated a larger LD volume per cell following Oleic Acid stimulation, and the coating of LDs by Perilipin-2 was much reduced. Additionally, Trappc9 KOs developed obesity, which was significantly more severe in females than in males. Our findings indicate that, beyond previously reported Rab11-related vesicle transport defects, dysfunctions in LD homeostasis might contribute to the neurobiological symptoms of Trappc9 deficiency.
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Affiliation(s)
- Sultan Aljuraysi
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mark Platt
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK
| | - Michela Pulix
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Harish Poptani
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK.
| | - Antonius Plagge
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK.
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6
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Niedziółka SM, Datta S, Uśpieński T, Baran B, Skarżyńska W, Humke EW, Rohatgi R, Niewiadomski P. The exocyst complex and intracellular vesicles mediate soluble protein trafficking to the primary cilium. Commun Biol 2024; 7:213. [PMID: 38378792 PMCID: PMC10879184 DOI: 10.1038/s42003-024-05817-2] [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: 03/17/2022] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
The efficient transport of proteins into the primary cilium is a crucial step for many signaling pathways. Dysfunction of this process can lead to the disruption of signaling cascades or cilium assembly, resulting in developmental disorders and cancer. Previous studies on the protein delivery to the cilium were mostly focused on the membrane-embedded receptors. In contrast, how soluble proteins are delivered into the cilium is poorly understood. In our work, we identify the exocyst complex as a key player in the ciliary trafficking of soluble Gli transcription factors. In line with the known function of the exocyst in intracellular vesicle transport, we demonstrate that soluble proteins, including Gli2/3 and Lkb1, can use the endosome recycling machinery for their delivery to the primary cilium. Finally, we identify GTPases: Rab14, Rab18, Rab23, and Arf4 that are involved in vesicle-mediated Gli protein ciliary trafficking. Our data pave the way for a better understanding of ciliary transport and uncover transport mechanisms inside the cell.
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Affiliation(s)
- S M Niedziółka
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - S Datta
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - T Uśpieński
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - B Baran
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - W Skarżyńska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - E W Humke
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- IGM Biosciences, Inc, Mountain View, CA, USA
| | - R Rohatgi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - P Niewiadomski
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
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7
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Sood C, Verma JK, Basak R, Kapoor A, Gupta S, Mukhopadhyay A. Leishmania highjack host lipid body for its proliferation in macrophages by overexpressing host Rab18 and TRAPPC9 by downregulating miR-1914-3p expression. PLoS Pathog 2024; 20:e1012024. [PMID: 38412149 PMCID: PMC10898768 DOI: 10.1371/journal.ppat.1012024] [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: 04/29/2023] [Accepted: 02/05/2024] [Indexed: 02/29/2024] Open
Abstract
Lipids stored in lipid-bodies (LBs) in host cells are potential sources of fatty acids for pathogens. However, the mechanism of recruitment of LBs from the host cells by pathogens to acquire fatty acids is not known. Here, we have found that Leishmania specifically upregulates the expression of host Rab18 and its GEF, TRAPPC9 by downregulating the expression of miR-1914-3p by reducing the level of Dicer in macrophages via their metalloprotease gp63. Our results also show that miR-1914-3p negatively regulates the expression of Rab18 and its GEF in cells. Subsequently, Leishmania containing parasitophorous vacuoles (Ld-PVs) recruit and retain host Rab18 and TRAPPC9. Leishmania infection also induces LB biogenesis in host cells and recruits LBs on Ld-PVs and acquires FLC12-labeled fatty acids from LBs. Moreover, overexpression of miR-1914-3p in macrophages significantly inhibits the recruitment of LBs and thereby suppresses the multiplication of parasites in macrophages as parasites are unable to acquire fatty acids. These results demonstrate a novel mechanism how Leishmania acquire fatty acids from LBs for their growth in macrophages.
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Affiliation(s)
- Chandni Sood
- National Institute of Immunology, New Delhi, India
| | - Jitender Kumar Verma
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
- National Institute of Immunology, New Delhi, India
| | - Rituparna Basak
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Anjali Kapoor
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Swarnima Gupta
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Amitabha Mukhopadhyay
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
- National Institute of Immunology, New Delhi, India
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Martin Carli JF, Dzieciatkowska M, Hernandez TL, Monks J, McManaman JL. Comparative proteomic analysis of human milk fat globules and paired membranes and mouse milk fat globules identifies core cellular systems contributing to mammary lipid trafficking and secretion. Front Mol Biosci 2023; 10:1259047. [PMID: 38169886 PMCID: PMC10759240 DOI: 10.3389/fmolb.2023.1259047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/22/2023] [Indexed: 01/05/2024] Open
Abstract
Introduction: Human milk delivers critical nutritional and immunological support to human infants. Milk fat globules (MFGs) and their associated membranes (MFGMs) contain the majority of milk lipids and many bioactive components that contribute to neonatal development and health, yet their compositions have not been fully defined, and the mechanisms responsible for formation of these structures remain incompletely understood. Methods: In this study, we used untargeted mass spectrometry to quantitatively profile the protein compositions of freshly obtained MFGs and their paired, physically separated MFGM fractions from 13 human milk samples. We also quantitatively profiled the MFG protein compositions of 9 pooled milk samples from 18 lactating mouse dams. Results: We identified 2,453 proteins and 2,795 proteins in the majority of human MFG and MFGM samples, respectively, and 1,577 proteins in mouse MFGs. Using paired analyses of protein abundance in MFGMs compared to MFGs (MFGM-MFG; 1% FDR), we identified 699 proteins that were more highly abundant in MFGMs (MFGM-enriched), and 201 proteins that were less abundant in MFGMs (cytoplasmic). MFGM-enriched proteins comprised membrane systems (apical plasma membrane and multiple vesicular membranes) hypothesized to be responsible for lipid and protein secretion and components of membrane transport and signaling systems. Cytoplasmic proteins included ribosomal and proteasomal systems. Comparing abundance between human and mouse MFGs, we found a positive correlation (R 2 = 0.44, p < 0.0001) in the relative abundances of 1,279 proteins that were found in common across species. Discussion: Comparative pathway enrichment analyses between human and mouse samples reveal similarities in membrane trafficking and signaling pathways involved in milk fat secretion and identify potentially novel immunological components of MFGs. Our results advance knowledge of the composition and relative quantities of proteins in human and mouse MFGs in greater detail, provide a quantitative profile of specifically enriched human MFGM proteins, and identify core cellular systems involved in milk lipid secretion.
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Affiliation(s)
- Jayne F. Martin Carli
- Section of Nutrition, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Monika Dzieciatkowska
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Teri L. Hernandez
- College of Nursing, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jenifer Monks
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - James L. McManaman
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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Papaioannou P, Wallace MJ, Malhotra N, Mohler PJ, El Refaey M. Biochemical Structure and Function of TRAPP Complexes in the Cardiac System. JACC Basic Transl Sci 2023; 8:1599-1612. [PMID: 38205348 PMCID: PMC10774597 DOI: 10.1016/j.jacbts.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/14/2023] [Indexed: 01/12/2024]
Abstract
Trafficking protein particle (TRAPP) is well reported to play a role in the trafficking of protein products within the Golgi and endoplasmic reticulum. Dysfunction in TRAPP has been associated with disorders in the nervous and cardiovascular systems, but the majority of literature focuses on TRAPP function in the nervous system solely. Here, we highlight the known pathways of TRAPP and hypothesize potential impacts of TRAPP dysfunction on the cardiovascular system, particularly the role of TRAPP as a guanine-nucleotide exchange factor for Rab1 and Rab11. We also review the various cardiovascular phenotypes associated with changes in TRAPP complexes and their subunits.
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Affiliation(s)
- Peter Papaioannou
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiac Surgery, Department of Surgery, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Michael J. Wallace
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Nipun Malhotra
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiac Surgery, Department of Surgery, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Peter J. Mohler
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Mona El Refaey
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiac Surgery, Department of Surgery, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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10
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Renier TJ, Paetz OR, Paal MC, Long AB, Brown MR, Vuong SH, Perumal SK, Kharbanda KK, Listenberger LL. Changing the phospholipid composition of lipid droplets alters localization of select lipid droplet proteins. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000960. [PMID: 38021172 PMCID: PMC10656625 DOI: 10.17912/micropub.biology.000960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023]
Abstract
Our experiments aim to determine if decreasing the amount of phosphatidylcholine (PC) relative to phosphatidylethanolamine (PE) at the lipid droplet surface changes the localization of specific lipid droplet proteins. We manipulate lipid droplet phospholipids in both a cultured mouse hepatocyte (AML12) cell line and on synthetic lipid droplets. Decreasing the PC:PE ratio increases perilipin 2, decreases DGAT2, and does not change rab18 or lanosterol synthase levels on lipid droplets. These differences may be explained by the distinct structural motifs that mediate the protein-lipid droplet interactions.
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Affiliation(s)
- Timothy J. Renier
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
| | - Olivia R. Paetz
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
| | - Matthew C. Paal
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Alex B. Long
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
| | - Margaret R. Brown
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
| | - Sunny H. Vuong
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
| | - Sathish Kumar Perumal
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, United States
| | - Kusum K. Kharbanda
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, United States
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Laura L. Listenberger
- Departments of Biology and Chemistry, St. Olaf College, Northfield, Minnesota, United States
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11
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Kiss RS, Chicoine J, Khalil Y, Sladek R, Chen H, Pisaturo A, Martin C, Dale JD, Brudenell TA, Kamath A, Kyei-Boahen J, Hafiane A, Daliah G, Alecki C, Hopes TS, Heier M, Aligianis IA, Lebrun JJ, Aspden J, Paci E, Kerksiek A, Lütjohann D, Clayton P, Wills JC, von Kriegsheim A, Nilsson T, Sheridan E, Handley MT. Comparative proximity biotinylation implicates the small GTPase RAB18 in sterol mobilization and biosynthesis. J Biol Chem 2023; 299:105295. [PMID: 37774976 PMCID: PMC10641524 DOI: 10.1016/j.jbc.2023.105295] [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: 03/16/2023] [Revised: 09/14/2023] [Accepted: 09/17/2023] [Indexed: 10/01/2023] Open
Abstract
Loss of functional RAB18 causes the autosomal recessive condition Warburg Micro syndrome. To better understand this disease, we used proximity biotinylation to generate an inventory of potential RAB18 effectors. A restricted set of 28 RAB18 interactions were dependent on the binary RAB3GAP1-RAB3GAP2 RAB18-guanine nucleotide exchange factor complex. Twelve of these 28 interactions are supported by prior reports, and we have directly validated novel interactions with SEC22A, TMCO4, and INPP5B. Consistent with a role for RAB18 in regulating membrane contact sites, interactors included groups of microtubule/membrane-remodeling proteins, membrane-tethering and docking proteins, and lipid-modifying/transporting proteins. Two of the putative interactors, EBP and OSBPL2/ORP2, have sterol substrates. EBP is a Δ8-Δ7 sterol isomerase, and ORP2 is a lipid transport protein. This prompted us to investigate a role for RAB18 in cholesterol biosynthesis. We found that the cholesterol precursor and EBP-product lathosterol accumulates in both RAB18-null HeLa cells and RAB3GAP1-null fibroblasts derived from an affected individual. Furthermore, de novo cholesterol biosynthesis is impaired in cells in which RAB18 is absent or dysregulated or in which ORP2 expression is disrupted. Our data demonstrate that guanine nucleotide exchange factor-dependent Rab interactions are highly amenable to interrogation by proximity biotinylation and may suggest that Micro syndrome is a cholesterol biosynthesis disorder.
