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Abstract
Platelet dense granules (DGs) are membrane bound compartments that store polyphosphate and small molecules such as ADP, ATP, Ca2+, and serotonin. The release of DG contents plays a central role in platelet aggregation to form a hemostatic plug. Accordingly, congenital deficiencies in the biogenesis of platelet DGs underlie human genetic disorders that cause storage pool disease and manifest with prolonged bleeding. DGs belong to a family of lysosome-related organelles, which also includes melanosomes, the compartments where the melanin pigments are synthesized. These organelles share several characteristics including an acidic lumen and, at least in part, the molecular machinery involved in their biogenesis. As a result, many genes affect both DG and melanosome biogenesis and the corresponding patients present not only with bleeding but also with oculocutaneous albinism. The identification and characterization of such genes has been instrumental in dissecting the pathways responsible for organelle biogenesis. Because the study of melanosome biogenesis has advanced more rapidly, this knowledge has been extrapolated to explain how DGs are produced. However, some progress has recently been made in studying platelet DG biogenesis directly in megakaryocytes and megakaryocytoid cells. DGs originate from an endosomal intermediate compartment, the multivesicular body. Maturation and differentiation into a DG begins when newly synthesized DG-specific proteins are delivered from early/recycling endosomal compartments. The machinery that orchestrates this vesicular trafficking is composed of a combination of both ubiquitous and cell type-specific proteins. Here, we review the current knowledge on DG biogenesis. In particular, we focus on the individual human and murine genes encoding the molecular machinery involved in this process and how their deficiencies result in disease.
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Affiliation(s)
- Andrea L Ambrosio
- a Department of Biochemistry and Molecular Biology , Colorado State University , Fort Collins , Colorado , USA
| | - Santiago M Di Pietro
- a Department of Biochemistry and Molecular Biology , Colorado State University , Fort Collins , Colorado , USA
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Bultema JJ, Di Pietro SM. Reduce, reuse, recycle: a retrieval transport pathway for the membrane fusion machinery involved in melanosome biogenesis. Pigment Cell Melanoma Res 2016; 30:10-12. [PMID: 27804227 DOI: 10.1111/pcmr.12551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 10/24/2016] [Accepted: 10/26/2016] [Indexed: 01/09/2023]
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Mahanty S, Ravichandran K, Chitirala P, Prabha J, Jani RA, Setty SRG. Rab9A is required for delivery of cargo from recycling endosomes to melanosomes. Pigment Cell Melanoma Res 2016; 29:43-59. [PMID: 26527546 PMCID: PMC4690521 DOI: 10.1111/pcmr.12434] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 09/19/2015] [Accepted: 10/15/2015] [Indexed: 01/02/2023]
Abstract
Melanosomes are a type of lysosome-related organelle that is commonly defective in Hermansky–Pudlak syndrome. Biogenesis of melanosomes is regulated by BLOC-1, -2, -3, or AP-1, -3 complexes, which mediate cargo transport from recycling endosomes to melanosomes. Although several Rab GTPases have been shown to regulate these trafficking steps, the precise role of Rab9A remains unknown. Here, we found that a cohort of Rab9A associates with the melanosomes and its knockdown in melanocytes results in hypopigmented melanosomes due to mistargeting of melanosomal proteins to lysosomes. In addition, the Rab9A-depletion phenotype resembles Rab38/32-inactivated or BLOC-3-deficient melanocytes, suggesting that Rab9A works in line with BLOC-3 and Rab38/32 during melanosome cargo transport. Furthermore, silencing of Rab9A, Rab38/32 or its effector VARP, or BLOC-3-deficiency in melanocytes decreased the length of STX13-positive recycling endosomal tubules and targeted the SNARE to lysosomes. This result indicates a defect in directing recycling endosomal tubules to melanosomes. Thus, Rab9A and its co-regulatory GTPases control STX13-mediated cargo delivery to maturing melanosomes.
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Affiliation(s)
- Sarmistha Mahanty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Keerthana Ravichandran
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Praneeth Chitirala
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Jyothi Prabha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Riddhi Atul Jani
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
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Ripoll L, Heiligenstein X, Raposo G, Delevoye C. Illuminating the dark side of recycling endosomes. Cell Cycle 2016; 15:1309-10. [PMID: 27184333 DOI: 10.1080/15384101.2016.1160682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Léa Ripoll
- a Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments , Paris , France
| | - Xavier Heiligenstein
- a Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments , Paris , France
| | - Graça Raposo
- a Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments , Paris , France.,b Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA) , Paris , France
| | - Cédric Delevoye
- a Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments , Paris , France.,b Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA) , Paris , France
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55
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Abstract
Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains unknown. Here, we show that TPC2 is expressed in melanocytes and localizes to the melanosome-limiting membrane and, to a lesser extent, to endolysosomal compartments by confocal fluorescence and immunogold electron microscopy. Immunomagnetic isolation of TPC2-containing organelles confirmed its coresidence with melanosomal markers. TPCN2 knockout by means of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 gene editing elicited a dramatic increase in pigment content in MNT-1 melanocytic cells. This effect was rescued by transient expression of TPC2-GFP. Consistently, siRNA-mediated knockdown of TPC2 also caused a substantial increase in melanin content in both MNT-1 cells and primary human melanocytes. Using a newly developed genetically encoded pH sensor targeted to melanosomes, we determined that the melanosome lumen in TPC2-KO MNT-1 cells and primary melanocytes subjected to TPC2 knockdown is less acidic than in control cells. Fluorescence and electron microscopy analysis revealed that TPC2-KO MNT-1 cells have significantly larger melanosomes than control cells, but the number of organelles is unchanged. TPC2 likely regulates melanosomes pH and size by mediating Ca(2+) release from the organelle, which is decreased in TPC2-KO MNT-1 cells, as determined with the Ca(2+) sensor tyrosinase-GCaMP6. Thus, our data show that TPC2 regulates pigmentation through two fundamental determinants of melanosome function: pH and size.
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56
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Admoni-Elisha L, Nakdimon I, Shteinfer A, Prezma T, Arif T, Arbel N, Melkov A, Zelichov O, Levi I, Shoshan-Barmatz V. Novel Biomarker Proteins in Chronic Lymphocytic Leukemia: Impact on Diagnosis, Prognosis and Treatment. PLoS One 2016; 11:e0148500. [PMID: 27078856 PMCID: PMC4831809 DOI: 10.1371/journal.pone.0148500] [Citation(s) in RCA: 11] [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: 09/06/2015] [Accepted: 01/19/2016] [Indexed: 12/31/2022] Open
Abstract
In many cancers, cells undergo re-programming of metabolism, cell survival and anti-apoptotic defense strategies, with the proteins mediating this reprogramming representing potential biomarkers. Here, we searched for novel biomarker proteins in chronic lymphocytic leukemia (CLL) that can impact diagnosis, treatment and prognosis by comparing the protein expression profiles of peripheral blood mononuclear cells from CLL patients and healthy donors using specific antibodies, mass spectrometry and binary logistic regression analyses and other bioinformatics tools. Mass spectrometry (LC-HR-MS/MS) analysis identified 1,360 proteins whose expression levels were modified in CLL-derived lymphocytes. Some of these proteins were previously connected to different cancer types, including CLL, while four other highly expressed proteins were not previously reported to be associated with cancer, and here, for the first time, DDX46 and AK3 are linked to CLL. Down-regulation expression of two of these proteins resulted in cell growth inhibition. High DDX46 expression levels were associated with shorter survival of CLL patients and thus can serve as a prognosis marker. The proteins with modified expression include proteins involved in RNA splicing and translation and particularly mitochondrial proteins involved in apoptosis and metabolism. Thus, we focused on several metabolism- and apoptosis-modulating proteins, particularly on the voltage-dependent anion channel 1 (VDAC1), regulating both metabolism and apoptosis. Expression levels of Bcl-2, VDAC1, MAVS, AIF and SMAC/Diablo were markedly increased in CLL-derived lymphocytes. VDAC1 levels were highly correlated with the amount of CLL-cancerous CD19+/CD5+ cells and with the levels of all other apoptosis-modulating proteins tested. Binary logistic regression analysis demonstrated the ability to predict probability of disease with over 90% accuracy. Finally, based on the changes in the levels of several proteins in CLL patients, as revealed from LC-HR-MS/MS, we could distinguish between patients in a stable disease state and those who would be later transferred to anti-cancer treatments. The over-expressed proteins can thus serve as potential biomarkers for early diagnosis, prognosis, new targets for CLL therapy, and treatment guidance of CLL, forming the basis for personalized therapy.
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MESH Headings
- Aged
- Biomarkers, Tumor/blood
- Biomarkers, Tumor/genetics
- Blotting, Western
- Chromatography, Liquid
- Female
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/blood
- Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis
- Leukocytes, Mononuclear/metabolism
- Male
- Prognosis
- Proteome/analysis
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Tandem Mass Spectrometry/methods
- Tumor Cells, Cultured
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Affiliation(s)
- Lee Admoni-Elisha
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Itay Nakdimon
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Anna Shteinfer
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Tal Prezma
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Tasleem Arif
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Nir Arbel
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Anna Melkov
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Ori Zelichov
- Department of Hematology, Soroka University Medical Center and the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Itai Levi
- Department of Hematology, Soroka University Medical Center and the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
- * E-mail:
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57
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Westmoreland D, Shaw M, Grimes W, Metcalf DJ, Burden JJ, Gomez K, Knight AE, Cutler DF. Super-resolution microscopy as a potential approach to diagnosis of platelet granule disorders. J Thromb Haemost 2016; 14:839-49. [PMID: 26806224 PMCID: PMC4982064 DOI: 10.1111/jth.13269] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 01/06/2016] [Accepted: 01/12/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Many platelet functions are dependent on bioactive molecules released from their granules. Deficiencies of these granules in number, shape or content are associated with bleeding. The small size of these granules is such that imaging them for diagnosis has traditionally required electron microscopy. However, recently developed super-resolution microscopes provide sufficient spatial resolution to effectively image platelet granules. When combined with automated image analysis, these methods provide a quantitative, unbiased, rapidly acquired dataset that can readily and reliably reveal differences in platelet granules between individuals. OBJECTIVE To demonstrate the ability of structured illumination microscopy (SIM) to efficiently differentiate between healthy volunteers and three patients with Hermansky-Pudlak syndrome. METHODS Blood samples were taken from three patients with Hermansky-Pudlak syndrome and seven controls. Patients 1-3 have gene defects in HPS1, HPS6 and HPS5, respectively; all controls were healthy volunteers. Platelet-rich plasma was isolated from blood and the platelets fixed, stained for CD63 and processed for analysis by immunofluorescence microscopy, using a custom-built SIM microscope. RESULTS SIM can successfully resolve CD63-positive structures in fixed platelets. A determination of the number of CD63-positive structures per platelet allowed us to conclude that each patient was significantly different from all of the controls with 99% confidence. CONCLUSIONS A super-resolution imaging approach is effective and rapid in objectively differentiating between patients with a platelet bleeding disorder and healthy volunteers. CD63 is a useful marker for predicting Hermansky-Pudlak syndrome and could be used in the diagnosis of patients suspected of other platelet granule disorders.
