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Tebbe L, Kakakhel M, Al-Ubaidi MR, Naash MI. The role of syntaxins in retinal function and health. Front Cell Neurosci 2024; 18:1380064. [PMID: 38799985 PMCID: PMC11119284 DOI: 10.3389/fncel.2024.1380064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/16/2024] [Indexed: 05/29/2024] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptor (SNARE) superfamily plays a pivotal role in cellular trafficking by facilitating membrane fusion events. These SNARE proteins, including syntaxins, assemble into complexes that actively facilitate specific membrane fusion events. Syntaxins, as integral components of the SNARE complex, play a crucial role in initiating and regulating these fusion activities. While specific syntaxins have been extensively studied in various cellular processes, including neurotransmitter release, autophagy and endoplasmic reticulum (ER)-to-Golgi protein transport, their roles in the retina remain less explored. This review aims to enhance our understanding of syntaxins' functions in the retina by shedding light on how syntaxins mediate membrane fusion events unique to the retina. Additionally, we seek to establish a connection between syntaxin mutations and retinal diseases. By exploring the intricate interplay of syntaxins in retinal function and health, we aim to contribute to the broader comprehension of cellular trafficking in the context of retinal physiology and pathology.
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Affiliation(s)
| | | | | | - Muna I. Naash
- *Correspondence: Muna I. Naash, ; Muayyad R. Al-Ubaidi,
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2
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Kinghorn K, Gill A, Marvin A, Li R, Quigley K, Singh S, Gore MT, le Noble F, Gabhann FM, Bautch VL. A defined clathrin-mediated trafficking pathway regulates sFLT1/VEGFR1 secretion from endothelial cells. Angiogenesis 2024; 27:67-89. [PMID: 37695358 PMCID: PMC10881643 DOI: 10.1007/s10456-023-09893-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 08/07/2023] [Indexed: 09/12/2023]
Abstract
FLT1/VEGFR1 negatively regulates VEGF-A signaling and is required for proper vessel morphogenesis during vascular development and vessel homeostasis. Although a soluble isoform, sFLT1, is often mis-regulated in disease and aging, how sFLT1 is trafficked and secreted from endothelial cells is not well understood. Here we define requirements for constitutive sFLT1 trafficking and secretion in endothelial cells from the Golgi to the plasma membrane, and we show that sFLT1 secretion requires clathrin at or near the Golgi. Perturbations that affect sFLT1 trafficking blunted endothelial cell secretion and promoted intracellular mis-localization in cells and zebrafish embryos. siRNA-mediated depletion of specific trafficking components revealed requirements for RAB27A, VAMP3, and STX3 for post-Golgi vesicle trafficking and sFLT1 secretion, while STX6, ARF1, and AP1 were required at the Golgi. Live-imaging of temporally controlled sFLT1 release from the endoplasmic reticulum showed clathrin-dependent sFLT1 trafficking at the Golgi into secretory vesicles that then trafficked to the plasma membrane. Depletion of STX6 altered vessel sprouting in 3D, suggesting that endothelial cell sFLT1 secretion influences proper vessel sprouting. Thus, specific trafficking components provide a secretory path from the Golgi to the plasma membrane for sFLT1 in endothelial cells that utilizes a specialized clathrin-dependent intermediate, suggesting novel therapeutic targets.
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Affiliation(s)
- Karina Kinghorn
- Curriculum in Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, USA
| | - Amy Gill
- Department of Biomedical Engineering, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Allison Marvin
- Department of Biology, The University of North Carolina at Chapel Hill, CB No. 3280, Chapel Hill, NC, 27599, USA
| | - Renee Li
- Department of Biology, The University of North Carolina at Chapel Hill, CB No. 3280, Chapel Hill, NC, 27599, USA
| | - Kaitlyn Quigley
- Department of Biology, The University of North Carolina at Chapel Hill, CB No. 3280, Chapel Hill, NC, 27599, USA
| | - Simcha Singh
- Department of Biology, The University of North Carolina at Chapel Hill, CB No. 3280, Chapel Hill, NC, 27599, USA
| | - Michaelanthony T Gore
- Department of Biology, The University of North Carolina at Chapel Hill, CB No. 3280, Chapel Hill, NC, 27599, USA
| | - Ferdinand le Noble
- Department of Cell and Developmental Biology, Institute of Zoology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Victoria L Bautch
- Curriculum in Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, USA.
- Department of Biology, The University of North Carolina at Chapel Hill, CB No. 3280, Chapel Hill, NC, 27599, USA.
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA.
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.
