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Singh V, Menard MA, Serrano GE, Beach TG, Zhao HT, Riley-DiPaolo A, Subrahmanian N, LaVoie MJ, Volpicelli-Daley LA. Cellular and subcellular localization of Rab10 and phospho-T73 Rab10 in the mouse and human brain. Acta Neuropathol Commun 2023; 11:201. [PMID: 38110990 PMCID: PMC10726543 DOI: 10.1186/s40478-023-01704-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 12/03/2023] [Indexed: 12/20/2023] Open
Abstract
Autosomal dominant pathogenic mutations in Leucine-rich repeat kinase 2 (LRRK2) cause Parkinson's disease (PD). The most common mutation, G2019S-LRRK2, increases the kinase activity of LRRK2 causing hyper-phosphorylation of its substrates. One of these substrates, Rab10, is phosphorylated at a conserved Thr73 residue (pRab10), and is one of the most abundant LRRK2 Rab GTPases expressed in various tissues. The involvement of Rab10 in neurodegenerative disease, including both PD and Alzheimer's disease makes pinpointing the cellular and subcellular localization of Rab10 and pRab10 in the brain an important step in understanding its functional role, and how post-translational modifications could impact function. To establish the specificity of antibodies to the phosphorylated form of Rab10 (pRab10), Rab10 specific antisense oligonucleotides were intraventricularly injected into the brains of mice. Further, Rab10 knock out induced neurons, differentiated from human induced pluripotent stem cells were used to test the pRab10 antibody specificity. To amplify the weak immunofluorescence signal of pRab10, tyramide signal amplification was utilized. Rab10 and pRab10 were expressed in the cortex, striatum and the substantia nigra pars compacta. Immunofluorescence for pRab10 was increased in G2019S-LRRK2 knockin mice. Neurons, astrocytes, microglia and oligodendrocytes all showed Rab10 and pRab10 expression. While Rab10 colocalized with endoplasmic reticulum, lysosome and trans-Golgi network markers, pRab10 did not localize to these organelles. However, pRab10, did overlap with markers of the presynaptic terminal in both mouse and human cortex, including α-synuclein. Results from this study suggest Rab10 and pRab10 are expressed in all brain areas and cell types tested in this study, but pRab10 is enriched at the presynaptic terminal. As Rab10 is a LRRK2 kinase substrate, increased kinase activity of G2019S-LRRK2 in PD may affect Rab10 mediated membrane trafficking at the presynaptic terminal in neurons in disease.
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Affiliation(s)
- Vijay Singh
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Marissa A Menard
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Geidy E Serrano
- Department of Neuropathology, Banner Sun Health Research Institute, Sun City, AZ, 85351, USA
| | - Thomas G Beach
- Department of Neuropathology, Banner Sun Health Research Institute, Sun City, AZ, 85351, USA
| | - Hien T Zhao
- Ionis Pharmaceuticals Inc, Carlsbad, CA, 92010, USA
| | - Alexis Riley-DiPaolo
- Department of Neuroscience at the University of Florida, Gainesville, FL, 32611, USA
| | - Nitya Subrahmanian
- Department of Neurology, Center for Translational Research in Neurodegenerative Disease, Fixel Institute for Neurologic Disease, University of Florida, Gainesville, FL, 32610, USA
| | - Matthew J LaVoie
- Department of Neurology, Center for Translational Research in Neurodegenerative Disease, Fixel Institute for Neurologic Disease, University of Florida, Gainesville, FL, 32610, USA
| | - Laura A Volpicelli-Daley
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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2
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Rioux DJ, Prosser DC. A CIE change in our understanding of endocytic mechanisms. Front Cell Dev Biol 2023; 11:1334798. [PMID: 38192364 PMCID: PMC10773762 DOI: 10.3389/fcell.2023.1334798] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 12/04/2023] [Indexed: 01/10/2024] Open
Abstract
The past six decades have seen major advances in our understanding of endocytosis, ranging from descriptive studies based on electron microscopy to biochemical and genetic characterization of factors required for vesicle formation. Most studies focus on clathrin as the major coat protein; indeed, clathrin-mediated endocytosis (CME) is the primary pathway for internalization. Clathrin-independent (CIE) pathways also exist, although mechanistic understanding of these pathways remains comparatively elusive. Here, we discuss how early studies of CME shaped our understanding of endocytosis and describe recent advances in CIE, including pathways in model organisms that are poised to provide key insights into endocytic regulation.
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Affiliation(s)
- Daniel J. Rioux
- Life Sciences, Virginia Commonwealth University, Richmond, VA, United States
- Department of Biology, Virginia Commonwealth University, Richmond, VA, United States
| | - Derek C. Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, VA, United States
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Mizumoto K, Jin Y, Bessereau JL. Synaptogenesis: unmasking molecular mechanisms using Caenorhabditis elegans. Genetics 2023; 223:iyac176. [PMID: 36630525 PMCID: PMC9910414 DOI: 10.1093/genetics/iyac176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/22/2022] [Indexed: 01/13/2023] Open
Abstract
The nematode Caenorhabditis elegans is a research model organism particularly suited to the mechanistic understanding of synapse genesis in the nervous system. Armed with powerful genetics, knowledge of complete connectomics, and modern genomics, studies using C. elegans have unveiled multiple key regulators in the formation of a functional synapse. Importantly, many signaling networks display remarkable conservation throughout animals, underscoring the contributions of C. elegans research to advance the understanding of our brain. In this chapter, we will review up-to-date information of the contribution of C. elegans to the understanding of chemical synapses, from structure to molecules and to synaptic remodeling.
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Affiliation(s)
- Kota Mizumoto
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z3, Canada
| | - Yishi Jin
- Department of Neurobiology, University of California San Diego, La Jolla, CA 92093, USA
| | - Jean-Louis Bessereau
- Univ Lyon, University Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U 1314, Melis, 69008 Lyon, France
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Rennich BJ, Luth ES, Hofer J, Juo P. Low-Density Lipoprotein Receptor LRP-2 regulates GLR-1 glutamate receptors and glutamatergic behavior in C. elegans. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000837. [PMID: 37179968 PMCID: PMC10172966 DOI: 10.17912/micropub.biology.000837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023]
Abstract
We identified the Low-Density Lipoprotein (LDL) Receptor Related Protein-2 (LRP-2) in a RNAi screen for genes that regulate glutamatergic behavior in C. elegans . lrp-2 loss-of-function mutants have defects in glutamatergic mechanosensory nose-touch behavior and suppress increased spontaneous reversals induced by GLR-1(A/T), a constitutively-active form of the AMPA-type glutamate receptor GLR-1. Total and surface levels of GLR-1 are increased throughout the ventral nerve cord of lrp-2 mutants suggesting that LRP-2 promotes glutamatergic signaling by regulating some aspect of GLR-1 trafficking, localization or function.
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Affiliation(s)
- Bethany J Rennich
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111
- Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111
| | - Eric S Luth
- Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111
- Biology, Simmons University, Boston, MA 02115
| | - Julia Hofer
- Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111
| | - Peter Juo
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111
- Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111
- Correspondence to: Peter Juo (
)
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Panzer JK, Tamayo A, Caicedo A. Restoring glutamate receptor signaling in pancreatic alpha cells rescues glucagon responses in type 1 diabetes. Cell Rep 2022; 41:111792. [PMID: 36516761 DOI: 10.1016/j.celrep.2022.111792] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/19/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
Glucagon secretion from pancreatic alpha cells is crucial to prevent hypoglycemia. People with type 1 diabetes lose this glucoregulatory mechanism and are susceptible to dangerous hypoglycemia for reasons still unclear. Here we determine that alpha cells in living pancreas slices from donors with type 1 diabetes do not mount an adequate glucagon response and cannot activate the positive autocrine feedback mediated by AMPA/kainate glutamate receptors. This feedback is required to elicit full glucagon responses in the healthy state. Reactivating residual AMPA/kainate receptor function with positive allosteric modulators restores glucagon secretion in human slices from donors with type 1 diabetes as well as glucose counterregulation in non-obese diabetic mice. Our study thus identifies a defect in autocrine signaling that contributes to alpha cell failure. The use of positive allosteric modulators of AMPA/kainate receptors overcomes this deficiency and prevents hypoglycemia, an effect that could be used to improve the management of diabetes.
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Affiliation(s)
- Julia K Panzer
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Alejandro Tamayo
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Zhang R, Cao YY, Du J, Thakur K, Tang SM, Hu F, Wei ZJ. Transcriptome Analysis Reveals the Gene Expression Changes in the Silkworm ( Bombyx mori) in Response to Hydrogen Sulfide Exposure. INSECTS 2021; 12:insects12121110. [PMID: 34940198 PMCID: PMC8706860 DOI: 10.3390/insects12121110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/27/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022]
Abstract
Simple Summary The fat body is one of the most important tissues in the body of insects due to its number of functions. Nowadays the new physiological function of H2S has gained attention as a novel signaling molecule. H2S performs crucial regulatory functions involving growth, the cardiovascular system, oxidative stress, and inflammation in many organisms. In this study, RNA-seq technology was used to investigate the fat body of the silkworm at the transcriptional level after H2S exposure during the 5th larvae stage. A total of 1200 (DEGs) was identified after 7.5 µM H2S treatment, of which 977 DEGs were up-regulated and 223 DEGs were down-regulated. DEGs were mainly involved in the transport pathway, cellular community, carbohydrate metabolism, and immune-associated signal transduction. Present research provides new insights on the gene expression changes in the fat body of silkworms after H2S exposure. Abstract Hydrogen sulfide (H2S) has been recognized for its beneficial influence on physiological alterations. The development (body weight) and economic characteristics (cocoon weight, cocoon shell ratio, and cocoon shell weight) of silkworms were increased after continuous 7.5 µM H2S treatment. In the present study, gene expression changes in the fat body of silkworms at the 5th instar larvae in response to the H2S were investigated through comparative transcriptome analysis. Moreover, the expression pattern of significant differentially expressed genes (DEGs) at the 5th instar larvae was confirmed by quantitative real-time PCR (qRT-PCR) after H2S exposure. A total of 1200 (DEGs) was identified, of which 977 DEGs were up-regulated and 223 DEGs were down-regulated. Most of the DEGs were involved in the transport pathway, cellular community, carbohydrate metabolism, and immune-associated signal transduction. The up regulated genes under H2S exposure were involved in endocytosis, glycolysis/gluconeogenesis, the citrate cycle (TCA cycle), and the synthesis of fibroin, while genes related to inflammation were down-regulated, indicating that H2S could promote energy metabolism, the transport pathway, silk synthesis, and inhibit inflammation in the silkworm. In addition, the expression levels of these genes were increased or decreased in a time-dependent manner during the 5th instar larvae. These results provided insight into the effects of H2S on silkworms at the transcriptional level and a substantial foundation for understanding H2S function.
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Affiliation(s)
- Rui Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; (R.Z.); (Y.-Y.C.); (K.T.)
| | - Yu-Yao Cao
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; (R.Z.); (Y.-Y.C.); (K.T.)
| | - Juan Du
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China;
| | - Kiran Thakur
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; (R.Z.); (Y.-Y.C.); (K.T.)
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China;
| | - Shun-Ming Tang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China;
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Fei Hu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; (R.Z.); (Y.-Y.C.); (K.T.)
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China;
- Correspondence: (F.H.); (Z.-J.W.)
| | - Zhao-Jun Wei
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; (R.Z.); (Y.-Y.C.); (K.T.)
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China;
- Correspondence: (F.H.); (Z.-J.W.)