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Affiliation(s)
- D Westmoreland
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Endothelial Cell Biology Laboratory, London, UK
| | - M Shaw
- Analytical Science Division, National Physical Laboratory, Teddington, Middlesex, London, UK
| | - W Grimes
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Endothelial Cell Biology Laboratory, London, UK
- Imaging Informatics Division, Bioinformatics Institute, Singapore, Singapore
| | | | - J J Burden
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Electron Microscopy Laboratory, London, UK
| | - K Gomez
- Katherine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK
| | - A E Knight
- Analytical Science Division, National Physical Laboratory, Teddington, Middlesex, London, UK
| | - D F Cutler
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Endothelial Cell Biology Laboratory, London, UK
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58
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Delevoye C, Heiligenstein X, Ripoll L, Gilles-Marsens F, Dennis MK, Linares RA, Derman L, Gokhale A, Morel E, Faundez V, Marks MS, Raposo G. BLOC-1 Brings Together the Actin and Microtubule Cytoskeletons to Generate Recycling Endosomes. Curr Biol 2015; 26:1-13. [PMID: 26725201 DOI: 10.1016/j.cub.2015.11.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/15/2015] [Accepted: 11/09/2015] [Indexed: 12/18/2022]
Abstract
Recycling endosomes consist of a tubular network that emerges from vacuolar sorting endosomes and diverts cargoes toward the cell surface, the Golgi, or lysosome-related organelles. How recycling tubules are formed remains unknown. We show that recycling endosome biogenesis requires the protein complex BLOC-1. Mutations in BLOC-1 subunits underlie an inherited disorder characterized by albinism, the Hermansky-Pudlak Syndrome, and are associated with schizophrenia risk. We show here that BLOC-1 coordinates the kinesin KIF13A-dependent pulling of endosomal tubules along microtubules to the Annexin A2/actin-dependent stabilization and detachment of recycling tubules. These components cooperate to extend, stabilize and form tubular endosomal carriers that function in cargo recycling and in the biogenesis of pigment granules in melanocytic cells. By shaping recycling endosomal tubules, our data reveal that dysfunction of the BLOC-1-KIF13A-Annexin A2 molecular network underlies the pathophysiology of neurological and pigmentary disorders.
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Affiliation(s)
- Cédric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 75005 Paris, France.
| | - Xavier Heiligenstein
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
| | - Léa Ripoll
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
| | - Floriane Gilles-Marsens
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
| | - Megan K Dennis
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ricardo A Linares
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Laura Derman
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
| | - Avanti Gokhale
- Department of Cell Biology and the Center for Social Translational Neuroscience, Emory University, Atlanta, GA 30322, USA
| | - Etienne Morel
- INSERM U1151-CNRS UMR 8253, Institut Necker Enfants-Malades (INEM) Université, Paris Descartes-Sorbonne Paris Cité Paris, 75993 Paris Cedex 14, France
| | - Victor Faundez
- Department of Cell Biology and the Center for Social Translational Neuroscience, Emory University, Atlanta, GA 30322, USA
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Graça Raposo
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 75005 Paris, France
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59
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Marubashi S, Shimada H, Fukuda M, Ohbayashi N. RUTBC1 Functions as a GTPase-activating Protein for Rab32/38 and Regulates Melanogenic Enzyme Trafficking in Melanocytes. J Biol Chem 2015; 291:1427-40. [PMID: 26620560 DOI: 10.1074/jbc.m115.684043] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/06/2022] Open
Abstract
Two cell type-specific Rab proteins, Rab32 and Rab38 (Rab32/38), have been proposed as regulating the trafficking of melanogenic enzymes, including tyrosinase and tyrosinase-related protein 1 (Tyrp1), to melanosomes in melanocytes. Like other GTPases, Rab32/38 function as switch molecules that cycle between a GDP-bound inactive form and a GTP-bound active form; the cycle is thought to be regulated by an activating enzyme, guanine nucleotide exchange factor (GEF), and an inactivating enzyme, GTPase-activating protein (GAP), which stimulates the GTPase activity of Rab32/38. Although BLOC-3 has already been identified as a Rab32/38-specific GEF that regulates the trafficking of tyrosinase and Tyrp1, no physiological GAP for Rab32/38 in melanocytes has ever been identified, and it has remained unclear whether Rab32/38 is involved in the trafficking of dopachrome tautomerase, another melanogenic enzyme, in mouse melanocytes. In this study we investigated RUTBC1, which was originally characterized as a Rab9-binding protein and GAP for Rab32 and Rab33B in vitro, and the results demonstrated that RUTBC1 functions as a physiological GAP for Rab32/38 in the trafficking of all three melanogenic enzymes in mouse melanocytes. The results of this study also demonstrated the involvement of Rab9A in the regulation of the RUTBC1 localization and in the trafficking of all three melanogenic enzymes. We discovered that either excess activation or inactivation of Rab32/38 achieved by manipulating RUTBC1 inhibits the trafficking of all three melanogenic enzymes. These results collectively indicate that proper spatiotemporal regulation of Rab32/38 is essential for the trafficking of all three melanogenic enzymes in mouse melanocytes.
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Affiliation(s)
- Soujiro Marubashi
- From the Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan and
| | - Hikaru Shimada
- From the Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan and
| | - Mitsunori Fukuda
- From the Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan and
| | - Norihiko Ohbayashi
- From the Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan and the Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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60
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Rodriguez-Fernandez IA, Dell’Angelica EC. Identification of Atg2 and ArfGAP1 as Candidate Genetic Modifiers of the Eye Pigmentation Phenotype of Adaptor Protein-3 (AP-3) Mutants in Drosophila melanogaster. PLoS One 2015; 10:e0143026. [PMID: 26565960 PMCID: PMC4643998 DOI: 10.1371/journal.pone.0143026] [Citation(s) in RCA: 7] [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: 06/29/2015] [Accepted: 10/29/2015] [Indexed: 11/19/2022] Open
Abstract
The Adaptor Protein (AP)-3 complex is an evolutionary conserved, molecular sorting device that mediates the intracellular trafficking of proteins to lysosomes and related organelles. Genetic defects in AP-3 subunits lead to impaired biogenesis of lysosome-related organelles (LROs) such as mammalian melanosomes and insect eye pigment granules. In this work, we have performed a forward screening for genetic modifiers of AP-3 function in the fruit fly, Drosophila melanogaster. Specifically, we have tested collections of large multi-gene deletions–which together covered most of the autosomal chromosomes–to identify chromosomal regions that, when deleted in single copy, enhanced or ameliorated the eye pigmentation phenotype of two independent AP-3 subunit mutants. Fine-mapping led us to define two non-overlapping, relatively small critical regions within fly chromosome 3. The first critical region included the Atg2 gene, which encodes a conserved protein involved in autophagy. Loss of one functional copy of Atg2 ameliorated the pigmentation defects of mutants in AP-3 subunits as well as in two other genes previously implicated in LRO biogenesis, namely Blos1 and lightoid, and even increased the eye pigment content of wild-type flies. The second critical region included the ArfGAP1 gene, which encodes a conserved GTPase-activating protein with specificity towards GTPases of the Arf family. Loss of a single functional copy of the ArfGAP1 gene ameliorated the pigmentation phenotype of AP-3 mutants but did not to modify the eye pigmentation of wild-type flies or mutants in Blos1 or lightoid. Strikingly, loss of the second functional copy of the gene did not modify the phenotype of AP-3 mutants any further but elicited early lethality in males and abnormal eye morphology when combined with mutations in Blos1 and lightoid, respectively. These results provide genetic evidence for new functional links connecting the machinery for biogenesis of LROs with molecules implicated in autophagy and small GTPase regulation.
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Affiliation(s)
- Imilce A. Rodriguez-Fernandez
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Esteban C. Dell’Angelica
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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61
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Increased dysbindin-1B isoform expression in schizophrenia and its propensity in aggresome formation. Cell Discov 2015; 1:15032. [PMID: 27462430 PMCID: PMC4860834 DOI: 10.1038/celldisc.2015.32] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 09/13/2015] [Indexed: 02/06/2023] Open
Abstract
Genetic variations in the human dysbindin-1 gene (DTNBP1) have been associated with schizophrenia. As a result of alternative splicing, the human DTNBP1 gene generates at least three distinct protein isoforms, dysbindin-1A, -1B and -1C. Significant effort has focused on dysbindin-1A, an important player in multiple steps of neurodevelopment. However, the other isoforms, dysbindin-1B and dysbindin-1C have not been well characterized. Nor have been associated with human diseases. Here we report an increase in expression of DTNBP1b mRNA in patients with paranoid schizophrenia as compared with healthy controls. A single-nucleotide polymorphism located in intron 9, rs117610176, has been identified and associated with paranoid schizophrenia, and its C allele leads to an increase of DTNBP1b mRNA splicing. Our data show that different dysbindin splicing isoforms exhibit distinct subcellular distribution, suggesting their distinct functional activities. Dysbindin-1B forms aggresomes at the perinuclear region, whereas dysbindin-1A and -1C proteins exhibit diffused patterns in the cytoplasm. Dysbindin-1A interacts with dysbindin-1B, getting recruited to the aggresome structure when co-expressed with dysbindin-1B. Moreover, cortical neurons over-expressing dysbindin-1B show reduction in neurite outgrowth, suggesting that dysbindin-1B may interfere with dysbindin-1A function in a dominant-negative manner. Taken together, our study uncovers a previously unknown association of DTNBP1b expression with schizophrenia in addition to its distinct biochemical and functional properties.
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62
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Pu J, Schindler C, Jia R, Jarnik M, Backlund P, Bonifacino JS. BORC, a multisubunit complex that regulates lysosome positioning. Dev Cell 2015; 33:176-88. [PMID: 25898167 DOI: 10.1016/j.devcel.2015.02.011] [Citation(s) in RCA: 252] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 01/14/2015] [Accepted: 02/11/2015] [Indexed: 01/10/2023]
Abstract
The positioning of lysosomes within the cytoplasm is emerging as a critical determinant of many lysosomal functions. Here we report the identification of a multisubunit complex named BORC that regulates lysosome positioning. BORC comprises eight subunits, some of which are shared with the BLOC-1 complex involved in the biogenesis of lysosome-related organelles, and the others of which are products of previously uncharacterized open reading frames. BORC associates peripherally with the lysosomal membrane, where it functions to recruit the small GTPase Arl8. This initiates a chain of interactions that promotes the kinesin-dependent movement of lysosomes toward the plus ends of microtubules in the peripheral cytoplasm. Interference with BORC or other components of this pathway results in collapse of the lysosomal population into the pericentriolar region. In turn, this causes reduced cell spreading and migration, highlighting the importance of BORC-dependent centrifugal transport for non-degradative functions of lysosomes.
