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Schmeisser K, Kaptan D, Raghuraman BK, Shevchenko A, Rodenfels J, Penkov S, Kurzchalia TV. Mobilization of cholesterol induces the transition from quiescence to growth in Caenorhabditis elegans through steroid hormone and mTOR signaling. Commun Biol 2024; 7:121. [PMID: 38267699 PMCID: PMC10808130 DOI: 10.1038/s42003-024-05804-7] [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: 01/14/2023] [Accepted: 01/11/2024] [Indexed: 01/26/2024] Open
Abstract
Recovery from the quiescent developmental stage called dauer is an essential process in C. elegans and provides an excellent model to understand how metabolic transitions contribute to developmental plasticity. Here we show that cholesterol bound to the small secreted proteins SCL-12 or SCL-13 is sequestered in the gut lumen during the dauer state. Upon recovery from dauer, bound cholesterol undergoes endocytosis into lysosomes of intestinal cells, where SCL-12 and SCL-13 are degraded and cholesterol is released. Free cholesterol activates mTORC1 and is used for the production of dafachronic acids. This leads to promotion of protein synthesis and growth, and a metabolic switch at the transcriptional level. Thus, mobilization of sequestered cholesterol stores is the key event for transition from quiescence to growth, and cholesterol is the major signaling molecule in this process.
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Affiliation(s)
- Kathrin Schmeisser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Damla Kaptan
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jonathan Rodenfels
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Physics of Life (PoL), Technical University Dresden, Dresden, Germany
| | - Sider Penkov
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Faculty of Medicine, Technical University Dresden, Dresden, Germany
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2
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O'Keeffe C, Greenwald I. EGFR signal transduction is downregulated in C. elegans vulval precursor cells during dauer diapause. Development 2022; 149:dev201094. [PMID: 36227589 PMCID: PMC9793418 DOI: 10.1242/dev.201094] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022]
Abstract
Caenorhabditis elegans larvae display developmental plasticity in response to environmental conditions: in adverse conditions, second-stage larvae enter a reversible, long-lived dauer stage instead of proceeding to reproductive adulthood. Dauer entry interrupts vulval induction and is associated with a reprogramming-like event that preserves the multipotency of vulval precursor cells (VPCs), allowing vulval development to reinitiate if conditions improve. Vulval induction requires the LIN-3/EGF-like signal from the gonad, which activates EGFR-Ras-ERK signal transduction in the nearest VPC, P6.p. Here, using a biosensor and live imaging we show that EGFR-Ras-ERK activity is downregulated in P6.p in dauers. We investigated this process using gene mutations or transgenes to manipulate different steps of the pathway, and by analyzing LET-23/EGFR subcellular localization during dauer life history. We found that the response to EGF is attenuated at or upstream of Ras activation, and discuss potential membrane-associated mechanisms that could achieve this. We also describe other findings pertaining to the maintenance of VPC competence and quiescence in dauer larvae. Our analysis indicates that VPCs have L2-like and unique dauer stage features rather than features of L3 VPCs in continuous development.
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Affiliation(s)
- Catherine O'Keeffe
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Iva Greenwald
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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3
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Lee S, Lim GE, Kim YN, Koo HS, Shim J. AP2M1 Supports TGF-β Signals to Promote Collagen Expression by Inhibiting Caveolin Expression. Int J Mol Sci 2021; 22:ijms22041639. [PMID: 33561975 PMCID: PMC7915421 DOI: 10.3390/ijms22041639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 12/28/2022] Open
Abstract
The extracellular matrix (ECM) is important for normal development and disease states, including inflammation and fibrosis. To understand the complex regulation of ECM, we performed a suppressor screening using Caenorhabditis elegans expressing the mutant ROL-6 collagen protein. One cuticle mutant has a mutation in dpy-23 that encodes the μ2 adaptin (AP2M1) of clathrin-associated protein complex II (AP-2). The subsequent suppressor screening for dpy-23 revealed the lon-2 mutation. LON-2 functions to regulate body size through negative regulation of the tumor growth factor-beta (TGF-β) signaling pathway responsible for ECM production. RNA-seq analysis showed a dominant change in the expression of collagen genes and cuticle components. We noted an increase in the cav-1 gene encoding caveolin-1, which functions in clathrin-independent endocytosis. By knockdown of cav-1, the reduced TGF-β signal was significantly restored in the dpy-23 mutant. In conclusion, the dpy-23 mutation upregulated cav-1 expression in the hypodermis, and increased CAV-1 resulted in a decrease of TβRI. Finally, the reduction of collagen expression including rol-6 by the reduced TGF-β signal influenced the cuticle formation of the dpy-23 mutant. These findings could help us to understand the complex process of ECM regulation in organism development and disease conditions.
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Affiliation(s)
- Saerom Lee
- Research Institute, National Cancer Center, 323 Ilsan-ro, Goyang-si 10408, Gyeonggi-do, Korea; (S.L.); (G.-E.L.); (Y.-N.K.)
- Department of Biochemistry, Yonsei University, 50, Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Ga-Eun Lim
- Research Institute, National Cancer Center, 323 Ilsan-ro, Goyang-si 10408, Gyeonggi-do, Korea; (S.L.); (G.-E.L.); (Y.-N.K.)
| | - Yong-Nyun Kim
- Research Institute, National Cancer Center, 323 Ilsan-ro, Goyang-si 10408, Gyeonggi-do, Korea; (S.L.); (G.-E.L.); (Y.-N.K.)
| | - Hyeon-Sook Koo
- Department of Biochemistry, Yonsei University, 50, Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
- Correspondence: (H.-S.K.); (J.S.); Tel.: +82-2-2123-2695 (H.-S.K.); +82-31-920-2262 (J.S.)
| | - Jaegal Shim
- Research Institute, National Cancer Center, 323 Ilsan-ro, Goyang-si 10408, Gyeonggi-do, Korea; (S.L.); (G.-E.L.); (Y.-N.K.)
- Correspondence: (H.-S.K.); (J.S.); Tel.: +82-2-2123-2695 (H.-S.K.); +82-31-920-2262 (J.S.)
