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Loh YP, Xiao L, Park JJ. Trafficking of hormones and trophic factors to secretory and extracellular vesicles: a historical perspective and new hypothesis. EXTRACELLULAR VESICLES AND CIRCULATING NUCLEIC ACIDS 2023; 4:568-587. [PMID: 38435713 PMCID: PMC10906782 DOI: 10.20517/evcna.2023.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
It is well known that peptide hormones and neurotrophic factors are intercellular messengers that are packaged into secretory vesicles in endocrine cells and neurons and released by exocytosis upon the stimulation of the cells in a calcium-dependent manner. These secreted molecules bind to membrane receptors, which then activate signal transduction pathways to mediate various endocrine/trophic functions. Recently, there is evidence that these molecules are also in extracellular vesicles, including small extracellular vesicles (sEVs), which appear to be taken up by recipient cells. This finding raised the hypothesis that they may have functions differentiated from their classical secretory hormone/neurotrophic factor actions. In this article, the historical perspective and updated mechanisms for the sorting and packaging of hormones and neurotrophic factors into secretory vesicles and their transport in these organelles for release at the plasma membrane are reviewed. In contrast, little is known about the packaging of hormones and neurotrophic factors into extracellular vesicles. One proposal is that these molecules could be sorted at the trans-Golgi network, which then buds to form Golgi-derived vesicles that can fuse to endosomes and subsequently form intraluminal vesicles. They are then taken up by multivesicular bodies to form extracellular vesicles, which are subsequently released. Other possible mechanisms for packaging RSP proteins into sEVs are discussed. We highlight some studies in the literature that suggest the dual vesicular pathways for the release of hormones and neurotrophic factors from the cell may have some physiological significance in intercellular communication.
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Affiliation(s)
- Y. Peng Loh
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lan Xiao
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joshua J. Park
- Scientific Review Branch, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Štepihar D, Florke Gee RR, Hoyos Sanchez MC, Fon Tacer K. Cell-specific secretory granule sorting mechanisms: the role of MAGEL2 and retromer in hypothalamic regulated secretion. Front Cell Dev Biol 2023; 11:1243038. [PMID: 37799273 PMCID: PMC10548473 DOI: 10.3389/fcell.2023.1243038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023] Open
Abstract
Intracellular protein trafficking and sorting are extremely arduous in endocrine and neuroendocrine cells, which synthesize and secrete on-demand substantial quantities of proteins. To ensure that neuroendocrine secretion operates correctly, each step in the secretion pathways is tightly regulated and coordinated both spatially and temporally. At the trans-Golgi network (TGN), intrinsic structural features of proteins and several sorting mechanisms and distinct signals direct newly synthesized proteins into proper membrane vesicles that enter either constitutive or regulated secretion pathways. Furthermore, this anterograde transport is counterbalanced by retrograde transport, which not only maintains membrane homeostasis but also recycles various proteins that function in the sorting of secretory cargo, formation of transport intermediates, or retrieval of resident proteins of secretory organelles. The retromer complex recycles proteins from the endocytic pathway back to the plasma membrane or TGN and was recently identified as a critical player in regulated secretion in the hypothalamus. Furthermore, melanoma antigen protein L2 (MAGEL2) was discovered to act as a tissue-specific regulator of the retromer-dependent endosomal protein recycling pathway and, by doing so, ensures proper secretory granule formation and maturation. MAGEL2 is a mammalian-specific and maternally imprinted gene implicated in Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. In this review, we will briefly discuss the current understanding of the regulated secretion pathway, encompassing anterograde and retrograde traffic. Although our understanding of the retrograde trafficking and sorting in regulated secretion is not yet complete, we will review recent insights into the molecular role of MAGEL2 in hypothalamic neuroendocrine secretion and how its dysregulation contributes to the symptoms of Prader-Willi and Schaaf-Yang patients. Given that the activation of many secreted proteins occurs after they enter secretory granules, modulation of the sorting efficiency in a tissue-specific manner may represent an evolutionary adaptation to environmental cues.
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Affiliation(s)
- Denis Štepihar
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rebecca R. Florke Gee
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Maria Camila Hoyos Sanchez
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Klementina Fon Tacer
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
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3
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Watanabe A, Hataida H, Inoue N, Kamon K, Baba K, Sasaki K, Kimura R, Sasaki H, Eura Y, Ni WF, Shibasaki Y, Waguri S, Kokame K, Shiba Y. Arf GTPase-activating proteins SMAP1 and AGFG2 regulate the size of Weibel-Palade bodies and exocytosis of von Willebrand factor. Biol Open 2021; 10:271213. [PMID: 34369554 PMCID: PMC8430232 DOI: 10.1242/bio.058789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 07/28/2021] [Indexed: 01/22/2023] Open
Abstract
Arf GTPase-Activating proteins (ArfGAPs) mediate the hydrolysis of GTP bound to ADP-ribosylation factors (Arfs), which are critical to form transport intermediates. ArfGAPs have been thought to be negative regulators of Arfs; however, accumulating evidence indicates that ArfGAPs are important for cargo sorting and promote membrane traffic. Weibel-Palade bodies (WPBs) are cigar-shaped secretory granules in endothelial cells that contain von Willebrand factor (vWF) as their main cargo. WPB biogenesis at the Golgi was reported to be regulated by Arf and their regulators, but the role of ArfGAPs has been unknown. In this study, we performed siRNA screening of ArfGAPs to investigate the role of ArfGAPs in the biogenesis of WPBs. We found two ArfGAPs, SMAP1 and AGFG2, to be involved in WPB size and vWF exocytosis, respectively. SMAP1 depletion resulted in small-sized WPBs, and the lysosomal inhibitor leupeptin recovered the size of WPBs. The results indicate that SMAP1 functions in preventing the degradation of cigar-shaped WPBs. On the other hand, AGFG2 downregulation resulted in the inhibition of vWF secretion upon Phorbol 12-myristate 13-acetate (PMA) or histamine stimulation, suggesting that AGFG2 plays a role in vWF exocytosis. Our study revealed unexpected roles of ArfGAPs in vWF transport. Summary: The Arf GTPase-activating proteins SMAP1 and AGFG2 regulate the size of Weibel-Palade bodies and exocytosis of von Willebrand factor.
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Affiliation(s)
- Asano Watanabe
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Hikari Hataida
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Naoya Inoue
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Kosuke Kamon
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Keigo Baba
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Kuniaki Sasaki
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Rika Kimura
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Honoka Sasaki
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Yuka Eura
- Department of Molecular Pathogenesis, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
| | - Wei-Fen Ni
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, 80201, Taiwan
| | - Yuji Shibasaki
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Koichi Kokame
- Department of Molecular Pathogenesis, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
| | - Yoko Shiba
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
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4
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Ma CIJ, Burgess J, Brill JA. Maturing secretory granules: Where secretory and endocytic pathways converge. Adv Biol Regul 2021; 80:100807. [PMID: 33866198 DOI: 10.1016/j.jbior.2021.100807] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 10/21/2022]
Abstract
Secretory granules (SGs) are specialized organelles responsible for the storage and regulated release of various biologically active molecules from the endocrine and exocrine systems. Thus, proper SG biogenesis is critical to normal animal physiology. Biogenesis of SGs starts at the trans-Golgi network (TGN), where immature SGs (iSGs) bud off and undergo maturation before fusing with the plasma membrane (PM). How iSGs mature is unclear, but emerging studies have suggested an important role for the endocytic pathway. The requirement for endocytic machinery in SG maturation blurs the line between SGs and another class of secretory organelles called lysosome-related organelles (LROs). Therefore, it is important to re-evaluate the differences and similarities between SGs and LROs.