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Affiliation(s)
- Robert S Kiss
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
| | - Jarred Chicoine
- Metabolic Disorders and Complications (MEDIC) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Youssef Khalil
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Robert Sladek
- Metabolic Disorders and Complications (MEDIC) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - He Chen
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Alessandro Pisaturo
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Cyril Martin
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Jessica D Dale
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom
| | - Tegan A Brudenell
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom
| | - Archith Kamath
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom; Division of Medical Sciences, University of Oxford, Oxford, United Kingdom
| | - Jeffrey Kyei-Boahen
- Department of Medicine, McGill University Health Centre, CHAL Research Program, Montreal, Canada
| | - Anouar Hafiane
- Department of Medicine, McGill University Health Centre, CHAL Research Program, Montreal, Canada
| | - Girija Daliah
- Department of Medicine, McGill University Health Centre, Cancer Research Program, Montreal, Canada
| | - Célia Alecki
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Tayah S Hopes
- Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Martin Heier
- Department of Clinical Neuroscience for Children, Oslo University Hospital, Oslo, Norway
| | - Irene A Aligianis
- Medical and Developmental Genetics, Medical Research Council Human Genetics Unit, Edinburgh, United Kingdom
| | - Jean-Jacques Lebrun
- Department of Medicine, McGill University Health Centre, Cancer Research Program, Montreal, Canada
| | - Julie Aspden
- Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Emanuele Paci
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Anja Kerksiek
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Dieter Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Peter Clayton
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Jimi C Wills
- Cancer Research United Kingdom Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom; Firefinch Software Ltd, Edinburgh, United Kingdom
| | - Alex von Kriegsheim
- Cancer Research United Kingdom Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
| | - Tommy Nilsson
- Cancer Research Program (CRP), Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Eamonn Sheridan
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom
| | - Mark T Handley
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom; Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.
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12
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Hu M, Bodnar B, Zhang Y, Xie F, Li F, Li S, Zhao J, Zhao R, Gedupoori N, Mo Y, Lin L, Li X, Meng W, Yang X, Wang H, Barbe MF, Srinivasan S, Bethea JR, Mo X, Xu H, Hu W. Defective neurite elongation and branching in Nibp/Trappc9 deficient zebrafish and mice. Int J Biol Sci 2023; 19:3226-3248. [PMID: 37416774 PMCID: PMC10321293 DOI: 10.7150/ijbs.78489] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 06/06/2023] [Indexed: 07/08/2023] Open
Abstract
Loss of function in transport protein particles (TRAPP) links a new set of emerging genetic disorders called "TRAPPopathies". One such disorder is NIBP syndrome, characterized by microcephaly and intellectual disability, and caused by mutations of NIBP/TRAPPC9, a crucial and unique member of TRAPPII. To investigate the neural cellular/molecular mechanisms underlying microcephaly, we developed Nibp/Trappc9-deficient animal models using different techniques, including morpholino knockdown and CRISPR/Cas mutation in zebrafish and Cre/LoxP-mediated gene targeting in mice. Nibp/Trappc9 deficiency impaired the stability of the TRAPPII complex at actin filaments and microtubules of neurites and growth cones. This deficiency also impaired elongation and branching of neuronal dendrites and axons, without significant effects on neurite initiation or neural cell number/types in embryonic and adult brains. The positive correlation of TRAPPII stability and neurite elongation/branching suggests a potential role for TRAPPII in regulating neurite morphology. These results provide novel genetic/molecular evidence to define patients with a type of non-syndromic autosomal recessive intellectual disability and highlight the importance of developing therapeutic approaches targeting the TRAPPII complex to cure TRAPPopathies.
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Affiliation(s)
- Min Hu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Brittany Bodnar
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Yonggang Zhang
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Fangxin Xie
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
- Department of Clinical Laboratory, Xi'an NO. 3 Hospital, Xi'an, Shaanxi, 710018, China
| | - Fang Li
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Siying Li
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Jin Zhao
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Ruotong Zhao
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Naveen Gedupoori
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Yifan Mo
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Lanyi Lin
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Xue Li
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wentong Meng
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Xiaofeng Yang
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Hong Wang
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Mary F. Barbe
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Shanthi Srinivasan
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - John R. Bethea
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Xianming Mo
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Hong Xu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wenhui Hu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
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13
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Yin G, Huang J, Petela J, Jiang H, Zhang Y, Gong S, Wu J, Liu B, Shi J, Gao Y. Targeting small GTPases: emerging grasps on previously untamable targets, pioneered by KRAS. Signal Transduct Target Ther 2023; 8:212. [PMID: 37221195 DOI: 10.1038/s41392-023-01441-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/28/2023] [Accepted: 04/14/2023] [Indexed: 05/25/2023] Open
Abstract
Small GTPases including Ras, Rho, Rab, Arf, and Ran are omnipresent molecular switches in regulating key cellular functions. Their dysregulation is a therapeutic target for tumors, neurodegeneration, cardiomyopathies, and infection. However, small GTPases have been historically recognized as "undruggable". Targeting KRAS, one of the most frequently mutated oncogenes, has only come into reality in the last decade due to the development of breakthrough strategies such as fragment-based screening, covalent ligands, macromolecule inhibitors, and PROTACs. Two KRASG12C covalent inhibitors have obtained accelerated approval for treating KRASG12C mutant lung cancer, and allele-specific hotspot mutations on G12D/S/R have been demonstrated as viable targets. New methods of targeting KRAS are quickly evolving, including transcription, immunogenic neoepitopes, and combinatory targeting with immunotherapy. Nevertheless, the vast majority of small GTPases and hotspot mutations remain elusive, and clinical resistance to G12C inhibitors poses new challenges. In this article, we summarize diversified biological functions, shared structural properties, and complex regulatory mechanisms of small GTPases and their relationships with human diseases. Furthermore, we review the status of drug discovery for targeting small GTPases and the most recent strategic progress focused on targeting KRAS. The discovery of new regulatory mechanisms and development of targeting approaches will together promote drug discovery for small GTPases.
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Affiliation(s)
- Guowei Yin
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China.
| | - Jing Huang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Johnny Petela
- Wake Forest University School of Medicine, Winston-Salem, NC, 27101, USA
| | - Hongmei Jiang
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China
| | - Yuetong Zhang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Siqi Gong
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China
- School of Medicine, Sun Yat-Sen University, Shenzhen, 518107, China
| | - Jiaxin Wu
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Bei Liu
- National Biomedical Imaging Center, School of Future Technology, Peking University, Beijing, 100871, China
| | - Jianyou Shi
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology, Chengdu, 610072, China.
| | - Yijun Gao
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
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14
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Hong Y, Xia Z, Sun Y, Lan Y, Di T, Yang J, Sun J, Qiu M, Luo Q, Yang D. A Comprehensive Pan-Cancer Analysis of the Regulation and Prognostic Effect of Coat Complex Subunit Zeta 1. Genes (Basel) 2023; 14:genes14040889. [PMID: 37107648 PMCID: PMC10137353 DOI: 10.3390/genes14040889] [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: 02/14/2023] [Revised: 03/26/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
The Coatomer protein complex Zeta 1 (COPZ1) has been reported to play an essential role in maintaining the survival of some types of tumors. In this study, we sought to explore the molecular characteristics of COPZ1 and its clinical prognostic value through a pan-cancers bioinformatic analysis. We found that COPZ1 was extremely prevalent in a variety of cancer types, and high expression of COPZ1 was linked to poor overall survival in many cancers, while low expression in LAML and PADC was correlated with tumorigenesis. Besides, the CRISPR Achilles' knockout analysis revealed that COPZ1 was vital for many tumor cells' survival. We further demonstrated that the high expression level of COPZ1 in tumors was regulated in multi-aspects, including abnormal CNV, DNA-methylation, transcription factor and microRNAs. As for the functional exploration of COPZ1, we found a positive relationship between COPZ1's expression and stemness and hypoxia signature, especially the contribution of COPZ1 on EMT ability in SARC. GSEA analysis revealed that COPZ1 was associated with many immune response pathways. Further investigation demonstrated that COPZ expression was negatively correlated with immune score and stromal score, and low expression of COPZ1 has been associated to more antitumor immune cell infiltration and pro-inflammatory cytokines. The further analysis of COPZ1 expression and anti-inflammatory M2 cells showed a consistent result. Finally, we verified the expression of COPZ1 in HCC cells, and proved its ability of sustaining tumor growth and invasion with biological experiments. Our study provides a multi-dimensional pan-cancer analysis of COPZ and demonstrates that COPZ1 can serve as both a prospective target for the treatment of cancer and a prognostic marker for a variety of cancer types.
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Affiliation(s)
- Ye Hong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Pediatric Oncology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Zengfei Xia
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Experimental Research, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Yuting Sun
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Medical Oncology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Yingxia Lan
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Pediatric Oncology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Tian Di
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Experimental Research, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Jing Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Medical Oncology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Jian Sun
- Department of Clinical Research, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510060, China
| | - Miaozhen Qiu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Medical Oncology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Qiuyun Luo
- Department of Cancer Research, The Eighth Affiliated Hospital of Sun Yat-Sen University, Shenzhen 518033, China
| | - Dajun Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
- Department of Experimental Research, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
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15
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The role of CaMKK2 in Golgi-associated vesicle trafficking. Biochem Soc Trans 2023; 51:331-342. [PMID: 36815702 PMCID: PMC9987998 DOI: 10.1042/bst20220833] [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: 12/10/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023]
Abstract
Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is a serine/threonine-protein kinase, that is involved in maintaining various physiological and cellular processes within the cell that regulate energy homeostasis and cell growth. CaMKK2 regulates glucose metabolism by the activation of downstream kinases, AMP-activated protein kinase (AMPK) and other calcium/calmodulin-dependent protein kinases. Consequently, its deregulation has a role in multiple human metabolic diseases including obesity and cancer. Despite the importance of CaMKK2, its signalling pathways and pathological mechanisms are not completely understood. Recent work has been aimed at broadening our understanding of the biological functions of CaMKK2. These studies have uncovered new interaction partners that have led to the description of new functions that include lipogenesis and Golgi vesicle trafficking. Here, we review recent insights into the role of CaMKK2 in membrane trafficking mechanisms and discuss the functional implications in a cellular context and for disease.