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4
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Pol A, Morales-Paytuví F, Bosch M, Parton RG. Non-caveolar caveolins – duties outside the caves. J Cell Sci 2020; 133:133/9/jcs241562. [DOI: 10.1242/jcs.241562] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
ABSTRACT
Caveolae are invaginations of the plasma membrane that are remarkably abundant in adipocytes, endothelial cells and muscle. Caveolae provide cells with resources for mechanoprotection, can undergo fission from the plasma membrane and can regulate a variety of signaling pathways. Caveolins are fundamental components of caveolae, but many cells, such as hepatocytes and many neurons, express caveolins without forming distinguishable caveolae. Thus, the function of caveolins goes beyond their roles as caveolar components. The membrane-organizing and -sculpting capacities of caveolins, in combination with their complex intracellular trafficking, might contribute to these additional roles. Furthermore, non-caveolar caveolins can potentially interact with proteins normally excluded from caveolae. Here, we revisit the non-canonical roles of caveolins in a variety of cellular contexts including liver, brain, lymphocytes, cilia and cancer cells, as well as consider insights from invertebrate systems. Non-caveolar caveolins can determine the intracellular fluxes of active lipids, including cholesterol and sphingolipids. Accordingly, caveolins directly or remotely control a plethora of lipid-dependent processes such as the endocytosis of specific cargoes, sorting and transport in endocytic compartments, or different signaling pathways. Indeed, loss-of-function of non-caveolar caveolins might contribute to the common phenotypes and pathologies of caveolin-deficient cells and animals.
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Affiliation(s)
- Albert Pol
- Cell Compartments and Signaling Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, 08036, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010, Barcelona, Spain
| | - Frederic Morales-Paytuví
- Cell Compartments and Signaling Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
| | - Marta Bosch
- Cell Compartments and Signaling Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, 08036, Barcelona, Spain
| | - Robert G. Parton
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ), Brisbane, Queensland 4072, Australia
- Centre for Microscopy and Microanalysis (CMM) IMB, The University of Queensland (UQ), Brisbane, Queensland 4072, Australia
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5
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Jain A, Gali H, Kihara D. Identification of Moonlighting Proteins in Genomes Using Text Mining Techniques. Proteomics 2018; 18:e1800083. [PMID: 30260564 PMCID: PMC6404977 DOI: 10.1002/pmic.201800083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/13/2018] [Indexed: 12/31/2022]
Abstract
Moonlighting proteins is an emerging concept for considering protein functions, which indicate proteins with two or more independent and distinct functions. An increasing number of moonlighting proteins have been reported in the past years; however, a systematic study of the topic has been hindered because the secondary functions of proteins are usually found serendipitously by experiments. Toward systematic identification and study of moonlighting proteins, computational methods for identifying moonlighting proteins from several different information sources, database entries, literature, and large-scale omics data have been developed. In this study, an overview for finding moonlighting proteins is discussed. Then, the literature-mining method, DextMP, is applied to find new moonlighting proteins in three genomes, Arabidopsis thaliana, Caenorhabditis elegans, and Drosophila melanogaster. Potential moonlighting proteins identified by DextMP are further examined by a two-step manual literature checking procedure, which finally yielded 13 new moonlighting proteins. Identified moonlighting proteins are categorized into two classes based on the clarity of the distinctness of two functions of the proteins. A few cases of the identified moonlighting proteins are described in detail. Further direction for improving the DextMP algorithm is also discussed.
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Affiliation(s)
- Aashish Jain
- Department of Biological Science, Purdue University, West Lafayette, IN, 47907, USA
- Department of Computer Science, Purdue University, West Lafayette, IN, 47907, USA
| | - Hareesh Gali
- Department of Computer Science, Purdue University, West Lafayette, IN, 47907, USA
| | - Daisuke Kihara
- Department of Biological Science, Purdue University, West Lafayette, IN, 47907, USA
- Department of Computer Science, Purdue University, West Lafayette, IN, 47907, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45229, USA
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6
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Mendoza-Topaz C, Nelson G, Howard G, Hafner S, Rademacher P, Frick M, Nichols BJ. Cells respond to deletion of CAV1 by increasing synthesis of extracellular matrix. PLoS One 2018; 13:e0205306. [PMID: 30346954 PMCID: PMC6197626 DOI: 10.1371/journal.pone.0205306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/21/2018] [Indexed: 12/21/2022] Open
Abstract
A range of cellular functions have been attributed to caveolae, flask-like invaginations of the plasma membrane. Here, we have used RNA-seq to achieve quantitative transcriptional profiling of primary embryonic fibroblasts from caveolin 1 knockout mice (CAV1-/- MEFs), and thereby to gain hypothesis-free insight into how these cells respond to the absence of caveolae. Components of the extracellular matrix were decisively over-represented within the set of genes displaying altered expression in CAV1-/- MEFs when compared to congenic wild-type controls. This was confirmed biochemically and by imaging for selected examples. Up-regulation of components of the extracellular matrix was also observed in a second cell line, NIH-3T3 cells genome edited to delete CAV1. Up-regulation of components of the extracellular matrix was detected in vivo by assessing collagen deposition and compliance of CAV1-/- lungs. We discuss the implications of these findings in terms of the cellular function of caveolae.
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Affiliation(s)
- C. Mendoza-Topaz
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - G. Nelson
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - G. Howard
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - S. Hafner
- Institute of Pathophysiological Anesthesiology and Process Engineering, University of Ulm, Ulm, Germany
| | - P. Rademacher
- Institute of Pathophysiological Anesthesiology and Process Engineering, University of Ulm, Ulm, Germany
| | - M. Frick
- Institute of General Physiology, University of Ulm, Ulm, Germany
| | - B. J. Nichols
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
- * E-mail:
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7
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Roitenberg N, Bejerano-Sagie M, Boocholez H, Moll L, Marques FC, Golodetzki L, Nevo Y, Elami T, Cohen E. Modulation of caveolae by insulin/IGF-1 signaling regulates aging of Caenorhabditis elegans. EMBO Rep 2018; 19:embr.201745673. [PMID: 29945933 DOI: 10.15252/embr.201745673] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/27/2018] [Accepted: 05/29/2018] [Indexed: 11/09/2022] Open
Abstract
Reducing insulin/IGF-1 signaling (IIS) extends lifespan, promotes protein homeostasis (proteostasis), and elevates stress resistance of worms, flies, and mammals. How these functions are orchestrated across the organism is only partially understood. Here, we report that in the nematode Caenorhabditis elegans, the IIS positively regulates the expression of caveolin-1 (cav-1), a gene which is primarily expressed in neurons of the adult worm and underlies the formation of caveolae, a subtype of lipid microdomains that serve as platforms for signaling complexes. Accordingly, IIS reduction lowers cav-1 expression and lessens the quantity of neuronal caveolae. Reduced cav-1 expression extends lifespan and mitigates toxic protein aggregation by modulating the expression of aging-regulating and signaling-promoting genes. Our findings define caveolae as aging-governing signaling centers and underscore the potential for cav-1 as a novel therapeutic target for the promotion of healthy aging.