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Affiliation(s)
- Cheng-I Jonathan Ma
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Medical Sciences Building, Room 2374, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Jason Burgess
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Room 4396, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Medical Sciences Building, Room 2374, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Room 4396, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
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5
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Shitara A, Bleck CKE, Weigert R. Cdc42 controls secretory granules morphology in rodent salivary glands in vivo. Commun Integr Biol 2020; 13:22-26. [PMID: 32128025 PMCID: PMC7039664 DOI: 10.1080/19420889.2020.1724605] [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: 11/06/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 10/27/2022] Open
Abstract
We previously reported that the small GTPase Cdc42 negatively regulates endocytosis in the salivary gland of live mice. By using intravital subcellular microscopy, we showed that depletion of Cdc42 causes the mis-sorting of plasma membrane components into intracellular vesicles, ultimately leading to the impairment of the homeostasis of the apical plasma membrane. In this study, we report that, besides, Cdc42 depletion alters the ultrastructure of large secretory granules analyzed by transmission electron microscopy. We found that lack of Cdc42 increases the number of granules per cell and alters their structure. Specifically, granules are smaller, less circular and exhibit heterogeneous electron densities in their lumen. Our findings suggest a novel role for Cdc42 in controlling granule biogenesis and/or maturation.
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Affiliation(s)
- Akiko Shitara
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.,Intracellular Membrane Trafficking Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Department of Pharmacology, Asahi University School of Dentistry, Mizuho, Japan
| | - Christopher K E Bleck
- Electron Microscopy Core Facility, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.,Intracellular Membrane Trafficking Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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6
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Makowski SL, Kuna RS, Field SJ. Induction of membrane curvature by proteins involved in Golgi trafficking. Adv Biol Regul 2019; 75:100661. [PMID: 31668661 PMCID: PMC7056495 DOI: 10.1016/j.jbior.2019.100661] [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: 08/30/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/22/2022]
Abstract
The Golgi apparatus serves a key role in processing and sorting lipids and proteins for delivery to their final cellular destinations. Vesicle exit from the Golgi initiates with directional deformation of the lipid bilayer to produce a bulge. Several mechanisms have been described by which lipids and proteins can induce directional membrane curvature to promote vesicle budding. Here we review some of the mechanisms implicated in inducing membrane curvature at the Golgi to promote vesicular trafficking to various cellular destinations.
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Affiliation(s)
- Stefanie L Makowski
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ramya S Kuna
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Seth J Field
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA.
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7
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Sahu BS, Mahata S, Bandyopadhyay K, Mahata M, Avolio E, Pasqua T, Sahu C, Bandyopadhyay GK, Bartolomucci A, Webster NJG, Van Den Bogaart G, Fischer-Colbrie R, Corti A, Eiden LE, Mahata SK. Catestatin regulates vesicular quanta through modulation of cholinergic and peptidergic (PACAPergic) stimulation in PC12 cells. Cell Tissue Res 2018; 376:51-70. [PMID: 30467710 DOI: 10.1007/s00441-018-2956-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/30/2018] [Indexed: 12/23/2022]
Abstract
We have previously shown that the chromogranin A (CgA)-derived peptide catestatin (CST: hCgA352-372) inhibits nicotine-induced secretion of catecholamines from the adrenal medulla and chromaffin cells. In the present study, we seek to determine whether CST regulates dense core (DC) vesicle (DCV) quanta (catecholamine and chromogranin/secretogranin proteins) during acute (0.5-h treatment) or chronic (24-h treatment) cholinergic (nicotine) or peptidergic (PACAP, pituitary adenylyl cyclase activating polypeptide) stimulation of PC12 cells. In acute experiments, we found that both nicotine (60 μM) and PACAP (0.1 μM) decreased intracellular norepinephrine (NE) content and increased 3H-NE secretion, with both effects markedly inhibited by co-treatment with CST (2 μM). In chronic experiments, we found that nicotine and PACAP both reduced DCV and DC diameters and that this effect was likewise prevented by CST. Nicotine or CST alone increased expression of CgA protein and together elicited an additional increase in CgA protein, implying that nicotine and CST utilize separate signaling pathways to activate CgA expression. In contrast, PACAP increased expression of CgB and SgII proteins, with a further potentiation by CST. CST augmented the expression of tyrosine hydroxylase (TH) but did not increase intracellular NE levels, presumably due to its inability to cause post-translational activation of TH through serine phosphorylation. Co-treatment of CST with nicotine or PACAP increased quantal size, plausibly due to increased synthesis of CgA, CgB and SgII by CST. We conclude that CST regulates DCV quanta by acutely inhibiting catecholamine secretion and chronically increasing expression of CgA after nicotinic stimulation and CgB and SgII after PACAPergic stimulation.
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Affiliation(s)
- Bhavani Shankar Sahu
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA. .,Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA.
| | - Sumana Mahata
- California Institute of Technology, Pasadena, CA, USA
| | - Keya Bandyopadhyay
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA
| | - Manjula Mahata
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA
| | | | | | - Chinmayi Sahu
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Gautam K Bandyopadhyay
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA
| | - Alessandro Bartolomucci
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Nicholas J G Webster
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA.,VA San Diego Healthcare System, San Diego, CA, USA
| | | | | | - Angelo Corti
- IRCCS San Raffaele Scientific Institute, San Raffaele Vita-Salute University, Milan, Italy
| | - Lee E Eiden
- Section on Molecular Neuroscience, NIMH-IRP, Bethesda, MD, USA
| | - Sushil K Mahata
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA. .,VA San Diego Healthcare System, San Diego, CA, USA.
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8
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Hummer BH, de Leeuw NF, Burns C, Chen L, Joens MS, Hosford B, Fitzpatrick JAJ, Asensio CS. HID-1 controls formation of large dense core vesicles by influencing cargo sorting and trans-Golgi network acidification. Mol Biol Cell 2017; 28:3870-3880. [PMID: 29074564 PMCID: PMC5739301 DOI: 10.1091/mbc.e17-08-0491] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/05/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022] Open
Abstract
The peripheral membrane protein HID-1 localizes to the trans-Golgi network, where it contributes to the formation of large dense core vesicles of neuroendocrine cells by influencing cargo sorting and trans-Golgi network acidification. Large dense core vesicles (LDCVs) mediate the regulated release of neuropeptides and peptide hormones. They form at the trans-Golgi network (TGN), where their soluble content aggregates to form a dense core, but the mechanisms controlling biogenesis are still not completely understood. Recent studies have implicated the peripheral membrane protein HID-1 in neuropeptide sorting and insulin secretion. Using CRISPR/Cas9, we generated HID-1 KO rat neuroendocrine cells, and we show that the absence of HID-1 results in specific defects in peptide hormone and monoamine storage and regulated secretion. Loss of HID-1 causes a reduction in the number of LDCVs and affects their morphology and biochemical properties, due to impaired cargo sorting and dense core formation. HID-1 KO cells also exhibit defects in TGN acidification together with mislocalization of the Golgi-enriched vacuolar H+-ATPase subunit isoform a2. We propose that HID-1 influences early steps in LDCV formation by controlling dense core formation at the TGN.