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Kadgien CA, Kamesh A, Milnerwood AJ. Endosomal traffic and glutamate synapse activity are increased in VPS35 D620N mutant knock-in mouse neurons, and resistant to LRRK2 kinase inhibition. Mol Brain 2021; 14:143. [PMID: 34530877 PMCID: PMC8447518 DOI: 10.1186/s13041-021-00848-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/27/2021] [Indexed: 12/26/2022] Open
Abstract
Vacuolar protein sorting 35 (VPS35) regulates neurotransmitter receptor recycling from endosomes. A missense mutation (D620N) in VPS35 leads to autosomal-dominant, late-onset Parkinson's disease. Here, we study the basic neurobiology of VPS35 and Parkinson's disease mutation effects in the D620N knock-in mouse and the effect of leucine-rich repeat kinase 2 (LRRK2) inhibition on synaptic phenotypes. The study was conducted using a VPS35 D620N knock-in mouse that expresses VPS35 at endogenous levels. Protein levels, phosphorylation states, and binding ratios in brain lysates from knock-in mice and wild-type littermates were assayed by co-immunoprecipitation and western blot. Dendritic protein co-localization, AMPA receptor surface expression, synapse density, and glutamatergic synapse activity in primary cortical cultures from knock-in and wild-type littermates were assayed using immunocytochemistry and whole-cell patch clamp electrophysiology. In brain tissue, we confirm VPS35 forms complexes with LRRK2 and AMPA-type glutamate receptor GluA1 subunits, in addition to NMDA-type glutamate receptor GluN1 subunits and D2-type dopamine receptors. Receptor and LRRK2 binding was unaltered in D620N knock-in mice, but we confirm the mutation results in reduced binding of VPS35 with WASH complex member FAM21, and increases phosphorylation of the LRRK2 kinase substrate Rab10, which is reversed by LRRK2 kinase inhibition in vivo. In cultured cortical neurons from knock-in mice, pRab10 is also increased, and reversed by LRRK2 inhibition. The mutation also results in increased endosomal recycling protein cluster density (VPS35-FAM21 co-clusters and Rab11 clusters), glutamate transmission, and GluA1 surface expression. LRRK2 kinase inhibition, which reversed Rab10 hyper-phosphorylation, did not rescue elevated glutamate release or surface GluA1 expression in knock-in neurons, but did alter AMPAR traffic in wild-type cells. The results improve our understanding of the cell biology of VPS35, and the consequences of the D620N mutation in developing neuronal networks. Together the data support a chronic synaptopathy model for latent neurodegeneration, providing phenotypes and candidate pathophysiological stresses that may drive eventual transition to late-stage parkinsonism in VPS35 PD. The study demonstrates the VPS35 mutation has effects that are independent of ongoing LRRK2 kinase activity, and that LRRK2 kinase inhibition alters basal physiology of glutamate synapses in vitro.
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Affiliation(s)
- Chelsie A Kadgien
- Graduate Program in Neuroscience and Centre for Applied Neurogenetics, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
| | - Anusha Kamesh
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
| | - Austen J Milnerwood
- Graduate Program in Neuroscience and Centre for Applied Neurogenetics, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada.
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada.
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Luth ES, Hodul M, Rennich BJ, Riccio C, Hofer J, Markoja K, Juo P. VER/VEGF receptors regulate AMPA receptor surface levels and glutamatergic behavior. PLoS Genet 2021; 17:e1009375. [PMID: 33561120 PMCID: PMC7899335 DOI: 10.1371/journal.pgen.1009375] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 02/22/2021] [Accepted: 01/22/2021] [Indexed: 01/09/2023] Open
Abstract
Several intracellular trafficking pathways contribute to the regulation of AMPA receptor (AMPAR) levels at synapses and the control of synaptic strength. While much has been learned about these intracellular trafficking pathways, a major challenge is to understand how extracellular factors, such as growth factors, neuropeptides and hormones, impinge on specific AMPAR trafficking pathways to alter synaptic function and behavior. Here, we identify the secreted ligand PVF-1 and its cognate VEGF receptor homologs, VER-1 and VER-4, as regulators of glutamate signaling in C. elegans. Loss of function mutations in ver-1, ver-4, or pvf-1, result in decreased cell surface levels of the AMPAR GLR-1 and defects in glutamatergic behavior. Rescue experiments indicate that PVF-1 is expressed and released from muscle, whereas the VERs function in GLR-1-expressing neurons to regulate surface levels of GLR-1 and glutamatergic behavior. Additionally, ver-4 is unable to rescue glutamatergic behavior in the absence of pvf-1, suggesting that VER function requires endogenous PVF-1. Inducible expression of a pvf-1 rescuing transgene suggests that PVF-1 can function in the mature nervous system to regulate GLR-1 signaling. Genetic double mutant analysis suggests that the VERs act together with the VPS-35/retromer recycling complex to promote cell surface levels of GLR-1. Our data support a genetic model whereby PVF-1/VER signaling acts with retromer to promote recycling and cell surface levels of GLR-1 to control behavior. Sensation, behavior, and cognition all depend on the proper function of neuronal connections called synapses. Synapses that use the neurotransmitter glutamate to signal between nerve cells are the most abundant type in our brain. Presynaptic neurons release glutamate, which activates glutamate receptors on postsynaptic neurons. Dysfunction of glutamate synapses leads to several neurological disorders, and changing their strength–in part by altering glutamate receptors numbers on the surface of the postsynaptic cell—provides the cellular basis of learning and memory. Much remains to be learned about how factors released from other cell types affects synaptic communication. We took advantage of light-activated molecular switches engineered into specific sensory neurons of C. elegans worms to trigger a behavioral reflex that depends on glutamate synapses. Using this behavior, we identified proteins called VER-1 and VER-4 as important for glutamate synapse function. We found that worms missing these VER proteins or their activator PVF-1 have reduced levels of glutamate receptors at the postsynaptic surface and defects in glutamate-dependent behaviors. Our results suggest that inter-tissue cross-talk between muscle PVF-1 and neuronal VERs is important for controlling the number of glutamate receptors at the cell surface, robust neuronal communication and behavioral responses.
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Affiliation(s)
- Eric S. Luth
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Department of Biology, Simmons University, Boston, Massachusetts, United States of America
| | - Molly Hodul
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Bethany J. Rennich
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Carmino Riccio
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Julia Hofer
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Kaitlin Markoja
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Peter Juo
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Park L, Luth ES, Jones K, Hofer J, Nguyen I, Watters KE, Juo P. The Snail transcription factor CES-1 regulates glutamatergic behavior in C. elegans. PLoS One 2021; 16:e0245587. [PMID: 33529210 PMCID: PMC7853468 DOI: 10.1371/journal.pone.0245587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 01/04/2021] [Indexed: 11/18/2022] Open
Abstract
Regulation of AMPA-type glutamate receptor (AMPAR) expression and function alters synaptic strength and is a major mechanism underlying synaptic plasticity. Although transcription is required for some forms of synaptic plasticity, the transcription factors that regulate AMPA receptor expression and signaling are incompletely understood. Here, we identify the Snail family transcription factor ces-1 in an RNAi screen for conserved transcription factors that regulate glutamatergic behavior in C. elegans. ces-1 was originally discovered as a selective cell death regulator of neuro-secretory motor neuron (NSM) and I2 interneuron sister cells in C. elegans, and has almost exclusively been studied in the NSM cell lineage. We found that ces-1 loss-of-function mutants have defects in two glutamatergic behaviors dependent on the C. elegans AMPA receptor GLR-1, the mechanosensory nose-touch response and spontaneous locomotion reversals. In contrast, ces-1 gain-of-function mutants exhibit increased spontaneous reversals, and these are dependent on glr-1 consistent with these genes acting in the same pathway. ces-1 mutants have wild type cholinergic neuromuscular junction function, suggesting that they do not have a general defect in synaptic transmission or muscle function. The effect of ces-1 mutation on glutamatergic behaviors is not due to ectopic cell death of ASH sensory neurons or GLR-1-expressing neurons that mediate one or both of these behaviors, nor due to an indirect effect on NSM sister cell deaths. Rescue experiments suggest that ces-1 may act, in part, in GLR-1-expressing neurons to regulate glutamatergic behaviors. Interestingly, ces-1 mutants suppress the increased reversal frequencies stimulated by a constitutively-active form of GLR-1. However, expression of glr-1 mRNA or GFP-tagged GLR-1 was not decreased in ces-1 mutants suggesting that ces-1 likely promotes GLR-1 function. This study identifies a novel role for ces-1 in regulating glutamatergic behavior that appears to be independent of its canonical role in regulating cell death in the NSM cell lineage.
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Affiliation(s)
- Lidia Park
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Cell, Developmental and Molecular Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Eric S. Luth
- Department of Biology, Simmons University, Boston, Massachusetts, United States of America
| | - Kelsey Jones
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Julia Hofer
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Irene Nguyen
- Department of Biology, Simmons University, Boston, Massachusetts, United States of America
| | - Katherine E. Watters
- Graduate Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Peter Juo
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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van Gelder CAGH, Penning R, Veth TS, Catsburg LAE, Hoogenraad CC, MacGillavry HD, Altelaar M. Temporal Quantitative Proteomics of mGluR-induced Protein Translation and Phosphorylation in Neurons. Mol Cell Proteomics 2020; 19:1952-1968. [PMID: 32912969 PMCID: PMC7710149 DOI: 10.1074/mcp.ra120.002199] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/04/2020] [Indexed: 01/12/2023] Open
Abstract
At neuronal synapses, activation of group I metabotropic glutamate receptors (mGluR1/5) triggers a form of long-term depression (mGluR-LTD) that relies on new protein synthesis and the internalization of AMPA-type glutamate receptors. Dysregulation of these processes has been implicated in the development of mental disorders such as autism spectrum disorders and therefore merit a better understanding on a molecular level. Here, to study mGluR-induced signaling pathways, we integrated quantitative phosphoproteomics with the analyses of newly synthesized proteins via bio-orthogonal amino acids (azidohomoalanine) in a pulsed labeling strategy in cultured hippocampal neurons stimulated with DHPG, a specific agonist for group I mGluRs. We identified several kinases with important roles in DHPG-induced mGluR activation, which we confirmed using small molecule kinase inhibitors. Furthermore, changes in the AMPA receptor endocytosis pathway in both protein synthesis and protein phosphorylation were identified, whereby Intersectin-1 was validated as a novel player in this pathway. This study revealed several new insights into the molecular pathways downstream of group I mGluR activation in hippocampal neurons, and provides a rich resource for further analyses.
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Affiliation(s)
- Charlotte A G H van Gelder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Renske Penning
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Tim S Veth
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Lisa A E Catsburg
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Harold D MacGillavry
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands.
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11
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Kuhlmann N, Milnerwood AJ. A Critical LRRK at the Synapse? The Neurobiological Function and Pathophysiological Dysfunction of LRRK2. Front Mol Neurosci 2020; 13:153. [PMID: 32973447 PMCID: PMC7482583 DOI: 10.3389/fnmol.2020.00153] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/22/2020] [Indexed: 12/25/2022] Open
Abstract
Since the discovery of LRRK2 mutations causal to Parkinson's disease (PD) in the early 2000s, the LRRK2 protein has been implicated in a plethora of cellular processes in which pathogenesis could occur, yet its physiological function remains elusive. The development of genetic models of LRRK2 PD has helped identify the etiological and pathophysiological underpinnings of the disease, and may identify early points of intervention. An important role for LRRK2 in synaptic function has emerged in recent years, which links LRRK2 to other genetic forms of PD, most notably those caused by mutations in the synaptic protein α-synuclein. This point of convergence may provide useful clues as to what drives dysfunction in the basal ganglia circuitry and eventual death of substantia nigra (SN) neurons. Here, we discuss the evolution and current state of the literature placing LRRK2 at the synapse, through the lens of knock-out, overexpression, and knock-in animal models. We hope that a deeper understanding of LRRK2 neurobiology, at the synapse and beyond, will aid the eventual development of neuroprotective interventions for PD, and the advancement of useful treatments in the interim.
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Affiliation(s)
- Naila Kuhlmann
- Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.,Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Austen J Milnerwood
- Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.,Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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12
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Shafaq-Zadah M, Dransart E, Johannes L. Clathrin-independent endocytosis, retrograde trafficking, and cell polarity. Curr Opin Cell Biol 2020; 65:112-121. [PMID: 32688213 PMCID: PMC7588825 DOI: 10.1016/j.ceb.2020.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 10/29/2022]
Abstract
Several mechanisms allow for cargo internalization into cells within membrane-bound endocytic carriers. How these internalization processes couple to specific pathways of intracellular distribution remains poorly explored. Here, we review uptake reactions that are independent of the conventional clathrin machinery. We discuss how these link to retrograde trafficking from endosomes to the Golgi apparatus and exemplify biological situations in which the polarized secretion capacity of the Golgi apparatus allows for retrograde cargoes to be delivered to specialized areas of the plasma membrane, such as the leading edge of migratory cells or the immunological synapse of immune cells. We also address the evidence that allows to position apicobasal polarity of epithelial cells in this context. The underlying theme is thereby the functional coupling between specific types of endocytosis to intracellular retrograde trafficking for protein cargoes that need to be localized in a highly polarized and dynamic manner to plasmalemmal subdomains.