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16
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Luo Y, Liu W, Sun J, Zhang ZR, Yang WC. Quantitative proteomics reveals key pathways in the symbiotic interface and the likely extracellular property of soybean symbiosome. J Genet Genomics 2023; 50:7-19. [PMID: 35470091 DOI: 10.1016/j.jgg.2022.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 02/06/2023]
Abstract
An effective symbiosis between legumes and rhizobia relies largely on diverse proteins at the plant-rhizobium interface for material transportation and signal transduction during symbiotic nitrogen fixation. Here, we report a comprehensive proteome atlas of the soybean symbiosome membrane (SM), peribacteroid space (PBS), and root microsomal fraction (RMF) using state-of-the-art label-free quantitative proteomic technology. In total, 1759 soybean proteins with diverse functions are detected in the SM, and 1476 soybean proteins and 369 rhizobial proteins are detected in the PBS. The diversity of SM proteins detected suggests multiple origins of the SM. Quantitative comparative analysis highlights amino acid metabolism and nutrient uptake in the SM, indicative of the key pathways in nitrogen assimilation. The detection of soybean secretory proteins in the PBS and receptor-like kinases in the SM provides evidence for the likely extracellular property of the symbiosome and the potential signaling communication between both symbionts at the symbiotic interface. Our proteomic data provide clues for how some of the sophisticated regulation between soybean and rhizobium at the symbiotic interface is achieved, and suggest approaches for symbiosis engineering.
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Affiliation(s)
- Yu Luo
- The State Key Laboratory for Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Wei Liu
- The State Key Laboratory for Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Juan Sun
- The State Key Laboratory for Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng-Rong Zhang
- The State Key Laboratory for Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei-Cai Yang
- The State Key Laboratory for Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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17
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Ahmadi S, Pachis ST, Kalogeropoulos K, McGeoghan F, Canbay V, Hall SR, Crittenden EP, Dawson CA, Bartlett KE, Gutiérrez JM, Casewell NR, Keller UAD, Laustsen AH. Proteomics and histological assessment of an organotypic model of human skin following exposure to Naja nigricollis venom. Toxicon 2022; 220:106955. [DOI: 10.1016/j.toxicon.2022.106955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/03/2022] [Accepted: 10/16/2022] [Indexed: 11/06/2022]
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18
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Gasparian A, Aksenova M, Oliver D, Levina E, Doran R, Lucius M, Piroli G, Oleinik N, Ogretmen B, Mythreye K, Frizzell N, Broude E, Wyatt MD, Shtutman M. Depletion of COPI in cancer cells: the role of reactive oxygen species in the induction of lipid accumulation, noncanonical lipophagy and apoptosis. Mol Biol Cell 2022; 33:ar135. [PMID: 36222847 PMCID: PMC9727790 DOI: 10.1091/mbc.e21-08-0420] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The coatomer protein complex 1 (COPI) is a multisubunit complex that coats intracellular vesicles and is involved in intracellular protein trafficking. Recently we and others found that depletion of COPI complex subunits zeta (COPZ1) and delta (ARCN1) preferentially kills tumor cells relative to normal cells. Here we delineate the specific cellular effects and sequence of events of COPI complex depletion in tumor cells. We find that this depletion leads to the inhibition of mitochondrial oxidative phosphorylation and the elevation of reactive oxygen species (ROS) production, followed by accumulation of lipid droplets (LDs) and autophagy-associated proteins LC3-II and SQSTM1/p62 and, finally, apoptosis of the tumor cells. Inactivation of ROS in COPI-depleted cells with the mitochondrial-specific quencher, mitoquinone mesylate, attenuated apoptosis and markedly decreased both the size and the number of LDs. COPI depletion caused ROS-dependent accumulation of LC3-II and SQSTM1 which colocalizes with LDs. Lack of double-membrane autophagosomes and insensitivity to Atg5 deletion suggested an accumulation of a microlipophagy complex on the surface of LDs induced by depletion of the COPI complex. Our findings suggest a sequence of cellular events triggered by COPI depletion, starting with inhibition of oxidative phosphorylation, followed by ROS activation and accumulation of LDs and apoptosis.
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Affiliation(s)
- A. Gasparian
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. Aksenova
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - D. Oliver
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - E. Levina
- Department of Biological Sciences College of Art and Science, University of South Carolina, Columbia, SC 29208
| | - R. Doran
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. Lucius
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - G. Piroli
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC 29208
| | - N. Oleinik
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
| | - B. Ogretmen
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
| | - K. Mythreye
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - N. Frizzell
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC 29208
| | - E. Broude
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. D. Wyatt
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. Shtutman
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208,*Address correspondence to: M. Shtutman ()
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19
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Ge S, Zhang RX, Wang YF, Sun P, Chu J, Li J, Sun P, Wang J, Hetherington AM, Liang YK. The Arabidopsis Rab protein RABC1 affects stomatal development by regulating lipid droplet dynamics. THE PLANT CELL 2022; 34:4274-4292. [PMID: 35929087 PMCID: PMC9614440 DOI: 10.1093/plcell/koac239] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/13/2022] [Indexed: 05/13/2023]
Abstract
Lipid droplets (LDs) are evolutionarily conserved organelles that serve as hubs of cellular lipid and energy metabolism in virtually all organisms. Mobilization of LDs is important in light-induced stomatal opening. However, whether and how LDs are involved in stomatal development remains unknown. We show here that Arabidopsis thaliana LIPID DROPLETS AND STOMATA 1 (LDS1)/RABC1 (At1g43890) encodes a member of the Rab GTPase family that is involved in regulating LD dynamics and stomatal morphogenesis. The expression of RABC1 is coordinated with the different phases of stomatal development. RABC1 targets to the surface of LDs in response to oleic acid application in a RABC1GEF1-dependent manner. RABC1 physically interacts with SEIPIN2/3, two orthologues of mammalian seipin, which function in the formation of LDs. Disruption of RABC1, RABC1GEF1, or SEIPIN2/3 resulted in aberrantly large LDs, severe defects in guard cell vacuole morphology, and stomatal function. In conclusion, these findings reveal an aspect of LD function and uncover a role for lipid metabolism in stomatal development in plants.
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Affiliation(s)
| | | | - Yi-Fei Wang
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Pengyue Sun
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Jiaheng Chu
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jiao Li
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Peng Sun
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jianbo Wang
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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20
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Trappc9 Deficiency Impairs the Plasticity of Stem Cells. Int J Mol Sci 2022; 23:ijms23094900. [PMID: 35563289 PMCID: PMC9101649 DOI: 10.3390/ijms23094900] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/24/2022] [Accepted: 04/25/2022] [Indexed: 02/04/2023] Open
Abstract
Genetic mutations of trappc9 cause intellectual disability with the atrophy of brain structures and variable obesity by poorly understood mechanisms. Trappc9-deficient mice develop phenotypes resembling pathological changes in humans and appear overweight shortly after weaning, and thus are useful for studying the pathogenesis of obesity. Here, we investigated the effects of trappc9 deficiency on the proliferation and differentiation capacity of adipose-derived stem cells (ASCs). We isolated ASCs from mice before overweight was developed and found that trappc9-null ASCs exhibited signs of premature senescence and cell death. While the lineage commitment was retained, trappc9-null ASCs preferred adipogenic differentiation. We observed a profound accumulation of lipid droplets in adipogenic cells derived from trappc9-deficient ASCs and marked differences in the distribution patterns and levels of calcium deposited in osteoblasts obtained from trappc9-null ASCs. Biochemical studies revealed that trappc9 deficiency resulted in an upregulated expression of rab1, rab11, and rab18, and agitated autophagy in ASCs. Moreover, we found that the content of neural stem cells in both the subventricular zone of the lateral ventricle and the subgranular zone of the dentate gyrus vastly declined in trappc9-null mice. Collectively, our results suggest that obesity, as well as brain structure hypoplasia induced by the deficiency of trappc9, involves an impairment in the plasticity of stem cells.
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Lipid Dyshomeostasis and Inherited Cerebellar Ataxia. Mol Neurobiol 2022; 59:3800-3828. [PMID: 35420383 PMCID: PMC9148275 DOI: 10.1007/s12035-022-02826-2] [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: 03/29/2021] [Accepted: 04/01/2022] [Indexed: 12/04/2022]
Abstract
Cerebellar ataxia is a form of ataxia that originates from dysfunction of the cerebellum, but may involve additional neurological tissues. Its clinical symptoms are mainly characterized by the absence of voluntary muscle coordination and loss of control of movement with varying manifestations due to differences in severity, in the site of cerebellar damage and in the involvement of extracerebellar tissues. Cerebellar ataxia may be sporadic, acquired, and hereditary. Hereditary ataxia accounts for the majority of cases. Hereditary ataxia has been tentatively divided into several subtypes by scientists in the field, and nearly all of them remain incurable. This is mainly because the detailed mechanisms of these cerebellar disorders are incompletely understood. To precisely diagnose and treat these diseases, studies on their molecular mechanisms have been conducted extensively in the past. Accumulating evidence has demonstrated that some common pathogenic mechanisms exist within each subtype of inherited ataxia. However, no reports have indicated whether there is a common mechanism among the different subtypes of inherited cerebellar ataxia. In this review, we summarize the available references and databases on neurological disorders characterized by cerebellar ataxia and show that a subset of genes involved in lipid homeostasis form a new group that may cause ataxic disorders through a common mechanism. This common signaling pathway can provide a valuable reference for future diagnosis and treatment of ataxic disorders.