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Affiliation(s)
- Blake H Hummer
- Department of Biological Sciences, University of Denver, Denver, CO 80210
| | - Noah F de Leeuw
- Department of Biological Sciences, University of Denver, Denver, CO 80210
| | - Christian Burns
- Department of Biological Sciences, University of Denver, Denver, CO 80210
| | - Lan Chen
- Department of Biological Sciences, University of Denver, Denver, CO 80210
| | - Matthew S Joens
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO 63110
| | - Bethany Hosford
- Department of Biological Sciences, University of Denver, Denver, CO 80210
| | - James A J Fitzpatrick
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO 63110
| | - Cedric S Asensio
- Department of Biological Sciences, University of Denver, Denver, CO 80210
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9
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Sahu BS, Manna PT, Edgar JR, Antrobus R, Mahata SK, Bartolomucci A, Borner GHH, Robinson MS. Role of clathrin in dense core vesicle biogenesis. Mol Biol Cell 2017; 28:2676-2685. [PMID: 28814506 PMCID: PMC5620375 DOI: 10.1091/mbc.e16-10-0742] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 07/13/2017] [Accepted: 08/07/2017] [Indexed: 11/11/2022] Open
Abstract
The dense core vesicles (DCVs) of neuroendocrine cells are a rich source of bioactive molecules such as peptides, hormones, and neurotransmitters, but relatively little is known about how they are formed. Using fractionation profiling, a method that combines subcellular fractionation with mass spectrometry, we identified ∼1200 proteins in PC12 cell vesicle-enriched fractions, with DCV-associated proteins showing distinct profiles from proteins associated with other types of vesicles. To investigate the role of clathrin in DCV biogenesis, we stably transduced PC12 cells with an inducible short hairpin RNA targeting clathrin heavy chain, resulting in ∼85% protein loss. DCVs could still be observed in the cells by electron microscopy, but mature profiles were approximately fourfold less abundant than in mock-treated cells. By quantitative mass spectrometry, DCV-associated proteins were found to be reduced approximately twofold in clathrin-depleted cells as a whole and approximately fivefold in vesicle-enriched fractions. Our combined data sets enabled us to identify new candidate DCV components. Secretion assays revealed that clathrin depletion causes a near-complete block in secretagogue-induced exocytosis. Taken together, our data indicate that clathrin has a function in DCV biogenesis beyond its established role in removing unwanted proteins from the immature vesicle.
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Affiliation(s)
- Bhavani S Sahu
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Paul T Manna
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Sushil K Mahata
- Department of Medicine, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161.,Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Alessandro Bartolomucci
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455
| | - Georg H H Borner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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10
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Topalidou I, Cattin-Ortolá J, Pappas AL, Cooper K, Merrihew GE, MacCoss MJ, Ailion M. The EARP Complex and Its Interactor EIPR-1 Are Required for Cargo Sorting to Dense-Core Vesicles. PLoS Genet 2016; 12:e1006074. [PMID: 27191843 PMCID: PMC4871572 DOI: 10.1371/journal.pgen.1006074] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/30/2016] [Indexed: 12/15/2022] Open
Abstract
The dense-core vesicle is a secretory organelle that mediates the regulated release of peptide hormones, growth factors, and biogenic amines. Dense-core vesicles originate from the trans-Golgi of neurons and neuroendocrine cells, but it is unclear how this specialized organelle is formed and acquires its specific cargos. To identify proteins that act in dense-core vesicle biogenesis, we performed a forward genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We previously reported the identification of two conserved proteins that interact with the small GTPase RAB-2 to control normal dense-core vesicle cargo-sorting. Here we identify several additional conserved factors important for dense-core vesicle cargo sorting: the WD40 domain protein EIPR-1 and the endosome-associated recycling protein (EARP) complex. By assaying behavior and the trafficking of dense-core vesicle cargos, we show that mutants that lack EIPR-1 or EARP have defects in dense-core vesicle cargo-sorting similar to those of mutants in the RAB-2 pathway. Genetic epistasis data indicate that RAB-2, EIPR-1 and EARP function in a common pathway. In addition, using a proteomic approach in rat insulinoma cells, we show that EIPR-1 physically interacts with the EARP complex. Our data suggest that EIPR-1 is a new interactor of the EARP complex and that dense-core vesicle cargo sorting depends on the EARP-dependent trafficking of cargo through an endosomal sorting compartment. Animal cells package and store many important signaling molecules in specialized compartments called dense-core vesicles. Molecules stored in dense-core vesicles include peptide hormones like insulin and small molecule neurotransmitters like dopamine. Defects in the release of these compounds can lead to a wide range of metabolic and mental disorders in humans, including diabetes, depression, and drug addiction. However, it is not well understood how dense-core vesicles are formed in cells and package the appropriate molecules. Here we use a genetic screen in the microscopic worm C. elegans to identify proteins that are important for early steps in the generation of dense-core vesicles, such as packaging the correct molecular cargos in the vesicles. We identify several factors that are conserved between worms and humans and point to a new role for a protein complex that had previously been shown to be important for controlling trafficking in other cellular compartments. The identification of this complex suggests new cellular trafficking events that may be important for the generation of dense-core vesicles.
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Affiliation(s)
- Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Jérôme Cattin-Ortolá
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Andrea L. Pappas
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Kirsten Cooper
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Gennifer E. Merrihew
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael J. MacCoss
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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11
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Kanagaraj P, Gautier-Stein A, Riedel D, Schomburg C, Cerdà J, Vollack N, Dosch R. Souffle/Spastizin controls secretory vesicle maturation during zebrafish oogenesis. PLoS Genet 2014; 10:e1004449. [PMID: 24967841 PMCID: PMC4072560 DOI: 10.1371/journal.pgen.1004449] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/02/2014] [Indexed: 12/20/2022] Open
Abstract
During oogenesis, the egg prepares for fertilization and early embryogenesis. As a consequence, vesicle transport is very active during vitellogenesis, and oocytes are an outstanding system to study regulators of membrane trafficking. Here, we combine zebrafish genetics and the oocyte model to identify the molecular lesion underlying the zebrafish souffle (suf) mutation. We demonstrate that suf encodes the homolog of the Hereditary Spastic Paraplegia (HSP) gene SPASTIZIN (SPG15). We show that in zebrafish oocytes suf mutants accumulate Rab11b-positive vesicles, but trafficking of recycling endosomes is not affected. Instead, we detect Suf/Spastizin on cortical granules, which undergo regulated secretion. We demonstrate genetically that Suf is essential for granule maturation into secretion competent dense-core vesicles describing a novel role for Suf in vesicle maturation. Interestingly, in suf mutants immature, secretory precursors accumulate, because they fail to pinch-off Clathrin-coated buds. Moreover, pharmacological inhibition of the abscission regulator Dynamin leads to an accumulation of immature secretory granules and mimics the suf phenotype. Our results identify a novel regulator of secretory vesicle formation in the zebrafish oocyte. In addition, we describe an uncharacterized cellular mechanism for Suf/Spastizin activity during secretion, which raises the possibility of novel therapeutic avenues for HSP research. Oocytes of egg laying animals frequently represent the biggest cell type of a species. The size of the egg is a consequence of active transport processes, e.g. the import of yolk proteins, which results in the massive storage of vesicles. In addition, secretory vesicles termed cortical granules are stored in the oocyte to be discharged right after fertilization during cortical reaction, which also occurs in mammals. Their secretion leads to chorion expansion, which prevents the lethal entry of additional sperm and protects the developing embryo against physical damage. Mutants with a defect in membrane transport are successful tools to discover genes regulating vesicle formation. We molecularly identify the disrupted gene in the recessive maternal-effect mutation souffle, which encodes a homolog of human SPASTIZIN. SPASTIZIN was previously implicated in endocytosis, but our cellular analysis of mutant oocytes connects this gene also with the regulation of cortical granule exocytosis. More precisely, we show that Suf/Spastizin is crucial for the maturation of cortical granules into secretion competent vesicles describing a novel role for this protein. Since SPASITIZN causes the disease Hereditary Spastic Paraplegia in humans, our results will help to decipher the pathogenesis of this neurodegenerative disorder.