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Affiliation(s)
- Massiullah Shafaq-Zadah
- Institut Curie, PSL Research University, Cellular and Chemical Biology Unit, INSERM U1143, CNRS UMR3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
| | - Estelle Dransart
- Institut Curie, PSL Research University, Cellular and Chemical Biology Unit, INSERM U1143, CNRS UMR3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Ludger Johannes
- Institut Curie, PSL Research University, Cellular and Chemical Biology Unit, INSERM U1143, CNRS UMR3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
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13
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Petridi S, Middleton CA, Ugbode C, Fellgett A, Covill L, Elliott CJH. In Vivo Visual Screen for Dopaminergic Rab ↔ LRRK2-G2019S Interactions in Drosophila Discriminates Rab10 from Rab3. G3 (BETHESDA, MD.) 2020; 10:1903-1914. [PMID: 32321836 PMCID: PMC7263684 DOI: 10.1534/g3.120.401289] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 04/22/2020] [Indexed: 02/07/2023]
Abstract
LRRK2 mutations cause Parkinson's, but the molecular link from increased kinase activity to pathological neurodegeneration remains undetermined. Previous in vitro assays indicate that LRRK2 substrates include at least 8 Rab GTPases. We have now examined this hypothesis in vivo in a functional, electroretinogram screen, expressing each Rab with/without LRRK2-G2019S in selected Drosophila dopaminergic neurons. Our screen discriminated Rab10 from Rab3. The strongest Rab/LRRK2-G2019S interaction is with Rab10; the weakest with Rab3. Rab10 is expressed in a different set of dopaminergic neurons from Rab3. Thus, anatomical and physiological patterns of Rab10 are related. We conclude that Rab10 is a valid substrate of LRRK2 in dopaminergic neurons in vivo We propose that variations in Rab expression contribute to differences in the rate of neurodegeneration recorded in different dopaminergic nuclei in Parkinson's.
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Affiliation(s)
- Stavroula Petridi
- Department of Biology and York Biomedical Research Institute, University of York, YO1 5DD, UK
| | - C Adam Middleton
- Department of Biology and York Biomedical Research Institute, University of York, YO1 5DD, UK
| | - Chris Ugbode
- Department of Biology and York Biomedical Research Institute, University of York, YO1 5DD, UK
| | - Alison Fellgett
- Department of Biology and York Biomedical Research Institute, University of York, YO1 5DD, UK
| | - Laura Covill
- Department of Biology and York Biomedical Research Institute, University of York, YO1 5DD, UK
| | - Christopher J H Elliott
- Department of Biology and York Biomedical Research Institute, University of York, YO1 5DD, UK
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14
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Chao H, Deng L, Xu F, Fu B, Zhu Z, Dong Z, Liu YN, Zeng T. RAB14 activates MAPK signaling to promote bladder tumorigenesis. Carcinogenesis 2020; 40:1341-1351. [PMID: 30809635 DOI: 10.1093/carcin/bgz039] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 01/22/2019] [Accepted: 02/24/2019] [Indexed: 12/16/2022] Open
Abstract
Bladder cancer (BC) is a fatal invasive malignancy accounting for approximately 5% of all cancer deaths in humans; however, the underlying molecular mechanisms and potential targeted therapeutics for BC patients remain unclear. We report herein that RAB14 was overexpressed in BC tissues and cells with high metastatic potential and its abundance was significantly associated with lymph node metastasis (P = 0.001), a high-grade tumor stage (P = 0.009), poor differentiation (P < 0.001) and unfavorable prognoses of BC patients (P = 0.003, log-rank test). Interference by RAB14 mediated a reduction in the TWIST1 protein and inhibited cell migration and invasion (P < 0.05). Moreover, silencing RAB14 reduced cell proliferation and induced apoptosis in vitro and suppressed tumorigenesis in a mouse xenograft model. We demonstrated that RAB14-promoted BC cancer development and progression were associated with activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase signaling through upregulation of MAPK1/MAPK8 and downregulation of dual-specificity protein phosphatase 6/Src homology 2 domain containing transforming protein/Fos proto-oncogene, AP-1 transcription factor subunit (FOS). We provide evidence that RAB14 acts as a tumor promoter and modulates the invasion and metastatic potential of BC cells via activating the MAPK pathway.
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Affiliation(s)
- Haichao Chao
- Institute of Clinical Medicine, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, P.R. China
| | - Leihong Deng
- Medical Department of Graduate School, Nanchang University, Nanchang, P.R. China
| | - Fanghua Xu
- Pathology Department, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, P.R. China
| | - Bin Fu
- Department of Urology, The First Affiliated Hospital of Nanchang University, Nanchang, P.R. China
| | - Zunwei Zhu
- Department of Urology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, P.R. China
| | - Zhifeng Dong
- Medical Department of Graduate School, Nanchang University, Nanchang, P.R. China
| | - Yen-Nien Liu
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Tao Zeng
- Department of Urology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, P.R. China
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15
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Gao J, Zhao L, Luo Q, Liu S, Lin Z, Wang P, Fu X, Chen J, Zhang H, Lin L, Shi A. An EHBP-1-SID-3-DYN-1 axis promotes membranous tubule fission during endocytic recycling. PLoS Genet 2020; 16:e1008763. [PMID: 32384077 PMCID: PMC7239482 DOI: 10.1371/journal.pgen.1008763] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 05/20/2020] [Accepted: 04/07/2020] [Indexed: 12/16/2022] Open
Abstract
The ACK family tyrosine kinase SID-3 is involved in the endocytic uptake of double-stranded RNA. Here we identified SID-3 as a previously unappreciated recycling regulator in the Caenorhabditis elegans intestine. The RAB-10 effector EHBP-1 is required for the endosomal localization of SID-3. Accordingly, animals with loss of SID-3 phenocopied the recycling defects observed in ehbp-1 and rab-10 single mutants. Moreover, we detected sequential protein interactions between EHBP-1, SID-3, NCK-1, and DYN-1. In the absence of SID-3, DYN-1 failed to localize at tubular recycling endosomes, and membrane tubules breaking away from endosomes were mostly absent, suggesting that SID-3 acts synergistically with the downstream DYN-1 to promote endosomal tubule fission. In agreement with these observations, overexpression of DYN-1 significantly increased recycling transport in SID-3-deficient cells. Finally, we noticed that loss of RAB-10 or EHBP-1 compromised feeding RNAi efficiency in multiple tissues, implicating basolateral recycling in the transport of RNA silencing signals. Taken together, our study demonstrated that in C. elegans intestinal epithelia, SID-3 acts downstream of EHBP-1 to direct fission of recycling endosomal tubules in concert with NCK-1 and DYN-1. After endocytic uptake, a recycling transport system is deployed to deliver endocytosed macromolecules, fluid, membranes, and membrane proteins back to the cell surface. This process is essential for a series of biological processes such as cytokinesis, cell migration, maintenance of cell polarity, and synaptic plasticity. Recycling endosomes mainly consist of membrane tubules and often undergo membrane fission to generate vesicular carriers, which mediates the delivery of cargo proteins back to the plasma membrane. Previous studies suggested that RAB-10 and its effector protein EHBP-1 function jointly to generate and maintain recycling endosomal tubules. However, the mechanism coupling recycling endosomal tubulation and membrane fission remains elusive. Here, we identified SID-3 as a new interactor of EHBP-1. EHBP-1 is required for the endosomal localization of SID-3 and initiates a protein interaction cascade involving SID-3, NCK-1, and DYN-1/dynamin. We also found that SID-3 functions downstream of EHBP-1 to encourage membrane scission, and that ectopic expression of DYN-1 improves recycling transport in SID-3-depleted cells. Our findings revealed EHBP-1 as a point of convergence between RAB-10-mediated endosomal tubulation and SID-3-assisted membrane tubule fission during endocytic recycling.
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Affiliation(s)
- Jinghu Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Linyue Zhao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Qian Luo
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shuyao Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ziyang Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Peixiang Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xin Fu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hongjie Zhang
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau SAR, China
| | - Long Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (LL); (AS)
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute for Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (LL); (AS)
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16
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Mathews PM, Levy E. Exosome Production Is Key to Neuronal Endosomal Pathway Integrity in Neurodegenerative Diseases. Front Neurosci 2019; 13:1347. [PMID: 31911768 PMCID: PMC6920185 DOI: 10.3389/fnins.2019.01347] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/29/2019] [Indexed: 12/28/2022] Open
Abstract
Dysfunction of the endosomal–lysosomal system is a prominent pathogenic factor in Alzheimer’s disease (AD) and other neurodevelopmental and neurodegenerative disorders. We and others have extensively characterized the neuronal endosomal pathway pathology that results from either triplication of the amyloid-β precursor protein (APP) gene in Down syndrome (DS) or from expression of the apolipoprotein E ε4 allele (APOE4), the greatest genetic risk factor for late-onset AD. More recently brain exosomes, extracellular vesicles that are generated within and released from endosomal compartments, have been shown to be altered in DS and by APOE4 expression. In this review, we discuss the emerging data arguing for an interdependence between exosome production and endosomal pathway integrity in the brain. In vitro and in vivo studies indicate that altered trafficking through the endosomal pathway or compromised cargo turnover within lysosomes can affect the production, secretion, and content of exosomes. Conversely, exosome biogenesis can affect the endosomal–lysosomal system. Indeed, we propose that efficient exosome release helps to modulate flux through the neuronal endosomal pathway by decompressing potential “traffic jams.” Exosome secretion may have the added benefit of unburdening the neuron’s lysosomal system by delivering endosomal–lysosomal material into the extracellular space, where other cell types may contribute to the degradation of neuronal debris. Thus, maintaining robust neuronal exosome production may prevent or mitigate endosomal and lysosomal abnormalities linked to aging and neurodegenerative diseases. While the current evidence suggests that the exosomal system in the brain can be modulated both by membrane lipid composition and the expression of key proteins that contribute to the formation and secretion of exosomes, how exosomal pathway-regulatory elements sense and respond to perturbations in the endosomal pathway is not well understood. Based upon findings from the extensively studied DS and APOE4 models, we propose that enhanced neuronal exosome secretion can be a protective response, reducing pathological disruption of the endosomal–lysosomal system in disease-vulnerable neurons. Developing therapeutic approaches that help to maintain or enhance neuronal exosome biogenesis and release may be beneficial in a range of disorders of the central nervous system.
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Affiliation(s)
- Paul M Mathews
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, United States.,Department of Psychiatry, New York University Langone Health, New York, NY, United States.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, United States
| | - Efrat Levy
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, United States.,Department of Psychiatry, New York University Langone Health, New York, NY, United States.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, United States.,Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, NY, United States
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17
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Yan T, Wang L, Gao J, Siedlak SL, Huntley ML, Termsarasab P, Perry G, Chen SG, Wang X. Rab10 Phosphorylation is a Prominent Pathological Feature in Alzheimer's Disease. J Alzheimers Dis 2019; 63:157-165. [PMID: 29562525 DOI: 10.3233/jad-180023] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the leading cause of dementia in the elderly, characterized by neurofibrillary tangles (NFTs), senile plaques (SPs), and a progressive loss of neuronal cells in selective brain regions. Rab10, a small Rab GTPase involved in vesicular trafficking, has recently been identified as a novel protein associated with AD. Interestingly, Rab10 is a key substrate of leucine-rich repeat kinase 2 (LRRK2), a serine/threonine protein kinase genetically associated with the second most common neurodegenerative disease Parkinson's disease. However, the phosphorylation state of Rab10 has not yet been investigated in AD. Here, using a specific antibody recognizing LRRK2-mediated Rab10 phosphorylation at the amino acid residue threonine 73 (pRab10-T73), we performed immunocytochemical analysis of pRab10-T73 in hippocampal tissues of patients with AD. pRab10-T73 was prominent in NFTs in neurons within the hippocampus in all cases of AD examined, whereas immunoreactivity was very faint in control cases. Other characteristic AD pathological structures including granulovacuolar degeneration, dystrophic neurites and neuropil threads also contained pRab10-T73. The pRab10-T73 immunoreactivity was diminished greatly following dephosphorylation with alkaline phosphatase. pRab10-T73 was further found to be highly co-localized with hyperphosphorylated tau (pTau) in AD, and demonstrated similar pathological patterns as pTau in Down syndrome and progressive supranuclear palsy. Although pRab10-T73 immunoreactivity could be noted in dystrophic neurites surrounding SPs, SPs were largely negative for pRab10-T73. These findings indicate that Rab10 phosphorylation could be responsible for aberrations in the vesicle trafficking observed in AD leading to neurodegeneration.