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22
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Rawlins LE, Almousa H, Khan S, Collins SC, Milev MP, Leslie J, Saint-Dic D, Khan V, Hincapie AM, Day JO, McGavin L, Rowley C, Harlalka GV, Vancollie VE, Ahmad W, Lelliott CJ, Gul A, Yalcin B, Crosby AH, Sacher M, Baple EL. Biallelic variants in TRAPPC10 cause a microcephalic TRAPPopathy disorder in humans and mice. PLoS Genet 2022; 18:e1010114. [PMID: 35298461 PMCID: PMC8963566 DOI: 10.1371/journal.pgen.1010114] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/29/2022] [Accepted: 02/20/2022] [Indexed: 11/25/2022] Open
Abstract
The highly evolutionarily conserved transport protein particle (TRAPP) complexes (TRAPP II and III) perform fundamental roles in subcellular trafficking pathways. Here we identified biallelic variants in TRAPPC10, a component of the TRAPP II complex, in individuals with a severe microcephalic neurodevelopmental disorder. Molecular studies revealed a weakened interaction between mutant TRAPPC10 and its putative adaptor protein TRAPPC2L. Studies of patient lymphoblastoid cells revealed an absence of TRAPPC10 alongside a concomitant absence of TRAPPC9, another key TRAPP II complex component associated with a clinically overlapping neurodevelopmental disorder. The TRAPPC9/10 reduction phenotype was recapitulated in TRAPPC10-/- knockout cells, which also displayed a membrane trafficking defect. Notably, both the reduction in TRAPPC9 levels and the trafficking defect in these cells could be rescued by wild type but not mutant TRAPPC10 gene constructs. Moreover, studies of Trappc10-/- knockout mice revealed neuroanatomical brain defects and microcephaly, paralleling findings seen in the human condition as well as in a Trappc9-/- mouse model. Together these studies confirm autosomal recessive TRAPPC10 variants as a cause of human disease and define TRAPP-mediated pathomolecular outcomes of importance to TRAPPC9 and TRAPPC10 mediated neurodevelopmental disorders in humans and mice. Microcephalic neurodevelopmental disorders are a group of conditions that are often inherited in families, involving small head size and abnormal brain development and function. This often results in delayed development of an affected child, affecting their movement, language and/or non-verbal communication and learning, as well as seizures and neuropsychiatric problems. A group of proteins called the transport protein particles (TRAPPs) are important for the transport of cargos inside cells. Alterations within a number of the TRAPP proteins have previously been associated with human inherited diseases called the ‘TRAPPopathies’, which involve neurodevelopmental and skeletal abnormalities. Here we show that TRAPPC10 gene alterations cause a new TRAPPopathy microcephalic neurodevelopmental disorder, and we provide a detailed clinical description of the condition termed ‘TRAPPC10-related disorder’. Our studies in mice lacking the TRAPPC10 gene identified similar features to those of affected humans, including small brain size and skeletal abnormalities. Our molecular studies showed that an affected individual with an alteration in the TRAPPC10 gene has no functional TRAPPC10 protein in their cells, which in turn causes a reduction in levels of another important TRAPP molecule, TRAPPC9. Cells lacking TRAPPC10 also display abnormalities in cellular transport processes. Together our data confirm alterations in TRAPPC10 as a cause of a microcephalic neurodevelopmental disorder in both humans and mice.
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Affiliation(s)
- Lettie E. Rawlins
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, United Kingdom
| | - Hashem Almousa
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Shazia Khan
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Stephan C. Collins
- Institute of Genetics and Molecular and Cellular Biology, Inserm, Illkirch, France
- Inserm, University of Bourgogne Franche-Comté, Dijon, France
| | - Miroslav P. Milev
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Joseph Leslie
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
| | - Djenann Saint-Dic
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Valeed Khan
- Department of Molecular Diagnostics, Rehman Medical Institute, Peshawar, Pakistan
| | | | - Jacob O. Day
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Faculty of Health, University of Plymouth, Plymouth, United Kingdom
| | - Lucy McGavin
- University Hospitals Plymouth NHS Trust, Plymouth, United Kingdom
| | | | - Gaurav V. Harlalka
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Department of Pharmacology, Rajarshi Shahu College of Pharmacy, Malvihir, Buldana, India
| | | | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | | | - Asma Gul
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Binnaz Yalcin
- Institute of Genetics and Molecular and Cellular Biology, Inserm, Illkirch, France
- Inserm, University of Bourgogne Franche-Comté, Dijon, France
| | - Andrew H. Crosby
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
| | - Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Emma L. Baple
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, United Kingdom
- * E-mail:
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23
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Xie K, Liu Y, Li X, Zhang H, Zhang S, Mak HY, Liu P. Dietary S. maltophilia induces supersized lipid droplets by enhancing lipogenesis and ER-LD contacts in C. elegans. Gut Microbes 2022; 14:2013762. [PMID: 35112996 PMCID: PMC8816401 DOI: 10.1080/19490976.2021.2013762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Dietary and symbiotic bacteria can exert powerful influence on metazoan lipid metabolism. Recent studies have emerged that microbiota have a role in animal obesity and related health disorders, but the mechanisms by which bacteria influence lipid storage in their host are unknown. To reduce the complexity of the relationship between gut microbiota and the host, Caenorhabditis elegans (C. elegans) has been chosen as a model organism to study interspecies interaction. Here, we demonstrate that feeding C. elegans with an opportunistic pathogenic bacterium Stenotrophomonas maltophilia (S. maltophilia) retards growth and promotes excessive neutral lipid storage. Gene expression analysis reveals that dietary S. maltophilia induces a lipogenic transcriptional response that includes the SREBP ortholog SBP-1, and fatty acid desaturases FAT-6 and FAT-7. Live imaging and ultrastructural analysis suggest that excess neutral lipid is stored in greatly expanded lipid droplets (LDs), as a result of enhanced endoplasmic reticulum (ER)-LD interaction. We also report that loss of function mutations in dpy-9 in C. elegans confers resistance to S. maltophilia. Dietary S. maltophilia induces supersized LDs by enhancing lipogenesis and ER-LD contacts in C. elegans. This work delineates a new model for understanding microbial regulation of metazoan physiology.
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Affiliation(s)
- Kang Xie
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Yangli Liu
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Xixia Li
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Shuyan Zhang
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Ho Yi Mak
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China,CONTACT Pingsheng Liu National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing100101, China
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24
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Dubińska-Magiera M, Lewandowski D, Cysewski D, Pawlak S, Najbar B, Daczewska M. Lipid droplets in skeletal muscle during grass snake (Natrix natrix L.) development. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159086. [PMID: 34822977 DOI: 10.1016/j.bbalip.2021.159086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 10/19/2021] [Accepted: 11/15/2021] [Indexed: 11/21/2022]
Abstract
Lipid droplets (LDs) are common organelles observed in Eucaryota. They are multifunctional organelles (involved in lipid storage, metabolism, and trafficking) that originate from endoplasmic reticulum (ER). LDs consist of a neutral lipid core, made up of diacyl- and triacylglycerols (DAGs and TAGs) and cholesterol esters (CEs), surrounded by a phospholipid monolayer and proteins, which are necessary for their structure and dynamics. Here, we report the protein and lipid composition as well as characterization and dynamics of grass snake (Natrix natrix) skeletal muscle LDs at different developmental stages. In the present study, we used detailed morphometric, LC-MS, quantitative lipidomic analyses of LDs isolated from the skeletal muscles of the snake embryos, immunofluorescence, and TEM. Our study also provides a valuable insight concerning the LDs' multifunctionality and ability to interact with a variety of organelles. These LD features are reflected in their proteome composition, which contains scaffold proteins, metabolic enzymes signalling polypeptides, proteins necessary for the formation of docking sites, and many others. We also provide insights into the biogenesis and growth of muscle LDs goes beyond the conventional mechanism based on the synthesis and incorporation of TAGs and LD fusion. We assume that the formation and functioning of grass snake muscle LDs are based on additional mechanisms that have not yet been identified, which could be related to the unique features of reptiles that are manifested in the after-hatching period of life, such as a reptile-specific strategy for energy saving during hibernation.
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Affiliation(s)
- Magda Dubińska-Magiera
- Department of Animal Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland
| | - Damian Lewandowski
- Department of Animal Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland.
| | - Dominik Cysewski
- Mass Spectrometry Laboratory, IBB PAS, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Seweryn Pawlak
- Department of Animal Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland
| | - Bartłomiej Najbar
- Faculty of Biological Sciences, University of Zielona Góra, Szafrana 1, 65-516 Zielona Góra 1, Poland
| | - Małgorzata Daczewska
- Department of Animal Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland
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25
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Biallelic loss of TRAPPC9 function links vesicle trafficking pathway to autosomal recessive intellectual disability. J Hum Genet 2022; 67:279-284. [PMID: 34983975 DOI: 10.1038/s10038-021-01007-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 11/08/2022]
Abstract
BACKGROUND The trafficking protein particle (TRAPP) complex subunit 9 (C9) protein is a member of TRAPP-II complexes and regulates vesicle trafficking. Biallelic mutations in the TRAPPC9 gene are responsible for intellectual disability with expanded developmental delay, epilepsy, microcephaly, and brain atrophy. TRAPPC9-related disease list is still expanding, however, the functional effects of only a limited fraction of these have been studied. METHODS In a patient with a pathological variant in TRAPPC9, clinical examination and cranial imaging findings were evaluated. Whole-exome sequencing, followed by Sanger sequencing was performed to detect and verify the variant. To confirm the functional effect of the mutation; variant mRNA and protein expression levels were evaluated by qRT-PCR and Western blotting. Immunostaining for TRAPPC9 and lipid droplet accumulation were examined. RESULTS We have identified a novel homozygous c.696C>G (p.Phe232Leu) pathogenic variant in TRAPPC9 (NM_031466.6) gene as a cause of severe developmental delay. Functional characterization of the TRAPPC9 variant resulted in decreased mRNA and protein expression. The intracellular findings showed that TRAPPC9 protein build-up around the nucleus in mutant type while there was no specific accumulation in the control cell line. This disrupted protein pattern affected the amount of neutral lipid-carrying vesicles and their homogenous distribution at a decreasing level. CONCLUSION Biallelic variants in the TRAPPC9 gene have been reported as the underlying cause of intellectual disability. This study provides functional evidence of the novel variant in TRAPPC9 We demonstrated that the loss of function variant exclusively targeting TRAPPC9 may explicate the neurological findings through vesicle trafficking.
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Rab2A regulates the progression of nonalcoholic fatty liver disease downstream of AMPK-TBC1D1 axis by stabilizing PPARγ. PLoS Biol 2022; 20:e3001522. [PMID: 35061665 PMCID: PMC8809606 DOI: 10.1371/journal.pbio.3001522] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 02/02/2022] [Accepted: 12/21/2021] [Indexed: 12/16/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) affects approximately a quarter of the population worldwide, and persistent overnutrition is one of the major causes. However, the underlying molecular basis has not been fully elucidated, and no specific drug has been approved for this disease. Here, we identify a regulatory mechanism that reveals a novel function of Rab2A in the progression of NAFLD based on energy status and PPARγ. The mechanistic analysis shows that nutrition repletion suppresses the phosphorylation of AMPK-TBC1D1 signaling, augments the level of GTP-bound Rab2A, and then increases the protein stability of PPARγ, which ultimately promotes the hepatic accumulation of lipids in vitro and in vivo. Furthermore, we found that blocking the AMPK-TBC1D1 pathway in TBC1D1S231A-knock-in (KI) mice led to a markedly increased GTP-bound Rab2A and subsequent fatty liver in aged mice. Our studies also showed that inhibition of Rab2A expression alleviated hepatic lipid deposition in western diet-induced obesity (DIO) mice by reducing the protein level of PPARγ and the expression of PPARγ target genes. Our findings not only reveal a new molecular mechanism regulating the progression of NAFLD during persistent overnutrition but also have potential implications for drug discovery to combat this disease. Non-alcoholic fatty liver disease (NAFLD) affects approximately a quarter of the global population; persistent overnutrition is one of the major causes, but the molecular mechanism remains unclear. This study shows that overnutrition suppresses the phosphorylation of AMPK and TBC1D1, augmenting the level of GTP-bound Rab2A and increasing the stability of PPARγ, which ultimately promotes the hepatic accumulation of lipids.