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Jones E, Hill E, Linehan J, Nazari T, Caulder A, Codner GF, Hutchison M, Mackenzie M, Farmer M, Coysh T, De Oliveira MW, Al-Doujaily H, Sandberg M, Viré E, Cunningham TJ, Asante EA, Brandner S, Collinge J, Mead S. Characterisation and prion transmission study in mice with genetic reduction of sporadic Creutzfeldt-Jakob disease risk gene Stx6. Neurobiol Dis 2024; 190:106363. [PMID: 37996040 PMCID: PMC7615600 DOI: 10.1016/j.nbd.2023.106363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 11/25/2023] Open
Abstract
Sporadic Creutzfeldt-Jakob disease (sCJD), the most common human prion disease, is thought to occur when the cellular prion protein (PrPC) spontaneously misfolds and assembles into prion fibrils, culminating in fatal neurodegeneration. In a genome-wide association study of sCJD, we recently identified risk variants in and around the gene STX6, with evidence to suggest a causal increase of STX6 expression in disease-relevant brain regions. STX6 encodes syntaxin-6, a SNARE protein primarily involved in early endosome to trans-Golgi network retrograde transport. Here we developed and characterised a mouse model with genetic depletion of Stx6 and investigated a causal role of Stx6 expression in mouse prion disease through a classical prion transmission study, assessing the impact of homozygous and heterozygous syntaxin-6 knockout on disease incubation periods and prion-related neuropathology. Following inoculation with RML prions, incubation periods in Stx6-/- and Stx6+/- mice differed by 12 days relative to wildtype. Similarly, in Stx6-/- mice, disease incubation periods following inoculation with ME7 prions also differed by 12 days. Histopathological analysis revealed a modest increase in astrogliosis in ME7-inoculated Stx6-/- animals and a variable effect of Stx6 expression on microglia activation, however no differences in neuronal loss, spongiform change or PrP deposition were observed at endpoint. Importantly, Stx6-/- mice are viable and fertile with no gross impairments on a range of neurological, biochemical, histological and skeletal structure tests. Our results provide some support for a pathological role of Stx6 expression in prion disease, which warrants further investigation in the context of prion disease but also other neurodegenerative diseases considering syntaxin-6 appears to have pleiotropic risk effects in progressive supranuclear palsy and Alzheimer's disease.
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Affiliation(s)
- Emma Jones
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Elizabeth Hill
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Jacqueline Linehan
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Tamsin Nazari
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Adam Caulder
- Mary Lyon Centre at MRC Harwell, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Gemma F Codner
- Mary Lyon Centre at MRC Harwell, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Marie Hutchison
- Mary Lyon Centre at MRC Harwell, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Matthew Mackenzie
- Mary Lyon Centre at MRC Harwell, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Michael Farmer
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Thomas Coysh
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Michael Wiggins De Oliveira
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Huda Al-Doujaily
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Malin Sandberg
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Emmanuelle Viré
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Thomas J Cunningham
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Emmanuel A Asante
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Sebastian Brandner
- Division of Neuropathology and Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - John Collinge
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK
| | - Simon Mead
- Medical Research Council Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, London W1W 7FF, UK.
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Zhou L, Wang Z, Chen X, Li X, Ge C, Min X, Zhao F, Chen T, Li J. Syntaxin-6 promotes the progression of hepatocellular carcinoma and alters its sensitivity to chemotherapies by activating the USF2/LC3B axis. Int J Biol Sci 2023; 19:3892-3907. [PMID: 37564208 PMCID: PMC10411479 DOI: 10.7150/ijbs.86636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 07/18/2023] [Indexed: 08/12/2023] Open
Abstract
Syntaxin-6 (STX6), a protein of the syntaxin family, is located in the trans-Golgi network and is involved in a variety of intracellular membrane transport events. STX6 is overexpressed in different human malignant tumors. However, little is known about its exact function and molecular mechanism in hepatocellular carcinoma (HCC). In this study, we found that the expression of STX6 was significantly increased in HCC tissues and was associated with poor survival. Gain- and loss-of-function experiments showed that STX6 promotes cell proliferation and metastasis of HCC cells both in vitro and in vivo. Mechanistically, STX6 was negatively regulated by the upstream stimulatory factor 2 (USF2). In addition, STX6 facilitates the association of autophagosomes with lysosomes. Importantly, we demonstrated that STX6 overexpression, despite enhanced resistance to lenvatinib, sensitizes HCC cells to the autophagy activator rapamycin. This study revealed that, under the control of USF2, STX6 accelerates the degradation of microtubule-associated protein 1 light chain 3 beta (LC3) by promoting autophagic flux, ultimately promoting HCC progression. Collectively, we suggest that the USF2-STX6-LC3B axis is a potential therapeutic target in liver cancer.