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Affiliation(s)
- Noa Roitenberg
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Michal Bejerano-Sagie
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Hana Boocholez
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Lorna Moll
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Filipa Carvalhal Marques
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Ludmila Golodetzki
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Yuval Nevo
- Computation Center, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Tayir Elami
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Ehud Cohen
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel - Canada, The Hebrew University School of Medicine, Jerusalem, Israel
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8
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9
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Spencer A, Yu L, Guili V, Reynaud F, Ding Y, Ma J, Jullien J, Koubi D, Gauthier E, Cluet D, Falk J, Castellani V, Yuan C, Rudkin BB. Nerve Growth Factor Signaling from Membrane Microdomains to the Nucleus: Differential Regulation by Caveolins. Int J Mol Sci 2017; 18:E693. [PMID: 28338624 PMCID: PMC5412279 DOI: 10.3390/ijms18040693] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/08/2017] [Accepted: 03/13/2017] [Indexed: 11/16/2022] Open
Abstract
Membrane microdomains or "lipid rafts" have emerged as essential functional modules of the cell, critical for the regulation of growth factor receptor-mediated responses. Herein we describe the dichotomy between caveolin-1 and caveolin-2, structural and regulatory components of microdomains, in modulating proliferation and differentiation. Caveolin-2 potentiates while caveolin-1 inhibits nerve growth factor (NGF) signaling and subsequent cell differentiation. Caveolin-2 does not appear to impair NGF receptor trafficking but elicits prolonged and stronger activation of MAPK (mitogen-activated protein kinase), Rsk2 (ribosomal protein S6 kinase 2), and CREB (cAMP response element binding protein). In contrast, caveolin-1 does not alter initiation of the NGF signaling pathway activation; rather, it acts, at least in part, by sequestering the cognate receptors, TrkA and p75NTR, at the plasma membrane, together with the phosphorylated form of the downstream effector Rsk2, which ultimately prevents CREB phosphorylation. The non-phosphorylatable caveolin-1 serine 80 mutant (S80V), no longer inhibits TrkA trafficking or subsequent CREB phosphorylation. MC192, a monoclonal antibody towards p75NTR that does not block NGF binding, prevents exit of both NGF receptors (TrkA and p75NTR) from lipid rafts. The results presented herein underline the role of caveolin and receptor signaling complex interplay in the context of neuronal development and tumorigenesis.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- CREB-Binding Protein/metabolism
- Caveolin 1/antagonists & inhibitors
- Caveolin 1/genetics
- Caveolin 1/metabolism
- Caveolin 2/antagonists & inhibitors
- Caveolin 2/genetics
- Caveolin 2/metabolism
- Cell Differentiation/drug effects
- Cell Nucleus/metabolism
- Cells, Cultured
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Membrane Microdomains/metabolism
- Mice
- Nerve Growth Factor/pharmacology
- Nerve Tissue Proteins
- PC12 Cells
- Phosphorylation/drug effects
- Protein Binding
- Protein Transport/drug effects
- RNA Interference
- RNA, Small Interfering/metabolism
- Rats
- Receptor, Nerve Growth Factor/metabolism
- Receptor, trkA/chemistry
- Receptor, trkA/immunology
- Receptor, trkA/metabolism
- Receptors, Growth Factor
- Receptors, Nerve Growth Factor/chemistry
- Receptors, Nerve Growth Factor/immunology
- Receptors, Nerve Growth Factor/metabolism
- Ribosomal Protein S6 Kinases, 90-kDa/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Ambre Spencer
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
- East China Normal University, School of Life Sciences, Laboratory of Molecular and Cellular Neurophysiology, Shanghai 200062, China.
| | - Lingli Yu
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
- East China Normal University, School of Life Sciences, Laboratory of Molecular and Cellular Neurophysiology, Shanghai 200062, China.
| | - Vincent Guili
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
| | - Florie Reynaud
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, CGphiMC UMR5534, 69622 Villeurbanne Cedex, France.
| | - Yindi Ding
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
- East China Normal University, School of Life Sciences, Laboratory of Molecular and Cellular Neurophysiology, Shanghai 200062, China.
| | - Ji Ma
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- East China Normal University, School of Life Sciences, Laboratory of Molecular and Cellular Neurophysiology, Shanghai 200062, China.
| | - Jérôme Jullien
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
| | - David Koubi
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
| | - Emmanuel Gauthier
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
| | - David Cluet
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
| | - Julien Falk
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, CGphiMC UMR5534, 69622 Villeurbanne Cedex, France.
| | - Valérie Castellani
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, CGphiMC UMR5534, 69622 Villeurbanne Cedex, France.
| | - Chonggang Yuan
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- East China Normal University, School of Life Sciences, Laboratory of Molecular and Cellular Neurophysiology, Shanghai 200062, China.
| | - Brian B Rudkin
- East China Normal University, Key Laboratory of Brain Functional Genomics of the Ministry of Education of PR China, Joint Laboratory of Neuropathogenesis, ECNU, ENS Lyon, CNRS, Shanghai 200062, China.
- Univ. Lyon, Ecole normale supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS, Differentiation & Cell Cycle Group, Laboratoire de Biologie Moléculaire de la Cellule, UMR5239, 69007 Lyon, France.
- Univ. Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France.