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Affiliation(s)
- Jing Pu
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christina Schindler
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rui Jia
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michal Jarnik
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter Backlund
- Biomedical Mass Spectrometry Facility, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Juan S Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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Dennis MK, Mantegazza AR, Snir OL, Tenza D, Acosta-Ruiz A, Delevoye C, Zorger R, Sitaram A, de Jesus-Rojas W, Ravichandran K, Rux J, Sviderskaya EV, Bennett DC, Raposo G, Marks MS, Setty SRG. BLOC-2 targets recycling endosomal tubules to melanosomes for cargo delivery. ACTA ACUST UNITED AC 2015; 209:563-77. [PMID: 26008744 PMCID: PMC4442807 DOI: 10.1083/jcb.201410026] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Quantitative analyses of melanosome cargo localization and trafficking and of endosomal membrane dynamics in immortalized melanocytes from mouse Hermansky–Pudlak syndrome models show that BLOC-2 functions to specify the delivery of recycling endosomal cargo transport intermediates to maturing melanosomes. Hermansky–Pudlak syndrome (HPS) is a group of disorders characterized by the malformation of lysosome-related organelles, such as pigment cell melanosomes. Three of nine characterized HPS subtypes result from mutations in subunits of BLOC-2, a protein complex with no known molecular function. In this paper, we exploit melanocytes from mouse HPS models to place BLOC-2 within a cargo transport pathway from recycling endosomal domains to maturing melanosomes. In BLOC-2–deficient melanocytes, the melanosomal protein TYRP1 was largely depleted from pigment granules and underwent accelerated recycling from endosomes to the plasma membrane and to the Golgi. By live-cell imaging, recycling endosomal tubules of wild-type melanocytes made frequent and prolonged contacts with maturing melanosomes; in contrast, tubules from BLOC-2–deficient cells were shorter in length and made fewer, more transient contacts with melanosomes. These results support a model in which BLOC-2 functions to direct recycling endosomal tubular transport intermediates to maturing melanosomes and thereby promote cargo delivery and optimal pigmentation.
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Affiliation(s)
- Megan K Dennis
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Adriana R Mantegazza
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Olivia L Snir
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Danièle Tenza
- Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France
| | - Amanda Acosta-Ruiz
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Cédric Delevoye
- Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France
| | - Richard Zorger
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Anand Sitaram
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Wilfredo de Jesus-Rojas
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Keerthana Ravichandran
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - John Rux
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 In Silico Molecular, LLC, Blue Bell, PA 19422
| | - Elena V Sviderskaya
- Molecular Cell Sciences Research Centre, St. George's, University of London, London SW17 0RE, England, UK
| | - Dorothy C Bennett
- Molecular Cell Sciences Research Centre, St. George's, University of London, London SW17 0RE, England, UK
| | - Graça Raposo
- Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France Institut Curie, Centre de Recherche; Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 144; and Cell and Tissue Imaging Facility, Centre National de la Recherche Scientifique UMR144, Paris F-75248, France
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104
| | - Subba Rao Gangi Setty
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Penn Vision Research Center, University of Pennsylvania, Philadelphia, PA 19104 Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
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Abstract
Dysbindin is a schizophrenia susceptibility factor and subunit of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) required for lysosome-related organelle biogenesis, and in neurons, synaptic vesicle assembly, neurotransmission, and plasticity. Protein networks, or interactomes, downstream of dysbindin/BLOC-1 remain partially explored despite their potential to illuminate neurodevelopmental disorder mechanisms. Here, we conducted a proteome-wide search for polypeptides whose cellular content is sensitive to dysbindin/BLOC-1 loss of function. We identified components of the vesicle fusion machinery as factors downregulated in dysbindin/BLOC-1 deficiency in neuroectodermal cells and iPSC-derived human neurons, among them the N-ethylmaleimide-sensitive factor (NSF). Human dysbindin/BLOC-1 coprecipitates with NSF and vice versa, and both proteins colocalized in a Drosophila model synapse. To test the hypothesis that NSF and dysbindin/BLOC-1 participate in a pathway-regulating synaptic function, we examined the role for NSF in dysbindin/BLOC-1-dependent synaptic homeostatic plasticity in Drosophila. As previously described, we found that mutations in dysbindin precluded homeostatic synaptic plasticity elicited by acute blockage of postsynaptic receptors. This dysbindin mutant phenotype is fully rescued by presynaptic expression of either dysbindin or Drosophila NSF. However, neither reduction of NSF alone or in combination with dysbindin haploinsufficiency impaired homeostatic synaptic plasticity. Our results demonstrate that dysbindin/BLOC-1 expression defects result in altered cellular content of proteins of the vesicle fusion apparatus and therefore influence synaptic plasticity.
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Di Giovanni J, Sheng ZH. Regulation of synaptic activity by snapin-mediated endolysosomal transport and sorting. EMBO J 2015; 34:2059-77. [PMID: 26108535 DOI: 10.15252/embj.201591125] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/29/2015] [Indexed: 11/09/2022] Open
Abstract
Recycling synaptic vesicles (SVs) transit through early endosomal sorting stations, which raises a fundamental question: are SVs sorted toward endolysosomal pathways? Here, we used snapin mutants as tools to assess how endolysosomal sorting and trafficking impact presynaptic activity in wild-type and snapin(-/-) neurons. Snapin acts as a dynein adaptor that mediates the retrograde transport of late endosomes (LEs) and interacts with dysbindin, a subunit of the endosomal sorting complex BLOC-1. Expressing dynein-binding defective snapin mutants induced SV accumulation at presynaptic terminals, mimicking the snapin(-/-) phenotype. Conversely, over-expressing snapin reduced SV pool size by enhancing SV trafficking to the endolysosomal pathway. Using a SV-targeted Ca(2+) sensor, we demonstrate that snapin-dysbindin interaction regulates SV positional priming through BLOC-1/AP-3-dependent sorting. Our study reveals a bipartite regulation of presynaptic activity by endolysosomal trafficking and sorting: LE transport regulates SV pool size, and BLOC-1/AP-3-dependent sorting fine-tunes the Ca(2+) sensitivity of SV release. Therefore, our study provides new mechanistic insights into the maintenance and regulation of SV pool size and synchronized SV fusion through snapin-mediated LE trafficking and endosomal sorting.
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Affiliation(s)
- Jerome Di Giovanni
- Synaptic Functions Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Zu-Hang Sheng
- Synaptic Functions Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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66
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Guo H, Zhang J, Zhang X, Wang Y, Yu H, Yin X, Li J, Du P, Plumas J, Chaperot L, Chen J, Su L, Liu Y, Zhang L. SCARB2/LIMP-2 Regulates IFN Production of Plasmacytoid Dendritic Cells by Mediating Endosomal Translocation of TLR9 and Nuclear Translocation of IRF7. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:4737-49. [PMID: 25862818 PMCID: PMC4506778 DOI: 10.4049/jimmunol.1402312] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 03/14/2015] [Indexed: 12/15/2022]
Abstract
Scavenger receptor class B, member 2 (SCARB2) is essential for endosome biogenesis and reorganization and serves as a receptor for both β-glucocerebrosidase and enterovirus 71. However, little is known about its function in innate immune cells. In this study, we show that, among human peripheral blood cells, SCARB2 is most highly expressed in plasmacytoid dendritic cells (pDCs), and its expression is further upregulated by CpG oligodeoxynucleotide stimulation. Knockdown of SCARB2 in pDC cell line GEN2.2 dramatically reduces CpG-induced type I IFN production. Detailed studies reveal that SCARB2 localizes in late endosome/lysosome of pDCs, and knockdown of SCARB2 does not affect CpG oligodeoxynucleotide uptake but results in the retention of TLR9 in the endoplasmic reticulum and an impaired nuclear translocation of IFN regulatory factor 7. The IFN-I production by TLR7 ligand stimulation is also impaired by SCARB2 knockdown. However, SCARB2 is not essential for influenza virus or HSV-induced IFN-I production. These findings suggest that SCARB2 regulates TLR9-dependent IFN-I production of pDCs by mediating endosomal translocation of TLR9 and nuclear translocation of IFN regulatory factor 7.
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Affiliation(s)
- Hao Guo
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; University of Chinese Academy of Sciences, Beijing, BJ 100080, China
| | - Jialong Zhang
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China
| | - Xuyuan Zhang
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; University of Chinese Academy of Sciences, Beijing, BJ 100080, China
| | - Yanbing Wang
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China
| | - Haisheng Yu
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; University of Chinese Academy of Sciences, Beijing, BJ 100080, China
| | - Xiangyun Yin
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; University of Chinese Academy of Sciences, Beijing, BJ 100080, China
| | - Jingyun Li
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; University of Chinese Academy of Sciences, Beijing, BJ 100080, China
| | - Peishuang Du
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China
| | - Joel Plumas
- Department of Research and Development, Etablissement Français du Sang Rhône-Alpes Grenoble, La Tronche 38701, France
| | - Laurence Chaperot
- Department of Research and Development, Etablissement Français du Sang Rhône-Alpes Grenoble, La Tronche 38701, France
| | - Jianzhu Chen
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Lishan Su
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; and
| | - Yongjun Liu
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China; Baylor Institute for Immunology Research, Baylor Research Institute, Dallas, TX 75204
| | - Liguo Zhang
- Key Laboratory of Immunity and Infection, Institute of Biophysics, Chinese Academy of Sciences, Beijing, BJ 100101, China;
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Rana M, Lachmann J, Ungermann C. Identification of a Rab GTPase-activating protein cascade that controls recycling of the Rab5 GTPase Vps21 from the vacuole. Mol Biol Cell 2015; 26:2535-49. [PMID: 25971802 PMCID: PMC4571306 DOI: 10.1091/mbc.e15-02-0062] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/06/2015] [Indexed: 01/30/2023] Open
Abstract
Endocytic transport depends on two consecutive Rabs, Vps21 (Rab5 in metazoans) and Ypt7 (Rab7), which bind to effectors on early and late endosomes. This study now shows that inactivation of Vps21 via its GTPase-activating protein (GAP) Msb3 requires both Ypt7 and fusion with the vacuole. The data suggest an endosomal GAP cascade that includes the effector of Ypt7. Transport within the endocytic pathway depends on a consecutive function of the endosomal Rab5 and the late endosomal/lysosomal Rab7 GTPases to promote membrane recycling and fusion in the context of endosomal maturation. We previously identified the hexameric BLOC-1 complex as an effector of the yeast Rab5 Vps21, which also recruits the GTPase-activating protein (GAP) Msb3. This raises the question of when Vps21 is inactivated on endosomes. We provide evidence for a Rab cascade in which activation of the Rab7 homologue Ypt7 triggers inactivation of Vps21. We find that the guanine nucleotide exchange factor (GEF) of Ypt7 (the Mon1-Ccz1 complex) and BLOC-1 both localize to the same endosomes. Overexpression of Mon1-Ccz1, which generates additional Ypt7-GTP, or overexpression of activated Ypt7 promotes relocalization of Vps21 from endosomes to the endoplasmic reticulum (ER), which is indicative of Vps21 inactivation. This ER relocalization is prevented by loss of either BLOC-1 or Msb3, but it also occurs in mutants lacking endosome–vacuole fusion machinery such as the HOPS tethering complex, an effector of Ypt7. Importantly, BLOC-1 interacts with the HOPS on vacuoles, suggesting a direct Ypt7-dependent cross-talk. These data indicate that efficient Vps21 recycling requires both Ypt7 and endosome–vacuole fusion, thus suggesting extended control of a GAP cascade beyond Rab interactions.