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Affiliation(s)
- Tingxiang Yan
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Luwen Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Ju Gao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Sandra L Siedlak
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Mikayla L Huntley
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Pichet Termsarasab
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Shu G Chen
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
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18
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Peng KY, Pérez-González R, Alldred MJ, Goulbourne CN, Morales-Corraliza J, Saito M, Saito M, Ginsberg SD, Mathews PM, Levy E. Apolipoprotein E4 genotype compromises brain exosome production. Brain 2019; 142:163-175. [PMID: 30496349 PMCID: PMC6308312 DOI: 10.1093/brain/awy289] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 09/28/2018] [Indexed: 12/20/2022] Open
Abstract
In addition to being the greatest genetic risk factor for Alzheimer's disease, expression of the ɛ4 allele of apolipoprotein E can lead to cognitive decline during ageing that is independent of Alzheimer's amyloid-β and tau pathology. In human post-mortem tissue and mouse models humanized for apolipoprotein E, we examined the impact of apolipoprotein E4 expression on brain exosomes, vesicles that are produced within and secreted from late-endocytic multivesicular bodies. Compared to humans or mice homozygous for the risk-neutral ɛ3 allele we show that the ɛ4 allele, whether homozygous or heterozygous with an ɛ3 allele, drives lower exosome levels in the brain extracellular space. In mice, we show that the apolipoprotein E4-driven change in brain exosome levels is age-dependent: while not present at age 6 months, it is detectable at 12 months of age. Expression levels of the exosome pathway regulators tumor susceptibility gene 101 (TSG101) and Ras-related protein Rab35 (RAB35) were found to be reduced in the brain at the protein and mRNA levels, arguing that apolipoprotein E4 genotype leads to a downregulation of exosome biosynthesis and release. Compromised exosome production is likely to have adverse effects, including diminishing a cell's ability to eliminate materials from the endosomal-lysosomal system. This reduction in brain exosome levels in 12-month-old apolipoprotein E4 mice occurs earlier than our previously reported brain endosomal pathway changes, arguing that an apolipoprotein E4-driven failure in exosome production plays a primary role in endosomal and lysosomal deficits that occur in apolipoprotein E4 mouse and human brains. Disruption of these interdependent endosomal-exosomal-lysosomal systems in apolipoprotein E4-expressing individuals may contribute to amyloidogenic amyloid-β precursor protein processing, compromise trophic signalling and synaptic function, and interfere with a neuron's ability to degrade material, all of which are events that lead to neuronal vulnerability and higher risk of Alzheimer's disease development. Together, these data suggest that exosome pathway dysfunction is a previously unappreciated component of the brain pathologies that occur as a result of apolipoprotein E4 expression.
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Affiliation(s)
- Katherine Y Peng
- Department of Neurology, New York University Langone Health, New York, NY, USA.,Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA
| | - Rocío Pérez-González
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA
| | - Melissa J Alldred
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, New York University Langone Health, New York, NY, USA
| | - Chris N Goulbourne
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA
| | - Jose Morales-Corraliza
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, New York University Langone Health, New York, NY, USA
| | - Mariko Saito
- Department of Psychiatry, New York University Langone Health, New York, NY, USA.,Division of Neurochemistry, Nathan S. Kline Institute, Orangeburg, New York, USA
| | - Mitsuo Saito
- Department of Psychiatry, New York University Langone Health, New York, NY, USA.,Division of Analytical Psychopharmacology, Nathan S. Kline Institute, Orangeburg, New York, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, New York University Langone Health, New York, NY, USA.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, USA.,Department of Neuroscience and Physiology, New York University Langone Health, New York, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, New York University Langone Health, New York, NY, USA.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, New York University Langone Health, New York, NY, USA.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, USA.,Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, NY, USA
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19
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Low Electric Treatment activates Rho GTPase via Heat Shock Protein 90 and Protein Kinase C for Intracellular Delivery of siRNA. Sci Rep 2019; 9:4114. [PMID: 30858501 PMCID: PMC6412017 DOI: 10.1038/s41598-019-40904-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 01/28/2019] [Indexed: 11/08/2022] Open
Abstract
Low electric treatment (LET) promotes intracellular delivery of naked siRNA by altering cellular physiology. However, which signaling molecules and cellular events contribute to LET-mediated siRNA uptake are unclear. Here, we used isobaric tags in relative and absolute quantification (iTRAQ) proteomic analysis to identify changes in the levels of phosphorylated proteins that occur during cellular uptake of siRNA promoted by LET. iTRAQ analysis revealed that heat shock protein 90 (Hsp90)α and myristoylated alanine-rich C-kinase substrate (Marcks) were highly phosphorylated following LET of NIH 3T3 cells, but not untreated cells. Furthermore, the levels of phosphorylated Hsp90α and protein kinase C (PKC)γ were increased by LET both with siRNA and liposomes having various physicochemical properties used as model macromolecules, suggesting that PKCγ activated partly by Ca2+ influx as well as Hsp90 chaperone function were involved in LET-mediated cellular siRNA uptake. Furthermore, LET with siRNA induced activation of Rho GTPase via Hsp90 and PKC, which could contribute to cellular siRNA uptake accompanied by actin cytoskeleton remodeling. Collectively, our results suggested that LET-induced Rho GTPase activation via Hsp90 and PKC would participate in actin-dependent cellular uptake of siRNA.
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20
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Tavana JP, Rosene M, Jensen NO, Ridge PG, Kauwe JS, Karch CM. RAB10: an Alzheimer's disease resilience locus and potential drug target. Clin Interv Aging 2018; 14:73-79. [PMID: 30643396 PMCID: PMC6312396 DOI: 10.2147/cia.s159148] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Alzheimer’s disease (AD) is mainly a late-onset neurodegenerative disorder. Substantial efforts have been made to solve the complex genetic architecture of AD as a means to identify therapeutic targets. Unfortunately, to date, no disease-altering therapeutics have been developed. As therapeutics are likely to be most effective in the early stages of disease (ie, before the onset of symptoms), a recent focus of AD research has been the identification of protective factors that prevent disease. One example is the discovery of a rare variant in the 3′-UTR of RAB10 that is protective for AD. Here, we review the possible genetic, molecular, and functional role of RAB10 in AD and potential therapeutic approaches to target RAB10.
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Affiliation(s)
- Justina P Tavana
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
| | - Matthew Rosene
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA,
| | - Nick O Jensen
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA,
| | - Perry G Ridge
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
| | - John Sk Kauwe
- Department of Biology, Brigham Young University, Provo, UT 84602, USA.,Department of Neuroscience, Brigham Young University, Provo, UT 84602, USA
| | - Celeste M Karch
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA, .,Hope Center for Neurological Disorders, Washington University in St Louis, St Louis, MO, USA,
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21
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Sheehan P, Yue Z. Deregulation of autophagy and vesicle trafficking in Parkinson's disease. Neurosci Lett 2018; 697:59-65. [PMID: 29627340 DOI: 10.1016/j.neulet.2018.04.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 12/19/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disease characterized pathologically by the selective loss of dopaminergic neurons in the substantia nigra and the intracellular accumulation of α-synuclein in the Lewy bodies. While the pathogenic mechanisms of PD are poorly understood, many lines of evidence point to a role of altered autophagy and membrane trafficking in the development of the disease. Emerging studies show that connections between the deregulation of autophagy and synaptic vesicle (SV) trafficking may contribute to PD. Here we review the evidence that many PD related-genes have roles in both autophagy and SV trafficking and examine how deregulation of these pathways contributes to PD pathogenesis. This review also discusses recent studies aimed at uncovering the role of PD-linked genes in autophagy-lysosome function.
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Affiliation(s)
- Patricia Sheehan
- Department of Neurology, The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029, USA
| | - Zhenyu Yue
- Department of Neurology, The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029, USA.
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Gong T, Yan Y, Zhang J, Liu S, Liu H, Gao J, Zhou X, Chen J, Shi A. PTRN-1/CAMSAP promotes CYK-1/formin-dependent actin polymerization during endocytic recycling. EMBO J 2018; 37:embj.201798556. [PMID: 29567645 DOI: 10.15252/embj.201798556] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 02/18/2018] [Accepted: 02/27/2018] [Indexed: 01/01/2023] Open
Abstract
Cargo sorting and membrane carrier initiation in recycling endosomes require appropriately coordinated actin dynamics. However, the mechanism underlying the regulation of actin organization during recycling transport remains elusive. Here we report that the loss of PTRN-1/CAMSAP stalled actin exchange and diminished the cytosolic actin structures. Furthermore, we found that PTRN-1 is required for the recycling of clathrin-independent cargo hTAC-GFP The N-terminal calponin homology (CH) domain and central coiled-coils (CC) region of PTRN-1 can synergistically sustain the flow of hTAC-GFP We identified CYK-1/formin as a binding partner of PTRN-1. The N-terminal GTPase-binding domain (GBD) of CYK-1 serves as the binding interface for the PTRN-1 CH domain. The presence of the PTRN-1 CH domain promoted CYK-1-mediated actin polymerization, which suggests that the PTRN-1-CH:CYK-1-GBD interaction efficiently relieves autoinhibitory interactions within CYK-1. As expected, the overexpression of the CYK-1 formin homology domain 2 (FH2) substantially restored actin structures and partially suppressed the hTAC-GFP overaccumulation phenotype in ptrn-1 mutants. We conclude that the PTRN-1 CH domain is required to stimulate CYK-1 to facilitate actin dynamics during endocytic recycling.
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Affiliation(s)
- Ting Gong
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yanling Yan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jing Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shuai Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hang Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jinghu Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xin Zhou
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China .,Institute for Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China.,Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Altered Development of Synapse Structure and Function in Striatum Caused by Parkinson's Disease-Linked LRRK2-G2019S Mutation. J Neurosci 2017; 36:7128-41. [PMID: 27383589 DOI: 10.1523/jneurosci.3314-15.2016] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 05/26/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) can cause Parkinson's disease (PD), and the most common disease-associated mutation, G2019S, increases kinase activity. Because LRRK2 expression levels rise during synaptogenesis and are highest in dorsal striatal spiny projection neurons (SPNs), we tested the hypothesis that the LRRK2-G2019S mutation would alter development of excitatory synaptic networks in dorsal striatum. To circumvent experimental confounds associated with LRRK2 overexpression, we used mice expressing LRRK2-G2019S or D2017A (kinase-dead) knockin mutations. In whole-cell recordings, G2019S SPNs exhibited a fourfold increase in sEPSC frequency compared with wild-type SPNs in postnatal day 21 mice. Such heightened neural activity was increased similarly in direct- and indirect-pathway SPNs, and action potential-dependent activity was particularly elevated. Excitatory synaptic activity in D2017A SPNs was similar to wild type, indicating a selective effect of G2019S. Acute exposure to LRRK2 kinase inhibitors normalized activity, supporting that excessive neural activity in G2019S SPNs is mediated directly and is kinase dependent. Although dendritic arborization and densities of excitatory presynaptic terminals and postsynaptic dendritic spines in G2019S SPNs were similar to wild type, G2019S SPNs displayed larger spines that were matched functionally by a shift toward larger postsynaptic response amplitudes. Acutely isolating striatum from overlying neocortex normalized sEPSC frequency in G2019S mutants, supporting that abnormal corticostriatal activity is involved. These findings indicate that the G2019S mutation imparts a gain-of-abnormal function to SPN activity and morphology during a stage of development when activity can permanently modify circuit structure and function. SIGNIFICANCE STATEMENT Mutations in the kinase domain of leucine-rich repeat kinase 2 (LRRK2) follow Parkinson's disease (PD) heritability. How such mutations affect brain function is poorly understood. LRRK2 expression levels rise after birth at a time when synapses are forming and are highest in dorsal striatum, suggesting that LRRK2 regulates development of striatal circuits. During a period of postnatal development when activity plays a large role in permanently shaping neural circuits, our data show how the most common PD-causing LRRK2 mutation dramatically alters excitatory synaptic activity and the shape of postsynaptic structures in striatum. These findings provide new insight into early functional and structural aberrations in striatal connectivity that may predispose striatal circuitry to both motor and nonmotor dysfunction later in life.