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10
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Otis JP, Shen MC, Quinlivan V, Anderson JL, Farber SA. Intestinal epithelial cell caveolin 1 regulates fatty acid and lipoprotein cholesterol plasma levels. Dis Model Mech 2017; 10:283-295. [PMID: 28130355 PMCID: PMC5374320 DOI: 10.1242/dmm.027300] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/23/2017] [Indexed: 12/16/2022] Open
Abstract
Caveolae and their structural protein caveolin 1 (CAV1) have roles in cellular lipid processing and systemic lipid metabolism. Global deletion of CAV1 in mice results in insulin resistance and increases in atherogenic plasma lipids and cholesterol, but protects from diet-induced obesity and atherosclerosis. Despite the fundamental role of the intestinal epithelia in the regulation of dietary lipid processing and metabolism, the contributions of CAV1 to lipid metabolism in this tissue have never been directly investigated. In this study the cellular dynamics of intestinal Cav1 were visualized in zebrafish and the metabolic contributions of CAV1 were determined with mice lacking CAV1 in intestinal epithelial cells (CAV1IEC-KO). Live imaging of Cav1–GFP and fluorescently labeled caveolae cargos shows localization to the basolateral and lateral enterocyte plasma membrane (PM), suggesting Cav1 mediates transport between enterocytes and the submucosa. CAV1IEC-KO mice are protected from the elevation in circulating fasted low-density lipoprotein (LDL) cholesterol associated with a high-fat diet (HFD), but have increased postprandial LDL cholesterol, total free fatty acids (FFAs), palmitoleic acid, and palmitic acid. The increase in circulating FAs in HFD CAV1IEC-KO mice is mirrored by decreased hepatic FAs, suggesting a non-cell-autonomous role for intestinal epithelial cell CAV1 in promoting hepatic FA storage. In conclusion, CAV1 regulates circulating LDL cholesterol and several FA species via the basolateral PM of enterocytes. These results point to intestinal epithelial cell CAV1 as a potential therapeutic target to lower circulating FFAs and LDL cholesterol, as high levels are associated with development of type II diabetes and cardiovascular disease. Summary: Caveolin 1, which forms caveolae, localizes to the basolateral membrane of zebrafish intestinal epithelial cells and regulates circulating murine fatty acid and lipoprotein cholesterol levels.
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Affiliation(s)
- Jessica P Otis
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Meng-Chieh Shen
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Vanessa Quinlivan
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA.,Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Jennifer L Anderson
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Steven A Farber
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA .,Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
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11
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Soayfane Z, Tercé F, Cantiello M, Robenek H, Nauze M, Bézirard V, Allart S, Payré B, Capilla F, Cartier C, Peres C, Al Saati T, Théodorou V, Nelson DW, Yen CLE, Collet X, Coméra C. Exposure to dietary lipid leads to rapid production of cytosolic lipid droplets near the brush border membrane. Nutr Metab (Lond) 2016; 13:48. [PMID: 27478484 PMCID: PMC4965885 DOI: 10.1186/s12986-016-0107-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/21/2016] [Indexed: 12/17/2022] Open
Abstract
Background Intestinal absorption of dietary lipids involves their hydrolysis in the lumen of proximal intestine as well as uptake, intracellular transport and re-assembly of hydrolyzed lipids in enterocytes, leading to the formation and secretion of the lipoproteins chylomicrons and HDL. In this study, we examined the potential involvement of cytosolic lipid droplets (CLD) whose function in the process of lipid absorption is poorly understood. Methods Intestinal lipid absorption was studied in mouse after gavage. Three populations of CLD were purified by density ultracentrifugations, as well as the brush border membranes, which were analyzed by western-blots. Immunofluorescent localization of membranes transporters or metabolic enzymes, as well as kinetics of CLD production, were also studied in intestine or Caco-2 cells. Results We isolated three populations of CLD (ranging from 15 to 1000 nm) which showed differential expression of the major lipid transporters scavenger receptor BI (SR-BI), cluster of differentiation 36 (CD-36), Niemann Pick C-like 1 (NPC1L1), and the ATP-binding cassette transporters ABCG5/G8 but also caveolin 2 and fatty acid binding proteins. The enzyme monoacylglycerol acyltransferase 2 (MGAT2) was identified in the brush border membrane (BBM) in addition to the endoplasmic reticulum, suggesting local synthesis of triglycerides and CLD at both places. Conclusions We show a very fast production of CLD by enterocytes associated with a transfer of apical constituents as lipid transporters. Our findings suggest that following their uptake by enterocytes, lipids can be partially metabolized at the BBM and packaged into CLD for their transportation to the ER. Electronic supplementary material The online version of this article (doi:10.1186/s12986-016-0107-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zeina Soayfane
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France
| | - François Tercé
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France
| | - Michela Cantiello
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France
| | - Horst Robenek
- Leibniz-Institut für Arterioskleroseforschung, Universität Münster, Münster, Germany
| | - Michel Nauze
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France
| | - Valérie Bézirard
- UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France
| | - Sophie Allart
- INSERM UMR 1043 (INSERM/UPS/CNRS/USC Inra), CHU Purpan, Toulouse, France
| | - Bruno Payré
- CMEAB, Faculté de Médecine Rangueil, Toulouse, France
| | - Florence Capilla
- INSERM/UPS - US006/CREFRE, Service d'Histopathologie, CHU Purpan, Toulouse, France
| | - Christel Cartier
- UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France
| | - Christine Peres
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France
| | - Talal Al Saati
- INSERM/UPS - US006/CREFRE, Service d'Histopathologie, CHU Purpan, Toulouse, France
| | - Vassilia Théodorou
- UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France
| | - David W Nelson
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI USA
| | - Chi-Liang Eric Yen
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI USA
| | - Xavier Collet
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France
| | - Christine Coméra
- Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.,UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France
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12
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Cheng JPX, Nichols BJ. Caveolae: One Function or Many? Trends Cell Biol 2015; 26:177-189. [PMID: 26653791 DOI: 10.1016/j.tcb.2015.10.010] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/16/2015] [Accepted: 10/22/2015] [Indexed: 02/07/2023]
Abstract
Caveolae are small, bulb-shaped plasma membrane invaginations. Mutations that ablate caveolae lead to diverse phenotypes in mice and humans, making it challenging to uncover their molecular mechanisms. Caveolae have been described to function in endocytosis and transcytosis (a specialized form of endocytosis) and in maintaining membrane lipid composition, as well as acting as signaling platforms. New data also support a model in which the central function of caveolae could be related to the protection of cells from mechanical stress within the plasma membrane. We present evidence for these diverse roles and consider in vitro and in vivo experiments confirming a mechanoprotective role. We conclude by highlighting current gaps in our knowledge of how mechanical signals may be transduced by caveolae.