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Affiliation(s)
- Meenakshi Rana
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Jens Lachmann
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
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Zhao Z, Xu J, Chen J, Kim S, Reimers M, Bacanu SA, Yu H, Liu C, Sun J, Wang Q, Jia P, Xu F, Zhang Y, Kendler KS, Peng Z, Chen X. Transcriptome sequencing and genome-wide association analyses reveal lysosomal function and actin cytoskeleton remodeling in schizophrenia and bipolar disorder. Mol Psychiatry 2015; 20:563-572. [PMID: 25113377 PMCID: PMC4326626 DOI: 10.1038/mp.2014.82] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 05/23/2014] [Accepted: 06/17/2014] [Indexed: 12/20/2022]
Abstract
Schizophrenia (SCZ) and bipolar disorder (BPD) are severe mental disorders with high heritability. Clinicians have long noticed the similarities of clinic symptoms between these disorders. In recent years, accumulating evidence indicates some shared genetic liabilities. However, what is shared remains elusive. In this study, we conducted whole transcriptome analysis of post-mortem brain tissues (cingulate cortex) from SCZ, BPD and control subjects, and identified differentially expressed genes in these disorders. We found 105 and 153 genes differentially expressed in SCZ and BPD, respectively. By comparing the t-test scores, we found that many of the genes differentially expressed in SCZ and BPD are concordant in their expression level (q⩽0.01, 53 genes; q⩽0.05, 213 genes; q⩽0.1, 885 genes). Using genome-wide association data from the Psychiatric Genomics Consortium, we found that these differentially and concordantly expressed genes were enriched in association signals for both SCZ (P<10(-7)) and BPD (P=0.029). To our knowledge, this is the first time that a substantially large number of genes show concordant expression and association for both SCZ and BPD. Pathway analyses of these genes indicated that they are involved in the lysosome, Fc gamma receptor-mediated phagocytosis, regulation of actin cytoskeleton pathways, along with several cancer pathways. Functional analyses of these genes revealed an interconnected pathway network centered on lysosomal function and the regulation of actin cytoskeleton. These pathways and their interacting network were principally confirmed by an independent transcriptome sequencing data set of the hippocampus. Dysregulation of lysosomal function and cytoskeleton remodeling has direct impacts on endocytosis, phagocytosis, exocytosis, vesicle trafficking, neuronal maturation and migration, neurite outgrowth and synaptic density and plasticity, and different aspects of these processes have been implicated in SCZ and BPD.
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Affiliation(s)
- Zhongming Zhao
- Departments of Biomedical Informatics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jiabao Xu
- Beijing Genomics Institute (BGI), Shenzhen, Guangdong, 518083, China
| | - Jingchun Chen
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Sanghyeon Kim
- Stanley Laboratory of Brain Research, 9800 Medical Center Drive, Rockville, MD 20850, USA
| | - Mark Reimers
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Silviu-Alin Bacanu
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Hui Yu
- Departments of Biomedical Informatics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Chunyu Liu
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60637, USA
| | - Jingchun Sun
- Departments of Biomedical Informatics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Quan Wang
- Departments of Biomedical Informatics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Peilin Jia
- Departments of Biomedical Informatics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Fengping Xu
- Beijing Genomics Institute (BGI), Shenzhen, Guangdong, 518083, China
| | - Yong Zhang
- Beijing Genomics Institute (BGI), Shenzhen, Guangdong, 518083, China
| | - Kenneth S. Kendler
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Zhiyu Peng
- Beijing Genomics Institute (BGI), Shenzhen, Guangdong, 518083, China
| | - Xiangning Chen
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
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70
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Lee SA, Kim SM, Suh BK, Sun HY, Park YU, Hong JH, Park C, Nguyen MD, Nagata KI, Yoo JY, Park SK. Disrupted-in-schizophrenia 1 (DISC1) regulates dysbindin function by enhancing its stability. J Biol Chem 2015; 290:7087-96. [PMID: 25635053 DOI: 10.1074/jbc.m114.614750] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Dysbindin and DISC1 are schizophrenia susceptibility factors playing roles in neuronal development. Here we show that the physical interaction between dysbindin and DISC1 is critical for the stability of dysbindin and for the process of neurite outgrowth. We found that DISC1 forms a complex with dysbindin and increases its stability in association with a reduction in ubiquitylation. Furthermore, knockdown of DISC1 or expression of a deletion mutant, DISC1 lacking amino acid residues 403-504 of DISC1 (DISC1(Δ403-504)), effectively decreased levels of endogenous dysbindin. Finally, the neurite outgrowth defect induced by knockdown of DISC1 was partially reversed by coexpression of dysbindin. Taken together, these results indicate that dysbindin and DISC1 form a physiologically functional complex that is essential for normal neurite outgrowth.
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Affiliation(s)
- Seol-Ae Lee
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Seong-Mo Kim
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Bo Kyoung Suh
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Hwa-Young Sun
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Young-Un Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Ji-Ho Hong
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Cana Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Minh Dang Nguyen
- the Hotchkiss Brain Institute, Departments of Clinical Neurosciences, Cell Biology and Anatomy, and Biochemistry and Molecular Biology, University of Calgary, Calgary T2N 4N1, Canada, and
| | - Koh-Ichi Nagata
- the Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Joo-Yeon Yoo
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Sang Ki Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea,
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71
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Kondo T, Namiki T, Coelho SG, Valencia JC, Hearing VJ. Oculocutaneous albinism: Developing novel antibodies targeting the proteins associated with OCA2 and OCA4. J Dermatol Sci 2015; 77:21-7. [DOI: 10.1016/j.jdermsci.2014.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 10/05/2014] [Accepted: 11/10/2014] [Indexed: 12/31/2022]
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Bultema JJ, Boyle JA, Malenke PB, Martin FE, Dell'Angelica EC, Cheney RE, Di Pietro SM. Myosin vc interacts with Rab32 and Rab38 proteins and works in the biogenesis and secretion of melanosomes. J Biol Chem 2014; 289:33513-28. [PMID: 25324551 DOI: 10.1074/jbc.m114.578948] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class V myosins are actin-based motors with conserved functions in vesicle and organelle trafficking. Herein we report the discovery of a function for Myosin Vc in melanosome biogenesis as an effector of melanosome-associated Rab GTPases. We isolated Myosin Vc in a yeast two-hybrid screening for proteins that interact with Rab38, a Rab protein involved in the biogenesis of melanosomes and other lysosome-related organelles. Rab38 and its close homolog Rab32 bind to Myosin Vc but not to Myosin Va or Myosin Vb. Binding depends on residues in the switch II region of Rab32 and Rab38 and regions of the Myosin Vc coiled-coil tail domain. Myosin Vc also interacts with Rab7a and Rab8a but not with Rab11, Rab17, and Rab27. Although Myosin Vc is not particularly abundant on pigmented melanosomes, its knockdown in MNT-1 melanocytes caused defects in the trafficking of integral membrane proteins to melanosomes with substantially increased surface expression of Tyrp1, nearly complete loss of Tyrp2, and significant Vamp7 mislocalization. Knockdown of Myosin Vc in MNT-1 cells more than doubled the abundance of pigmented melanosomes but did not change the number of unpigmented melanosomes. Together the data demonstrate a novel role for Myosin Vc in melanosome biogenesis and secretion.
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Affiliation(s)
- Jarred J Bultema
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, the Department of Chemistry and Biochemistry, University of Colorado, Colorado Springs, Colorado Springs, Colorado 80918
| | - Judith A Boyle
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Parker B Malenke
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Faye E Martin
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Esteban C Dell'Angelica
- the Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095, and
| | - Richard E Cheney
- the Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Santiago M Di Pietro
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523,
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Blank U, Madera-Salcedo IK, Danelli L, Claver J, Tiwari N, Sánchez-Miranda E, Vázquez-Victorio G, Ramírez-Valadez KA, Macias-Silva M, González-Espinosa C. Vesicular trafficking and signaling for cytokine and chemokine secretion in mast cells. Front Immunol 2014; 5:453. [PMID: 25295038 PMCID: PMC4170139 DOI: 10.3389/fimmu.2014.00453] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/05/2014] [Indexed: 12/31/2022] Open
Abstract
Upon activation mast cells (MCs) secrete numerous inflammatory compounds stored in their cytoplasmic secretory granules by a process called anaphylactic degranulation, which is responsible for type I hypersensitivity responses. Prestored mediators include histamine and MC proteases but also some cytokines and growth factors making them available within minutes for a maximal biological effect. Degranulation is followed by the de novo synthesis of lipid mediators such as prostaglandins and leukotrienes as well as a vast array of cytokines, chemokines, and growth factors, which are responsible for late phase inflammatory responses. While lipid mediators diffuse freely out of the cell through lipid bilayers, both anaphylactic degranulation and secretion of cytokines, chemokines, and growth factors depends on highly regulated vesicular trafficking steps that occur along the secretory pathway starting with the translocation of proteins to the endoplasmic reticulum. Vesicular trafficking in MCs also intersects with endocytic routes, notably to form specialized cytoplasmic granules called secretory lysosomes. Some of the mediators like histamine reach granules via specific vesicular monoamine transporters directly from the cytoplasm. In this review, we try to summarize the available data on granule biogenesis and signaling events that coordinate the complex steps that lead to the release of the inflammatory mediators from the various vesicular carriers in MCs.