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A Decade of Mighty Lipophagy: What We Know and What Facts We Need to Know? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:5539161. [PMID: 34777688 PMCID: PMC8589519 DOI: 10.1155/2021/5539161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/30/2021] [Accepted: 10/15/2021] [Indexed: 12/24/2022]
Abstract
Lipids are integral cellular components that act as substrates for energy provision, signaling molecules, and essential constituents of biological membranes along with a variety of other biological functions. Despite their significance, lipid accumulation may result in lipotoxicity, impair autophagy, and lysosomal function that may lead to certain diseases and metabolic syndromes like obesity and even cell death. Therefore, these lipids are continuously recycled and redistributed by the process of selective autophagy specifically termed as lipophagy. This selective form of autophagy employs lysosomes for the maintenance of cellular lipid homeostasis. In this review, we have reviewed the current literature about how lipid droplets (LDs) are recruited towards lysosomes, cross-talk between a variety of autophagy receptors present on LD surface and lysosomes, and lipid hydrolysis by lysosomal enzymes. In addition to it, we have tried to answer most of the possible questions related to lipophagy regulation at different levels. Moreover, in the last part of this review, we have discussed some of the pathological states due to the accumulation of these LDs and their possible treatments under the light of currently available findings.
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28
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Cao S, Yang J, Fu J, Chen H, Jia H. The Dissection of SNAREs Reveals Key Factors for Vesicular Trafficking to the Endosome-like Compartment and Apicoplast via the Secretory System in Toxoplasma gondii. mBio 2021; 12:e0138021. [PMID: 34340555 PMCID: PMC8406237 DOI: 10.1128/mbio.01380-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/02/2021] [Indexed: 12/18/2022] Open
Abstract
Vesicular trafficking is a fundamental cellular process involved in material transport in eukaryotes, but the diversity of the intracellular compartments has prevented researchers from obtaining a clear understanding of the specific functions of vesicular trafficking factors, including SNAREs, tethers, and Rab GTPases, in Apicomplexa. In this study, we analyzed the localization of SNAREs and investigated their roles in vesicular trafficking in Toxoplasma gondii. Our results revealed the specific localizations of SNAREs in the endoplasmic reticulum (ER) (T. gondii Stx18 [TgStx18] and TgStx19), Golgi stacks (TgGS27), and endosome-like compartment (TgStx10 and TgStx12). The conditional ablation of ER- and Golgi-residing SNAREs caused severe defects in the secretory system. Most importantly, we found an R-SNARE (TgVAMP4-2) that is targeted to the apicoplast; to our knowledge, this work provides the first information showing a SNARE protein on endosymbiotic organelles and functioning in vesicular trafficking in eukaryotes. Conditional knockout of TgVAMP4-2 blocked the entrance of TgCPN60, TgACP, TgATrx2, and TgATrx1 into the apicoplast and interfered with the targeting of TgAPT1 and TgFtsH1 to the outermost membrane of the apicoplast. Together, our findings revealed the functions of SNAREs in the secretory system and the transport of nucleus-encoded proteins to an endosymbiotic organelle in a model organism of Apicomplexa. IMPORTANCE SNAREs are essential for the fusion of the transport vesicles and target membranes and, thus, provide perfect targets for obtaining a global view of the vesicle transport system. In this study, we report that a novel Qc-SNARE (TgStx19) instead of Use1 is located at the ER and acts as a partner of TgStx18 in T. gondii. TgGS27 and the tethering complex TRAPP III are conserved and critical for the biogenesis of the Golgi complex in T. gondii. A novel R-SNARE, TgVAMP4-2, is found on the outermost membrane of the apicoplast. The transport of NEAT proteins into the secondary endosymbiotic organelle depends on its function. To our knowledge, this work provides the first mention of a SNARE located on endosymbiotic organelles that functions in vesicular trafficking in eukaryotes.
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Affiliation(s)
- Shinuo Cao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Juan Yang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Jiawen Fu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Heming Chen
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Honglin Jia
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
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29
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Deng Y, Zhou C, Mirza AH, Bamigbade AT, Zhang S, Xu S, Liu P. Rab18 binds PLIN2 and ACSL3 to mediate lipid droplet dynamics. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158923. [PMID: 33713834 DOI: 10.1016/j.bbalip.2021.158923] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 02/26/2021] [Accepted: 03/05/2021] [Indexed: 01/16/2023]
Abstract
Lipid droplet (LD) is a vital organelle governing lipid homeostasis and Rab18 has been linked to lipid metabolism. However, the mechanisms of Rab18-mediated LD dynamics in myoblast cells remain elusive. Here, we report that Rab18 plays an important role in oleic acid (OA)-induced LD accumulation in mouse myoblast C2C12 cells. Rab18 was translocated from the endoplasmic reticulum (ER) to LDs during LD accumulation, which was regulated by perilipin 2 (PLIN2), a major LD protein. LD-associated Rab18 bound with the C terminus of PLIN2 and the LD localization of Rab18 was diminished when PLIN2 was depleted. Moreover, loss of function of Rab18 led to reduced triacylglycerol (TAG) level and fewer but larger LDs. In contrast, overexpression of Rab18 resulted in elevated TAG content and LD number. Furthermore, LD-associated Rab18 interacted with acyl-CoA synthetase long-chain family member 3 (ACSL3), which in turn promoted the LD localization of this protein. These data show that Rab18 interacts with PLIN2 and forms a complex with PLIN2 and ACSL3, which plays a critical role in LD accumulation and dynamics of myoblast cells.
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Affiliation(s)
- Yaqin Deng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chang Zhou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ahmed Hammad Mirza
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Adekunle T Bamigbade
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuyan Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Shimeng Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Galindo A, Planelles-Herrero VJ, Degliesposti G, Munro S. Cryo-EM structure of metazoan TRAPPIII, the multi-subunit complex that activates the GTPase Rab1. EMBO J 2021; 40:e107608. [PMID: 34018214 PMCID: PMC8204870 DOI: 10.15252/embj.2020107608] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/30/2021] [Accepted: 04/11/2021] [Indexed: 12/19/2022] Open
Abstract
The TRAPP complexes are nucleotide exchange factors that play essential roles in membrane traffic and autophagy. TRAPPII activates Rab11, and TRAPPIII activates Rab1, with the two complexes sharing a core of small subunits that affect nucleotide exchange but being distinguished by specific large subunits that are essential for activity in vivo. Crystal structures of core subunits have revealed the mechanism of Rab activation, but how the core and the large subunits assemble to form the complexes is unknown. We report a cryo‐EM structure of the entire Drosophila TRAPPIII complex. The TRAPPIII‐specific subunits TRAPPC8 and TRAPPC11 hold the catalytic core like a pair of tongs, with TRAPPC12 and TRAPPC13 positioned at the joint between them. TRAPPC2 and TRAPPC2L link the core to the two large arms, with the interfaces containing residues affected by disease‐causing mutations. The TRAPPC8 arm is positioned such that it would contact Rab1 that is bound to the core, indicating how the arm could determine the specificity of the complex. A lower resolution structure of TRAPPII shows a similar architecture and suggests that the TRAPP complexes evolved from a single ur‐TRAPP.
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Affiliation(s)
| | | | | | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK
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31
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da Silva Campelo M, Neto JFC, Lima ABN, das Chagas Neto FC, da Costa Gonzaga ML, de Aguiar Soares S, Leal LKAM, Ribeiro MENP, Ricardo NMPS. Polysaccharides and extracts from Agaricus brasiliensis Murill - A comprehensive review. Int J Biol Macromol 2021; 183:1697-1714. [PMID: 34022313 DOI: 10.1016/j.ijbiomac.2021.05.112] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/28/2021] [Accepted: 05/16/2021] [Indexed: 12/25/2022]
Abstract
Edible mushrooms have been increasingly introduced into the human diet, which has driven research into their functional properties. Thus, Agaricus brasiliensis Murill or Agaricus blazei Murill (ABM) is a species native to the Brazilian biome, whose fruiting body has been used not only for dietary purposes, but also in the development of functional foods or as source of molecules of pharmacological interest. The bioactivity of ABM has been related to the presence of polysaccharides, although the contribution of other metabolites cannot be discharged. This work describes the polysaccharides isolation methodology and preparation of the extracts of ABM and their biological activities. Furthermore, it presents a general outline of its characterizations regarding composition, chemical structure and properties in solution. The ABM and its chemical constituents exhibit several biological activities that support their potential use for prevention or treatment of diseases with inflammatory background, such as cancer, diabetes and atherosclerosis. The mechanism of action of the extracts and polysaccharides from ABM is mainly related to a modulation of immune system response or reduction of inflammatory response. This review shows that the ABM has great potential in the pharmaceutical, biotechnological and food sectors that deserves additional research using standardized products.
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Affiliation(s)
- Matheus da Silva Campelo
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil
| | - João Francisco Câmara Neto
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil
| | - Ana Beatriz Nogueira Lima
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil
| | - Francisco Cirineu das Chagas Neto
- Centro de Estudos Farmacêuticos e Cosméticos, Departamento de Farmácia, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60430-160, Brasil
| | - Maria Leônia da Costa Gonzaga
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil
| | - Sandra de Aguiar Soares
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil
| | - Luzia Kalyne Almeida Moreira Leal
- Centro de Estudos Farmacêuticos e Cosméticos, Departamento de Farmácia, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60430-160, Brasil.
| | - Maria Elenir Nobre Pinho Ribeiro
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil.
| | - Nágila Maria Pontes Silva Ricardo
- Laboratório de Polímeros e Inovação de Materiais, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza - CE, CEP: 60455-760, Brasil.