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Affiliation(s)
- Lianer Zhou
- State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Zhenyu Wang
- Department of Oncology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Xiaoxia Chen
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Xianxian Li
- State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Chao Ge
- State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Xuejie Min
- State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Fangyu Zhao
- State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Taoyang Chen
- Qi Dong Liver Cancer Institute, Qi Dong 226200, China
| | - Jinjun Li
- State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
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5
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Sumya FT, Pokrovskaya ID, D'Souza Z, Lupashin VV. Acute COG complex inactivation unveiled its immediate impact on Golgi and illuminated the nature of intra-Golgi recycling vesicles. Traffic 2023; 24:52-75. [PMID: 36468177 PMCID: PMC9969905 DOI: 10.1111/tra.12876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/12/2022] [Accepted: 11/29/2022] [Indexed: 12/07/2022]
Abstract
Conserved Oligomeric Golgi (COG) complex controls Golgi trafficking and glycosylation, but the precise COG mechanism is unknown. The auxin-inducible acute degradation system was employed to investigate initial defects resulting from COG dysfunction. We found that acute COG inactivation caused a massive accumulation of COG-dependent (CCD) vesicles that carry the bulk of Golgi enzymes and resident proteins. v-SNAREs (GS15, GS28) and v-tethers (giantin, golgin84, and TMF1) were relocalized into CCD vesicles, while t-SNAREs (STX5, YKT6), t-tethers (GM130, p115), and most of Rab proteins remained Golgi-associated. Airyscan microscopy and velocity gradient analysis revealed that different Golgi residents are segregated into different populations of CCD vesicles. Acute COG depletion significantly affected three Golgi-based vesicular coats-COPI, AP1, and GGA, suggesting that COG uniquely orchestrates tethering of multiple types of intra-Golgi CCD vesicles produced by different coat machineries. This study provided the first detailed view of primary cellular defects associated with COG dysfunction in human cells.
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Affiliation(s)
- Farhana Taher Sumya
- Department of Physiology and Cell Biology University of Arkansas for Medical Sciences Little Rock Arkansas USA
| | - Irina D. Pokrovskaya
- Department of Physiology and Cell Biology University of Arkansas for Medical Sciences Little Rock Arkansas USA
| | - Zinia D'Souza
- Department of Physiology and Cell Biology University of Arkansas for Medical Sciences Little Rock Arkansas USA
| | - Vladimir V. Lupashin
- Department of Physiology and Cell Biology University of Arkansas for Medical Sciences Little Rock Arkansas USA
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6
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Kinghorn K, Gill A, Marvin A, Li R, Quigley K, le Noble F, Mac Gabhann F, Bautch VL. A defined clathrin-mediated trafficking pathway regulates sFLT1/VEGFR1 secretion from endothelial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525517. [PMID: 36747809 PMCID: PMC9900880 DOI: 10.1101/2023.01.27.525517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
FLT1/VEGFR1 negatively regulates VEGF-A signaling and is required for proper vessel morphogenesis during vascular development and vessel homeostasis. Although a soluble isoform, sFLT1, is often mis-regulated in disease and aging, how sFLT1 is trafficked and secreted from endothelial cells is not well understood. Here we define requirements for constitutive sFLT1 trafficking and secretion in endothelial cells from the Golgi to the plasma membrane, and we show that sFLT1 secretion requires clathrin at or near the Golgi. Perturbations that affect sFLT1 trafficking blunted endothelial cell secretion and promoted intracellular mis-localization in cells and zebrafish embryos. siRNA-mediated depletion of specific trafficking components revealed requirements for RAB27A, VAMP3, and STX3 for post-Golgi vesicle trafficking and sFLT1 secretion, while STX6, ARF1, and AP1 were required at the Golgi. Depletion of STX6 altered vessel sprouting in a 3D angiogenesis model, indicating that endothelial cell sFLT1 secretion is important for proper vessel sprouting. Thus, specific trafficking components provide a secretory path from the Golgi to the plasma membrane for sFLT1 in endothelial cells that utilizes a specialized clathrin-dependent intermediate, suggesting novel therapeutic targets.
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Affiliation(s)
- Karina Kinghorn
- Curriculum in Cell Biology and Physiology, University of North Carolina, Chapel Hill NC USA
| | - Amy Gill
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore MD, USA
| | - Allison Marvin
- Department of Biology, University of North Carolina, Chapel Hill NC USA
| | - Renee Li
- Department of Biology, University of North Carolina, Chapel Hill NC USA
| | - Kaitlyn Quigley
- Department of Biology, University of North Carolina, Chapel Hill NC USA
| | - Ferdinand le Noble
- Department of Cell and Developmental Biology, Institute of Zoology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Feilim Mac Gabhann
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore MD, USA
| | - Victoria L Bautch
- Curriculum in Cell Biology and Physiology, University of North Carolina, Chapel Hill NC USA
- Department of Biology, University of North Carolina, Chapel Hill NC USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill NC USA
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill NC USA
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7
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Li W, Li K, Wei H, Sun Y, Liao Y, Zou Y, Chen X, Deng C, Chen S, He Y, Huo M, Zhang C. Syntaxin-6, a Reliable Biomarker for Predicting the Prognosis of Patients with Cancer and the Effectiveness of Immunotherapy. Cancers (Basel) 2022; 15:cancers15010027. [PMID: 36612024 PMCID: PMC9817965 DOI: 10.3390/cancers15010027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/17/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
Syntaxin-6 (STX6), a vesicular transport protein, is a direct target of the tumor suppressor gene P53, supporting cancer growth dependent on P53. However, STX6's function in the tumor microenvironment has yet to be reported. In this research, we comprehensively explored the role of the oncogene STX6 in pan-cancer by combining data from several databases, including the Cancer Genome Atlas, CPTAC, cBioPortal, and TIMER. Then, we verified the carcinogenic effect of STX6 in hepatocellular carcinoma (HCC) and colorectal cancer (CRC) through a series of experiments in vitro and in vivo. Bioinformatics analysis demonstrated that STX6 is an oncogene for several cancers and is mainly involved in the cell cycle, epithelial-mesenchymal transition, oxidative phosphorylation, and tumor immune modulation, especially for tumor-associated fibroblasts (CAFs) and NKT cells. Additionally, a high level of STX6 could indicate patients' resistance to immunotherapy. Our own data indicated that the STX6 level was upregulated in HCC and CRC. Knockdown of the STX6 levels could arrest the cell cycle and restrain cell proliferation, migration, and invasion. RNA-seq indicated that STX6 was significantly involved in pathways for cancer, such as the MAPK signal pathway. In a mouse model, knockdown of STX6 inhibited tumor growth and potentiated anti-PD-1 efficacy. In light of the essential roles STX6 plays in carcinogenesis and cancer immunology, it has the potential to be a predictive biomarker and a target for cancer immunotherapy.