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Affiliation(s)
- Ulrich Blank
- INSERM UMRS 1149 , Paris , France ; CNRS ERL8252 , Paris , France ; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX , Paris , France
| | - Iris Karina Madera-Salcedo
- INSERM UMRS 1149 , Paris , France ; CNRS ERL8252 , Paris , France ; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX , Paris , France
| | - Luca Danelli
- INSERM UMRS 1149 , Paris , France ; CNRS ERL8252 , Paris , France ; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX , Paris , France
| | - Julien Claver
- INSERM UMRS 1149 , Paris , France ; CNRS ERL8252 , Paris , France ; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX , Paris , France
| | - Neeraj Tiwari
- INSERM UMRS 1149 , Paris , France ; CNRS ERL8252 , Paris , France ; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX , Paris , France
| | | | - Genaro Vázquez-Victorio
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City , México
| | | | - Marina Macias-Silva
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City , México
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74
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Li K, Yang L, Zhang C, Niu Y, Li W, Liu JJ. HPS6 interacts with dynactin p150Glued to mediate retrograde trafficking and maturation of lysosomes. J Cell Sci 2014; 127:4574-88. [PMID: 25189619 DOI: 10.1242/jcs.141978] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Hermansky-Pudlak syndrome 6 protein (HPS6) has originally been identified as a subunit of the BLOC-2 protein complex that is involved in the biogenesis of lysosome-related organelles. Here, we demonstrate that HPS6 directly interacts with the dynactin p150(Glued) subunit of the dynein-dynactin motor complex and acts as cargo adaptor for the retrograde motor to mediate the transport of lysosomes from the cell periphery to the perinuclear region. Small interfering RNA (siRNA)-mediated knockdown of HPS6 in HeLa cells not only partially blocks centripetal movement of lysosomes but also causes delay in lysosome-mediated protein degradation. Moreover, lysosomal acidification and degradative capacity, as well as fusion between late endosomes and/or multivesicular bodies and lysosomes are also impaired when HPS6 is depleted, suggesting that perinuclear positioning mediated by the dynein-dynactin motor complex is required for lysosome maturation and activity. Our results have uncovered a so-far-unknown specific role for HPS6 in the spatial distribution of the lysosomal compartment.
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Affiliation(s)
- Ke Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100039, China
| | - Lin Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Cheng Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yang Niu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100039, China
| | - Wei Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jia-Jia Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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75
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Zhang A, He X, Zhang L, Yang L, Woodman P, Li W. Biogenesis of lysosome-related organelles complex-1 subunit 1 (BLOS1) interacts with sorting nexin 2 and the endosomal sorting complex required for transport-I (ESCRT-I) component TSG101 to mediate the sorting of epidermal growth factor receptor into endosomal compartments. J Biol Chem 2014; 289:29180-94. [PMID: 25183008 DOI: 10.1074/jbc.m114.576561] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biogenesis of lysosome-related organelles complex-1 (BLOC-1) is a component of the molecular machinery required for the biogenesis of specialized organelles and lysosomal targeting of cargoes via the endosomal to lysosomal trafficking pathway. BLOS1, one subunit of BLOC-1, is implicated in lysosomal trafficking of membrane proteins. We found that the degradation and trafficking of epidermal growth factor receptor (EGFR) were delayed in BLOS1 knockdown cells, which were rescued through BLOS1 overexpression. A key feature to the delayed EGFR degradation is the accumulation of endolysosomes in BLOS1 knockdown cells or BLOS1 knock-out mouse embryonic fibroblasts. BLOS1 interacted with SNX2 (a retromer subunit) and TSG101 (an endosomal sorting complex required for transport subunit-I) to mediate EGFR lysosomal trafficking. These results suggest that coordination of the endolysosomal trafficking proteins is important for proper targeting of EGFR to lysosomes.
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Affiliation(s)
- Aili Zhang
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China, the University of Chinese Academy of Sciences, Beijing 100039, China, and
| | - Xin He
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ling Zhang
- the Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Lin Yang
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Philip Woodman
- the Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Wei Li
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China,
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76
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Melanocytic galectin-3 is associated with tyrosinase-related protein-1 and pigment biosynthesis. J Invest Dermatol 2014; 135:202-211. [PMID: 25054620 PMCID: PMC4268419 DOI: 10.1038/jid.2014.315] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 03/13/2014] [Accepted: 04/08/2014] [Indexed: 02/04/2023]
Abstract
Galectin-3 is a family member of the carbohydrate-binding proteins widely expressed by many cell types and exhibits multiple cellular functions. We demonstrate that melanocytes express galectin-3, which is predominantly localized to the cell body peripherally along the Golgi zone. Downregulation of galectin-3 in human melanocytes using short hairpin RNA technology resulted in the reduction of both melanin synthesis and expression/activity of tyrosinase-related protein-1 (Tyrp-1). In the cell body, galectin-3 colocalizes with melanosome-destined cargo, specifically tyrosinase and Tyrp-1. We studied melanocytes cultured from patients with forms of Hermansky-Pudlak syndrome (HPS) containing defects in trafficking steps governed by biogenesis of lysosome-related organelle complex-2 (BLOC-2) (HPS-5), BLOC-3 (HPS-1), and adaptin-3 (HPS-2). We found that galectin-3 expression mimicked the defective expression of the tyrosinase cargo in dendrites of HPS-5 melanocytes, but it was not altered in HPS-1 or HPS-2 melanocytes. In addition, galectin-3 colocalized predominantly with the HPS-5 component of BLOC-2 in normal human melanocytes. These data indicate that galectin-3 is a regulatory component in melanin synthesis affecting the expression of Tyrp-1.
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77
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Abstract
The counterbalancing action of the endocytosis and secretory pathways maintains a dynamic equilibrium that regulates the composition of the plasma membrane, allowing it to maintain homeostasis and to change rapidly in response to alterations in the extracellular environment and/or intracellular metabolism. These pathways are intimately integrated with intercellular signaling systems and play critical roles in all cells. Studies in Caenorhabditis elegans have revealed diverse roles of membrane trafficking in physiology and development and have also provided molecular insight into the fundamental mechanisms that direct cargo sorting, vesicle budding, and membrane fisson and fusion. In this review, we summarize progress in understanding membrane trafficking mechanisms derived from work in C. elegans, focusing mainly on work done in non-neuronal cell-types, especially the germline, early embryo, coelomocytes, and intestine.
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Affiliation(s)
- Ken Sato
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371-8512, Japan. ;
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78
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Wei AH, He X, Li W. Hypopigmentation in Hermansky-Pudlak syndrome. J Dermatol 2014; 40:325-9. [PMID: 23668540 DOI: 10.1111/1346-8138.12025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 09/20/2012] [Indexed: 11/28/2022]
Abstract
Hermansky-Pudlak syndrome (HPS) is characterized by oculocutaneous albinism, bleeding tendency, and ceroid deposition which often leads to death in midlife. Currently, nine genes have been identified as causative for HPS in humans. Hypopigmentation is the prominent feature of HPS, attributable to the disrupted biogenesis of melanosome, a member of the lysosome-related organelle (LRO) family. Current understanding of the cargo transporting mechanisms into the melanosomes expands our knowledge of the pathogenesis of hypopigmentation in HPS patients.
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Affiliation(s)
- Ai-Hua Wei
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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79
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Gautreau A, Oguievetskaia K, Ungermann C. Function and regulation of the endosomal fusion and fission machineries. Cold Spring Harb Perspect Biol 2014; 6:6/3/a016832. [PMID: 24591520 DOI: 10.1101/cshperspect.a016832] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Organelles within the endomembrane system are connected via vesicle flux. Along the endocytic pathway, endosomes are among the most versatile organelles. They sort cargo through tubular protrusions for recycling or through intraluminal vesicles for degradation. Sorting involves numerous machineries, which mediate fission of endosomal transport intermediates and fusion with other endosomes or eventually with lysosomes. Here we review the recent advances in our understanding of these processes with a particular focus on the Rab GTPases, tethering factors, and retromer. The cytoskeleton has also been recently recognized as a central player in membrane dynamics of endosomes, and this review covers the regulation of the machineries that govern the formation of branched actin networks through the WASH and Arp2/3 complexes in relation with cargo recycling and endosomal fission.
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Affiliation(s)
- Alexis Gautreau
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS UPR3082, 91190 Gif-sur-Yvette, France
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80
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Delahaye JL, Foster OK, Vine A, Saxton DS, Curtin TP, Somhegyi H, Salesky R, Hermann GJ. Caenorhabditis elegans HOPS and CCZ-1 mediate trafficking to lysosome-related organelles independently of RAB-7 and SAND-1. Mol Biol Cell 2014; 25:1073-96. [PMID: 24501423 PMCID: PMC3967972 DOI: 10.1091/mbc.e13-09-0521] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
As early endosomes mature, the SAND-1/CCZ-1 complex acts as a guanine nucleotide exchange factor (GEF) for RAB-7 to promote the activity of its effector, HOPS, which facilitates late endosome-lysosome fusion and the consumption of AP-3-containing vesicles. We show that CCZ-1 and the HOPS complex are essential for the biogenesis of gut granules, cell type-specific, lysosome-related organelles (LROs) that coexist with conventional lysosomes in Caenorhabditis elegans intestinal cells. The HOPS subunit VPS-18 promotes the trafficking of gut granule proteins away from lysosomes and functions downstream of or in parallel to the AP-3 adaptor. CCZ-1 also acts independently of AP-3, and ccz-1 mutants mistraffic gut granule proteins. Our results indicate that SAND-1 does not participate in the formation of gut granules. In the absence of RAB-7 activity, gut granules are generated; however, their size and protein composition are subtly altered. These observations suggest that CCZ-1 acts in partnership with a protein other than SAND-1 as a GEF for an alternate Rab to promote gut granule biogenesis. Point mutations in GLO-1, a Rab32/38-related protein, predicted to increase spontaneous guanine nucleotide exchange, specifically suppress the loss of gut granules by ccz-1 and glo-3 mutants. GLO-3 is known to be required for gut granule formation and has homology to SAND-1/Mon1-related proteins, suggesting that CCZ-1 functions with GLO-3 upstream of the GLO-1 Rab, possibly as a GLO-1 GEF. These results support LRO formation occurring via processes similar to conventional lysosome biogenesis, albeit with key molecular differences.
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Affiliation(s)
- Jared L Delahaye
- Department of Biology, Lewis & Clark College, Portland, OR 97219 Program in Biochemistry and Molecular Biology, Lewis & Clark College, Portland, OR 97219
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81
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Croucher PJP, Brewer MS, Winchell CJ, Oxford GS, Gillespie RG. De novo characterization of the gene-rich transcriptomes of two color-polymorphic spiders, Theridion grallator and T. californicum (Araneae: Theridiidae), with special reference to pigment genes. BMC Genomics 2013; 14:862. [PMID: 24314324 PMCID: PMC3878950 DOI: 10.1186/1471-2164-14-862] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 11/25/2013] [Indexed: 12/17/2022] Open
Abstract
Background A number of spider species within the family Theridiidae exhibit a dramatic abdominal (opisthosomal) color polymorphism. The polymorphism is inherited in a broadly Mendelian fashion and in some species consists of dozens of discrete morphs that are convergent across taxa and populations. Few genomic resources exist for spiders. Here, as a first necessary step towards identifying the genetic basis for this trait we present the near complete transcriptomes of two species: the Hawaiian happy-face spider Theridion grallator and Theridion californicum. We mined the gene complement for pigment-pathway genes and examined differential expression (DE) between morphs that are unpatterned (plain yellow) and patterned (yellow with superimposed patches of red, white or very dark brown). Results By deep sequencing both RNA-seq and normalized cDNA libraries from pooled specimens of each species we were able to assemble a comprehensive gene set for both species that we estimate to be 98-99% complete. It is likely that these species express more than 20,000 protein-coding genes, perhaps 4.5% (ca. 870) of which might be unique to spiders. Mining for pigment-associated Drosophila melanogaster genes indicated the presence of all ommochrome pathway genes and most pteridine pathway genes and DE analyses further indicate a possible role for the pteridine pathway in theridiid color patterning. Conclusions Based upon our estimates, T. grallator and T. californicum express a large inventory of protein-coding genes. Our comprehensive assembly illustrates the continuing value of sequencing normalized cDNA libraries in addition to RNA-seq in order to generate a reference transcriptome for non-model species. The identification of pteridine-related genes and their possible involvement in color patterning is a novel finding in spiders and one that suggests a biochemical link between guanine deposits and the pigments exhibited by these species.