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Abstract
Synaptic connections in the brain are continuously weakened or strengthened in response to changes in neuronal activity. This process, known as synaptic plasticity, is the cellular basis for learning and memory, and is thought to be altered in several neuronal disorders. An important aspect of synaptic plasticity is the tightly controlled trafficking and synaptic targeting of the AMPA-type glutamate receptors, which are the major mediators of fast excitatory transmission in the brain. This review addresses the role of Rab GTPases in AMPA receptor trafficking in neurons under basal conditions and during activity-induced synaptic plasticity, especially during long-term potentiation (LTP) and long-term depression (LTD). We highlight the importance of the tight spatio-temporal control of Rab activity and suggest that this is critical for proper neuronal functions. We also discuss how abnormal AMPA receptor trafficking and malfunctioning of Rabs can lead to neurologic disorders or memory problems.
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Affiliation(s)
- Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart , Stuttgart , Germany.,Stuttgart Research Center Systems Biology, University of Stuttgart , Stuttgart , Germany
| | - Katalin Schlett
- Department of Physiology and Neurobiology, Eötvös Loránd University , Budapest , Hungary.,MTA-ELTE NAP B Neuronal Cell Biology Research Group, Eötvös Loránd University , Budapest , Hungary
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25
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Rab14 Act as Oncogene and Induce Proliferation of Gastric Cancer Cells via AKT Signaling Pathway. PLoS One 2017; 12:e0170620. [PMID: 28107526 PMCID: PMC5249107 DOI: 10.1371/journal.pone.0170620] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 01/06/2017] [Indexed: 01/08/2023] Open
Abstract
Rab14 is a member of RAS oncogene family, and its dysfunction has been reported to be involved in various types of human cancer. However, its expression and function were still unclear in gastric cancer. The aim of this study was to investigate the function and mechanism of Rab14 in gastric cancer cell lines. Quantitative real-time PCR (qRT-PCR) was performed in 17 gastric adenocarcinoma tissues and 4 cell lines to detect the expression of Rab14. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT), colony formation and flow cytometry assays were employed to determine the proliferative ability, cell cycle transition and apoptosis in vitro in BGC-823 or SGC-7901 cells. Western blot was performed to investigate the pathways and mechanism of Rab14 regulation. In this study, we show that Rab14 presents a significant up-regulated expression among the paired tissue samples and cell lines in gastric cancer. When we overexpressed Rab14 in SGC-7901 cells or silenced Rab14 in BGC-823 cells, we found that Rab14 could modify cell growth, cell cycle or apoptosis, which accompanied with an obvious regulation of CCND1, CDK2 and BAX involving in AKT signaling pathway. In conclusion, this study provides a new evidence on that Rab14 functions as a novel tumor oncogene and could be a potential therapeutic target in gastric cancer.
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26
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Wang P, Liu H, Wang Y, Liu O, Zhang J, Gleason A, Yang Z, Wang H, Shi A, Grant BD. RAB-10 Promotes EHBP-1 Bridging of Filamentous Actin and Tubular Recycling Endosomes. PLoS Genet 2016; 12:e1006093. [PMID: 27272733 PMCID: PMC4894640 DOI: 10.1371/journal.pgen.1006093] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 05/10/2016] [Indexed: 12/21/2022] Open
Abstract
EHBP-1 (Ehbp1) is a conserved regulator of endocytic recycling, acting as an effector of small GTPases including RAB-10 (Rab10). Here we present evidence that EHBP-1 associates with tubular endosomal phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] enriched membranes through an N-terminal C2-like (NT-C2) domain, and define residues within the NT-C2 domain that mediate membrane interaction. Furthermore, our results indicate that the EHBP-1 central calponin homology (CH) domain binds to actin microfilaments in a reaction that is stimulated by RAB-10(GTP). Loss of any aspect of this RAB-10/EHBP-1 system in the C. elegans intestinal epithelium leads to retention of basolateral recycling cargo in endosomes that have lost their normal tubular endosomal network (TEN) organization. We propose a mechanism whereby RAB-10 promotes the ability of endosome-bound EHBP-1 to also bind to the actin cytoskeleton, thereby promoting endosomal tubulation. Endosomes are intracellular organelles that sort protein and lipid components integral to the membrane, as well as more loosely associated lumenal content, for delivery to distinct intracellular destinations. Endosomes associated with recycling cargo back to the plasma membrane are often tubular in morphology, and this morphology is thought to be essential for recycling function. Our previous work identified a particularly dramatic network of endosomal tubules involved in membrane protein recycling in the basolateral intestinal epithelial cells of C. elegans. Our subsequent genetic analysis of basolateral recycling in this system identified a number of key regulators of these endosomes, including the small GTPase RAB-10 and its effector EHBP-1. Our new work presented here shows that EHBP-1 promotes endosomal tubulation by linking the membrane lipid PI(4,5)P2 to the actin cytoskeleton, and that the linkage of EHBP-1 to actin is enhanced by the interaction of EHBP-1 with RAB-10. This work has broad implications for how endosomal tubulation occurs in all cells, and has specific implications for the role of EHBP-1 in related processes such as insulin-stimulated recycling of glucose transporters in human adipocytes, a process intimately linked to type II diabetes.
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Affiliation(s)
- Peixiang Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hang Liu
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yu Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ou Liu
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Jing Zhang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Adenrele Gleason
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Zhenrong Yang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hui Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anbing Shi
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute for Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (AS); (BDG)
| | - Barth D. Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail: (AS); (BDG)
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27
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Rincón-Arévalo H, Castaño D, Villa-Pulgarín J, Rojas M, Vásquez G, Correa LA, Ramírez-Pineda JR, Yassin LM. Dyslipidemia-associated alterations in B cell subpopulation frequency and phenotype during experimental atherosclerosis. Atherosclerosis 2016; 247:118-26. [DOI: 10.1016/j.atherosclerosis.2015.12.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/10/2015] [Accepted: 12/15/2015] [Indexed: 01/01/2023]
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Zhang D, Dubey J, Koushika SP, Rongo C. RAB-6.1 and RAB-6.2 Promote Retrograde Transport in C. elegans. PLoS One 2016; 11:e0149314. [PMID: 26891225 PMCID: PMC4758642 DOI: 10.1371/journal.pone.0149314] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/30/2016] [Indexed: 12/25/2022] Open
Abstract
Retrograde transport is a critical mechanism for recycling certain membrane cargo. Following endocytosis from the plasma membrane, retrograde cargo is moved from early endosomes to Golgi followed by transport (recycling) back to the plasma membrane. The complete molecular and cellular mechanisms of retrograde transport remain unclear. The small GTPase RAB-6.2 mediates the retrograde recycling of the AMPA-type glutamate receptor (AMPAR) subunit GLR-1 in C. elegans neurons. Here we show that RAB-6.2 and a close paralog, RAB-6.1, together regulate retrograde transport in both neurons and non-neuronal tissue. Mutants for rab-6.1 or rab-6.2 fail to recycle GLR-1 receptors, resulting in GLR-1 turnover and behavioral defects indicative of diminished GLR-1 function. Loss of both rab-6.1 and rab-6.2 results in an additive effect on GLR-1 retrograde recycling, indicating that these two C. elegans Rab6 isoforms have overlapping functions. MIG-14 (Wntless) protein, which undergoes retrograde recycling, undergoes a similar degradation in intestinal epithelia in both rab-6.1 and rab-6.2 mutants, suggesting a broader role for these proteins in retrograde transport. Surprisingly, MIG-14 is localized to separate, spatially segregated endosomal compartments in rab-6.1 mutants compared to rab-6.2 mutants. Our results indicate that RAB-6.1 and RAB-6.2 have partially redundant functions in overall retrograde transport, but also have their own unique cellular- and subcellular functions.
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Affiliation(s)
- Donglei Zhang
- The Waksman Institute, Department of Genetics, Rutgers The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Jyoti Dubey
- Department of Biological Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
- Institute for Stem Cell Biology and Regenerative Medicine (InStem), Bangalore, India
- Manipal University, Karnataka, India
| | - Sandhya P. Koushika
- Department of Biological Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Christopher Rongo
- The Waksman Institute, Department of Genetics, Rutgers The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
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29
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Park EC, Rongo C. The p38 MAP kinase pathway modulates the hypoxia response and glutamate receptor trafficking in aging neurons. eLife 2016; 5. [PMID: 26731517 PMCID: PMC4775213 DOI: 10.7554/elife.12010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/04/2016] [Indexed: 01/07/2023] Open
Abstract
Neurons are sensitive to low oxygen (hypoxia) and employ a conserved pathway to combat its effects. Here, we show that p38 MAP Kinase (MAPK) modulates this hypoxia response pathway in C. elegans. Mutants lacking p38 MAPK components pmk-1 or sek-1 resemble mutants lacking the hypoxia response component and prolyl hydroxylase egl-9, with impaired subcellular localization of Mint orthologue LIN-10, internalization of glutamate receptor GLR-1, and depression of GLR-1-mediated behaviors. Loss of p38 MAPK impairs EGL-9 protein localization in neurons and activates the hypoxia-inducible transcription factor HIF-1, suggesting that p38 MAPK inhibits the hypoxia response pathway through EGL-9. As animals age, p38 MAPK levels decrease, resulting in GLR-1 internalization; this age-dependent downregulation can be prevented through either p38 MAPK overexpression or removal of CDK-5, an antagonizing kinase. Our findings demonstrate that p38 MAPK inhibits the hypoxia response pathway and determines how aging neurons respond to hypoxia through a novel mechanism. DOI:http://dx.doi.org/10.7554/eLife.12010.001 The brain accounts for 2% of our body weight, but consumes about 20% of our oxygen intake. This oxygen gluttony is due to the tremendous appetite of brain cells for energy, which neurons satisfy through oxygen-dependent (aerobic) metabolism. As a result, the loss of oxygen to the brain during a stroke, heart attack, or due to another medical condition can be very damaging to cells in the brain. Human and other animal cells use a communication system called the hypoxia response pathway to sense oxygen and trigger a protective response when oxygen is low. This pathway includes an enzyme called prolyl hydroxylase, which senses oxygen and modifies another protein in the pathway that regulates the production of enzymes involved in metabolism. This alters the balance of enzymes involved in aerobic and oxygen-independent (anaerobic) metabolism in the cell. However, it is not clear how the activity of the prolyl hydroxylase is regulated. Much of our knowledge about the hypoxia response pathway has been gained from studies using a small worm called C. elegans. This worm uses the pathway to cope with hypoxia in the harsh environment of the soil. Mutant worms that lack the prolyl hydroxylase have several abnormalities including higher levels of anaerobic metabolism even in the presence of oxygen, and defects in the connections between neurons. Park and Rongo used C. elegans to study the pathway in more detail. The experiments show that another enzyme called p38 MAPK activates the prolyl hydroxylase. Mutant worms that lack this enzyme have similar abnormalities in the hypoxia response pathway as animals that lack the prolyl hydroxylase. In normal worms, decreasing levels of p38 MAPK as the animals grow older contribute to the decline in the nervous system. The p38 MAPK enzyme appears to work by regulating the activity of the prolyl hydroxylase and its location inside neurons. These findings provide a new target for the development of drugs that may help to protect us from tissue damage caused by hypoxia. Future challenges are to find out what activates p38 MAPK, and how it influences the location of prolyl hydroxylase in neurons. DOI:http://dx.doi.org/10.7554/eLife.12010.002
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Affiliation(s)
- Eun Chan Park
- The Waksman Institute, Rutgers The State University of New Jersey, New Jersey, United States.,Department of Genetics, Rutgers The State University of New Jersey, New Jersey, United States
| | - Christopher Rongo
- The Waksman Institute, Rutgers The State University of New Jersey, New Jersey, United States.,Department of Genetics, Rutgers The State University of New Jersey, New Jersey, United States
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30
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RAB-10 Regulates Dendritic Branching by Balancing Dendritic Transport. PLoS Genet 2015; 11:e1005695. [PMID: 26633194 PMCID: PMC4669152 DOI: 10.1371/journal.pgen.1005695] [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] [Received: 03/26/2015] [Accepted: 10/31/2015] [Indexed: 11/19/2022] Open
Abstract
The construction of a large dendritic arbor requires robust growth and the precise delivery of membrane and protein cargoes to specific subcellular regions of the developing dendrite. How the microtubule-based vesicular trafficking and sorting systems are regulated to distribute these dendritic development factors throughout the dendrite is not well understood. Here we identify the small GTPase RAB-10 and the exocyst complex as critical regulators of dendrite morphogenesis and patterning in the C. elegans sensory neuron PVD. In rab-10 mutants, PVD dendritic branches are reduced in the posterior region of the cell but are excessive in the distal anterior region of the cell. We also demonstrate that the dendritic branch distribution within PVD depends on the balance between the molecular motors kinesin-1/UNC-116 and dynein, and we propose that RAB-10 regulates dendrite morphology by balancing the activity of these motors to appropriately distribute branching factors, including the transmembrane receptor DMA-1. Building a complex dendritic arbor requires tremendous cellular growth, and how membrane and protein components are transported to support a rapidly growing, polarized dendrite remains unclear. We have identified the small GTPase RAB-10 as a key regulator of this process, providing insight into both dendritic development and the control of trafficking by small GTPases.