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Affiliation(s)
- Palsamy Kanagaraj
- Institut fuer Entwicklungsbiochemie, Georg-August Universitaet Goettingen, Goettingen, Germany
| | | | - Dietmar Riedel
- Max-Planck Institut fuer Biophysikalische Chemie, Goettingen, Germany
| | - Christoph Schomburg
- Institut fuer Entwicklungsbiochemie, Georg-August Universitaet Goettingen, Goettingen, Germany
| | - Joan Cerdà
- IRTA-Institute of Marine Sciences, CSIC, Barcelona, Spain
| | - Nadine Vollack
- Institut fuer Entwicklungsbiochemie, Georg-August Universitaet Goettingen, Goettingen, Germany
| | - Roland Dosch
- Institut fuer Entwicklungsbiochemie, Georg-August Universitaet Goettingen, Goettingen, Germany
- Departement de Zoologie et Biologie Animale, Universite de Geneve, Geneva, Switzerland
- * E-mail:
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12
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Ailion M, Hannemann M, Dalton S, Pappas A, Watanabe S, Hegermann J, Liu Q, Han HF, Gu M, Goulding MQ, Sasidharan N, Schuske K, Hullett P, Eimer S, Jorgensen EM. Two Rab2 interactors regulate dense-core vesicle maturation. Neuron 2014; 82:167-80. [PMID: 24698274 DOI: 10.1016/j.neuron.2014.02.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2014] [Indexed: 12/14/2022]
Abstract
Peptide neuromodulators are released from a unique organelle: the dense-core vesicle. Dense-core vesicles are generated at the trans-Golgi and then sort cargo during maturation before being secreted. To identify proteins that act in this pathway, we performed a genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We identified two conserved Rab2-binding proteins: RUND-1, a RUN domain protein, and CCCP-1, a coiled-coil protein. RUND-1 and CCCP-1 colocalize with RAB-2 at the Golgi, and rab-2, rund-1, and cccp-1 mutants have similar defects in sorting soluble and transmembrane dense-core vesicle cargos. RUND-1 also interacts with the Rab2 GAP protein TBC-8 and the BAR domain protein RIC-19, a RAB-2 effector. In summary, a pathway of conserved proteins controls the maturation of dense-core vesicles at the trans-Golgi network.
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Affiliation(s)
- Michael Ailion
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA; Department of Biochemistry, University of Washington, Seattle WA, 98195, USA.
| | - Mandy Hannemann
- European Neuroscience Institute, 37077 Göttingen, Germany; International Max Planck Research School Molecular Biology, 37077 Göttingen, Germany
| | - Susan Dalton
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Andrea Pappas
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Shigeki Watanabe
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Jan Hegermann
- European Neuroscience Institute, 37077 Göttingen, Germany; DFG research Center for Molecular Physiology of the Brain (CMPB), 37077 Göttingen, Germany
| | - Qiang Liu
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Hsiao-Fen Han
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Mingyu Gu
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Morgan Q Goulding
- Department of Biochemistry, University of Washington, Seattle WA, 98195, USA
| | | | - Kim Schuske
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Patrick Hullett
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Stefan Eimer
- European Neuroscience Institute, 37077 Göttingen, Germany; DFG research Center for Molecular Physiology of the Brain (CMPB), 37077 Göttingen, Germany
| | - Erik M Jorgensen
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
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13
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Jacob A, Jing J, Lee J, Schedin P, Gilbert SM, Peden AA, Junutula JR, Prekeris R. Rab40b regulates trafficking of MMP2 and MMP9 during invadopodia formation and invasion of breast cancer cells. J Cell Sci 2013; 126:4647-58. [PMID: 23902685 DOI: 10.1242/jcs.126573] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Invadopodia-dependent degradation of the basement membrane plays a major role during metastasis of breast cancer cells. Basement membrane degradation is mediated by targeted secretion of various matrix metalloproteinases (MMPs). Specifically, MMP2 and MMP9 (MMP2/9) possess the ability to hydrolyze components of the basement membrane and regulate various aspects of tumor growth and metastasis. However, the membrane transport machinery that mediates targeting of MMP2/9 to the invadopodia during cancer cell invasion remains to be defined. Because Rab GTPases are key regulators of membrane transport, we screened a human Rab siRNA library and identified Rab40b GTPase as a protein required for secretion of MMP2/9. We also have shown that Rab40b functions during at least two distinct steps of MMP2/9 transport. Here, we demonstrate that Rab40b is required for MMP2/9 sorting into VAMP4-containing secretory vesicles. We also show that Rab40b regulates transport of MMP2/9 secretory vesicles during invadopodia formation and is required for invadopodia-dependent extracellular matrix degradation. Finally, we demonstrate that Rab40b is also required for breast cancer cell invasion in vitro. On the basis of these findings, we propose that Rab40b mediates trafficking of MMP2/9 during invadopodia formation and metastasis of breast cancer cells.
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Affiliation(s)
- Abitha Jacob
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, USA
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14
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Satori CP, Henderson MM, Krautkramer EA, Kostal V, Distefano MM, Arriaga EA. Bioanalysis of eukaryotic organelles. Chem Rev 2013; 113:2733-811. [PMID: 23570618 PMCID: PMC3676536 DOI: 10.1021/cr300354g] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Chad P. Satori
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Michelle M. Henderson
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Elyse A. Krautkramer
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Vratislav Kostal
- Tescan, Libusina trida 21, Brno, 623 00, Czech Republic
- Institute of Analytical Chemistry ASCR, Veveri 97, Brno, 602 00, Czech Republic
| | - Mark M. Distefano
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Edgar A. Arriaga
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
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15
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Kögel T, Rudolf R, Hodneland E, Copier J, Regazzi R, Tooze SA, Gerdes HH. Rab3D is critical for secretory granule maturation in PC12 cells. PLoS One 2013; 8:e57321. [PMID: 23526941 PMCID: PMC3602456 DOI: 10.1371/journal.pone.0057321] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 01/21/2013] [Indexed: 11/19/2022] Open
Abstract
Neuropeptide- and hormone-containing secretory granules (SGs) are synthesized at the trans-Golgi network (TGN) as immature secretory granules (ISGs) and complete their maturation in the F-actin-rich cell cortex. This maturation process is characterized by acidification-dependent processing of cargo proteins, condensation of the SG matrix and removal of membrane and proteins not destined to mature secretory granules (MSGs). Here we addressed a potential role of Rab3 isoforms in these maturation steps by expressing their nucleotide-binding deficient mutants in PC12 cells. Our data show that the presence of Rab3D(N135I) decreases the restriction of maturing SGs to the F-actin-rich cell cortex, blocks the removal of the endoprotease furin from SGs and impedes the processing of the luminal SG protein secretogranin II. This strongly suggests that Rab3D is implicated in the subcellular localization and maturation of ISGs.