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32
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Xu D, Li P, Xu L. Characterization of the Role of Rab18 in Mediating LD-ER Contact and LD Growth. Methods Mol Biol 2021; 2293:229-241. [PMID: 34453721 DOI: 10.1007/978-1-0716-1346-7_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Lipid droplets (LDs) are dynamic cellular organelles found in most eukaryotic cells. Lipid incorporation from endoplasmic reticulum (ER) to LD is important in controlling LD growth and intracellular lipid homeostasis. However, the molecular link that mediates ER and LD cross talk remains elusive. Here, we describe the methodology used to characterize the function of Rab18 in regulating LD homeostasis and LD-ER contact. First, we focus on the quantitative assay used to measure intracellular LDs morphological changes. This is followed by a detailed description of the use of the APEX-label technology in combination with electron microscope (EM) to visualize ER-LD contact sites. These assays are valuable for the investigation of LD-associated proteins such as Rab18 in establishing membrane contact sites between LDs and other subcellular organelles.
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Affiliation(s)
- Dijin Xu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Peng Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Li Xu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
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33
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Jenkins ML, Harris NJ, Dalwadi U, Fleming KD, Ziemianowicz DS, Rafiei A, Martin EM, Schriemer DC, Yip CK, Burke JE. The substrate specificity of the human TRAPPII complex's Rab-guanine nucleotide exchange factor activity. Commun Biol 2020; 3:735. [PMID: 33277614 PMCID: PMC7719173 DOI: 10.1038/s42003-020-01459-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022] Open
Abstract
The TRAnsport Protein Particle (TRAPP) complexes act as Guanine nucleotide exchange factors (GEFs) for Rab GTPases, which are master regulators of membrane trafficking in eukaryotic cells. In metazoans, there are two large multi-protein TRAPP complexes: TRAPPII and TRAPPIII, with the TRAPPII complex able to activate both Rab1 and Rab11. Here we present detailed biochemical characterisation of Rab-GEF specificity of the human TRAPPII complex, and molecular insight into Rab binding. GEF assays of the TRAPPII complex against a panel of 20 different Rab GTPases revealed GEF activity on Rab43 and Rab19. Electron microscopy and chemical cross-linking revealed the architecture of mammalian TRAPPII. Hydrogen deuterium exchange MS showed that Rab1, Rab11 and Rab43 share a conserved binding interface. Clinical mutations in Rab11, and phosphomimics of Rab43, showed decreased TRAPPII GEF mediated exchange. Finally, we designed a Rab11 mutation that maintained TRAPPII-mediated GEF activity while decreasing activity of the Rab11-GEF SH3BP5, providing a tool to dissect Rab11 signalling. Overall, our results provide insight into the GTPase specificity of TRAPPII, and how clinical mutations disrupt this regulation. Here the authors reveal unique structural organization of the mammalian TRAPPII complex, which is critical in regulating membrane trafficking. They find that TRAPPII serves as a guanine nucleotide exchange factor for unexpected Rab GTPases such as Rab43 and Rab19.
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Affiliation(s)
- Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Noah J Harris
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Udit Dalwadi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Daniel S Ziemianowicz
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Atefeh Rafiei
- Department of Chemistry, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Emily M Martin
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Department of Chemistry, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Calvin K Yip
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada. .,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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34
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Leyland B, Zarka A, Didi-Cohen S, Boussiba S, Khozin-Goldberg I. High Resolution Proteome of Lipid Droplets Isolated from the Pennate Diatom Phaeodactylum tricornutum (Bacillariophyceae) Strain pt4 provides mechanistic insights into complex intracellular coordination during nitrogen deprivation. JOURNAL OF PHYCOLOGY 2020; 56:1642-1663. [PMID: 32779202 DOI: 10.1111/jpy.13063] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/14/2020] [Accepted: 07/12/2020] [Indexed: 05/08/2023]
Abstract
Lipid droplets (LDs) are an organelle conserved amongst all eukaryotes, consisting of a neutral lipid core surrounded by a polar lipid monolayer. Many species of microalgae accumulate LDs in response to stress conditions, such as nitrogen starvation. Here, we report the isolation and proteomic profiling of LD proteins from the model oleaginous pennate diatom Phaeodactylum tricornutum, strain Pt4 (UTEX 646). We also provide a quantitative description of LD morphological ontogeny, and fatty acid content. Novel cell disruption and LD isolation methods, combined with suspension-trapping and nanoflow liquid chromatography coupled to high resolution mass spectrometry, yielded an unprecedented number of LD proteins. Predictive annotation of the LD proteome suggests a broad assemblage of proteins with diverse functions, including lipid metabolism and vesicle trafficking, as well as ribosomal and proteasomal machinery. These proteins provide mechanistic insights into LD processes, and evidence for interactions between LDs and other organelles. We identify for the first time several key steps in diatom LD-associated triacylglycerol biosynthesis. Bioinformatic analyses of the LD proteome suggests multiple protein targeting mechanisms, including amphipathic helices, post-translational modifications, and translocation machinery. This work corroborates recent findings from other strains of P. tricornutum, other diatoms, and other eukaryotic organisms, suggesting that the fundamental proteins orchestrating LDs are conserved, and represent an ancient component of the eukaryotic endomembrane system. We postulate a comprehensive model of nitrogen starvation-induced diatom LDs on a molecular scale, and provide a wealth of candidates for metabolic engineering, with the potential to eventually customize LD contents.
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Affiliation(s)
- Ben Leyland
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Aliza Zarka
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Shoshana Didi-Cohen
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Sammy Boussiba
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Inna Khozin-Goldberg
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
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35
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Ke Y, Weng M, Chhetri G, Usman M, Li Y, Yu Q, Ding Y, Wang Z, Wang X, Sultana P, DiFiglia M, Li X. Trappc9 deficiency in mice impairs learning and memory by causing imbalance of dopamine D1 and D2 neurons. SCIENCE ADVANCES 2020; 6:6/47/eabb7781. [PMID: 33208359 PMCID: PMC7673810 DOI: 10.1126/sciadv.abb7781] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 10/01/2020] [Indexed: 05/06/2023]
Abstract
Genetic mutations in the gene encoding transport protein particle complex 9 (trappc9), a subunit of TRAPP that acts as a guanine nucleotide exchange factor for rab proteins, cause intellectual disability with brain structural malformations by elusive mechanisms. Here, we report that trappc9-deficient mice exhibit a broad range of behavioral deficits and postnatal delay in growth of the brain. Contrary to volume decline of various brain structures, the striatum of trappc9 null mice was enlarged. An imbalance existed between dopamine D1 and D2 receptor containing neurons in the brain of trappc9-deficient mice; pharmacological manipulation of dopamine receptors improved performances of trappc9 null mice to levels of wild-type mice on cognitive tasks. Loss of trappc9 compromised the activation of rab11 in the brain and resulted in retardation of endocytic receptor recycling in neurons. Our study elicits a pathogenic mechanism and a potential treatment for trappc9-linked disorders including intellectual disability.
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Affiliation(s)
- Yuting Ke
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Meiqian Weng
- Mucosal Immunology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Gaurav Chhetri
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Muhammad Usman
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Yan Li
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Qing Yu
- Department of Nephrology, Shanghai General Hospital, 650 Songjiang Road, Songjiang District, Shanghai 201620, China
| | - Yingzhuo Ding
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Zejian Wang
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Xiaolong Wang
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Pinky Sultana
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Xueyi Li
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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36
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Xu Y, Wang N, Tan HY, Li S, Zhang C, Zhang Z, Feng Y. Panax notoginseng saponins modulate the gut microbiota to promote thermogenesis and beige adipocyte reconstruction via leptin-mediated AMPKα/STAT3 signaling in diet-induced obesity. Am J Cancer Res 2020; 10:11302-11323. [PMID: 33042284 PMCID: PMC7532683 DOI: 10.7150/thno.47746] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/02/2020] [Indexed: 12/18/2022] Open
Abstract
Background: Activation of the thermogenic program in white and brown adipocytes presents a promising avenue for increasing energy expenditure during the treatment of obesity. The endogenous mechanism for promoting thermogenesis in brown adipocytes or browning in white adipocytes has indicated that the gut microbiota is a crucial regulator of the host energy balance. However, whether the effects of the therapeutic intervention-induced modulation of the gut microbiota on adipocyte browning involved the regulation of leptin remains unclear. Method: The adipose features were analyzed by body composition analysis, infrared camera observations, transmission electron microscopy and H&E staining. The gene and protein expression in adipose tissue were detected by qRT-PCR, immunoblotting, immunohistochemistry and immunofluorescence staining. The gut microbiome signature was identified by 16S rRNA gene amplicon sequencing, and both mice with high-fat diet-induced obesity (DIO) and mice with antibiotics-induced microbiome depletion were subjected to fecal microbiota transplantation. Results: Treatment with Panax notoginseng saponins (PNS) shaped the murine gut microbiome by increasing the abundances of Akkermansia muciniphila and Parabacteroides distasonis, and as a result, DIO mice harbored a distal gut microbiota with a significantly increased capacity to reduce host adiposity. The PNS-induced modulation of the gut microbiota in DIO mice could increase brown adipose tissue (BAT) thermogenesis and beige adipocyte reconstruction by activating the leptin-AMPK/STAT3 signaling pathway, which results in the promotion of energy expenditure. Leptin has an essential influence on the anti-obesity effects of PNS. In cases of leptin deficiency, the PNS-induced modulation of the gut microbiota exerts negative effects on thermogenesis and browning in white adipose tissue (WAT), which indicates that PNS fail to reduce obesity in leptin gene-deficient mice. The PNS-induced modulation of the gut microbiota exerted a minimal effect on DIO mice with antibiotic-induced microbiome depletion, which confirmed the correlation between altered gut microbiota and the remodeling of adipose tissues in DIO mice. The direct influence of leptin on browning via the AMPKα/STAT3 signaling pathway in C3H101/2 cells supported our in vivo results that signalling through the leptin-AMPK/STAT3 pathway induced by the PNS-modulated gut microbiota was involved in beige adipocyte reconstruction. Conclusion: Our results revealed that leptin signaling is critical for alterations in microbiota-fat crosstalk and provide promising avenues for therapeutic intervention in the treatment of obesity.