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Affiliation(s)
- Wenchao Li
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Kuan Li
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Hongfa Wei
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Yu Sun
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Yangjing Liao
- Department of Traditional Chinese Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510000, China
| | - Yuan Zou
- Department of Pathology, Southern Hospital, Southern Medical University, Guangzhou 510000, China
| | - Xiancong Chen
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Cuncan Deng
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Songyao Chen
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Yulong He
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
| | - Mingyu Huo
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Correspondence: (M.H.); (C.Z.)
| | - Changhua Zhang
- Digestive Diseases Center, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Guangdong Provincial Key Laboratory of Digestive Cancer Research, The Seventh Affiliated Hospital of Sun Yat-sen University, No. 628 Zhenyuan Road, Shenzhen 518107, China
- Correspondence: (M.H.); (C.Z.)
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Human Cytomegalovirus Manipulates Syntaxin 6 for Successful Trafficking and Subsequent Infection of Monocytes. J Virol 2022; 96:e0081922. [PMID: 35862696 PMCID: PMC9327712 DOI: 10.1128/jvi.00819-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Human cytomegalovirus (HCMV) exhibits a complex host-pathogen interaction with peripheral blood monocytes. We have identified a unique, cell-type specific retrograde-like intracellular trafficking pattern that HCMV utilizes to gain access to the monocyte nucleus and for productive infection. We show that infection of primary human monocytes, epithelial cells, and fibroblasts leads to an increase in the amount of the trafficking protein Syntaxin 6 (Stx6). However, only knockdown (KD) of Stx6 in monocytes inhibited viral trafficking to the trans-Golgi network (TGN), a requisite step for nuclear translocation in monocytes. Conversely, KD of Stx6 in epithelial cells and fibroblasts did not change the kinetics of nuclear translocation and productive infection. Stx6 predominantly functions at the level of the TGN where it facilitates retrograde transport, a trafficking pathway used by only a few cellular proteins and seldom by pathogens. We also newly identify that in monocytes, Stx6 exhibits an irregular vesicular localization rather than being concentrated at the TGN as seen in other cell-types. Lastly, we implicate that viral particles that associate with both Stx6 and EEA1 early in infection are the viral population that successfully traffics to the TGN at later time points and undergo nuclear translocation. Additionally, we show for the first time that HCMV enters the TGN, and that lack of Stx6 prevents viral trafficking to this organelle. We argue that we have identified an essential cell-type specific regulator that controls early steps in efficient productive infection of a cell-type required for viral persistence and disease. IMPORTANCE Human cytomegalovirus (HCMV) infection causes severe and often fatal disease in the immunocompromised. It is one of the leading infectious causes of birth defects and causes severe complications in transplant recipients. By uncovering the unique pathways used by the virus to infect key cells, such as monocytes, responsible for dissemination and persistence, we provide new potential targets for therapeutic intervention.