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Affiliation(s)
- Tanja Kögel
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Rüdiger Rudolf
- Interdisciplinary Center of Neurobiology, University of Heidelberg, Heidelberg, Germany
| | | | - John Copier
- London Research Institute Cancer Research United Kingdom, Lincoln's Inn Fields Laboratories, London, United Kingdom
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Sharon A. Tooze
- London Research Institute Cancer Research United Kingdom, Lincoln's Inn Fields Laboratories, London, United Kingdom
| | - Hans-Hermann Gerdes
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Interdisciplinary Center of Neurobiology, University of Heidelberg, Heidelberg, Germany
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16
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Bonnemaison ML, Eipper BA, Mains RE. Role of adaptor proteins in secretory granule biogenesis and maturation. Front Endocrinol (Lausanne) 2013; 4:101. [PMID: 23966980 PMCID: PMC3743005 DOI: 10.3389/fendo.2013.00101] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 07/31/2013] [Indexed: 12/29/2022] Open
Abstract
In the regulated secretory pathway, secretory granules (SGs) store peptide hormones that are released on demand. SGs are formed at the trans-Golgi network and must undergo a maturation process to become responsive to secretagogues. The production of mature SGs requires concentrating newly synthesized soluble content proteins in granules whose membranes contain the appropriate integral membrane proteins. The mechanisms underlying the sorting of soluble and integral membrane proteins destined for SGs from other proteins are not yet well understood. For soluble proteins, luminal pH and divalent metals can affect aggregation and interaction with surrounding membranes. The trafficking of granule membrane proteins can be controlled by both luminal and cytosolic factors. Cytosolic adaptor proteins (APs), which recognize the cytosolic domains of proteins that span the SG membrane, have been shown to play essential roles in the assembly of functional SGs. Adaptor protein 1A (AP-1A) is known to interact with specific motifs in its cargo proteins and with the clathrin heavy chain, contributing to the formation of a clathrin coat. AP-1A is present in patches on immature SG membranes, where it removes cargo and facilitates SG maturation. AP-1A recruitment to membranes can be modulated by Phosphofurin Acidic Cluster Sorting protein 1 (PACS-1), a cytosolic protein which interacts with both AP-1A and cargo that has been phosphorylated by casein kinase II. A cargo/PACS-1/AP-1A complex is necessary to drive the appropriate transport of several cargo proteins within the regulated secretory pathway. The Golgi-localized, γ-ear containing, ADP-ribosylation factor binding (GGA) family of APs serve a similar role. We review the functions of AP-1A, PACS-1, and GGAs in facilitating the retrieval of proteins from immature SGs and review examples of cargo proteins whose trafficking within the regulated secretory pathway is governed by APs.
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Affiliation(s)
- Mathilde L. Bonnemaison
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Betty A. Eipper
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT, USA
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Richard E. Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
- *Correspondence: Richard E. Mains, Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3401, USA e-mail:
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17
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Bogan JS, Xu Y, Hao M. Cholesterol accumulation increases insulin granule size and impairs membrane trafficking. Traffic 2012; 13:1466-80. [PMID: 22889194 DOI: 10.1111/j.1600-0854.2012.01407.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/09/2012] [Accepted: 08/13/2012] [Indexed: 11/28/2022]
Abstract
The formation of mature secretory granules is essential for proper storage and regulated release of hormones and neuropeptides. In pancreatic β cells, cholesterol accumulation causes defects in insulin secretion and may participate in the pathogenesis of type 2 diabetes. Using a novel cholesterol analog, we show for the first time that insulin granules are the major sites of intracellular cholesterol accumulation in live β cells. This is distinct from other, non-secretory cell types, in which cholesterol is concentrated in the recycling endosomes and the trans-Golgi network. Excess cholesterol was delivered specifically to insulin granules, which caused granule enlargement and retention of syntaxin 6 and VAMP4 in granule membranes, with concurrent depletion of these proteins from the trans-Golgi network. Clathrin also accumulated in the granules of cholesterol-overloaded cells, consistent with a possible defect in the last stage of granule maturation, during which clathrin-coated vesicles bud from the immature granules. Excess cholesterol also reduced the docking and fusion of insulin granules at the plasma membrane. Together, the data support a model in which cholesterol accumulation in insulin secretory granules impairs the ability of these vesicles to respond to stimuli, and thus reduces insulin secretion.
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Affiliation(s)
- Jonathan S Bogan
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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18
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Cellular Mechanisms for the Biogenesis and Transport of Synaptic and Dense-Core Vesicles. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 299:27-115. [DOI: 10.1016/b978-0-12-394310-1.00002-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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19
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Eissenberg JC, Ilvarsonn AM, Sly WS, Waheed A, Krzyzanek V, Pohlmann R, Waschkau D, Kretzschmar D, Dennes AC. Drosophila GGA model: an ultimate gateway to GGA analysis. Traffic 2011; 12:1821-38. [PMID: 21923734 PMCID: PMC3601743 DOI: 10.1111/j.1600-0854.2011.01285.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Golgi-localized, γ-ear-containing, ADP ribosylation factor-binding (GGA) proteins are monomeric adaptors implicated in clathrin-mediated vesicular transport between the trans Golgi network and endosomes, characterized mainly from cell culture analysis of lysosomal sorting. To provide the first demonstration of GGA's role in vivo, we used Drosophila which has a single GGA and a single lysosomal sorting receptor, lysosomal enzyme receptor protein (LERP). Using RNAi knockdowns, we show that the Drosophila GGA is required for lysosomal sorting. We further identified authentic components of the Drosophila lysosomal sorting system--the sorting receptor LERP, the sorting adaptor GGA and the lysosomal cargo cathepsins B1, D and L--to show that GGA depletion results in lysosomal dysfunction. Abnormal lysosomal morphology, missorting of lysosomal cathepsins and impaired lysosomal proteolysis show disturbed LERP trafficking after GGA depletion. GGA is highly expressed in the mushroom bodies and the pigment cells of the retina, and increasing or decreasing the levels of GGA in the eyes leads to retinal defects. Reduced GGA levels also enhance an eye defect caused by overexpression of the autophagy-associated protein Blue cheese (Bchs), implicating GGA in autophagic processes. This shows that Drosophila provides an excellent whole-animal model to gain new insights into the function of GGA in the physiological environment of a multicellular organism.