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Affiliation(s)
- Jade P X Cheng
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
| | - Benjamin J Nichols
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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13
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Shvets E, Bitsikas V, Howard G, Hansen CG, Nichols BJ. Dynamic caveolae exclude bulk membrane proteins and are required for sorting of excess glycosphingolipids. Nat Commun 2015; 6:6867. [PMID: 25897946 PMCID: PMC4410672 DOI: 10.1038/ncomms7867] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 03/06/2015] [Indexed: 12/19/2022] Open
Abstract
Caveolae have long been implicated in endocytosis. Recent data question this link, and in the absence of specific cargoes the potential cellular function of caveolar endocytosis remains unclear. Here we develop new tools, including doubly genome-edited cell lines, to assay the subcellular dynamics of caveolae using tagged proteins expressed at endogenous levels. We find that around 5% of the cellular pool of caveolae is present on dynamic endosomes, and is delivered to endosomes in a clathrin-independent manner. Furthermore, we show that caveolae are indeed likely to bud directly from the plasma membrane. Using a genetically encoded tag for electron microscopy and ratiometric light microscopy, we go on to show that bulk membrane proteins are depleted within caveolae. Although caveolae are likely to account for only a small proportion of total endocytosis, cells lacking caveolae show fundamentally altered patterns of membrane traffic when loaded with excess glycosphingolipid. Altogether, these observations support the hypothesis that caveolar endocytosis is specialized for transport of membrane lipid.
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Affiliation(s)
- Elena Shvets
- MRC-LMB, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | | | | | - Carsten Gram Hansen
- Sanford Consortium for Regenerative Medicine UCSD, 2880 Torrey Pines Scenic Drive, La Jolla, California 92037, USA
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14
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Solinger JA, Spang A. Loss of the Sec1/Munc18-family proteins VPS-33.2 and VPS-33.1 bypasses a block in endosome maturation in Caenorhabditis elegans. Mol Biol Cell 2014; 25:3909-25. [PMID: 25273556 PMCID: PMC4244200 DOI: 10.1091/mbc.e13-12-0710] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Evidence is presented for the existence of HOPS and CORVET tethering complexes in metazoans. A role is shown for the SM protein components of tethers in controlling the flux of material through the endosomal system. The end of the life of a transport vesicle requires a complex series of tethering, docking, and fusion events. Tethering complexes play a crucial role in the recognition of membrane entities and bringing them into close opposition, thereby coordinating and controlling cellular trafficking events. Here we provide a comprehensive RNA interference analysis of the CORVET and HOPS tethering complexes in metazoans. Knockdown of CORVET components promoted RAB-7 recruitment to subapical membranes, whereas in HOPS knockdowns, RAB-5 was found also on membrane structures close to the cell center, indicating the RAB conversion might be impaired in the absence of these tethering complexes. Unlike in yeast, metazoans have two VPS33 homologues, which are Sec1/Munc18 (SM)-family proteins involved in the regulation of membrane fusion. We assume that in wild type, each tethering complex contains a specific SM protein but that they may be able to substitute for each other in case of absence of the other. Of importance, knockdown of both SM proteins allowed bypass of the endosome maturation block in sand-1 mutants. We propose a model in which the SM proteins in tethering complexes are required for coordinated flux of material through the endosomal system.
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Affiliation(s)
- Jachen A Solinger
- Growth and Development, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - Anne Spang
- Growth and Development, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
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15
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Jiménez-Hidalgo M, Kurz CL, Pedrajas JR, Naranjo-Galindo FJ, González-Barrios M, Cabello J, Sáez AG, Lozano E, Button EL, Veal EA, Fierro-González JC, Swoboda P, Miranda-Vizuete A. Functional characterization of thioredoxin 3 (TRX-3), a Caenorhabditis elegans intestine-specific thioredoxin. Free Radic Biol Med 2014; 68:205-19. [PMID: 24316195 PMCID: PMC4018987 DOI: 10.1016/j.freeradbiomed.2013.11.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 11/13/2013] [Accepted: 11/22/2013] [Indexed: 01/15/2023]
Abstract
Thioredoxins are a class of evolutionarily conserved proteins that have been demonstrated to play a key role in many cellular processes involving redox reactions. We report here the genetic and biochemical characterization of Caenorhabditis elegans TRX-3, the first metazoan thioredoxin with an intestine-specific expression pattern. By using green fluorescent protein reporters we have found that TRX-3 is expressed in both the cytoplasm and the nucleus of intestinal cells, with a prominent localization at the apical membrane. Although intestinal function, reproductive capacity, longevity, and resistance of trx-3 loss-of-function mutants to many stresses are indistinguishable from those of wild-type animals, we have observed a slight reduction in size and a minor reduction in the defecation cycle timing of trx-3 mutants. Interestingly, trx-3 is induced upon infection by Photorhabdus luminescens and Candida albicans, and TRX-3 overexpression provides a modest protection against these pathogens. Together, our data indicate that TRX-3 function in the intestine is dispensable for C. elegans development but may be important to fight specific bacterial and fungal infections.
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Affiliation(s)
- María Jiménez-Hidalgo
- Centro Andaluz de Biología del Desarrollo, Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| | - Cyril Léopold Kurz
- Centre d'Immunologie de Marseille-Luminy, UM2 Aix-Marseille Université, Case 906, 13288 Marseille cedex 9, France
| | - José Rafael Pedrajas
- Grupo de Bioquímica y Señalización Celular, Departamento de Biología Experimental, Universidad de Jaén, 23071 Jaén, Spain
| | - Francisco José Naranjo-Galindo
- Centro Andaluz de Biología del Desarrollo, Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| | - María González-Barrios
- Centro Andaluz de Biología del Desarrollo, Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| | - Juan Cabello
- Center for Biomedical Research of La Rioja, 26006 Logroño, Spain
| | - Alberto G Sáez
- Unidad Funcional de Investigación en Enfermedades Crónicas, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
| | - Encarnación Lozano
- Unidad Funcional de Investigación en Enfermedades Crónicas, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
| | - Emma L Button
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Elizabeth A Veal
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Juan Carlos Fierro-González
- Center for Biosciences at Novum, Department of Biosciences and Nutrition, Karolinska Institute, S-14183 Huddinge, Sweden
| | - Peter Swoboda
- Center for Biosciences at Novum, Department of Biosciences and Nutrition, Karolinska Institute, S-14183 Huddinge, Sweden
| | - Antonio Miranda-Vizuete
- Centro Andaluz de Biología del Desarrollo, Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, 41013 Sevilla, Spain; Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain.