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Acat1/Soat1 knockout extends the mutant Npc1 mouse lifespan and ameliorates functional deficiencies in multiple organelles of mutant cells. Proc Natl Acad Sci U S A 2022; 119:e2201646119. [PMID: 35507892 PMCID: PMC9170141 DOI: 10.1073/pnas.2201646119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Niemann-Pick type C disease (NPCD) is an incurable genetic neurological disorder. Cells with NPC mutations fail to export cholesterol from endosomal organelle to multiple other organelles. ACAT1 is an enzyme that converts cholesterol to cholesteryl esters for storage. In mutant NPC cells, cholesterol storage still occurs, although at reduced rate. Here we show that in mutant NPC cells, ACAT1 blockade (A1B) decreases cholesterol storage such that it can be utilized to fulfill cholesterol needs in multiple organelles. In mutant NPC1 mice, Acat1 gene knockout reduces pathological onset and prolongs the lifespan by 34%. This work identifies ACAT1 as a target to treat NPCD and may help to explain why A1B has been reported to ameliorate preclinical models for Alzheimer’s disease. Multiple membrane organelles require cholesterol for proper function within cells. The Niemann-Pick type C (NPC) proteins export cholesterol from endosomes to other membrane compartments, including the endoplasmic reticulum (ER), plasma membrane (PM), trans-Golgi network (TGN), and mitochondria, to meet their cholesterol requirements. Defects in NPC cause malfunctions in multiple membrane organelles and lead to an incurable neurological disorder. Acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1), a resident enzyme in the ER, converts cholesterol to cholesteryl esters for storage. In mutant NPC cells, cholesterol storage still occurs in an NPC-independent manner. Here we report the interesting finding that in a mutant Npc1 mouse (Npc1nmf), Acat1 gene (Soat1) knockout delayed the onset of weight loss, motor impairment, and Purkinje neuron death. It also improved hepatosplenic pathology and prolonged lifespan by 34%. In mutant NPC1 fibroblasts, ACAT1 blockade (A1B) increased cholesterol content associated with TGN-rich membranes and mitochondria, while decreased cholesterol content associated with late endosomes. A1B also restored proper localization of syntaxin 6 and golgin 97 (key proteins in membrane trafficking at TGN) and improved the levels of cathepsin D (a key protease in lysosome and requires Golgi/endosome transport for maturation) and ABCA1 (a key protein controlling cholesterol release at PM). This work supports the hypothesis that diverting cholesterol from storage can benefit multiple diseases that involve cholesterol deficiencies in cell membranes.
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10
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Borghesan E, Smith EP, Myeni S, Binder K, Knodler LA, Celli J. A Brucella effector modulates the Arf6-Rab8a GTPase cascade to promote intravacuolar replication. EMBO J 2021; 40:e107664. [PMID: 34423453 PMCID: PMC8488576 DOI: 10.15252/embj.2021107664] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 01/15/2023] Open
Abstract
Remodeling of host cellular membrane transport pathways is a common pathogenic trait of many intracellular microbes that is essential to their intravacuolar life cycle and proliferation. The bacterium Brucella abortus generates a host endoplasmic reticulum‐derived vacuole (rBCV) that supports its intracellular growth, via VirB Type IV secretion system‐mediated delivery of effector proteins, whose functions and mode of action are mostly unknown. Here, we show that the effector BspF specifically promotes Brucella replication within rBCVs by interfering with vesicular transport between the trans‐Golgi network (TGN) and recycling endocytic compartment. BspF targeted the recycling endosome, inhibited retrograde traffic to the TGN, and interacted with the Arf6 GTPase‐activating Protein (GAP) ACAP1 to dysregulate Arf6‐/Rab8a‐dependent transport within the recycling endosome, which resulted in accretion of TGN‐associated vesicles by rBCVs and enhanced bacterial growth. Altogether, these findings provide mechanistic insight into bacterial modulation of membrane transport used to promote their own proliferation within intracellular vacuoles.
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Affiliation(s)
- Elizabeth Borghesan
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Erin P Smith
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Sebenzile Myeni
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Kelsey Binder
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Leigh A Knodler
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Jean Celli
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA.,Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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11
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Smuggle tau through a secret(ory) pathway. Biochem J 2021; 478:2921-2925. [PMID: 34319403 DOI: 10.1042/bcj20210324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 11/17/2022]
Abstract
Secretion of misfolded tau, a microtubule-binding protein enriched in nerve cells, is linked to the progression of tau pathology. However, the molecular mechanisms underlying tau secretion are poorly understood. Recent work by Lee et al. [Biochemical J. (2021) 478: 1471-1484] demonstrated that the transmembrane domains of syntaxin6 and syntaxin8 could be exploited for tau release, setting a stage for testing a novel hypothesis that has profound implications in tauopathies (e.g. Alzheimer's disease, FTDP-17, and CBD/PSP) and other related neurodegenerative diseases. The present commentary highlights the importance and limitations of the study, and discusses opportunities and directions for future investigations.
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12
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Beilina A, Bonet-Ponce L, Kumaran R, Kordich JJ, Ishida M, Mamais A, Kaganovich A, Saez-Atienzar S, Gershlick DC, Roosen DA, Pellegrini L, Malkov V, Fell MJ, Harvey K, Bonifacino JS, Moore DJ, Cookson MR. The Parkinson's Disease Protein LRRK2 Interacts with the GARP Complex to Promote Retrograde Transport to the trans-Golgi Network. Cell Rep 2021; 31:107614. [PMID: 32375042 PMCID: PMC7315779 DOI: 10.1016/j.celrep.2020.107614] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/17/2020] [Accepted: 04/13/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in Leucine-rich repeat kinase 2 (LRRK2) cause Parkinson's disease (PD). However, the precise function of LRRK2 remains unclear. We report an interaction between LRRK2 and VPS52, a subunit of the Golgi-associated retrograde protein (GARP) complex that identifies a function of LRRK2 in regulating membrane fusion at the trans-Golgi network (TGN). At the TGN, LRRK2 further interacts with the Golgi SNAREs VAMP4 and Syntaxin-6 and acts as a scaffolding platform that stabilizes the GARP-SNAREs complex formation. Therefore, LRRK2 influences both retrograde and post-Golgi trafficking pathways in a manner dependent on its GTP binding and kinase activity. This action is exaggerated by mutations associated with Parkinson's disease and can be blocked by kinase inhibitors. Disruption of GARP sensitizes dopamine neurons to mutant LRRK2 toxicity in C. elegans, showing that these pathways are interlinked in vivo and suggesting a link in PD.