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37
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Zhang C, Li C, Siu GKY, Luo X, Yu S. Distinct Roles of TRAPPC8 and TRAPPC12 in Ciliogenesis via Their Interactions With OFD1. Front Cell Dev Biol 2020; 8:148. [PMID: 32258032 PMCID: PMC7090148 DOI: 10.3389/fcell.2020.00148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/21/2020] [Indexed: 01/08/2023] Open
Abstract
The transport protein particle (TRAPP) complex was initially identified as a tethering factor for COPII vesicle. Subsequently, three forms (TRAPPI, II, and III) have been found and TRAPPIII has been reported to serve as a regulator in autophagy. This study investigates a new role of mammalian TRAPPIII in ciliogenesis. We found a ciliopathy protein, oral-facial-digital syndrome 1 (OFD1), interacting with the TRAPPIII-specific subunits TRAPPC8 and TRAPPC12. TRAPPC8 is necessary for the association of OFD1 with pericentriolar material 1 (PCM1). Its depletion reduces the extent of colocalized signals between OFD1 and PCM1, but does not compromise the structural integrity of centriolar satellites. The interaction between TRAPPC8 and OFD1 inhibits that between OFD1 and TRAPPC12, suggesting different roles of TRAPPIII-specific subunits in ciliogenesis and explaining the differences in cilium lengths in TRAPPC8-depleted and TRAPPC12-depleted hTERT-RPE1 cells. On the other hand, TRAPPC12 depletion causes increased ciliary length because TRAPPC12 is required for the disassembly of primary cilia. Overall, this study has revealed different roles of TRAPPC8 and TRAPPC12 in the assembly of centriolar satellites and demonstrated a possible tethering role of TRAPPIII during ciliogenesis.
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Affiliation(s)
- Caiyun Zhang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Chunman Li
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Gavin Ka Yu Siu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Xiaomin Luo
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Sidney Yu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
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38
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Affiliation(s)
- Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster
- Cells-in-Motion Cluster of Excellence (EXC 1003—CiM), University of Münster
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39
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Leyland B, Boussiba S, Khozin-Goldberg I. A Review of Diatom Lipid Droplets. BIOLOGY 2020; 9:biology9020038. [PMID: 32098118 PMCID: PMC7168155 DOI: 10.3390/biology9020038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 12/20/2022]
Abstract
The dynamic nutrient availability and photon flux density of diatom habitats necessitate buffering capabilities in order to maintain metabolic homeostasis. This is accomplished by the biosynthesis and turnover of storage lipids, which are sequestered in lipid droplets (LDs). LDs are an organelle conserved among eukaryotes, composed of a neutral lipid core surrounded by a polar lipid monolayer. LDs shield the intracellular environment from the accumulation of hydrophobic compounds and function as a carbon and electron sink. These functions are implemented by interconnections with other intracellular systems, including photosynthesis and autophagy. Since diatom lipid production may be a promising objective for biotechnological exploitation, a deeper understanding of LDs may offer targets for metabolic engineering. In this review, we provide an overview of diatom LD biology and biotechnological potential.
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40
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Bao J, Li X, Li Y, Huang C, Meng X, Li J. MicroRNA-141-5p Acts as a Tumor Suppressor via Targeting RAB32 in Chronic Myeloid Leukemia. Front Pharmacol 2020; 10:1545. [PMID: 32038235 PMCID: PMC6987442 DOI: 10.3389/fphar.2019.01545] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 11/29/2019] [Indexed: 12/11/2022] Open
Abstract
MicroRNA-141-5p (miR-141-5p), an important member of the miR-200 family, has been reported to be involved in cellular proliferation, migration, invasion, and drug resistance in different kinds of human malignant tumors. However, the role and function of miR-141-5p in chronic myeloid leukemia (CML) are unclear. In this current study, we found that the level of miR-141-5p was significantly decreased in peripheral blood cells from CML patients compared with normal blood cells and human leukemic cell line (K562 cells) compared with normal CD34+ cells, but was remarkably elevated in patients after treatment with nilotinib or imatinib. Suppression of miR-141-5p promoted K562 cell proliferation and migration in vitro. As expected, overexpression of miR-141-5p weakened K562 cell proliferation, migration, and promoted cell apoptosis. A xenograft model in nude mice showed that overexpression of miR-141-5p markedly suppressed tumor growth in vivo. Mechanistic studies suggested that RAB32 was the potential target of miR-141-5p, and silencing of RAB32 suppressed the proliferation and migration of K562 cells and promoted cell apoptosis. Taken together, our study demonstrates that miR-141-5p plays an important role in the activation of K562 cells in vitro and may act as a tumor suppressor via targeting RAB32 in the development of CML.
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Affiliation(s)
- Jing Bao
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China.,Department of Hematology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xiaofeng Li
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China
| | - Yuhuan Li
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China
| | - Cheng Huang
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China
| | - Xiaoming Meng
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China
| | - Jun Li
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China
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41
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Hazari Y, Bravo-San Pedro JM, Hetz C, Galluzzi L, Kroemer G. Autophagy in hepatic adaptation to stress. J Hepatol 2020; 72:183-196. [PMID: 31849347 DOI: 10.1016/j.jhep.2019.08.026] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/13/2019] [Accepted: 08/28/2019] [Indexed: 02/06/2023]
Abstract
Autophagy is an evolutionarily ancient process whereby eukaryotic cells eliminate disposable or potentially dangerous cytoplasmic material, to support bioenergetic metabolism and adapt to stress. Accumulating evidence indicates that autophagy operates as a critical quality control mechanism for the maintenance of hepatic homeostasis in both parenchymal (hepatocytes) and non-parenchymal (stellate cells, sinusoidal endothelial cells, Kupffer cells) compartments. In line with this notion, insufficient autophagy has been aetiologically involved in the pathogenesis of multiple liver disorders, including alpha-1-antitrypsin deficiency, Wilson disease, non-alcoholic steatohepatitis, liver fibrosis and hepatocellular carcinoma. Here, we critically discuss the importance of functional autophagy for hepatic physiology, as well as the mechanisms whereby defects in autophagy cause liver disease.
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Affiliation(s)
- Younis Hazari
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile; FONDAP Center for Geroscience (GERO), Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - José Manuel Bravo-San Pedro
- Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile; FONDAP Center for Geroscience (GERO), Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile; Buck Institute for Research in Aging, Novato, CA, USA.
| | - Lorenzo Galluzzi
- Department of Radiation Oncology, Weill Cornell Medical College, New York, NY, USA; Sandra and Edward Meyer Cancer Center, New York, NY, USA; Department of Dermatology, Yale School of Medicine, New Haven, CT, USA; Université Paris Descartes/Paris V, Paris, France
| | - Guido Kroemer
- Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Suzhou Institute for Systems Medicine, Chinese Academy of Sciences, Suzhou, China; Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden.
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42
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Bekbulat F, Schmitt D, Feldmann A, Huesmann H, Eimer S, Juretschke T, Beli P, Behl C, Kern A. RAB18 Loss Interferes With Lipid Droplet Catabolism and Provokes Autophagy Network Adaptations. J Mol Biol 2019; 432:1216-1234. [PMID: 31874152 DOI: 10.1016/j.jmb.2019.12.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/16/2019] [Accepted: 12/16/2019] [Indexed: 12/18/2022]
Abstract
Autophagy is dependent on appropriate lipid supply for autophagosome formation. The regulation of lipid acquisition and the autophagy network response to lipid-limiting conditions are mostly elusive. Here, we show that the knockout of the RAB GTPase RAB18 interferes with lipid droplet catabolism, causing an impaired fatty acid release. The resulting reduced lipid-droplet-derived lipid availability influences autophagy and provokes adaptive modifications of the autophagy network. These adjustments include increased expression and phosphorylation of ATG2B as well as augmented formation of the ATG12-ATG5 conjugate. Moreover, ATG9A shows an enhanced phosphorylation at amino acid residues tyrosine 8 and serine 14, resulting in an increased ATG9A trafficking. Via pharmacological inhibition of Y8 phosphorylation, we demonstrate that this ATG9A modification is important to maintain basal autophagy under RAB18 knockout conditions. However, while the network adaptations are sufficient to maintain basal autophagic activity, they are incapable of ensuring autophagy induction upon starvation, which is characterized by an enhanced lipid demand. Thus, here, we define the molecular role of RAB18 in connecting lipid droplets and autophagy, emphasize the significance of lipid droplets as lipid sources for the degradative pathway, and uncover a remarkable autophagy network plasticity, including phosphorylation-dependent ATG9A activation, to compensate reduced lipid availability in order to rescue basal autophagic activity.
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Affiliation(s)
- Fazilet Bekbulat
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Daniel Schmitt
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Anne Feldmann
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Heike Huesmann
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Stefan Eimer
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue-Str. 13, 60438 Frankfurt, Germany
| | - Thomas Juretschke
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Petra Beli
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Christian Behl
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany.
| | - Andreas Kern
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany.
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43
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Hugenroth M, Bohnert M. Come a little bit closer! Lipid droplet-ER contact sites are getting crowded. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118603. [PMID: 31733263 DOI: 10.1016/j.bbamcr.2019.118603] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/26/2019] [Accepted: 10/29/2019] [Indexed: 12/12/2022]
Abstract
Not so long ago, contact sites between the endoplasmic reticulum (ER) and lipid droplets (LDs) were largely unexplored on a molecular level. In recent years however, numerous proteins have been identified that are enriched or exclusively located at the interfaces between LDs and the ER. These comprise members of protein classes typically found in diverse types of contacts, such as organelle tethers and lipid transfer proteins, but also proteins that have no similarities to known contact site machineries. This structurally heterogeneous group of contact site residents might be required to fulfill unique aspects of LD-ER contact biology, such as de novo LD biogenesis, and maintenance of lipidic connections between LDs and ER. Here, we summarize the current knowledge on the molecular components of this special organelle contact site, and discuss their features and functions.
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Affiliation(s)
- Marie Hugenroth
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Germany.
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44
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Zappa F, Wilson C, Di Tullio G, Santoro M, Pucci P, Monti M, D'Amico D, Pisonero‐Vaquero S, De Cegli R, Romano A, Saleem MA, Polishchuk E, Failli M, Giaquinto L, De Matteis MA. The TRAPP complex mediates secretion arrest induced by stress granule assembly. EMBO J 2019; 38:e101704. [PMID: 31429971 PMCID: PMC6769382 DOI: 10.15252/embj.2019101704] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/29/2022] Open
Abstract
The TRAnsport Protein Particle (TRAPP) complex controls multiple membrane trafficking steps and is strategically positioned to mediate cell adaptation to diverse environmental conditions, including acute stress. We have identified the TRAPP complex as a component of a branch of the integrated stress response that impinges on the early secretory pathway. The TRAPP complex associates with and drives the recruitment of the COPII coat to stress granules (SGs) leading to vesiculation of the Golgi complex and arrest of ER export. The relocation of the TRAPP complex and COPII to SGs only occurs in cycling cells and is CDK1/2-dependent, being driven by the interaction of TRAPP with hnRNPK, a CDK substrate that associates with SGs when phosphorylated. In addition, CDK1/2 inhibition impairs TRAPP complex/COPII relocation to SGs while stabilizing them at ER exit sites. Importantly, the TRAPP complex controls the maturation of SGs. SGs that assemble in TRAPP-depleted cells are smaller and are no longer able to recruit RACK1 and Raptor, two TRAPP-interactive signaling proteins, sensitizing cells to stress-induced apoptosis.