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Affiliation(s)
- Joel C. Eissenberg
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Doisy Research Center, St. Louis, MO 63104, USA
| | - Anne M. Ilvarsonn
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Doisy Research Center, St. Louis, MO 63104, USA
| | - William S. Sly
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Doisy Research Center, St. Louis, MO 63104, USA
| | - Abdul Waheed
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Doisy Research Center, St. Louis, MO 63104, USA
| | - Vladislav Krzyzanek
- Institute of Medical Physics and Biophysics University of Muenster, 48149 Muenster, Germany
| | - Regina Pohlmann
- UKM, Institute of Physiological Chemistry and Pathobiochemistry, 48149 Münster, Germany
| | - Daniela Waschkau
- UKM, Institute of Physiological Chemistry and Pathobiochemistry, 48149 Münster, Germany
| | | | - André C. Dennes
- UKM, Institute of Physiological Chemistry and Pathobiochemistry, 48149 Münster, Germany
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20
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Abstract
hid-1 was originally identified as a Caenorhabditis elegans gene encoding a novel conserved protein that regulates the decision to enter into the enduring dauer larval stage. We isolated a novel allele of hid-1 in a forward genetic screen for mutants mislocalizing RBF-1 rabphilin, a RAB-27 effector. Here we demonstrate that HID-1 functions in the nervous system to regulate neuromuscular signaling and in the intestine to regulate the defecation motor program. We further show that a conserved N-terminal myristoylated motif of both invertebrate and vertebrate HID-1 is essential for its association with intracellular membranes in nematodes and PC12 cells. C. elegans neuronal HID-1 resides on intracellular membranes in neuronal cell somas; however, the kinesin UNC-104 also transports HID-1 to synaptic regions. HID-1 accumulates in the axons of unc-13 and unc-31 mutants, suggesting it is associated with neurosecretory vesicles. Consistent with this, genetic studies place HID-1 in a peptidergic signaling pathway. Finally, a hid-1 null mutation reduces the levels of endogenous neuropeptides and alters the secretion of fluorescent-tagged cargos derived from neuronal and intestinal dense core vesicles (DCVs). Taken together, our findings indicate that HID-1 is a novel component of a DCV-based neurosecretory pathway and that it regulates one or more aspects of the biogenesis, maturation, or trafficking of DCVs.
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Kögel T, Gerdes HH. Roles of myosin Va and Rab3D in membrane remodeling of immature secretory granules. Cell Mol Neurobiol 2010; 30:1303-8. [PMID: 21080055 PMCID: PMC3008937 DOI: 10.1007/s10571-010-9597-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 09/02/2010] [Indexed: 01/24/2023]
Abstract
Neuroendocrine secretory granules (SGs) are formed at the trans-Golgi network (TGN) as immature intermediates. In PC12 cells, these immature SGs (ISGs) are transported within seconds to the cell cortex, where they move along actin filaments and complete maturation. This maturation process comprises acidification-dependent processing of cargo proteins, condensation of the SG matrix, and removal of membrane and proteins not destined to mature SGs (MSGs) into ISG-derived vesicles (IDVs). We investigated the roles of myosin Va and Rab3 isoforms in the maturation of ISGs in neuroendocrine PC12 cells. The expression of dominant-negative mutants of myosin Va or Rab3D blocked the removal of the endoprotease furin from ISGs. Furthermore, expression of mutant Rab3D, but not of mutant myosin Va, impaired cargo processing of SGs. In conclusion, our data suggest an implication of myosin Va and Rab3D in the maturation of SGs where they participate in overlapping but not identical tasks.
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Affiliation(s)
- Tanja Kögel
- Department of Biomedicine, University of Bergen, Jonas Lies Vei 91, 5009 Bergen, Norway
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Skalski M, Yi Q, Kean MJ, Myers DW, Williams KC, Burtnik A, Coppolino MG. Lamellipodium extension and membrane ruffling require different SNARE-mediated trafficking pathways. BMC Cell Biol 2010; 11:62. [PMID: 20698987 PMCID: PMC2925818 DOI: 10.1186/1471-2121-11-62] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 08/10/2010] [Indexed: 12/26/2022] Open
Abstract
Background Intracellular membrane traffic is an essential component of the membrane remodeling that supports lamellipodium extension during cell adhesion. The membrane trafficking pathways that contribute to cell adhesion have not been fully elucidated, but recent studies have implicated SNARE proteins. Here, the functions of several SNAREs (SNAP23, VAMP3, VAMP4 and syntaxin13) are characterized during the processes of cell spreading and membrane ruffling. Results We report the first description of a SNARE complex, containing SNAP23, syntaxin13 and cellubrevin/VAMP3, that is induced by cell adhesion to an extracellular matrix. Impairing the function of the SNAREs in the complex using inhibitory SNARE domains disrupted the recycling endosome, impeded delivery of integrins to the cell surface, and reduced haptotactic cell migration and spreading. Blocking SNAP23 also inhibited the formation of PMA-stimulated, F-actin-rich membrane ruffles; however, membrane ruffle formation was not significantly altered by inhibition of VAMP3 or syntaxin13. In contrast, membrane ruffling, and not cell spreading, was sensitive to inhibition of two SNAREs within the biosynthetic secretory pathway, GS15 and VAMP4. Consistent with this, formation of a complex containing VAMP4 and SNAP23 was enhanced by treatment of cells with PMA. The results reveal a requirement for the function of a SNAP23-syntaxin13-VAMP3 complex in the formation of lamellipodia during cell adhesion and of a VAMP4-SNAP23-containing complex during PMA-induced membrane ruffling. Conclusions Our findings suggest that different SNARE-mediated trafficking pathways support membrane remodeling during ECM-induced lamellipodium extension and PMA-induced ruffle formation, pointing to important mechanistic differences between these processes.
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Affiliation(s)
- Michael Skalski
- Department of Molecular and Cellular Biology, University of Guleph, Guelph, ON N1G 2W1, Canada
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23
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Martijn C, Wiklund L. Effect of methylene blue on the genomic response to reperfusion injury induced by cardiac arrest and cardiopulmonary resuscitation in porcine brain. BMC Med Genomics 2010; 3:27. [PMID: 20594294 PMCID: PMC2904268 DOI: 10.1186/1755-8794-3-27] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 07/01/2010] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Cerebral ischemia/reperfusion injury is a common secondary effect of cardiac arrest which is largely responsible for postresuscitative mortality. Therefore development of therapies which restore and protect the brain function after cardiac arrest is essential. Methylene blue (MB) has been experimentally proven neuroprotective in a porcine model of global ischemia-reperfusion in experimental cardiac arrest. However, no comprehensive analyses have been conducted at gene expression level. METHODS Pigs underwent either untreated cardiac arrest (CA) or CA with subsequent cardiopulmonary resuscitation (CPR) accompanied with an infusion of saline or an infusion of saline with MB. Genome-wide transcriptional profiling using the Affymetrix porcine microarray was performed to 1) gain understanding of delayed neuronal death initiation in porcine brain during ischemia and after 30, 60 and 180 min following reperfusion, and 2) identify the mechanisms behind the neuroprotective effect of MB after ischemic injury (at 30, 60 and 180 min). RESULTS Our results show that restoration of spontaneous circulation (ROSC) induces major transcriptional changes related to stress response, inflammation, apoptosis and even cytoprotection. In contrast, the untreated ischemic and anoxic insult affected only few genes mainly involved in intra-/extracellular ionic balance. Furthermore, our data show that the neuroprotective role of MB is diverse and fulfilled by regulation of the expression of soluble guanylate cyclase and biological processes accountable for inhibition of apoptosis, modulation of stress response, neurogenesis and neuroprotection. CONCLUSIONS Our results support that MB could be a valuable intervention and should be investigated as a therapeutic agent against neural damage associated with I/R injury induced by cardiac arrest.