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Affiliation(s)
- Alexandra Beilina
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA
| | - Luis Bonet-Ponce
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA
| | - Ravindran Kumaran
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA
| | - Jennifer J Kordich
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Morié Ishida
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20814, USA
| | - Adamantios Mamais
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA
| | - Alice Kaganovich
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA
| | - Sara Saez-Atienzar
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA
| | - David C Gershlick
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20814, USA
| | - Dorien A Roosen
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA; School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | - Laura Pellegrini
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA; Department of Pharmacology, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK
| | - Vlad Malkov
- Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Matthew J Fell
- Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Kirsten Harvey
- Department of Pharmacology, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20814, USA
| | - Darren J Moore
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Mark R Cookson
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20814, USA.
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13
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Lučin P, Jug Vučko N, Karleuša L, Mahmutefendić Lučin H, Blagojević Zagorac G, Lisnić B, Pavišić V, Marcelić M, Grabušić K, Brizić I, Lukanović Jurić S. Cytomegalovirus Generates Assembly Compartment in the Early Phase of Infection by Perturbation of Host-Cell Factors Recruitment at the Early Endosome/Endosomal Recycling Compartment/Trans-Golgi Interface. Front Cell Dev Biol 2020; 8:563607. [PMID: 33042998 PMCID: PMC7516400 DOI: 10.3389/fcell.2020.563607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/18/2020] [Indexed: 12/02/2022] Open
Abstract
Beta-herpesviruses develop a unique structure within the infected cell known as an assembly compartment (AC). This structure, as large as the nucleus, is composed of host-cell-derived membranous elements. The biogenesis of the AC and its contribution to the final stages of beta-herpesvirus assembly are still unclear. In this study, we performed a spatial and temporal analysis of the AC in cells infected with murine CMV (MCMV), a member of the beta-herpesvirus family, using a panel of markers that characterize membranous organelle system. Out of 64 markers that were analyzed, 52 were cytosolic proteins that are recruited to membranes as components of membrane-shaping regulatory cascades. The analysis demonstrates that MCMV infection extensively reorganizes interface between early endosomes (EE), endosomal recycling compartment (ERC), and the trans-Golgi network (TGN), resulting in expansion of various EE-ERC-TGN intermediates that fill the broad area of the inner AC. These intermediates are displayed as over-recruitment of host-cell factors that control membrane flow at the EE-ERC-TGN interface. Most of the reorganization is accomplished in the early (E) phase of infection, indicating that the AC biogenesis is controlled by MCMV early genes. Although it is known that CMV infection affects the expression of a large number of host-cell factors that control membranous system, analysis of the host-cell transcriptome and protein expression in the E phase of infection demonstrated no sufficiently significant alteration in expression levels of analyzed markers. Thus, our study demonstrates that MCMV-encoded early phase function targets recruitment cascades of host cell-factors that control membranous flow at the EE-ERC-TGN interface in order to initiate the development of the AC.
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Affiliation(s)
- Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.,University North, University Center Varaždin, Varaždin, Croatia
| | - Natalia Jug Vučko
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Ljerka Karleuša
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.,University North, University Center Varaždin, Varaždin, Croatia
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.,University North, University Center Varaždin, Varaždin, Croatia
| | - Berislav Lisnić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Valentino Pavišić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Marina Marcelić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Kristina Grabušić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Ilija Brizić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Silvija Lukanović Jurić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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14
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Urbina FL, Gupton SL. SNARE-Mediated Exocytosis in Neuronal Development. Front Mol Neurosci 2020; 13:133. [PMID: 32848598 PMCID: PMC7427632 DOI: 10.3389/fnmol.2020.00133] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022] Open
Abstract
The formation of the nervous system involves establishing complex networks of synaptic connections between proper partners. This developmental undertaking requires the rapid expansion of the plasma membrane surface area as neurons grow and polarize, extending axons through the extracellular environment. Critical to the expansion of the plasma membrane and addition of plasma membrane material is exocytic vesicle fusion, a regulated mechanism driven by soluble N-ethylmaleimide-sensitive factor attachment proteins receptors (SNAREs). Since their discovery, SNAREs have been implicated in several critical neuronal functions involving exocytic fusion in addition to synaptic transmission, including neurite initiation and outgrowth, axon specification, axon extension, and synaptogenesis. Decades of research have uncovered a rich variety of SNARE expression and function. The basis of SNARE-mediated fusion, the opening of a fusion pore, remains an enigmatic event, despite an incredible amount of research, as fusion is not only heterogeneous but also spatially small and temporally fast. Multiple modes of exocytosis have been proposed, with full-vesicle fusion (FFV) and kiss-and-run (KNR) being the best described. Whereas most in vitro work has reconstituted fusion using VAMP-2, SNAP-25, and syntaxin-1; there is much to learn regarding the behaviors of distinct SNARE complexes. In the past few years, robust heterogeneity in the kinetics and fate of the fusion pore that varies by cell type have been uncovered, suggesting a paradigm shift in how the modes of exocytosis are viewed is warranted. Here, we explore both classic and recent work uncovering the variety of SNAREs and their importance in the development of neurons, as well as historical and newly proposed modes of exocytosis, their regulation, and proteins involved in the regulation of fusion kinetics.