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16
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Siddiqi S, Sheth A, Patel F, Barnes M, Mansbach CM. Intestinal caveolin-1 is important for dietary fatty acid absorption. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1831:1311-21. [PMID: 23665238 PMCID: PMC3751415 DOI: 10.1016/j.bbalip.2013.05.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 04/29/2013] [Accepted: 05/01/2013] [Indexed: 12/16/2022]
Abstract
How dietary fatty acids are absorbed into the enterocyte and transported to the ER is not established. We tested the possibility that caveolin-1 containing lipid rafts and endocytic vesicles were involved. Apical brush border membranes took up 15% of albumin bound (3)H-oleate whereas brush border membranes from caveolin-1 KO mice took up only 1%. In brush border membranes, the (3)H-oleate was in the detergent resistant fraction of an OptiPrep gradient. On OptiPrep gradients of intestinal cytosol, we also found the (3)H-oleate in the detergent resistant fraction, separate from OptiPrep gradients spiked with (3)H-oleate or (3)H-triacylglycerol. Caveolin-1 immuno-depletion of cytosol removed 91% of absorbed (3)H-oleate whereas immuno-depletion using IgG, or anti-caveolin-2 or -3 or anti-clathrin antibodies removed 20%. Electron microscopy showed the presence of caveolin-1 containing vesicles in WT mouse cytosol that were 4 fold increased by feeding intestinal sacs 1mM oleate. No vesicles were seen in caveolin-1 KO mouse cytosol. Caveolin-1 KO mice gained less weight on a 23% fat diet and had increased fat in their stool compared to WT mice. We conclude that dietary fatty acids are absorbed by caveolae in enterocyte brush border membranes, are endocytosed, and transported in cytosol in caveolin-1 containing endocytic vesicles.
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Affiliation(s)
- Shahzad Siddiqi
- Division of Gastroenterology, Department of Medicine, The University of Tennessee Health Science Center 38163
| | - Atur Sheth
- Division of Gastroenterology, Department of Medicine, The University of Tennessee Health Science Center 38163
| | - Feenalie Patel
- Division of Gastroenterology, Department of Medicine, The University of Tennessee Health Science Center 38163
| | - Matthew Barnes
- Division of Gastroenterology, Department of Medicine, The University of Tennessee Health Science Center 38163
| | - Charles M. Mansbach
- Division of Gastroenterology, Department of Medicine, The University of Tennessee Health Science Center 38163
- Veterans Affairs Medical Center, Memphis, TN 38104
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17
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Abstract
This chapter describes methods for studying membrane traffic and organelle biogenesis in Caenorhabditis elegans. These processes have traditionally been studied with yeast or mammalian cells, but C. elegans is emerging as an attractive alternative model system for cell biologists. C. elegans is well known for the ease of manipulation through classic and molecular genetic techniques. In addition, C. elegans is transparent, so fluorescent proteins can be observed in live animals. These properties have aided the development of functional assays for tracking cell biological processes in situ. Localization results obtained with fluorescent proteins can be validated with immunofluorescence and with biochemical methods, such as subcellular fractionation, adapted from methods developed for other organisms. C. elegans thus combines powerful genetics with a range of cell biological techniques to study subcellular processes in a tractable multicellular organism.
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Affiliation(s)
- Hanna Fares
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
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18
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Novel insights into the role of caveolin-2 in cell- and tissue-specific signaling and function. Biochem Res Int 2011; 2011:809259. [PMID: 22229094 PMCID: PMC3249596 DOI: 10.1155/2011/809259] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 10/13/2011] [Indexed: 11/28/2022] Open
Abstract
Caveolin-2 is one of the major protein components of cholesterol- and glycosphingolipid-rich flask-shaped invaginations of plasma membrane caveolae. A new body of evidence suggests that caveolin-2 plays an important, and often more direct, role than caveolin-1 in regulating signaling and function in a cell- and tissue type-specific manner. The purpose of this paper is to primarily focus on discussing how these recent discoveries may help better understand the specific contribution of caveolin-2 to lipid raft- and caveolae-regulated cell/tissue-specific signaling and functions.
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19
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Xie L, Vo-Ransdell C, Abel B, Willoughby C, Jang S, Sowa G. Caveolin-2 is a negative regulator of anti-proliferative function and signaling of transforming growth factor-β in endothelial cells. Am J Physiol Cell Physiol 2011; 301:C1161-74. [PMID: 21832243 DOI: 10.1152/ajpcell.00486.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Using a combination of wild-type (WT) and caveolin-2 (Cav-2) knockout along with retroviral reexpression approaches, we provide the evidence for the negative role of Cav-2 in regulating anti-proliferative function and signaling of transforming growth factor β (TGF-β) in endothelial cells (ECs). Although, TGF-β had a modest inhibitory effect on WT ECs, it profoundly inhibited proliferation of Cav-2 knockout ECs. To confirm the specificity of the observed difference in response to TGF-β, we have stably reexpressed Cav-2 in Cav-2 knockout ECs using a retroviral approach. Similar to WT ECs, the anti-proliferative effect of TGF-β was dramatically reduced in the Cav-2 reexpressing ECs. The reduced anti-proliferative effect of TGF-β in Cav-2-positive cells was evidenced by three independent proliferation assays: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cell count, and bromodeoxyuridine incorporation and correlated with a loss of TGF-β-mediated upregulation of cell cycle inhibitor p27 and subsequent reduction of the levels of hyperphosphorylated (inactive) form of the retinoblastoma protein in Cav-2 reexpressing ECs. Mechanistically, Cav-2 inhibits anti-proliferative action of TGF-β by suppressing Alk5-Smad2/3 pathway manifested by reduced magnitude and length of TGF-β-induced Smad2/3 phosphorylation as well as activation of activin receptor-like kinase-5 (Alk5)-Smad2/3 target genes plasminogen activator inhibitor-1 and collagen type I in Cav-2-positive ECs. Expression of Cav-2 does not appear to significantly change targeting of TGF-β receptors I and Smad2/3 to caveolar and lipid raft microdomains as determined by sucrose fractionation gradient. Overall, the negative regulation of TGF-β signaling and function by Cav-2 is independent of Cav-1 expression levels and is not because of changing targeting of Cav-1 protein to plasma membrane lipid raft/caveolar domains.