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31
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Brudvig JJ, Weimer JM. X MARCKS the spot: myristoylated alanine-rich C kinase substrate in neuronal function and disease. Front Cell Neurosci 2015; 9:407. [PMID: 26528135 PMCID: PMC4602126 DOI: 10.3389/fncel.2015.00407] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/25/2015] [Indexed: 11/18/2022] Open
Abstract
Intracellular protein-protein interactions are dynamic events requiring tightly regulated spatial and temporal checkpoints. But how are these spatial and temporal cues integrated to produce highly specific molecular response patterns? A helpful analogy to this process is that of a cellular map, one based on the fleeting localization and activity of various coordinating proteins that direct a wide array of interactions between key molecules. One such protein, myristoylated alanine-rich C-kinase substrate (MARCKS) has recently emerged as an important component of this cellular map, governing a wide variety of protein interactions in every cell type within the brain. In addition to its well-documented interactions with the actin cytoskeleton, MARCKS has been found to interact with a number of other proteins involved in processes ranging from intracellular signaling to process outgrowth. Here, we will explore these diverse interactions and their role in an array of brain-specific functions that have important implications for many neurological conditions.
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Affiliation(s)
- Jon J Brudvig
- Children's Health Research Center, Sanford Research Sioux Falls, SD, USA ; Basic Biomedical Sciences, University of South Dakota Vermillion, SD, USA
| | - Jill M Weimer
- Children's Health Research Center, Sanford Research Sioux Falls, SD, USA ; Department of Pediatrics, Sanford School of Medicine, University of South Dakota Vermillion, SD, USA
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32
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Basolateral Endocytic Recycling Requires RAB-10 and AMPH-1 Mediated Recruitment of RAB-5 GAP TBC-2 to Endosomes. PLoS Genet 2015; 11:e1005514. [PMID: 26393361 PMCID: PMC4578947 DOI: 10.1371/journal.pgen.1005514] [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: 04/19/2015] [Accepted: 08/18/2015] [Indexed: 11/27/2022] Open
Abstract
The small GTPase RAB-5/Rab5 is a master regulator of the early endosome, required for a myriad of coordinated activities, including the degradation and recycling of internalized cargo. Here we focused on the recycling function of the early endosome and the regulation of RAB-5 by GAP protein TBC-2 in the basolateral C. elegans intestine. We demonstrate that downstream basolateral recycling regulators, GTPase RAB-10/Rab10 and BAR domain protein AMPH-1/Amphiphysin, bind to TBC-2 and help to recruit it to endosomes. In the absence of RAB-10 or AMPH-1 binding to TBC-2, RAB-5 membrane association is abnormally high and recycling cargo is trapped in early endosomes. Furthermore, the loss of TBC-2 or AMPH-1 leads to abnormally high spatial overlap of RAB-5 and RAB-10. Taken together our results indicate that RAB-10 and AMPH-1 mediated down-regulation of RAB-5 is an important step in recycling, required for cargo exit from early endosomes and regulation of early endosome–recycling endosome interactions. When cargo is internalized from the cell surface by endocytosis, it enters a series of intracellular organelles called endosomes. Endosomes sort cargo, such that some cargos are sent to the lysosome for degradation, while others are recycled to the plasma membrane. Small GTPase proteins of the Rabs family are master regulators of endosomes, functioning by acting as molecular switches. As cargo moves through the endosomal system, it must pass from the domain controlled by one Rab-GTPase to the domain controlled by another. Little is known about how transitions along the recycling pathway are controlled. Here we analyze a group of protein interactions that act along the early-to-recycling pathway. Our work shows that RAB-5 deactivation mediated by TBC-2 and its recruiters RAB-10 and AMPH-1 is important for cargo recycling. This work provides mechanistic insight into how Rab proteins controlling different steps of trafficking interact during endocytic recycling.
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33
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Zou W, Yadav S, DeVault L, Jan YN, Sherwood DR. RAB-10-Dependent Membrane Transport Is Required for Dendrite Arborization. PLoS Genet 2015; 11:e1005484. [PMID: 26394140 PMCID: PMC4578882 DOI: 10.1371/journal.pgen.1005484] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/05/2015] [Indexed: 01/07/2023] Open
Abstract
Formation of elaborately branched dendrites is necessary for the proper input and connectivity of many sensory neurons. Previous studies have revealed that dendritic growth relies heavily on ER-to-Golgi transport, Golgi outposts and endocytic recycling. How new membrane and associated cargo is delivered from the secretory and endosomal compartments to sites of active dendritic growth, however, remains unknown. Using a candidate-based genetic screen in C. elegans, we have identified the small GTPase RAB-10 as a key regulator of membrane trafficking during dendrite morphogenesis. Loss of rab-10 severely reduced proximal dendritic arborization in the multi-dendritic PVD neuron. RAB-10 acts cell-autonomously in the PVD neuron and localizes to the Golgi and early endosomes. Loss of function mutations of the exocyst complex components exoc-8 and sec-8, which regulate tethering, docking and fusion of transport vesicles at the plasma membrane, also caused proximal dendritic arborization defects and led to the accumulation of intracellular RAB-10 vesicles. In rab-10 and exoc-8 mutants, the trans-membrane proteins DMA-1 and HPO-30, which promote PVD dendrite stabilization and branching, no longer localized strongly to the proximal dendritic membranes and instead were sequestered within intracellular vesicles. Together these results suggest a crucial role for the Rab10 GTPase and the exocyst complex in controlling membrane transport from the secretory and/or endosomal compartments that is required for dendritic growth. Dendrites are cellular extensions from neurons that gather information from other neurons or cues from the external environment to convey to the nervous system of an organism. Dendrites are often extensively branched, raising the question of how neurons supply plasma membrane and dendrite specific proteins from the source of synthesis inside the cell to developing dendrites. We have examined membrane trafficking in the PVD neuron in the nematode worm C. elegans to investigate how new membrane and dendrite proteins are trafficked. The PVD neuron is easy to visualize and has remarkably long and widely branched dendrites positioned along the skin of the worm, which transmits information about harsh touch and cold temperature to the nervous system. We have discovered that a key organizer of vesicle trafficking, the RAB-10 protein, localizes to membrane vesicles and is required to traffic these vesicles that contain plasma membrane and dendrite proteins to the growing PVD dendrite. Further, our work revealed that a complex of proteins, termed the exocyst, that helps fuse membrane vesicles at the plasma membrane, localizes with RAB-10 and is required for dendrite branching. Together, our work has revealed a novel mechanism for how neurons build dendrites that could be used to help repair damaged neurons in human diseases and during aging.
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Affiliation(s)
- Wei Zou
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Smita Yadav
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Laura DeVault
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - David R. Sherwood
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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Vanderwerf SM, Buck DC, Wilmarth PA, Sears LM, David LL, Morton DB, Neve KA. Role for Rab10 in Methamphetamine-Induced Behavior. PLoS One 2015; 10:e0136167. [PMID: 26291453 PMCID: PMC4546301 DOI: 10.1371/journal.pone.0136167] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/31/2015] [Indexed: 11/18/2022] Open
Abstract
Lipid rafts are specialized, cholesterol-rich membrane compartments that help to organize transmembrane signaling by restricting or promoting interactions with subsets of the cellular proteome. The hypothesis driving this study was that identifying proteins whose relative abundance in rafts is altered by the abused psychostimulant methamphetamine would contribute to fully describing the pathways involved in acute and chronic effects of the drug. Using a detergent-free method for preparing rafts from rat brain striatal membranes, we identified density gradient fractions enriched in the raft protein flotillin but deficient in calnexin and the transferrin receptor, markers of non-raft membranes. Dopamine D1- and D2-like receptor binding activity was highly enriched in the raft fractions, but pretreating rats with methamphetamine (2 mg/kg) once or repeatedly for 11 days did not alter the distribution of the receptors. LC-MS analysis of the protein composition of raft fractions from rats treated once with methamphetamine or saline identified methamphetamine-induced changes in the relative abundance of 23 raft proteins, including the monomeric GTP-binding protein Rab10, whose abundance in rafts was decreased 2.1-fold by acute methamphetamine treatment. Decreased raft localization was associated with a selective decrease in the abundance of Rab10 in a membrane fraction that includes synaptic vesicles and endosomes. Inhibiting Rab10 activity by pan-neuronal expression of a dominant-negative Rab10 mutant in Drosophila melanogaster decreased methamphetamine-induced activity and mortality and decreased caffeine-stimulated activity but not mortality, whereas inhibiting Rab10 activity selectively in cholinergic neurons had no effect. These results suggest that activation and redistribution of Rab10 is critical for some of the behavioral effects of psychostimulants.
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Affiliation(s)
- Scott M. Vanderwerf
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon, United States of America
| | - David C. Buck
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Phillip A. Wilmarth
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Leila M. Sears
- Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Larry L. David
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - David B. Morton
- Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Kim A. Neve
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
- Research Service, VA Portland Health Care System, Portland, Oregon, United States of America
- * E-mail:
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A Presynaptic Regulatory System Acts Transsynaptically via Mon1 to Regulate Glutamate Receptor Levels in Drosophila. Genetics 2015; 201:651-64. [PMID: 26290519 DOI: 10.1534/genetics.115.177402] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/10/2015] [Indexed: 11/18/2022] Open
Abstract
Mon1 is an evolutionarily conserved protein involved in the conversion of Rab5 positive early endosomes to late endosomes through the recruitment of Rab7. We have identified a role for Drosophila Mon1 in regulating glutamate receptor levels at the larval neuromuscular junction. We generated mutants in Dmon1 through P-element excision. These mutants are short-lived with strong motor defects. At the synapse, the mutants show altered bouton morphology with several small supernumerary or satellite boutons surrounding a mature bouton; a significant increase in expression of GluRIIA and reduced expression of Bruchpilot. Neuronal knockdown of Dmon1 is sufficient to increase GluRIIA levels, suggesting its involvement in a presynaptic mechanism that regulates postsynaptic receptor levels. Ultrastructural analysis of mutant synapses reveals significantly smaller synaptic vesicles. Overexpression of vglut suppresses the defects in synaptic morphology and also downregulates GluRIIA levels in Dmon1 mutants, suggesting that homeostatic mechanisms are not affected in these mutants. We propose that DMon1 is part of a presynaptically regulated transsynaptic mechanism that regulates GluRIIA levels at the larval neuromuscular junction.