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Affiliation(s)
- Fabio L. Urbina
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Stephanie L. Gupton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- UNC Neuroscience Center, Chapel Hill, NC, United States
- UNC Lineberger Comprehensive Cancer Center, Chapel Hill, NC, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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15
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Ireland SC, Huang H, Zhang J, Li J, Wang Y. Hydrogen peroxide induces Arl1 degradation and impairs Golgi-mediated trafficking. Mol Biol Cell 2020; 31:1931-1942. [PMID: 32583744 PMCID: PMC7525819 DOI: 10.1091/mbc.e20-01-0063] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/02/2020] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS)-induced oxidative stress has been associated with diseases such as amyotrophic lateral sclerosis, stroke, and cancer. While the effect of ROS on mitochondria and endoplasmic reticulum (ER) has been well documented, its consequence on the Golgi apparatus is less well understood. In this study, we characterized the Golgi structure and function in HeLa cells after exposure to hydrogen peroxide (H2O2), a reagent commonly used to introduce ROS to cells. Treatment of cells with 1 mM H2O2 for 10 min resulted in the degradation of Arl1 and dissociation of GRIP domain-containing proteins Golgin-97 and Golgin-245 from the trans-Golgi. This effect could be rescued by treatment of cells with a ROS scavenger N-acetyl cysteine or protease inhibitors. Structurally, H2O2 treatment reduced the number of cisternal membranes per Golgi stack, suggesting a loss of trans-Golgi cisternae. Functionally, H2O2 treatment inhibited both anterograde and retrograde protein transport, consistent with the loss of membrane tethers on the trans-Golgi cisternae. This study revealed membrane tethers at the trans-Golgi as novel specific targets of ROS in cells.
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Affiliation(s)
- Stephen C. Ireland
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Haoran Huang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Jianchao Zhang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI 48109-1085
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16
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Alshafie W, Francis V, Bednarz K, Pan YE, Stroh T, McPherson PS. Regulated resurfacing of a somatostatin receptor storage compartment fine-tunes pituitary secretion. J Cell Biol 2020; 219:132745. [PMID: 31825461 PMCID: PMC7039187 DOI: 10.1083/jcb.201904054] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/26/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022] Open
Abstract
In pituitary cells, internalized somatostatin receptor is held in a GLUT4-like storage compartment. The receptor rapidly resurfaces in response to selective signaling pathways in a process that fine-tunes pituitary hormone release. The surfacing of the glucose transporter GLUT4 driven by insulin receptor activation provides the prototypic example of a homeostasis response dependent on mobilization of an intracellular storage compartment. Here, we generalize this concept to a G protein–coupled receptor, somatostatin receptor subtype 2 (SSTR2), in pituitary cells. Following internalization in corticotropes, SSTR2 moves to a juxtanuclear syntaxin-6–positive compartment, where it remains until the corticotropes are stimulated with corticotropin releasing factor (CRF), whereupon SSTR2 exits the compartment on syntaxin-6–positive vesicular/tubular carriers that depend on Rab10 for their fusion with the plasma membrane. As SSTR2 activation antagonizes CRF-mediated hormone release, this storage/resurfacing mechanism may allow for a physiological homeostatic feedback system. In fact, we find that SSTR2 moves from an intracellular compartment to the cell surface in pituitary gland somatotropes, concomitant with increasing levels of serum growth hormone (GH) during natural GH cycles. Our data thus provide a mechanism by which signaling-mediated plasma membrane resurfacing of SSTR2 can fine-tune pituitary hormone release.