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Affiliation(s)
- Peter J P Croucher
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720-3114, USA.
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82
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Orozco IJ, Koppensteiner P, Ninan I, Arancio O. The schizophrenia susceptibility gene DTNBP1 modulates AMPAR synaptic transmission and plasticity in the hippocampus of juvenile DBA/2J mice. Mol Cell Neurosci 2013; 58:76-84. [PMID: 24321452 DOI: 10.1016/j.mcn.2013.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 10/31/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022] Open
Abstract
The dystrobrevin binding protein (DTNBP) 1 gene has emerged over the last decade as a potential susceptibility locus for schizophrenia. While no causative mutations have been found, reduced expression of the encoded protein, dysbindin, was reported in patients. Dysbindin likely plays a role in the neuronal trafficking of proteins including receptors. One important pathway suspected to be affected in schizophrenia is the fast excitatory glutamatergic transmission mediated by AMPA receptors. Here, we investigated excitatory synaptic transmission and plasticity in hippocampal neurons from dysbindin-deficient sandy mice bred on the DBA/2J strain. In cultured neurons an enhancement of AMPAR responses was observed. The enhancement of AMPAR-mediated transmission was confirmed in hippocampal CA3-CA1 synapses, and was not associated with changes in the expression of GluA1-4 subunits or an increase in GluR2-lacking receptor complexes. Lastly, an enhancement in LTP was also found in these mice. These data provide compelling evidence that dysbindin, a widely suspected susceptibility protein in schizophrenia, is important for AMPAR-mediated synaptic transmission and plasticity in the developing hippocampus.
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Affiliation(s)
- Ian J Orozco
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
| | - Peter Koppensteiner
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Ipe Ninan
- Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
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83
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Mullin AP, Gokhale A, Moreno-De-Luca A, Sanyal S, Waddington JL, Faundez V. Neurodevelopmental disorders: mechanisms and boundary definitions from genomes, interactomes and proteomes. Transl Psychiatry 2013; 3:e329. [PMID: 24301647 PMCID: PMC4030327 DOI: 10.1038/tp.2013.108] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 10/22/2013] [Indexed: 02/08/2023] Open
Abstract
Neurodevelopmental disorders such as intellectual disability, autism spectrum disorder and schizophrenia lack precise boundaries in their clinical definitions, epidemiology, genetics and protein-protein interactomes. This calls into question the appropriateness of current categorical disease concepts. Recently, there has been a rising tide to reformulate neurodevelopmental nosological entities from biology upward. To facilitate this developing trend, we propose that identification of unique proteomic signatures that can be strongly associated with patient's risk alleles and proteome-interactome-guided exploration of patient genomes could define biological mechanisms necessary to reformulate disorder definitions.
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Affiliation(s)
- A P Mullin
- Department of Cell Biology, Emory University School of Medicine, Center for Social Translational Neuroscience, Emory University, Atlanta, GA, USA
| | - A Gokhale
- Department of Cell Biology, Emory University School of Medicine, Center for Social Translational Neuroscience, Emory University, Atlanta, GA, USA
| | - A Moreno-De-Luca
- Autism and Developmental Medicine Institute, Genomic Medicine Institute, Geisinger Health System, Danville, PA, USA
| | - S Sanyal
- Department of Cell Biology, Emory University School of Medicine, Center for Social Translational Neuroscience, Emory University, Atlanta, GA, USA,Biogen-Idec, 14 Cambridge Center, Cambridge, MA, USA
| | - J L Waddington
- Molecular & Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - V Faundez
- Department of Cell Biology, Emory University School of Medicine, Center for Social Translational Neuroscience, Emory University, Atlanta, GA, USA,Center for Social Translational Neuroscience, Emory University, Atlanta, GA, USA,Department of Cell Biology, Emory University School of Medicine, Center for Social Translational Neuroscience, Emory University, Atlanta, GA 30322, USA. E-mail:
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84
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Kuratomi G, Saito A, Ozeki Y, Watanabe T, Fujii K, Shimoda K, Inukai T, Mori H, Ohmori K, Akiyama K. Association of the Hermansky-Pudlak syndrome type 4 (HPS4) gene variants with cognitive function in patients with schizophrenia and healthy subjects. BMC Psychiatry 2013; 13:276. [PMID: 24168225 PMCID: PMC3819706 DOI: 10.1186/1471-244x-13-276] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/25/2013] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The Hermansky-Pudlak Syndrome Type 4 (HPS4) gene, which encodes a subunit protein of the biogenesis of lysosome-related organelles complex (BLOC)-3, which is involved in late endosomal trafficking, is associated with schizophrenia; however, its clinical relevance in schizophrenia remains unknown. The purpose of the present study was to investigate whether HPS4 is associated with cognitive functions in patients with schizophrenia and healthy controls and with the clinical profiles of patients with schizophrenia. METHODS We investigated the association of variants of HPS4 with clinical symptoms and cognitive function in Japanese patients with schizophrenia (n = 240) and age-matched healthy control subjects (n = 240) with single nucleotide polymorphisms (SNP)- or haplotype-based linear regression. We analyzed five tagging SNPs (rs4822724, rs61276843, rs9608491, rs713998, and rs2014410) of HPS4 and 2-5 locus haplotypes of these five SNPs. The cognitive functions of patients and healthy subjects were evaluated with the Brief Assessment of Cognition in Schizophrenia, Japanese-language version, and the patients were assessed for their symptomatology with the Positive and Negative Symptom Scale (PANSS). RESULTS In patients with schizophrenia, rs713998 was significantly associated with executive function under the dominant genetic model (P = 0.0073). In healthy subjects, there was a significant association between working memory and two individual SNPs under the recessive model (rs9608491: P = 0.001; rs713998: P = 0.0065) and two haplotypes (rs9608491-713998: P = 0.0025; rs61276843-9608491-713998: P = 0.0064). No significant association was found between HPS4 SNPs and PANSS scores or premorbid IQ, as measured by the Japanese version of the National Adult Reading Test. CONCLUSIONS These findings suggested the involvement of HPS4 in the working memory of healthy subjects and in the executive function deficits in schizophrenia.
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Affiliation(s)
- Go Kuratomi
- Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
| | - Atsushi Saito
- Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
| | - Yuji Ozeki
- Department of Psychiatry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
| | - Takashi Watanabe
- Department of Psychiatry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
| | - Kumiko Fujii
- Department of Psychiatry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
| | - Kazutaka Shimoda
- Department of Psychiatry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
| | - Toshihiko Inukai
- Department of Internal Medicine (Endocrinology, Metabolism, and Hematology), Dokkyo Medical University Koshigaya Hospital, 2-1-50 Minamikoshigaya, Koshigaya, Saitama 3438555, Japan
| | - Harunobu Mori
- Mori Hospital, 419 Iidamachi, Utsunomiya, Tochigi 3210347, Japan
| | - Kenichi Ohmori
- Takizawa Hospital, 2-29 Hanabusahoncho Utsunomiya, Tochigi 3200828, Japan
| | - Kazufumi Akiyama
- Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan.
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85
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Morgan JR, Comstra HS, Cohen M, Faundez V. Presynaptic membrane retrieval and endosome biology: defining molecularly heterogeneous synaptic vesicles. Cold Spring Harb Perspect Biol 2013; 5:a016915. [PMID: 24086045 DOI: 10.1101/cshperspect.a016915] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The release and uptake of neurotransmitters by synaptic vesicles is a tightly controlled process that occurs in response to diverse stimuli at morphologically disparate synapses. To meet these architectural and functional synaptic demands, it follows that there should be diversity in the mechanisms that control their secretion and retrieval and possibly in the composition of synaptic vesicles within the same terminal. Here we pay particular attention to areas where such diversity is generated, such as the variance in exocytosis/endocytosis coupling, SNAREs defining functionally diverse synaptic vesicle populations and the adaptor-dependent sorting machineries capable of generating vesicle diversity. We argue that there are various synaptic vesicle recycling pathways at any given synapse and discuss several lines of evidence that support the role of the endosome in synaptic vesicle recycling.
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Affiliation(s)
- Jennifer R Morgan
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, Massachusetts 02543
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86
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Abstract
Hermansky-Pudlak Syndrome (HPS) is a set of genetically heterogeneous diseases caused by mutations in one of nine known HPS genes. HPS patients display oculocutaneous hypopigmentation and bleeding diathesis and, depending on the disease subtype, pulmonary fibrosis, congenital nystagmus, reduced visual acuity, and platelet aggregation deficiency. Mouse models for all known HPS subtypes have contributed greatly to our understanding of the disease, but many of the molecular and cellular mechanisms underlying HPS remain unknown. Here, we characterize ocular defects in the zebrafish (Danio rerio) mutant snow white (snw), which possesses a recessive, missense mutation in hps5 (hps5I76N). Melanosome biogenesis is disrupted in snw/hps5 mutants, resulting in hypopigmentation, a significant decrease in the number, size, and maturity of melanosomes, and the presence of ectopic multi-melanosome clusters throughout the mutant retina and choroid. snw/hps5I76N is the first Hps5 mutation identified within the N-terminal WD40 repeat protein-protein binding domain. Through in vitro coexpression assays, we demonstrate that Hps5I76N retains the ability to bind its protein complex partners, Hps3 and Hps6. Furthermore, while Hps5 and Hps6 stabilize each other's expression, this stabilization is disrupted by Hps5I76N. The snw/hps5I76N mutant provides a valuable resource for structure-function analyses of Hps5 and enables further elucidation of the molecular and cellular mechanisms underlying HPS.