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Zheng N, Jeyifous O, Munro C, Montgomery JM, Green WN. Synaptic activity regulates AMPA receptor trafficking through different recycling pathways. eLife 2015; 4. [PMID: 25970033 PMCID: PMC4451724 DOI: 10.7554/elife.06878] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/13/2015] [Indexed: 12/04/2022] Open
Abstract
Changes in glutamatergic synaptic strength in brain are dependent on AMPA-type glutamate receptor (AMPAR) recycling, which is assumed to occur through a single local pathway. In this study, we present evidence that AMPAR recycling occurs through different pathways regulated by synaptic activity. Without synaptic stimulation, most AMPARs recycled in dynamin-independent endosomes containing the GTPase, Arf6. Few AMPARs recycled in dynamin-dependent endosomes labeled by transferrin receptors (TfRs). AMPAR recycling was blocked by alterations in the GTPase, TC10, which co-localized with Arf6 endosomes. TC10 mutants that reduced AMPAR recycling had no effect on increased AMPAR levels with long-term potentiation (LTP) and little effect on decreased AMPAR levels with long-term depression. However, internalized AMPAR levels in TfR-containing recycling endosomes increased after LTP, indicating increased AMPAR recycling through the dynamin-dependent pathway with synaptic plasticity. LTP-induced AMPAR endocytosis is inconsistent with local recycling as a source of increased surface receptors, suggesting AMPARs are trafficked from other sites. DOI:http://dx.doi.org/10.7554/eLife.06878.001 Cells called neurons transmit information around the brain in the form of electrical signals. At a junction between two neurons—called a synapse—an electrical signal triggers the release of small molecules called neurotransmitters. These molecules travel across the gap between the two neurons and trigger a new electrical signal in the second neuron. Memories can be stored in synapses: high levels of activity can ‘strengthen’ the synapse, which increases the transfer of information between the neurons. In many synapses, a molecule called glutamate is the neurotransmitter. Proteins called AMPARs, which are found on the surface of the neuron, can detect glutamate and transmit the signal along the second neuron. The strength of synapses is controlled by changes in AMPAR levels through ‘recycling’, where AMPAR proteins are removed from synapses, internalized and later returned to synapses. It was thought that AMPARs are recycled via just one pathway at synapses. However, the amount of recycling is much higher when the synapses are active and it is not clear how this works. Now, Zheng et al. have used fluorescent tags to track the recycling of AMPARs in synapses from rats under a microscope. The experiments show that when the synapses are not active, most AMPARs are recycled via a pathway marked by a protein called Arf6. However, when the synapses are active, most AMPAR is recycled via a different route marked by so-called ‘transferrin receptor’ proteins. The experiments also reveal that a protein called TC10 is involved in recycling AMPARs alongside Arf6, but is not required for recycling when the synapses are active and being strengthened. Unexpectedly, AMPAR internalization—via the process involving transferrin receptors—increases during synapse strengthening. This suggests that some of the extra AMPAR proteins sent to the membrane have come from other parts of the neuron away from the synapse. Zheng et al.'s findings provide evidence that AMPARs are recycled through different routes depending on the activity of the synapse. The next challenge will be to directly test whether AMPARs are transported from other parts of the neuron to the strengthened synapse and to understand how this works. DOI:http://dx.doi.org/10.7554/eLife.06878.002
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Affiliation(s)
- Ning Zheng
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Okunola Jeyifous
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Charlotte Munro
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - William N Green
- Department of Neurobiology, University of Chicago, Chicago, United States
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Spatial and molecular cues for cell outgrowth during C. elegans uterine development. Dev Biol 2014; 396:121-35. [PMID: 25281934 DOI: 10.1016/j.ydbio.2014.09.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/19/2014] [Accepted: 09/22/2014] [Indexed: 01/04/2023]
Abstract
The Caenorhabditis elegans uterine seam cell (utse) is an H-shaped syncytium that connects the uterus to the body wall. Comprising nine nuclei that move outward in a bidirectional manner, this synctium undergoes remarkable shape change during development. Using cell ablation experiments, we show that three surrounding cell types affect utse development: the uterine toroids, the anchor cell and the sex myoblasts. The presence of the anchor cell (AC) nucleus within the utse is necessary for proper utse development and AC invasion genes fos-1, cdh-3, him-4, egl-43, zmp-1 and mig-10 promote utse cell outgrowth. Two types of uterine lumen epithelial cells, uterine toroid 1 (ut1) and uterine toroid 2 (ut2), mediate proper utse outgrowth and we show roles in utse development for two genes expressed in the uterine toroids: the RASEF ortholog rsef-1 and Trio/unc-73. The SM expressed gene unc-53/NAV regulates utse cell shape; ablation of sex myoblasts (SMs), which generate uterine and vulval muscles, cause defects in utse morphology. Our results clarify the nature of the interactions that exist between utse and surrounding tissue, identify new roles for genes involved in cell outgrowth, and present the utse as a new model system for understanding cell shape change and, putatively, diseases associated with cell shape change.
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Merali Z, Gao MM, Bowes T, Chen J, Evans K, Kassner A. Neuroproteome changes after ischemia/reperfusion injury and tissue plasminogen activator administration in rats: a quantitative iTRAQ proteomics study. PLoS One 2014; 9:e98706. [PMID: 24879061 PMCID: PMC4039533 DOI: 10.1371/journal.pone.0098706] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 05/02/2014] [Indexed: 01/02/2023] Open
Abstract
The thrombolytic, recombinant tissue plasminogen activator (rt-PA) is the only approved therapy for acute ischemic stroke (AIS). When administered after AIS, rt-PA has many adverse pleiotropic actions, which are currently poorly understood. The identification of proteins showing differential expression after rt-PA administration may provide insight into these pleiotropic actions. In this study we used a 2D-LC MS/MS iTRAQ proteomic analysis, western blotting, and pathway analysis to analyze changes in protein expression 24-hours after rt-PA administration in the cortical brain tissue of 36 rats that underwent a sham or transient middle cerebral artery occlusion surgery. After rt-PA administration we reported alterations in the expressions of 18 proteins, many of which were involved in excitatory neurotransmitter function or cytoskeletal structure. The expression changes of GAD2 and EAAT1 were validated with western blot. The interactions between the identified proteins were analyzed with the IPA pathway analysis tool and three proteins: DPYSL2, RTN4, and the NF-kB complex, were found to have characteristics of being key proteins in the network. The differential protein expressions we observed may reflect pleiotropic actions of rt-PA after experimental stroke, and shine light on the mechanisms of rt-PA's adverse effects. This may have important implications in clinical settings where thrombolytic therapy is used to treat AIS.
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Affiliation(s)
- Zamir Merali
- Physiology and Experimental Medicine, The Hospital For Sick Children, Toronto, Ontario, Canada
| | - Meah MingYang Gao
- Department of Medical Imaging, University Of Toronto, Toronto, Ontario, Canada
| | - Tim Bowes
- Department of Medical Imaging, University Of Toronto, Toronto, Ontario, Canada
| | - Jian Chen
- Ontario Cancer Biomarker Network, Toronto, Ontario Canada
| | - Kenneth Evans
- Ontario Cancer Biomarker Network, Toronto, Ontario Canada
| | - Andrea Kassner
- Department of Medical Imaging, University Of Toronto, Toronto, Ontario, Canada
- Physiology and Experimental Medicine, The Hospital For Sick Children, Toronto, Ontario, Canada
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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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40
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Abstract
The elongation rate of axons is tightly regulated during development. Recycling of the plasma membrane is known to regulate axon extension; however, the specific molecules involved in recycling within the growth cone have not been fully characterized. Here, we investigated whether the small GTPases Rab4 and Rab5 involved in short-loop recycling regulate the extension of Xenopus retinal axons. We report that, in growth cones, Rab5 and Rab4 proteins localize to endosomes, which accumulate markers that are constitutively recycled. Fluorescence recovery after photo-bleaching experiments showed that Rab5 and Rab4 are recruited to endosomes in the growth cone, suggesting that they control recycling locally. Dynamic image analysis revealed that Rab4-positive carriers can bud off from Rab5 endosomes and move to the periphery of the growth cone, suggesting that both Rab5 and Rab4 contribute to recycling within the growth cone. Inhibition of Rab4 function with dominant-negative Rab4 or Rab4 morpholino and constitutive activation of Rab5 decreases the elongation of retinal axons in vitro and in vivo, but, unexpectedly, does not disrupt axon pathfinding. Thus, Rab5- and Rab4-mediated control of endosome trafficking appears to be crucial for axon growth. Collectively, our results suggest that recycling from Rab5-positive endosomes via Rab4 occurs within the growth cone and thereby supports axon elongation.
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Kinesin-1 regulates synaptic strength by mediating the delivery, removal, and redistribution of AMPA receptors. Neuron 2014; 80:1421-37. [PMID: 24360545 DOI: 10.1016/j.neuron.2013.10.050] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2013] [Indexed: 01/22/2023]
Abstract
A primary determinant of the strength of neurotransmission is the number of AMPA-type glutamate receptors (AMPARs) at synapses. However, we still lack a mechanistic understanding of how the number of synaptic AMPARs is regulated. Here, we show that UNC-116, the C. elegans homolog of vertebrate kinesin-1 heavy chain (KIF5), modifies synaptic strength by mediating the rapid delivery, removal, and redistribution of synaptic AMPARs. Furthermore, by studying the real-time transport of C. elegans AMPAR subunits in vivo, we demonstrate that although homomeric GLR-1 AMPARs can diffuse to and accumulate at synapses in unc-116 mutants, glutamate-gated currents are diminished because heteromeric GLR-1/GLR-2 receptors do not reach synapses in the absence of UNC-116/KIF5-mediated transport. Our data support a model in which ongoing motor-driven delivery and removal of AMPARs controls not only the number but also the composition of synaptic AMPARs, and thus the strength of synaptic transmission.
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Abstract
Clathrin-mediated endocytosis (CME) is conserved among eukaryotes and has been extensively analyzed at a molecular level. Here, we present an analysis of CME in the human fungal pathogen Candida albicans that shows the same modular structure as those in other fungi and mammalian cells. Intriguingly, C. albicans is perfectly viable in the absence of Arp2/3, an essential component of CME in other systems. In C. albicans, Arp2/3 function remains essential for CME as all 15 proteins tested that participate in CME, including clathrin, lose their characteristic dynamics observed in wild-type (WT) cells. However, since arp2/3 cells are still able to endocytose lipids and fluid-phase markers, but not the Ste2 and Mup1 plasma membrane proteins, there must be an alternate clathrin-independent pathway we term Arp2/3-independent endocytosis (AIE). Characterization of AIE shows that endocytosis in arp2 mutants relies on actin cables and other Arp2/3-independent actin structures, as inhibition of actin functions prevented cargo uptake in arp2/3 mutants. Transmission electron microscopy (TEM) showed that arp2/3 mutants still formed invaginating tubules, cell structures whose proper functions are believed to heavily rely on Arp2/3. Finally, Prk1 and Sjl2, two proteins involved in patch disassembly during CME, were not correctly localized to sites of endocytosis in arp2 mutants, implying a role of Arp2/3 in CME patch disassembly. Overall, C. albicans contains an alternative endocytic pathway (AIE) that relies on actin cable function to permit clathrin-independent endocytosis (CIE) and provides a system to further explore alternate endocytic routes that likely exist in fungal species. There is a well-established process of endocytosis that is generally used by eukaryotic cells termed clathrin-mediated endocytosis (CME). Although the details are somewhat different between lower and higher eukaryotes, CME appears to be the dominant endocytic process in all eukaryotes. While fungi such as Saccharomyces cerevisiae have proven excellent models for dissecting the molecular details of endocytosis, loss of CME is so detrimental that it has been difficult to study alternate pathways functioning in its absence. Although the fungal pathogen Candida albicans has a CME pathway that functions similarly to that of S. cerevisiae, inactivation of this pathway does not compromise growth of yeast-form C. albicans. In these cells, lipids and fluid-phase molecules are still endocytosed in an actin-dependent manner, but membrane proteins are not. Thus, C. albicans provides a powerful model for the analysis of CME-independent endocytosis in lower eukaryotes.