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Affiliation(s)
- Cécile Martijn
- Department of Surgical Sciences/Anaesthesiology and Intensive Care Medicine, Uppsala University Hospital, SE-751 85 Uppsala, Sweden
| | - Lars Wiklund
- Department of Surgical Sciences/Anaesthesiology and Intensive Care Medicine, Uppsala University Hospital, SE-751 85 Uppsala, Sweden
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24
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Versatile roles for myosin Va in dense core vesicle biogenesis and function. Biochem Soc Trans 2010; 38:199-204. [PMID: 20074059 DOI: 10.1042/bst0380199] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The motor protein myosin Va is involved in multiple successive steps in the development of dense-core vesicles, such as in the membrane remodelling during their maturation, their transport along actin filaments and the regulation of their exocytosis. In the present paper, we summarize the current knowledge on the roles of myosin Va in the different steps of dense-core vesicle biogenesis and exocytosis, and compare findings obtained from different cell types and experimental systems.
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25
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Kögel T, Rudolf R, Hodneland E, Hellwig A, Kuznetsov SA, Seiler F, Söllner TH, Barroso J, Gerdes HH. Distinct Roles of Myosin Va in Membrane Remodeling and Exocytosis of Secretory Granules. Traffic 2010; 11:637-50. [DOI: 10.1111/j.1600-0854.2010.01048.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Exocrine, endocrine, and neuroendocrine cells store hormones and neuropeptides in secretory granules (SGs), which undergo regulated exocytosis in response to an appropriate stimulus. These cargo proteins are sorted at the trans-Golgi network into forming immature secretory granules (ISGs). ISGs undergo maturation while they are transported to and within the F-actin-rich cortex. This process includes homotypic fusion of ISGs, acidification of their lumen, processing, and aggregation of cargo proteins as well as removal of excess membrane and missorted cargo. The resulting mature secretory granules (MSGs) are stored in the F-actin-rich cell cortex, perhaps as segregated pools exhibiting specific responses to stimuli for regulated exocytosis. During the last decade our understanding of the maturation of ISGs advanced substantially. The use of biochemical approaches led to the identification of membrane molecules mechanistically involved in this process. Furthermore, live cell imaging in combination with fluorescently tagged marker proteins of SGs provided insights into the dynamics of maturing ISGs, and the functional implications of cytoskeletal elements and motor proteins.
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27
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Park JJ, Loh YP. How peptide hormone vesicles are transported to the secretion site for exocytosis. Mol Endocrinol 2008; 22:2583-95. [PMID: 18669645 DOI: 10.1210/me.2008-0209] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Post-Golgi transport of peptide hormone-containing vesicles from the site of genesis at the trans-Golgi network to the release site at the plasma membrane is essential for activity-dependent hormone secretion to mediate various endocrinological functions. It is known that these vesicles are transported on microtubules to the proximity of the release site, and they are then loaded onto an actin/myosin system for distal transport through the actin cortex to just below the plasma membrane. The vesicles are then tethered to the plasma membrane, and a subpopulation of them are docked and primed to become the readily releasable pool. Cytoplasmic tails of vesicular transmembrane proteins, as well as many cytosolic proteins including adaptor proteins, motor proteins, and guanosine triphosphatases, are involved in vesicle budding, the anchoring of the vesicles, and the facilitation of movement along the transport systems. In addition, a set of cytosolic proteins is also necessary for tethering/docking of the vesicles to the plasma membrane. Many of these proteins have been identified from different types of (neuro)endocrine cells. Here, we summarize the proteins known to be involved in the mechanisms of sorting various cargo proteins into regulated secretory pathway hormone-containing vesicles, movement of these vesicles along microtubules and actin filaments, and their eventual tethering/docking to the plasma membrane for hormone secretion.
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Affiliation(s)
- Joshua J Park
- Section on Cellular Neurobiology, National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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Williams D, Pessin JE. Mapping of R-SNARE function at distinct intracellular GLUT4 trafficking steps in adipocytes. ACTA ACUST UNITED AC 2008; 180:375-87. [PMID: 18227281 PMCID: PMC2213575 DOI: 10.1083/jcb.200709108] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The functional trafficking steps used by soluble NSF attachment protein receptor (SNARE) proteins have been difficult to establish because of substantial overlap in subcellular localization and because in vitro SNARE-dependent binding and fusion reactions can be promiscuous. Therefore, to functionally identify the site of action of the vesicle-associated membrane protein (VAMP) family of R-SNAREs, we have taken advantage of the temporal requirements of adipocyte biosynthetic sorting of a dual-tagged GLUT4 reporter (myc-GLUT4-GFP) coupled with small interfering RNA gene silencing. Using this approach, we confirm the requirement of VAMP2 and VAMP7 for insulin and osmotic shock trafficking from the vesicle storage sites, respectively, and fusion with the plasma membrane. Moreover, we identify a requirement for VAMP4 for the initial biosynthetic entry of GLUT4 from the Golgi apparatus into the insulin-responsive vesicle compartment, VAMP8, for plasma membrane endocytosis and VAMP2 for sorting to the specialized insulin-responsive compartment after plasma membrane endocytosis.
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Affiliation(s)
- Dumaine Williams
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
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Morvan J, Tooze SA. Discovery and progress in our understanding of the regulated secretory pathway in neuroendocrine cells. Histochem Cell Biol 2008; 129:243-52. [PMID: 18197413 PMCID: PMC2248607 DOI: 10.1007/s00418-008-0377-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2008] [Indexed: 01/24/2023]
Abstract
In this review we start with a historical perspective beginning with the early morphological work done almost 50 years ago. The importance of these pioneering studies is underscored by our brief summary of the key questions addressed by subsequent research into the mechanism of secretion. We then highlight important advances in our understanding of the formation and maturation of neuroendocrine secretory granules, first using in vitro reconstitution systems, then most recently biochemical approaches, and finally genetic manipulations in vitro and in vivo.
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Affiliation(s)
- Joëlle Morvan
- London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London, UK
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30
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Origins of the regulated secretory pathway. THE GOLGI APPARATUS 2008. [PMCID: PMC7121582 DOI: 10.1007/978-3-211-76310-0_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modes of transport of soluble (or luminal) secretory proteins synthesized in the endoplasmic reticulum (ER) could be divided into two groups. The socalled constitutive secretory pathway (CSP) is common to all eukaryotic cells, constantly delivering constitutive soluble secretory proteins (CSSPs) linked to the rate of protein synthesis but largely independent of external stimuli. In regulated secretion, protein is sorted from the Golgi into storage/secretory granules (SGs) whose contents are released when stimuli trigger their final fusion with the plasma membrane (Hannah et al. 1999).
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Ferraro F, Ma XM, Sobota JA, Eipper BA, Mains RE. Kalirin/Trio Rho guanine nucleotide exchange factors regulate a novel step in secretory granule maturation. Mol Biol Cell 2007; 18:4813-25. [PMID: 17881726 PMCID: PMC2096607 DOI: 10.1091/mbc.e07-05-0503] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The molecular mechanisms involved in the maturation of secretory granules, organelles that store hormones and neuropeptides, are poorly understood. As granule content proteins are processed, the composition of granule membranes changes, yielding constitutive-like secretion of immature content proteins and producing secretagogue-responsive mature granules. Constitutive-like secretion was not previously recognized as a process subject to regulation. We show that Kalirin and Trio, homologous Rho guanine nucleotide exchange factors (GEFs), which interact with a secretory granule resident protein, modulate cargo secretion from immature granules. Some of the Kalirin and Trio isoforms expressed in neuroendocrine cells colocalize with immature granules. Overexpression of their N-terminal GEF domain (GEF1) enhances secretion from immature granules, depleting cells of secretory cargo in the absence of secretagogue. This response requires GEF1 activity and is mimicked by Kalirin/Trio substrates Rac1 and RhoG. Accordingly, selective pharmacological inhibition of endogenous GEF1 activity decreases secretagogue-independent release of hormone precursors, accumulating product peptide in mature secretory granules. Kalirin/Trio modulation of cargo secretion from immature granules provides secretory cells with an extra layer of control over the sets of peptides released. Control of this step enhances the range of physiological responses that can be elicited, whereas lack of control could have pathological consequences.