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87
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Zlatic SA, Grossniklaus EJ, Ryder PV, Salazar G, Mattheyses AL, Peden AA, Faundez V. Chemical-genetic disruption of clathrin function spares adaptor complex 3-dependent endosome vesicle biogenesis. Mol Biol Cell 2013; 24:2378-88. [PMID: 23761069 PMCID: PMC3727930 DOI: 10.1091/mbc.e12-12-0860] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Clathrin–AP-3 association is dispensable for AP-3 vesicle budding from endosomes, which suggests that AP-3–clathrin interactions differ from those by which AP-1 and AP-2 adaptors productively engage clathrin in vesicle biogenesis. A role for clathrin in AP-3–dependent vesicle biogenesis has been inferred from biochemical interactions and colocalization between this adaptor and clathrin. The functionality of these molecular associations, however, is controversial. We comprehensively explore the role of clathrin in AP-3–dependent vesicle budding, using rapid chemical-genetic perturbation of clathrin function with a clathrin light chain–FKBP chimera oligomerizable by the drug AP20187. We find that AP-3 interacts and colocalizes with endogenous and recombinant FKBP chimeric clathrin polypeptides in PC12-cell endosomes. AP-3 displays, however, a divergent behavior from AP-1, AP-2, and clathrin chains. AP-3 cofractionates with clathrin-coated vesicle fractions isolated from PC12 cells even after clathrin function is acutely inhibited by AP20187. We predicted that AP20187 would inhibit AP-3 vesicle formation from endosomes after a brefeldin A block. AP-3 vesicle formation continued, however, after brefeldin A wash-out despite impairment of clathrin function by AP20187. These findings indicate that AP-3–clathrin association is dispensable for endosomal AP-3 vesicle budding and suggest that endosomal AP-3–clathrin interactions differ from those by which AP-1 and AP-2 adaptors productively engage clathrin in vesicle biogenesis.
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88
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Marks MS, Heijnen HFG, Raposo G. Lysosome-related organelles: unusual compartments become mainstream. Curr Opin Cell Biol 2013; 25:495-505. [PMID: 23726022 DOI: 10.1016/j.ceb.2013.04.008] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/24/2013] [Indexed: 11/16/2022]
Abstract
Lysosome-related organelles (LROs) comprise a group of cell type-specific subcellular compartments with unique composition, morphology and structure that share some features with endosomes and lysosomes and that function in varied processes such as pigmentation, hemostasis, lung plasticity and immunity. In recent years, studies of genetic diseases in which LRO functions are compromised have provided new insights into the mechanisms of LRO biogenesis and the regulated secretion of LRO contents. These insights have revealed previously unappreciated specialized endosomal sorting processes in all cell types, and are expanding our views of the plasticity of the endosomal and secretory systems in adapting to cell type-specific needs.
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Affiliation(s)
- Michael S Marks
- Department of Pathology & Laboratory Medicine and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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89
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John Peter AT, Lachmann J, Rana M, Bunge M, Cabrera M, Ungermann C. The BLOC-1 complex promotes endosomal maturation by recruiting the Rab5 GTPase-activating protein Msb3. ACTA ACUST UNITED AC 2013; 201:97-111. [PMID: 23547030 PMCID: PMC3613695 DOI: 10.1083/jcb.201210038] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Yeast BLOC-1 acts as both a Rab5–Vps21 effector and an adapter for the Rab-GAP Msb3 to promote endosomal maturation. Membrane microcompartments of the early endosomes serve as a sorting and signaling platform, where receptors are either recycled back to the plasma membrane or forwarded to the lysosome for destruction. In metazoan cells, three complexes, termed BLOC-1 to -3, mediate protein sorting from the early endosome to lysosomes and lysosome-related organelles. We now demonstrate that BLOC-1 is an endosomal Rab-GAP (GTPase-activating protein) adapter complex in yeast. The yeast BLOC-1 consisted of six subunits, which localized interdependently to the endosomes in a Rab5/Vps21-dependent manner. In the absence of BLOC-1 subunits, the balance between recycling and degradation of selected cargoes was impaired. Additionally, our data show that BLOC-1 is both a Vps21 effector and an adapter for its GAP Msb3. BLOC-1 and Msb3 interacted in vivo, and both mutants resulted in a redistribution of active Vps21 to the vacuole surface. We thus conclude that BLOC-1 controls the lifetime of active Rab5/Vps21 and thus endosomal maturation along the endocytic pathway.
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Affiliation(s)
- Arun T John Peter
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
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90
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Ryder PV, Vistein R, Gokhale A, Seaman MN, Puthenveedu MA, Faundez V. The WASH complex, an endosomal Arp2/3 activator, interacts with the Hermansky-Pudlak syndrome complex BLOC-1 and its cargo phosphatidylinositol-4-kinase type IIα. Mol Biol Cell 2013; 24:2269-84. [PMID: 23676666 PMCID: PMC3708732 DOI: 10.1091/mbc.e13-02-0088] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The WASH complex, an endosomal activator of the Arp2/3 complex involved in branched actin polymerization, is identified as a new factor in vesicle traffic mediated by the Hermansky–Pudlak syndrome complex BLOC-1. Vesicle biogenesis machinery components such as coat proteins can interact with the actin cytoskeleton for cargo sorting into multiple pathways. It is unknown, however, whether these interactions are a general requirement for the diverse endosome traffic routes. In this study, we identify actin cytoskeleton regulators as previously unrecognized interactors of complexes associated with the Hermansky–Pudlak syndrome. Two complexes mutated in the Hermansky–Pudlak syndrome, adaptor protein complex-3 and biogenesis of lysosome-related organelles complex-1 (BLOC-1), interact with and are regulated by the lipid kinase phosphatidylinositol-4-kinase type IIα (PI4KIIα). We therefore hypothesized that PI4KIIα interacts with novel regulators of these complexes. To test this hypothesis, we immunoaffinity purified PI4KIIα from isotope-labeled cell lysates to quantitatively identify interactors. Strikingly, PI4KIIα isolation preferentially coenriched proteins that regulate the actin cytoskeleton, including guanine exchange factors for Rho family GTPases such as RhoGEF1 and several subunits of the WASH complex. We biochemically confirmed several of these PI4KIIα interactions. Of importance, BLOC-1 complex, WASH complex, RhoGEF1, or PI4KIIα depletions altered the content and/or subcellular distribution of the BLOC-1–sensitive cargoes PI4KIIα, ATP7A, and VAMP7. We conclude that the Hermansky–Pudlak syndrome complex BLOC-1 and its cargo PI4KIIα interact with regulators of the actin cytoskeleton.
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Affiliation(s)
- P V Ryder
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
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91
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Syntaxin-3 is required for melanosomal localization of Tyrp1 in melanocytes. J Invest Dermatol 2013; 133:2237-46. [PMID: 23549422 DOI: 10.1038/jid.2013.156] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/28/2013] [Accepted: 03/11/2013] [Indexed: 11/08/2022]
Abstract
Melanogenic enzymes are transported by vesicular/membrane trafficking to immature melanosomes in melanocytes where they catalyze the synthesis of melanin pigments. Although several factors involved in melanogenic enzyme trafficking have been identified in the past decade, involvement of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins, which generally mediate membrane fusion, on melanosomes in the process of melanogenic enzyme trafficking has never been investigated. In this study we identified syntaxin-3, which was originally described as a target SNARE protein at the plasma membrane, as a melanosome-resident protein and investigated whether syntaxin-3 is involved in the trafficking of the melanogenic enzyme Tyrp1 (tyrosinase-related protein 1) in mouse melanocytes. The results showed that knockdown of endogenous syntaxin-3 protein in melanocytes caused a dramatic reduction in Tyrp1 signals, especially from peripheral melanosomes, presumably as a result of lysosomal degradation of Tyrp1. They also showed that syntaxin-3 interacts with another target SNARE SNAP23 (synaptosome-associated protein of 23 kDa) and with vesicle SNARE VAMP7 (vesicle-associated membrane protein 7), which has been shown to be localized at Tyrp1-containing vesicles/organelles. These findings suggested that the SNARE machinery composed of VAMP7 on Tyrp1-containing vesicles and syntaxin-3 and SNAP23 on melanosomes regulates Tyrp1 trafficking to the melanosome in melanocytes.
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92
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Wei AH, Li W. Hermansky-Pudlak syndrome: pigmentary and non-pigmentary defects and their pathogenesis. Pigment Cell Melanoma Res 2012; 26:176-92. [DOI: 10.1111/pcmr.12051] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Affiliation(s)
| | - Wei Li
- State Key Laboratory of Molecular Developmental Biology; Institute of Genetics & Developmental Biology; Chinese Academy of Sciences; Beijing; China
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93
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Bultema JJ, Di Pietro SM. Cell type-specific Rab32 and Rab38 cooperate with the ubiquitous lysosome biogenesis machinery to synthesize specialized lysosome-related organelles. Small GTPases 2012; 4:16-21. [PMID: 23247405 PMCID: PMC3620096 DOI: 10.4161/sgtp.22349] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Lysosome-related organelles (LROs) exist in specialized cells to serve specific functions and typically co-exist with conventional lysosomes. The biogenesis of LROs is known to utilize much of the common protein machinery used in the transport of integral membrane proteins to lysosomes. Consequently, an outstanding question in the field has been how specific cargoes are trafficked to LROs instead of lysosomes, particularly in cells that simultaneously produce both organelles. One LRO, the melanosome, is responsible for the production of the pigment melanin and has long been used as a model system to study the formation of specialized LROs. Importantly, melanocytes, where melanosomes are synthesized, are a cell type that also produces lysosomes and must therefore segregate traffic to each organelle. Two small GTPases, Rab32 and Rab38, are key proteins in the biogenesis of melanosomes and were recently shown to redirect the ubiquitous machinery—BLOC-2, AP-1 and AP-3—to traffic specialized cargoes to melanosomes in melanocytes. In addition, the study revealed Rab32 and Rab38 have both redundant and unique roles in the trafficking of melanin-producing enzymes and overall melanosome biogenesis. Here we review these findings, integrate them with previous knowledge on melanosome biogenesis and discuss their implications for biogenesis of other LROs.
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Affiliation(s)
- Jarred J Bultema
- Department of Biochemistry and Molecular Biology; Colorado State University; Fort Collins, CO USA
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94
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Fujita H, Kitawaki T, Sato T, Maeda T, Kamihira S, Takaori-Kondo A, Kadowaki N. The tyrosine kinase inhibitor dasatinib suppresses cytokine production by plasmacytoid dendritic cells by targeting endosomal transport of CpG DNA. Eur J Immunol 2012; 43:93-103. [PMID: 23112129 DOI: 10.1002/eji.201242699] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 09/21/2012] [Accepted: 10/24/2012] [Indexed: 12/30/2022]
Abstract
Plasmacytoid dendritic cells (pDCs) produce a vast amount of interferon (IFN)-α in response to nucleic acids from viruses and damaged self-cells through Toll-like receptor (TLR)7 and TLR9. Pharmaceutical agents that suppress IFN-α production by pDCs are instrumental in elucidating the mechanisms behind IFN-α production, and in developing novel therapies for inflammatory disorders that involve pDCs. Here, we show that a tyrosine kinase inhibitor for chronic myeloid leukemia with multiple targets, dasatinib, strongly suppresses production of IFN-α and proinflammatory cytokines by human pDCs stimulated with multimeric CpG oligodeoxynucleotides (CpG-A) without reducing viability. In contrast, other tyrosine kinase inhibitors, imatinib, and nilotinib, did not suppress the cytokine production at clinically relevant concentrations. Inhibitors of SRC family kinases (SFKs), which are prominent targets of dasatinib, also suppressed the cytokine production. Notably, however, dasatinib, but not SFK inhibitors, abrogated prolonged localization of CpG-A in early endosomes, which is a critical step for pDCs to produce a large amount of IFN-α. This study suggests that dasatinib suppresses IFN-α production by pDCs by inhibiting SFK-dependent pathways and SFK-independent endosomal retention of CpG DNA. Kinases controlling the distinctive endosomal trafficking in pDCs may be exploited as targets to develop novel therapies for pDC-related inflammatory disorders.