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Prosser DC, Wendland B. Conserved roles for yeast Rho1 and mammalian RhoA GTPases in clathrin-independent endocytosis. Small GTPases 2013; 3:229-35. [PMID: 23238351 PMCID: PMC3520887 DOI: 10.4161/sgtp.21631] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Eukaryotic cells use numerous endocytic pathways for nutrient uptake, protein turnover and response to the extracellular environment. While clathrin-mediated endocytosis (CME) has been extensively studied in yeast and mammalian cells, recent studies in higher eukaryotes have described multiple clathrin-independent endocytic pathways that depend upon Rho family GTPases and their effector proteins. In contrast, yeast cells have been thought to rely solely on CME. In a recent study, we used CME-defective yeast cells lacking clathrin-binding endocytic adaptor proteins in a genetic screen to identify novel factors involved in endocytosis. This approach revealed the existence of a clathrin-independent endocytic pathway involving the GTPase Rho1, which is the yeast homolog of RhoA. Further characterization of the yeast Rho1-mediated endocytic pathway suggested that the Rho1 pathway requires additional proteins that appear to play conserved roles in RhoA-dependent, clathrin-independent endocytic pathways in mammalian cells. Here, we discuss the parallels between the yeast Rho1-dependent and mammalian RhoA-dependent endocytic pathways, as well as the applications of yeast as a model for studying clathrin-independent endocytosis in higher eukaryotes.
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Affiliation(s)
- Derek C Prosser
- Department of Biology, The John Hopkins University, Baltimore, MD, USA.
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Lim YS, Tang BL. The Evi5 family in cellular physiology and pathology. FEBS Lett 2013; 587:1703-10. [PMID: 23669355 DOI: 10.1016/j.febslet.2013.04.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/23/2013] [Accepted: 04/28/2013] [Indexed: 02/03/2023]
Abstract
The Ecotropic viral integration site 5 (Evi5) and Evi5-like (Evi5L) belong to a small subfamily of the Tre-2/Bub2/Cdc16 (TBC) domain-containing proteins with enigmatically divergent roles as modulators of cell cycle progression, cytokinesis, and cellular membrane traffic. First recognized as a potential oncogene and a cell cycle regulator, Evi5 acts as a GTPase Activating Protein (GAP) for Rab11 in cytokinesis. On the other hand, its homologue Evi5L has Rab-GAP activity towards Rab10 as well as Rab23, and has been implicated in primary cilia formation. Recent genetic susceptibility analysis points to Evi5 as an important factor in susceptibility to multiple sclerosis. We discuss below the myriad of cellular functions exhibited by the Evi5 family members, and their associations with disease conditions.
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Affiliation(s)
- Yi Shan Lim
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, Singapore
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Vertebrate intersectin1 is repurposed to facilitate cortical midline connectivity and higher order cognition. J Neurosci 2013; 33:4055-65. [PMID: 23447614 DOI: 10.1523/jneurosci.4428-12.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Invertebrate studies have highlighted a role for EH and SH3 domain Intersectin (Itsn) proteins in synaptic vesicle recycling and morphology. Mammals have two Itsn genes (Itsn1 and Itsn2), both of which can undergo alternative splicing to include DBL/PH and C2 domains not present in invertebrate Itsn proteins. To probe for specific and redundant functions of vertebrate Itsn genes, we generated Itsn1, Itsn2, and double mutant mice. While invertebrate mutants showed severe synaptic abnormalities, basal synaptic transmission and plasticity were unaffected at Schaffer CA1 synapses in mutant mice. Surprisingly, intercortical tracts-corpus callosum, ventral hippocampal, and anterior commissures-failed to cross the midline in mice lacking Itsn1, but not Itsn2. In contrast, tracts extending within hemispheres and those that decussate to more caudal brain segments appeared normal. Itsn1 mutant mice showed severe deficits in Morris water maze and contextual fear memory tasks, whereas mice lacking Itsn2 showed normal learning and memory. Thus, coincident with the acquisition of additional signaling domains, vertebrate Itsn1 has been functionally repurposed to also facilitate interhemispheric connectivity essential for high order cognitive functions.
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Tsushima H, Malabarba MG, Confalonieri S, Senic-Matuglia F, Verhoef LGGC, Bartocci C, D'Ario G, Cocito A, Di Fiore PP, Salcini AE. A snapshot of the physical and functional wiring of the Eps15 homology domain network in the nematode. PLoS One 2013; 8:e56383. [PMID: 23424658 PMCID: PMC3570524 DOI: 10.1371/journal.pone.0056383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 01/13/2013] [Indexed: 12/12/2022] Open
Abstract
Protein interaction modules coordinate the connections within and the activity of intracellular signaling networks. The Eps15 Homology (EH) module, a protein-protein interaction domain that is a key feature of the EH-network, was originally identified in a few proteins involved in endocytosis and vesicle trafficking, and has subsequently also been implicated in actin reorganization, nuclear shuttling, and DNA repair. Here we report an extensive characterization of the physical connections and of the functional wirings of the EH-network in the nematode. Our data show that one of the major physiological roles of the EH-network is in neurotransmission. In addition, we found that the proteins of the network intersect, and possibly coordinate, a number of “territories” of cellular activity including endocytosis/recycling/vesicle transport, actin dynamics, general metabolism and signal transduction, ubiquitination/degradation of proteins, DNA replication/repair, and miRNA biogenesis and processing.
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Affiliation(s)
- Hanako Tsushima
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Maria Grazia Malabarba
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Dipartimento di Medicina, Chirurgia ed Odontoiatria, Università degli Studi di Milano, Milan, Italy
| | | | | | | | - Cristina Bartocci
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Giovanni D'Ario
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Andrea Cocito
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Pier Paolo Di Fiore
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Dipartimento di Medicina, Chirurgia ed Odontoiatria, Università degli Studi di Milano, Milan, Italy
- Istituto Europeo di Oncologia, Milan, Italy
- * E-mail: (PPDF); (AES)
| | - Anna Elisabetta Salcini
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
- * E-mail: (PPDF); (AES)
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47
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Shi A, Grant BD. Interactions between Rab and Arf GTPases regulate endosomal phosphatidylinositol-4,5-bisphosphate during endocytic recycling. Small GTPases 2013; 4:106-9. [PMID: 23392104 DOI: 10.4161/sgtp.23477] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
After endocytosis, a selective endocytic recycling process returns many endocytosed molecules back to the plasma membrane. The RAB-10/Rab10 GTPase is known to be a key recycling regulator for specific cargo molecules. New evidence, focused on C. elegans RAB-10 in polarized epithelia, points to a key role of RAB-10 in the regulation of endosomal phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) levels. In turn, PI(4,5)P2 levels strongly influence the recruitment of many peripheral membrane proteins, including those important for vesicle budding through their membrane bending activities. Part of the effect of RAB-10 on endosomal PI(4,5)P2 is through its newly identified effector CNT-1, a predicted GTPase activating protein (GAP) of the small GTPase ARF-6/Arf6. In mammals PI(4,5)P2 generating enzymes are known Arf6 effectors. In C. elegans we found that RAB-10, CNT-1 and ARF-6 are present on the same endosomes, that RAB-10 recruits CNT-1 to endosomes, and that loss of CNT-1 or RAB-10 leads to overaccumulation of endosomal PI(4,5)P2, presumably via hyperactivation of endosomal ARF-6. In turn this leads to over-recruitment of PI(4,5)P2-dependent membrane-bending proteins RME-1/Ehd and SDPN-1/Syndapin/PACSIN. Conversely, in arf-6 mutants, endosomal PI(4,5)P2 levels were reduced and endosomal recruitment of RME-1 and SDPN-1 failed. This work makes an unexpected link between distinct classes of small GTPases that control endocytic recycling, and provides insight into how this interaction affects endosome function at the level of lipid phosphorylation.
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Affiliation(s)
- Anbing Shi
- Department of Medical Genetics, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Gubar O, Morderer D, Tsyba L, Croisé P, Houy S, Ory S, Gasman S, Rynditch A. Intersectin: The Crossroad between Vesicle Exocytosis and Endocytosis. Front Endocrinol (Lausanne) 2013; 4:109. [PMID: 23986746 PMCID: PMC3753573 DOI: 10.3389/fendo.2013.00109] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/09/2013] [Indexed: 12/24/2022] Open
Abstract
Intersectins (ITSNs) are a family of highly conserved proteins with orthologs from nematodes to mammals. In vertebrates, ITSNs are encoded by two genes (itsn1 and itsn2), which act as scaffolds that were initially discovered as proteins involved in endocytosis. Further investigation demonstrated that ITSN1 is also implicated in several other processes including regulated exocytosis, thereby suggesting a role for ITSN1 in the coupling between exocytosis and endocytosis in excitatory cells. Despite a high degree of conservation amongst orthologs, ITSN function is not so well preserved as they have acquired new properties during evolution. In this review, we will discuss the role of ITSN1 and its orthologs in exo- and endocytosis, in particular in neurons and neuroendocrine cells.
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Affiliation(s)
- Olga Gubar
- State Key Laboratory of Molecular and Cellular Biology, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique-Unité Propre de Recherche 3212, Université de Strasbourg, Strasbourg, France
| | - Dmytro Morderer
- State Key Laboratory of Molecular and Cellular Biology, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
| | - Lyudmila Tsyba
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
| | - Pauline Croisé
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique-Unité Propre de Recherche 3212, Université de Strasbourg, Strasbourg, France
| | - Sébastien Houy
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique-Unité Propre de Recherche 3212, Université de Strasbourg, Strasbourg, France
| | - Stéphane Ory
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique-Unité Propre de Recherche 3212, Université de Strasbourg, Strasbourg, France
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique-Unité Propre de Recherche 3212, Université de Strasbourg, Strasbourg, France
| | - Alla Rynditch
- State Key Laboratory of Molecular and Cellular Biology, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, Kyiv, Ukraine
- *Correspondence: Alla Rynditch, Department of Functional Genomics, Institute of Molecular Biology and Genetics, 150, Zabolotnogo Street, 03680 Kyiv-143, Ukraine e-mail:
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Abstract
Seasonal flu affects 5–20% of the human population each year. Although mortality rates are typically <0.1% and the pandemic 2009 H1N1 influenza strain has been well contained by vaccination and strict hygiene, particularly virulent pandemic forms have emerged three times in the last century, resulting in millions of deaths. Current vaccine and therapeutic strategies are limited by the ability of the virus to generate variants that evade vaccine-induced immune responses and resist the therapeutic effects of antiviral drugs. Host genetic variations affect immune responses and may induce adverse effects during drug treatment or against vaccines. To develop new, first-in-class therapeutics, new antiviral targets and new chemical entities must be identified in the context of the immunogenomic repertoire of the patient. Since influenza and so many other viruses need to escape innate immunity to become pathogenic, the viral proteins responsible for this, as well as the host cell molecular pathways that lead to the antiviral response, are an excellent potential source of new therapeutic targets within a systems approach against influenza infections.
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Affiliation(s)
- Christian V Forst
- University of Texas Southwestern Medical Center, Department of Clinical Sciences, 5323 Harry Hines Boulevard, Dallas, TX 75390-9066, USA
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RAB-10-GTPase-mediated regulation of endosomal phosphatidylinositol-4,5-bisphosphate. Proc Natl Acad Sci U S A 2012; 109:E2306-15. [PMID: 22869721 DOI: 10.1073/pnas.1205278109] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Caenorhabditis elegans RAB-10 and mammalian Rab10 are key regulators of endocytic recycling, especially in the basolateral recycling pathways of polarized epithelial cells. To understand better how RAB-10 contributes to recycling endosome function, we sought to identify RAB-10 effectors. One RAB-10-binding partner that we identified, CNT-1, is the only C. elegans homolog of the mammalian Arf6 GTPase-activating proteins ACAP1 and ACAP2. Arf6 is known to regulate endosome-to-plasma membrane transport, in part through activation of type I phophatidylinositol-4-phosphate 5 kinase. Here we show that CNT-1 binds to RAB-10 through its C-terminal ankyrin repeats and colocalizes with RAB-10 and ARF-6 on recycling endosomes in vivo. Furthermore, we find that RAB-10 is required for the recruitment of CNT-1 to endosomal membranes in the intestinal epithelium. Consistent with negative regulation of ARF-6 by RAB-10 and CNT-1, we found overaccumulation of endosomal phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] in cnt-1 and rab-10 mutants and reduced endosomal PI(4,5)P2 levels in arf-6 mutants. These mutants produced similar effects on endosomal recruitment of the PI(4,5)P2-dependent membrane-bending proteins RME-1/Ehd and SDPN-1/Syndapin/Pacsin and resulted in endosomal trapping of specific recycling cargo. Our studies identify a RAB-10-to-ARF-6 regulatory loop required to regulate endosomal PI(4,5)P2, a key phosphoinositide in membrane traffic.
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