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Affiliation(s)
- Leike Xie
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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20
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Abstract
Calcineurin is a serine/threonine protein phosphatase controlled by Ca(2+) and calmodulin that has been implicated in various signaling pathways. Previously, we reported that calcineurin regulates coelomocyte endocytosis in Caenorhabditis elegans. So far, simple and powerful in vivo approaches have been developed to study various endocytic processes in C. elegans. Using these in vivo assays, we further analyzed the endocytic phenotypes of calcineurin mutants. We observed that the calcineurin mutants were defective in apical endocytosis in the intestine as well as synaptic vesicle recycling in the nerve cord. However, we found that calcineurin mutants displayed normal receptor-mediated endocytosis in oocytes. Therefore, our results suggest that calcineurin may regulate specific sets of endocytic processes in nematode.
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Affiliation(s)
- Hyun-Ok Song
- Department of Life Science, BK21 (Life Science for Global Warming Team), College of Natural Sciences, Hanyang University, Seoul 133-791, Korea
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21
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Rao W, Isaac RE, Keen JN. An analysis of the Caenorhabditis elegans lipid raft proteome using geLC-MS/MS. J Proteomics 2010; 74:242-53. [PMID: 21070894 DOI: 10.1016/j.jprot.2010.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 10/20/2010] [Accepted: 11/02/2010] [Indexed: 11/16/2022]
Abstract
Lipid rafts are microdomains of the phospholipid bilayer, proposed to form semi-stable "islands" that act as a platform for several important cellular processes; major classes of raft-resident proteins include signalling proteins and glycosylphosphatidylinositol (GPI)-anchored proteins. Proteomic studies into lipid rafts have been mainly carried out in mammalian cell lines and single cell organisms. The nematode Caenorhabditis elegans, the model organism with a well-defined developmental profile, is ideally suited for the study of this subcellular locale in a complex developmental context. A study of the lipid raft proteome of C. elegans is presented here. A total of 44 proteins were identified from the lipid raft fraction using geLC-MS/MS, of which 40 have been determined to be likely raft proteins after analysis of predicted functions. Prediction of GPI-anchoring of the proteins found 21 to be potentially modified in this way, two of which were experimentally confirmed to be GPI-anchored. This work is the first reported study of the lipid raft proteome in C. elegans. The results show that raft proteins, including numerous GPI-anchored proteins, may have a variety of potentially important roles within the nematode, and will hopefully lead to C. elegans becoming a useful model for the study of lipid rafts.
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Affiliation(s)
- Wei Rao
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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22
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Branicky R, Desjardins D, Liu JL, Hekimi S. Lipid transport and signaling in Caenorhabditis elegans. Dev Dyn 2010; 239:1365-77. [PMID: 20151418 DOI: 10.1002/dvdy.22234] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The strengths of the Caenorhabditis elegans model have been recently applied to the study of the pathways of lipid storage, transport, and signaling. As the lipid storage field has recently been reviewed, in this minireview we (1) discuss some recent studies revealing important physiological roles for lipases in mobilizing lipid reserves, (2) describe various pathways of lipid transport, with a particular focus on the roles of lipoproteins, (3) debate the utility of using C. elegans as a model for human dyslipidemias that impinge on atherosclerosis, and (4) describe several systems where lipids affect signaling, highlighting the particular properties of lipids as information-carrying molecules. We conclude that the study of lipid biology in C. elegans exemplifies the advantages afforded by a whole-animal model system where interactions between tissues and organs, and functions such as nutrient absorption, distribution, and storage, as well as reproduction can all be studied simultaneously.
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Affiliation(s)
- Robyn Branicky
- Department of Biology, McGill University, Montreal, Quebec, Canada
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23
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Abstract
Caveolin-2, a protein about 20 kD, is a major component of the inner surface of caveolae, small invaginations of the plasma membrane. Similar with caveolin-1 and caveolin-3, it serves as a protein marker of caveolae. Caveolin-1 and -2 are located next to each other at 7q31.1 on human chromosome, the proteins encoded are co-localized and form a stable hetero-oligomeric complex, distributing similarly in tissue and cultured cells. Caveolin-3 is located on different chromosomes but confirmed to interact with caveolin-2. Caveolin-2 is similar to caveolin-1 in many respects but differs from the latter in functional domains, especially in G-protein binding domain and caveolin scaffolding domain. The mRNAs of both caveolin-1 and caveolin-2 are most abundantly expressed in white adipose tissue and are induced during differentiation of 3T3-L1 cells to adipocytes. Caveolin-2-deficient mice demonstrate clear pulmonary defects, with little or no change in caveolin-1 expression and caveolae formation, suggesting that caveolin-2 plays a selective role in lung functions. Caveolin-2 is also involved in lipid metabolism and human cancers.
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Affiliation(s)
- Liu-luan Zhu
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
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24
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Parker S, Baylis HA. Overexpression of caveolins in Caenorhabditis elegans induces changes in egg-laying and fecundity. Commun Integr Biol 2010; 2:382-4. [PMID: 19907693 DOI: 10.4161/cib.2.5.8715] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 04/07/2009] [Indexed: 02/06/2023] Open
Abstract
Caveolae are small plasma membrane-associated invaginations that are enriched in proteins of the caveolin family in addition to, sphingolipids, glycosphingolipids and cholesterol. Caveolae have been implicated in several endocytic and trafficking mechanisms. Mutations in caveolins have been shown to cause disease and caveolae offer one site for pathogen entry. The Caenorhabditis elegans genome encodes two caveolins (cav-1 and cav-2); we have shown that these two proteins have distinct expression patterns. CAV-1 is found in the majority of cells in embryos and in the body-wall muscles, neurons and germ line of adult worms. CAV-2 is expressed in the intestine and is required for apical lipid trafficking. In the course of our studies, we generated several constructs to overexpress caveolins in C. elegans. Here we show that overexpression of cav-1 protects against the decrease in brood size associated with the effects of heat shock and the presence of extrachromosomal arrays in heat-shocked animals. Furthermore, we show that overexpression of cav-2 in the nervous system increases the rate of egg-laying and total number of eggs laid.