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Affiliation(s)
- Haruyuki Fujita
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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95
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Ambrosio AL, Boyle JA, Di Pietro SM. Mechanism of platelet dense granule biogenesis: study of cargo transport and function of Rab32 and Rab38 in a model system. Blood 2012; 120:4072-81. [PMID: 22927249 PMCID: PMC3496959 DOI: 10.1182/blood-2012-04-420745] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/12/2012] [Indexed: 12/21/2022] Open
Abstract
Dense granules are important in platelet aggregation to form a hemostatic plug as evidenced by the increased bleeding time in mice and humans with dense granule deficiency. Dense granules also are targeted by antiplatelet agents because of their role in thrombus formation. Therefore, the molecular understanding of the dense granule and its biogenesis is of vital importance. In this work, we establish a human megakaryocytic cell line (MEG-01) as a model system for the study of dense granule biogenesis using a variety of cell biology and biochemical approaches. Using this model system, we determine the late endocytic origin of these organelles by colocalization of the internalized fluid phase marker dextran with both mepacrine and transmembrane dense granule proteins. By mistargeting of mutant dense granule proteins, we demonstrate that sorting signals recognized by adaptor protein-3 are necessary for normal transport to dense granules. Furthermore, we show that tissue-specific Rab32 and Rab38 are crucial for the fusion of vesicles containing dense granule cargo with the maturing organelle. This work sheds light on the biogenesis of dense granules at the molecular level and opens the possibility of using this powerful model system for the investigation of new components of the biogenesis machinery.
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Affiliation(s)
- Andrea L Ambrosio
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
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96
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Gerondopoulos A, Langemeyer L, Liang JR, Linford A, Barr FA. BLOC-3 mutated in Hermansky-Pudlak syndrome is a Rab32/38 guanine nucleotide exchange factor. Curr Biol 2012; 22:2135-9. [PMID: 23084991 PMCID: PMC3502862 DOI: 10.1016/j.cub.2012.09.020] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/25/2012] [Accepted: 09/07/2012] [Indexed: 12/20/2022]
Abstract
Hermansky-Pudlak syndrome (HPS) is a human disease characterized by partial loss of pigmentation and impaired blood clotting [1–3]. These symptoms are caused by defects in the biogenesis of melanosomes and platelet dense granules, often referred to as lysosome-related organelles [2]. Genes mutated in HPS encode subunits of the biogenesis of lysosome-related organelles complexes (BLOCs). BLOC-1 and BLOC-2, together with the AP-3 clathrin adaptor complex, act at early endosomes to sort components required for melanin formation and melanosome biogenesis away from the degradative lysosomal pathway toward early stage melanosomes [4–6]. However the molecular functions of the Hps1-Hps4 complex BLOC-3 remain mysterious [7–9]. Like other trafficking pathways, melanosome biogenesis and transport of enzymes involved in pigmentation involves specific Rab GTPases, in this instance Rab32 and Rab38 [10–12]. We now demonstrate that BLOC-3 is a Rab32 and Rab38 guanine nucleotide exchange factor (GEF). Silencing of the BLOC-3 subunits Hps1 and Hps4 results in the mislocalization of Rab32 and Rab38 and reduction in pigmentation. In addition, we show that BLOC-3 can promote specific membrane recruitment of Rab32/38. BLOC-3 therefore defines a novel Rab GEF family with a specific function in the biogenesis of lysosome-related organelles.
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Affiliation(s)
- Andreas Gerondopoulos
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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97
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Hermann GJ, Scavarda E, Weis AM, Saxton DS, Thomas LL, Salesky R, Somhegyi H, Curtin TP, Barrett A, Foster OK, Vine A, Erlich K, Kwan E, Rabbitts BM, Warren K. C. elegans BLOC-1 functions in trafficking to lysosome-related gut granules. PLoS One 2012; 7:e43043. [PMID: 22916203 PMCID: PMC3419718 DOI: 10.1371/journal.pone.0043043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/16/2012] [Indexed: 12/18/2022] Open
Abstract
The human disease Hermansky-Pudlak syndrome results from defective biogenesis of lysosome-related organelles (LROs) and can be caused by mutations in subunits of the BLOC-1 complex. Here we show that C. elegans glo-2 and snpn-1, despite relatively low levels of amino acid identity, encode Pallidin and Snapin BLOC-1 subunit homologues, respectively. BLOC-1 subunit interactions involving Pallidin and Snapin were conserved for GLO-2 and SNPN-1. Mutations in glo-2 and snpn-1,or RNAi targeting 5 other BLOC-1 subunit homologues in a genetic background sensitized for glo-2 function, led to defects in the biogenesis of lysosome-related gut granules. These results indicate that the BLOC-1 complex is conserved in C. elegans. To address the function of C. elegans BLOC-1, we assessed the intracellular sorting of CDF-2::GFP, LMP-1, and PGP-2 to gut granules. We validated their utility by analyzing their mislocalization in intestinal cells lacking the function of AP-3, which participates in an evolutionarily conserved sorting pathway to LROs. BLOC-1(−) intestinal cells missorted gut granule cargo to the plasma membrane and conventional lysosomes and did not have obviously altered function or morphology of organelles composing the conventional lysosome protein sorting pathway. Double mutant analysis and comparison of AP-3(−) and BLOC-1(−) phenotypes revealed that BLOC-1 has some functions independent of the AP-3 adaptor complex in trafficking to gut granules. We discuss similarities and differences of BLOC-1 activity in the biogenesis of gut granules as compared to mammalian melanosomes, where BLOC-1 has been most extensively studied for its role in sorting to LROs. Our work opens up the opportunity to address the function of this poorly understood complex in cell and organismal physiology using the genetic approaches available in C. elegans.
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Affiliation(s)
- Greg J Hermann
- Department of Biology, Lewis and Clark College, Portland, Oregon, USA.
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98
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Sitaram A, Marks MS. Mechanisms of protein delivery to melanosomes in pigment cells. Physiology (Bethesda) 2012; 27:85-99. [PMID: 22505665 DOI: 10.1152/physiol.00043.2011] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vertebrate pigment cells in the eye and skin are useful models for cell types that use specialized endosomal trafficking pathways to partition cargo proteins to unique lysosome-related organelles such as melanosomes. This review describes current models of protein trafficking required for melanosome biogenesis in mammalian melanocytes.
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Affiliation(s)
- Anand Sitaram
- Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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99
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Schubert KO, Föcking M, Prehn JHM, Cotter DR. Hypothesis review: are clathrin-mediated endocytosis and clathrin-dependent membrane and protein trafficking core pathophysiological processes in schizophrenia and bipolar disorder? Mol Psychiatry 2012; 17:669-81. [PMID: 21986877 DOI: 10.1038/mp.2011.123] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Clathrin-mediated endocytosis (CME) is the best-characterized mechanism governing cellular membrane and protein trafficking. In this hypothesis review, we integrate recent evidence implicating CME and related cellular trafficking mechanisms in the pathophysiology of psychotic disorders such as schizophrenia and bipolar disorder. The evidence includes proteomic and genomic findings implicating proteins and genes of the clathrin interactome. Additionally, several important candidate genes for schizophrenia, such as dysbindin, are involved in processes closely linked to CME and membrane trafficking. We discuss that key aspects of psychosis neuropathology such as synaptic dysfunction, white matter changes and aberrant neurodevelopment are all influenced by clathrin-dependent processes, and that other cellular trafficking mechanisms previously linked to psychoses interact with the clathrin interactome in important ways. Furthermore, many antipsychotic drugs have been shown to affect clathrin-interacting proteins. We propose that the targeted pharmacological manipulation of the clathrin interactome may offer fruitful opportunities for novel treatments of schizophrenia.
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Affiliation(s)
- K O Schubert
- Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Republic of Ireland
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100
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Sitaram A, Dennis MK, Chaudhuri R, De Jesus-Rojas W, Tenza D, Setty SRG, Wood CS, Sviderskaya EV, Bennett DC, Raposo G, Bonifacino JS, Marks MS. Differential recognition of a dileucine-based sorting signal by AP-1 and AP-3 reveals a requirement for both BLOC-1 and AP-3 in delivery of OCA2 to melanosomes. Mol Biol Cell 2012; 23:3178-92. [PMID: 22718909 PMCID: PMC3418312 DOI: 10.1091/mbc.e11-06-0509] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OCA2 is used as a model melanosome cargo protein to define primary sequence elements required for acidic dileucine–motif binding to adaptors AP-1 and AP-3. OCA2 must bind to AP-3 for melanosome localization. BLOC-1 is also required and thus can cooperate with either adaptor for cargo delivery to lysosome-related organelles. Cell types that generate unique lysosome-related organelles (LROs), such as melanosomes in melanocytes, populate nascent LROs with cargoes that are diverted from endosomes. Cargo sorting toward melanosomes correlates with binding via cytoplasmically exposed sorting signals to either heterotetrameric adaptor AP-1 or AP-3. Some cargoes bind both adaptors, but the relative contribution of each adaptor to cargo recognition and their functional interactions with other effectors during transport to melanosomes are not clear. Here we exploit targeted mutagenesis of the acidic dileucine–based sorting signal in the pigment cell–specific protein OCA2 to dissect the relative roles of AP-1 and AP-3 in transport to melanosomes. We show that binding to AP-1 or AP-3 depends on the primary sequence of the signal and not its position within the cytoplasmic domain. Mutants that preferentially bound either AP-1 or AP-3 each trafficked toward melanosomes and functionally complemented OCA2 deficiency, but AP-3 binding was necessary for steady-state melanosome localization. Unlike tyrosinase, which also engages AP-3 for optimal melanosomal delivery, both AP-1– and AP-3–favoring OCA2 variants required BLOC-1 for melanosomal transport. These data provide evidence for distinct roles of AP-1 and AP-3 in OCA2 transport to melanosomes and indicate that BLOC-1 can cooperate with either adaptor during cargo sorting to LROs.
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Affiliation(s)
- Anand Sitaram
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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