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Affiliation(s)
- Francesco Ferraro
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT 06030-3401
| | - Xin-Ming Ma
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT 06030-3401
| | - Jacqueline A. Sobota
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT 06030-3401
| | - Betty A. Eipper
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT 06030-3401
| | - Richard E. Mains
- Neuroscience Department, University of Connecticut Health Center, Farmington, CT 06030-3401
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32
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Hinz G, Colanesi S, Hillmer S, Rogers JC, Robinson DG. Localization of vacuolar transport receptors and cargo proteins in the Golgi apparatus of developing Arabidopsis embryos. Traffic 2007; 8:1452-64. [PMID: 17696967 DOI: 10.1111/j.1600-0854.2007.00625.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Using immunogold electron microscopy, we have investigated the relative distribution of two types of vacuolar sorting receptors (VSR) and two different types of lumenal cargo proteins, which are potential ligands for these receptors in the secretory pathway of developing Arabidopsis embryos. Interestingly, both cargo proteins are deposited in the protein storage vacuole, which is the only vacuole present during the bent-cotyledon stage of embryo development. Cruciferin and aleurain do not share the same pattern of distribution in the Golgi apparatus. Cruciferin is mainly detected in the cis and medial cisternae, especially at the rims where storage proteins aggregate into dense vesicles (DVs). Aleurain is found throughout the Golgi stack, particularly in the trans cisternae and trans Golgi network where clathrin-coated vesicles (CCVs) are formed. Nevertheless, aleurain was detected in both DV and CCV. VSR-At1, a VSR that recognizes N-terminal vacuolar sorting determinants (VSDs) of the NPIR type, localizes mainly to the trans Golgi and is hardly detectable in DV. Receptor homology-transmembrane-RING H2 domain (RMR), a VSR that recognizes C-terminal VSDs, has a distribution that is very similar to that of cruciferin and is found in DV. Our results do not support a role for VSR-At1 in storage protein sorting, instead RMR proteins because of their distribution similar to that of cruciferin in the Golgi apparatus and their presence in DV are more likely candidates. Aleurain, which has an NPIR motif and seems to be primarily sorted via VSR-At1 into CCV, also possesses putative hydrophobic sorting determinants at its C-terminus that could allow the additional incorporation of this protein into DV.
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Affiliation(s)
- Giselbert Hinz
- Department of Cell Biology, Heidelberg Institute for Plant Sciences, University of Heidelberg, 69120 Heidelberg, Germany
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Lopes VS, Wasmeier C, Seabra MC, Futter CE. Melanosome maturation defect in Rab38-deficient retinal pigment epithelium results in instability of immature melanosomes during transient melanogenesis. Mol Biol Cell 2007; 18:3914-27. [PMID: 17671165 PMCID: PMC1995718 DOI: 10.1091/mbc.e07-03-0268] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Pathways of melanosome biogenesis in retinal pigment epithelial (RPE) cells have received less attention than those of skin melanocytes. Although the bulk of melanin synthesis in RPE cells occurs embryonically, it is not clear whether adult RPE cells continue to produce melanosomes. Here, we show that progression from pmel17-positive premelanosomes to tyrosinase-positive mature melanosomes in the RPE is largely complete before birth. Loss of functional Rab38 in the "chocolate" (cht) mouse causes dramatically reduced numbers of melanosomes in adult RPE, in contrast to the mild phenotype previously shown in skin melanocytes. Choroidal melanocytes in cht mice also have reduced melanosome numbers, but a continuing low level of melanosome biogenesis gradually overcomes the defect, unlike in the RPE. Partial compensation by Rab32 that occurs in skin melanocytes is less effective in the RPE, presumably because of the short time window for melanosome biogenesis. In cht RPE, premelanosomes form but delivery of tyrosinase is impaired. Premelanosomes that fail to deposit melanin are unstable in both cht and tyrosinase-deficient RPE. Together with the high levels of cathepsin D in immature melanosomes of the RPE, our results suggest that melanin deposition may protect the maturing melanosome from the activity of lumenal acid hydrolases.
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Affiliation(s)
- Vanda S. Lopes
- *Molecular and Cellular Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom; and
| | - Christina Wasmeier
- *Molecular and Cellular Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom; and
| | - Miguel C. Seabra
- *Molecular and Cellular Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom; and
| | - Clare E. Futter
- Institute of Ophthalmology, University College London, London EC1V 9EL, United Kingdom
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Derby MC, Gleeson PA. New Insights into Membrane Trafficking and Protein Sorting. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 261:47-116. [PMID: 17560280 DOI: 10.1016/s0074-7696(07)61002-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein transport in the secretory and endocytic pathways is a multistep process involving the generation of transport carriers loaded with defined sets of cargo, the shipment of the cargo-loaded transport carriers between compartments, and the specific fusion of these transport carriers with a target membrane. The regulation of these membrane-mediated processes involves a complex array of protein and lipid interactions. As the machinery and regulatory processes of membrane trafficking have been defined, it is increasingly apparent that membrane transport is intimately connected with a number of other cellular processes, such as quality control in the endoplasmic reticulum (ER), cytoskeletal dynamics, receptor signaling, and mitosis. The fidelity of membrane trafficking relies on the correct assembly of components on organelles. Recruitment of peripheral proteins plays a critical role in defining organelle identity and the establishment of membrane subdomains, essential for the regulation of vesicle transport. The molecular mechanisms for the biogenesis of membrane subdomains are also central to understanding how cargo is sorted and segregated and how different populations of transport carriers are generated. In this review we will focus on the emerging themes of organelle identity, membrane subdomains, regulation of Golgi trafficking, and advances in dissecting pathways in physiological systems.
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Affiliation(s)
- Merran C Derby
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
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35
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Borgonovo B, Ouwendijk J, Solimena M. Biogenesis of secretory granules. Curr Opin Cell Biol 2006; 18:365-70. [PMID: 16806882 DOI: 10.1016/j.ceb.2006.06.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 06/08/2006] [Indexed: 11/22/2022]
Abstract
Secretory granules of neuroendocrine cells store and release peptide hormones and neuropeptides in response to various stimuli. Generation of granules from the Golgi complex involves the aggregation of cargo proteins and their sorting from non-regulated secretory molecules. Recent findings on knockout mice lacking individual granule constituents have challenged the hypothesis that an 'essential' protein for the assembly of these organelles exists, while studies on polypyrimidine tract-binding protein and ICA512/IA-2 have provided insight into the mechanisms for adjusting granule production in relation to stimulation and secretory activity.
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Affiliation(s)
- Barbara Borgonovo
- Experimental Diabetology, Carl Gustav Carus Medical School, Dresden University of Technology, Fetscherstrasse 74, 01307 Dresden, Germany
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