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Affiliation(s)
- Scott Parker
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK.
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Hadwiger G, Dour S, Arur S, Fox P, Nonet ML. A monoclonal antibody toolkit for C. elegans. PLoS One 2010; 5:e10161. [PMID: 20405020 PMCID: PMC2854156 DOI: 10.1371/journal.pone.0010161] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Accepted: 03/22/2010] [Indexed: 01/12/2023] Open
Abstract
Background Antibodies are critical tools in many avenues of biological research. Though antibodies can be produced in the research laboratory setting, most research labs working with vertebrates avail themselves of the wide array of commercially available reagents. By contrast, few such reagents are available for work with model organisms. Methodology/Principal Findings We report the production of monoclonal antibodies directed against a wide range of proteins that label specific subcellular and cellular components, and macromolecular complexes. Antibodies were made to synaptobrevin (SNB-1), a component of synaptic vesicles; to Rim (UNC-10), a protein localized to synaptic active zones; to transforming acidic coiled-coil protein (TAC-1), a component of centrosomes; to CENP-C (HCP-4), which in worms labels the entire length of their holocentric chromosomes; to ORC2 (ORC-2), a subunit of the DNA origin replication complex; to the nucleolar phosphoprotein NOPP140 (DAO-5); to the nuclear envelope protein lamin (LMN-1); to EHD1 (RME-1) a marker for recycling endosomes; to caveolin (CAV-1), a marker for caveolae; to the cytochrome P450 (CYP-33E1), a resident of the endoplasmic reticulum; to β-1,3-glucuronyltransferase (SQV-8) that labels the Golgi; to a chaperonin (HSP-60) targeted to mitochondria; to LAMP (LMP-1), a resident protein of lysosomes; to the alpha subunit of the 20S subcomplex (PAS-7) of the 26S proteasome; to dynamin (DYN-1) and to the α-subunit of the adaptor complex 2 (APA-2) as markers for sites of clathrin-mediated endocytosis; to the MAGUK, protein disks large (DLG-1) and cadherin (HMR-1), both of which label adherens junctions; to a cytoskeletal linker of the ezrin-radixin-moesin family (ERM-1), which localized to apical membranes; to an ERBIN family protein (LET-413) which localizes to the basolateral membrane of epithelial cells and to an adhesion molecule (SAX-7) which localizes to the plasma membrane at cell-cell contacts. In addition to working in whole mount immunocytochemistry, most of these antibodies work on western blots and thus should be of use for biochemical fractionation studies. Conclusions/Significance We have produced a set of monoclonal antibodies to subcellular components of the nematode C. elegans for the research community. These reagents are being made available through the Developmental Studies Hybridoma Bank (DSHB).
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Affiliation(s)
- Gayla Hadwiger
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Scott Dour
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Swathi Arur
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Paul Fox
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Michael L. Nonet
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Hansen CG, Nichols BJ. Exploring the caves: cavins, caveolins and caveolae. Trends Cell Biol 2010; 20:177-86. [PMID: 20153650 DOI: 10.1016/j.tcb.2010.01.005] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 01/07/2010] [Accepted: 01/11/2010] [Indexed: 01/29/2023]
Abstract
Caveolae are ampullate (flask-shaped) invaginations that are abundant in the plasma membrane of many mammalian cell types. Although caveolae are implicated in a wide range of processes including endothelial transcytosis, lipid homeostasis and cellular signalling, a detailed molecular picture of many aspects of their function has been elusive. Until recently, the only extensively characterised protein components of caveolae were the caveolins. Recently, data from several laboratories have demonstrated that a family of four related proteins, termed cavins 1-4, plays key roles in caveolar biogenesis and function. Salient properties of the cavin family include their propensity to form complexes with each other and their different but overlapping tissue distribution. This review summarises recent data on the cavins, and sets them in the context of open questions on the construction and function of caveolae. The discovery of cavins implies that caveolae might have unexpectedly diverse structural properties, in accord with the wide range of functions attributed to these 'little caves'.
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Xie L, Frank PG, Lisanti MP, Sowa G. Endothelial cells isolated from caveolin-2 knockout mice display higher proliferation rate and cell cycle progression relative to their wild-type counterparts. Am J Physiol Cell Physiol 2009; 298:C693-701. [PMID: 20007452 DOI: 10.1152/ajpcell.00401.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The goal of this study was to determine whether caveolin-2 (Cav-2) is capable of controlling endothelial cell (EC) proliferation in vitro. To realize this goal, we have directly compared proliferation rates and cell cycle-associated signaling proteins between lung ECs isolated from wild-type (WT) and Cav-2 knockout (KO) mice. Using three independent proliferation assays, we have determined that Cav-2 KO ECs proliferate by ca. 2-fold faster than their WT counterparts. Cell cycle analysis by flow cytometry of propidium iodide-stained cells showed a relatively higher percentage of Cav-2 KO ECs in S and G(2)/M and lower percentage in G(o)/G(1) phases of cell cycle relative to their WT counterparts. Furthermore, an over 2-fold increase in the percentage of S phase-associated Cav-2 KO relative to WT ECs was independently determined with bromodeoxyuridine incorporation assay. Mechanistically, the increase in proliferation/cell cycle progression of Cav-2 KO ECs correlated well with elevated expression levels of predominantly S phase- and G(2)/M phase-associated cyclin A and B1, respectively. Further mechanistic analysis of molecular events controlling cell cycle progression revealed increased level of hyperphosphorylated (inactive) form of G(1) to S phase transition inhibitor, the retinoblastoma protein in hyperproliferating Cav-2 KO ECs. Conversely, the expression level of the two cyclin-dependent kinase inhibitors p16(INK4) and p27(Kip1) was reduced in Cav-2 KO ECs. Finally, increased phosphorylation (activation) of proproliferative extracellular signal-regulated kinase 1/2 was observed in hyperproliferating Cav-2 KO ECs. Overall, our data suggest that Cav-2 negatively regulates lung EC proliferation and cell cycle progression.
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Affiliation(s)
- Leike Xie
- Dept. of Medical Pharmacology and Physiology, Univ. of Missouri, 1 Hospital Drive, Rm. MA 415, Columbia, MO 65212, USA
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