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Affiliation(s)
- Francesca Zappa
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | - Cathal Wilson
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | | | - Michele Santoro
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | | | | | - Davide D'Amico
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | | | | | - Alessia Romano
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | - Moin A Saleem
- Bristol RenalBristol Medical SchoolUniversity of BristolBristolUK
| | - Elena Polishchuk
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | - Mario Failli
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
| | - Laura Giaquinto
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy
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45
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Cuenca A, Insinna C, Zhao H, John P, Weiss MA, Lu Q, Walia V, Specht S, Manivannan S, Stauffer J, Peden AA, Westlake CJ. The C7orf43/TRAPPC14 component links the TRAPPII complex to Rabin8 for preciliary vesicle tethering at the mother centriole during ciliogenesis. J Biol Chem 2019; 294:15418-15434. [PMID: 31467083 DOI: 10.1074/jbc.ra119.008615] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/25/2019] [Indexed: 01/08/2023] Open
Abstract
The primary cilium is a cellular sensor that detects light, chemicals, and movement and is important for morphogen and growth factor signaling. The small GTPase Rab11-Rab8 cascade is required for ciliogenesis. Rab11 traffics the guanine nucleotide exchange factor (GEF) Rabin8 to the centrosome to activate Rab8, needed for ciliary growth. Rabin8 also requires the transport particle protein complex (TRAPPC) proteins for centrosome recruitment during ciliogenesis. Here, using an MS-based approach for identifying Rabin8-interacting proteins, we identified C7orf43 (also known as microtubule-associated protein 11 (MAP11)) as being required for ciliation both in human cells and zebrafish embryos. We find that C7orf43 directly binds to Rabin8 and that C7orf43 knockdown diminishes Rabin8 preciliary centrosome accumulation. Interestingly, we found that C7orf43 co-sediments with TRAPPII complex subunits and directly interacts with TRAPPC proteins. Our findings establish that C7orf43 is a TRAPPII-specific complex component, referred to here as TRAPPC14. Additionally, we show that TRAPPC14 is dispensable for TRAPPII complex integrity but mediates Rabin8 association with the TRAPPII complex. Finally, we demonstrate that TRAPPC14 interacts with the distal appendage proteins Fas-binding factor 1 (FBF1) and centrosomal protein 83 (CEP83), which we show here are required for GFP-Rabin8 centrosomal accumulation, supporting a role for the TRAPPII complex in tethering preciliary vesicles to the mother centriole during ciliogenesis. In summary, our findings have revealed an uncharacterized TRAPPII-specific component, C7orf43/TRAPPC14, that regulates preciliary trafficking of Rabin8 and ciliogenesis and support previous findings that the TRAPPII complex functions as a membrane tether.
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Affiliation(s)
- Adrian Cuenca
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Christine Insinna
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Huijie Zhao
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Peter John
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Matthew A Weiss
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Quanlong Lu
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Vijay Walia
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Suzanne Specht
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Selvambigai Manivannan
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Jimmy Stauffer
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Andrew A Peden
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Christopher J Westlake
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
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46
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Yang Z, Lian Z, Liu G, Deng M, Sun B, Guo Y, Liu D, Li Y. Identification of genetic markers associated with milk production traits in Chinese Holstein cattle based on post genome-wide association studies. Anim Biotechnol 2019; 32:67-76. [PMID: 31424326 DOI: 10.1080/10495398.2019.1653901] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
With the rapid development of dairy industry, the breeding process of dairy cows has been accelerated. In previous genome-wide association studies (GWAS), a large number of genetic markers have been reported which may contribute to the selection of Holstein populations with superior milk-producing traits, but they remain to be further verified before practical application. In this study, 90 single nucleotide polymorphisms (SNPs) were selected, which were reported to be significantly associated with five milk production traits, including 305-day milk yield (305MY), 305-day milk fat percent (305FC), 305-day milk protein percent (305PC), 305-day milk fat yield (305FY) and 305-day milk protein yield (305PY). Effective 305-day data and fresh DNA samples were obtained from 295 healthy cows with gestational age of 1-4. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) was used to perform precise genotyping of these loci, followed by site association and haplotype analysis. Results showed that 36 out of 90 loci were supported to be used as genetic markers. In particular, several novel and effective haplotypes were also presented. Overall, our results verified tens of useful markers and provided a basis for further development of breeding strategies.
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Affiliation(s)
- Zhenwei Yang
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Zhiquan Lian
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Guangbin Liu
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Ming Deng
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Baoli Sun
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Yongqing Guo
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Dewu Liu
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Yaokun Li
- College of Animal Science, South China Agricultural University, Guangzhou, China.,National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
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47
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史 琳, 王 柯, 邓 玉, 王 莹, 朱 双, 杨 旭, 廖 文. [Role of lipophagy in the regulation of lipid metabolism and the molecular mechanism]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2019; 39:867-874. [PMID: 31340923 PMCID: PMC6765557 DOI: 10.12122/j.issn.1673-4254.2019.07.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Indexed: 01/02/2023]
Abstract
Recent studies have discovered a selective autophagy-lipophagy, which can selectively identify and degrade lipids and plays an important role in regulating cellular lipid metabolism and maintaining intracellular lipid homeostasis. The process of lipophagy can be directly or indirectly regulated by genes, enzymes, transcriptional regulators and other factors. This review examines the role of lipophagy in reducing liver lipid content, regulating pancreatic lipid metabolism, and regulating adipose tissue differentiation, and summarizes the findings of the molecules (Rab GTPase, enzymes, ion channels, transcription factors, small molecular substances) involved in the regulation of lipophagy, which points to new directions for the treatment of diseases caused by lipid accumulation.
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Affiliation(s)
- 琳娜 史
- 南方医科大学 南方医院营养科,广东 广州 510515Department of Nutrition, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 柯 王
- 华南理工大学食品科学与工程学院,广东 广 州 510640College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China
| | - 玉娣 邓
- 南方医科大学公共卫生学院,广东 广州 510515School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - 莹娜 王
- 广州市三兴生物技术有限公司,广东 广州 510000Guangzhou Sanxing Biotechnology Co., Ltd., Guangzhou 510000, China
| | - 双玲 朱
- 中山大学附属第一医院,广东 广州 510080First Affiliated Hospital, Sun Yat- sen University, Guangzhou 510080, China
| | - 旭珊 杨
- 南方医科大学公共卫生学院,广东 广州 510515School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - 文镇 廖
- 南方医科大学公共卫生学院,广东 广州 510515School of Public Health, Southern Medical University, Guangzhou 510515, China
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48
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RAB18 modulates autophagy in human stellate cells. J Clin Lipidol 2019; 13:832-838. [PMID: 31563421 DOI: 10.1016/j.jacl.2019.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 07/06/2019] [Accepted: 07/16/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Macroautophagy (or autophagy) is a conserved degradative pathway that breaks down sequestered cytoplasmic proteins and organelles in specialized double-membrane compartments called autophagosomes that fuse with lysosomes. Several proteins orchestrate this process, specifically Rab GTPases that are master regulators of molecular trafficking. RAB18 GTPase, a known mediator of stellate cell activation, is known to modulate autophagic flux in fibroblasts. However, its role in autophagy is unexplored in hepatic stellate cells. OBJECTIVE The aim of this study was to investigate the role of RAB18 in modulating autophagy in hepatic stellate cells. METHODS Role of RAB18 was determined by genetic depletion, pharmacologic inhibition, and overexpression studies to monitor autophagy flux and proteostasis in human LX2 stellate cell line. RESULTS RAB18 knockdown increases autophagy flux and regulates proteostasis. LX2 cells stimulated with transforming growth factor-beta robustly increases expression of profibrotic genes such as COL1A1 and ACTA2 along with RAB18 and its guanine nucleotide exchange factor, RAB3GAP1. CONCLUSION The study elucidates a role for RAB18 in autophagy and regulation of proteostasis in human stellate cells. Molecular insights into this process can provide therapeutic opportunities for intervention in liver fibrosis.
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49
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Jackson CL. Lipid droplet biogenesis. Curr Opin Cell Biol 2019; 59:88-96. [PMID: 31075519 DOI: 10.1016/j.ceb.2019.03.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/24/2019] [Accepted: 03/29/2019] [Indexed: 11/18/2022]
Abstract
Lipid droplets (LDs) store neutral lipids in their core as an energy source when nutrients are scarce. The center of an LD is hydrophobic, and hence it is surrounded by a phospholipid monolayer, unlike other organelles that have an aqueous interior and are bounded by a phospholipid bilayer. LDs arise from the ER, where neutral lipid synthesis enzymes are localized. A combination of biophysical analysis and modeling, in vitro reconstitution and cell biological analyses has provided a great deal of information over the past few years on the process of LD biogenesis from the ER. In addition to lipid composition, four protein families (seipin proteins, perilipins, FIT proteins and ER shaping proteins) are crucial for LD biogenesis. Recent studies have shown that LDs preferentially arise, along with peroxisomes, at special ER sites marked by the reticulon-like Pex30/MCTP2 protein. New functions for perilipins and FIT family proteins have been uncovered, and the cryo-electron microscopy structure of seipin coupled with high resolution imaging in cells has provided a more comprehensive picture of its function in LD biogenesis. Seipin, along with other proteins such as Rab18 and its effector NRZ, have been shown to carry out their functions at least in part through regulation of ER-LD contact sites, whose establishment and maintenance have emerged as an essential component of LD biogenesis and maturation.
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Affiliation(s)
- Catherine L Jackson
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.
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50
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Dejgaard SY, Presley JF. Rab18: new insights into the function of an essential protein. Cell Mol Life Sci 2019; 76:1935-1945. [PMID: 30830238 PMCID: PMC11105521 DOI: 10.1007/s00018-019-03050-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/14/2022]
Abstract
Rab18 is one of the small number of conserved Rab proteins which have been traced to the last eukaryotic common ancestor. It is found in organisms ranging from humans to trypanosomes, and localizes to multiple organelles, including most notably endoplasmic reticulum and lipid droplets. In humans, absence of Rab18 leads to a severe illness known as Warburg-Micro syndrome. Despite this evidence that Rab18 is essential, its role in cells remains mysterious. However, recent studies identifying effectors and interactors of Rab18, are now shedding light on its mechanism of action, suggesting functions related to organelle tethering and to autophagy. In this review, we examine the variety of roles proposed for Rab18 with a focus on new evidence giving insights into the molecular mechanisms it utilizes. Based on this summary of our current understanding, we identify priority areas for further research.
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Affiliation(s)
- Selma Yilmaz Dejgaard
- Department of Medical Biology, Near East University, Nicosia, Cyprus
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, QC, H3A 0C7, Canada
| | - John F Presley
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, QC, H3A 0C7, Canada.
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