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Affiliation(s)
- Walaa Alshafie
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Vincent Francis
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Klaudia Bednarz
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Yingzhou Edward Pan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Thomas Stroh
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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17
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Jones E, Mead S. Genetic risk factors for Creutzfeldt-Jakob disease. Neurobiol Dis 2020; 142:104973. [PMID: 32565065 DOI: 10.1016/j.nbd.2020.104973] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/18/2020] [Accepted: 06/13/2020] [Indexed: 10/24/2022] Open
Abstract
Prion diseases are a group of fatal neurodegenerative disorders of mammals that share a central role for prion protein (PrP, gene PRNP) in their pathogenesis. Prions are infectious agents that account for the observed transmission of prion diseases between humans and animals in certain circumstances. The prion mechanism invokes a misfolded and multimeric assembly of PrP (a prion) that grows by templating of the normal protein and propagates by fission. Aside from the medical and public health notoriety of acquired prion diseases, the conditions have attracted interest as it has been realized that common neurodegenerative disorders share so-called prion-like mechanisms. In this article we will expand on recent evidence for new genetic loci that alter the risk of human prion disease. The most common human prion disease, sporadic Creutzfeldt-Jakob disease (sCJD), is characterized by the seemingly spontaneous appearance of prions in the brain. Genetic variation within PRNP is associated with all types of prion diseases, in particular, heterozygous genotypes at codons 129 and 219 have long been known to be strong protective factors against sCJD. A large number of rare mutations have been described in PRNP that cause autosomal dominant inherited prion diseases. Two loci recently identified by genome-wide association study increase sCJD risk, including variants in or near to STX6 and GAL3ST1. STX6 encodes syntaxin-6, a component of SNARE complexes with cellular roles that include the fusion of intracellular vesicles with target membranes. GAL3ST1 encodes cerebroside sulfotransferase, the only enzyme that sulfates sphingolipids to make sulfatides, a major lipid component of myelin. We discuss how these roles may modify the pathogenesis of prion diseases and their relevance for other neurodegenerative disorders.
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Affiliation(s)
- Emma Jones
- MRC Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, 33 Cleveland Street, W1W 7FF, United Kingdom
| | - Simon Mead
- MRC Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, 33 Cleveland Street, W1W 7FF, United Kingdom.
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18
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Peak TC, Panigrahi GK, Praharaj P, Su Y, Shi L, Chyr J, Rivera-Chávez J, Flores-Bocanegra L, Singh R, Vander Griend DJ, Oberlies NH, Kerr BA, Hemal A, Bitting RL, Deep G. Syntaxin 6-mediated exosome secretion regulates enzalutamide resistance in prostate cancer. Mol Carcinog 2020; 59:62-72. [PMID: 31674708 PMCID: PMC6916724 DOI: 10.1002/mc.23129] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 12/12/2022]
Abstract
Prostate cancer (PCa) deaths are typically the result of metastatic castration-resistant PCa (mCRPC). Recently, enzalutamide (Enz), an oral androgen receptor inhibitor, was approved for treating patients with mCRPC. Invariably, all PCa patients eventually develop resistance against Enz. Therefore, novel strategies aimed at overcoming Enz resistance are needed to improve the survival of PCa patients. The role of exosomes in drug resistance has not been fully elucidated in PCa. Therefore, we set out to better understand the exosome's role in the mechanism underlying Enz-resistant PCa. Results showed that Enz-resistant PCa cells (C4-2B, CWR-R1, and LNCaP) secreted significantly higher amounts of exosomes (2-4 folds) compared to Enz-sensitive counterparts. Inhibition of exosome biogenesis in resistant cells by GW4869 and dimethyl amiloride strongly decreased their cell viability. Mechanistic studies revealed upregulation of syntaxin 6 as well as its increased colocalization with CD63 in Enz-resistant PCa cells compared to Enz-sensitive cells. Syntaxin 6 knockdown by specific small interfering RNAs in Enz-resistant PCa cells (C4-2B and CWR-R1) resulted in reduced cell number and increased cell death in the presence of Enz. Furthermore, syntaxin 6 knockdown significantly reduced the exosome secretion in both Enz-resistant C4-2B and CWR-R1 cells. The Cancer Genome Atlas analysis showed increased syntaxin 6 expressions associated with higher Gleason score and decreased progression-free survival in PCa patients. Importantly, IHC analysis showed higher syntaxin 6 expression in cancer tissues from Enz-treated patients compared to Enz naïve patients. Overall, syntaxin 6 plays an important role in the secretion of exosomes and increased survival of Enz-resistant PCa cells.
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Affiliation(s)
- Taylor C. Peak
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Gati K Panigrahi
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Prakash Praharaj
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Yixin Su
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Lihong Shi
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jacqueline Chyr
- School of Bioinformatics, University of Texas Health Science Center, Houston, Texas
| | - José Rivera-Chávez
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro; Greensboro, North Carolina
| | - Laura Flores-Bocanegra
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro; Greensboro, North Carolina
| | - Ravi Singh
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | | | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro; Greensboro, North Carolina
| | - Bethany A. Kerr
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Wake Forest Baptist Comprehensive Cancer Center
- Department of Urology
| | | | - Rhonda L. Bitting
- Internal Medicine-Hematology and Oncology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Wake Forest Baptist Comprehensive Cancer Center
- Department of Urology
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19
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Rösler TW, Tayaranian Marvian A, Brendel M, Nykänen NP, Höllerhage M, Schwarz SC, Hopfner F, Koeglsperger T, Respondek G, Schweyer K, Levin J, Villemagne VL, Barthel H, Sabri O, Müller U, Meissner WG, Kovacs GG, Höglinger GU. Four-repeat tauopathies. Prog Neurobiol 2019; 180:101644. [PMID: 31238088 DOI: 10.1016/j.pneurobio.2019.101644] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/21/2019] [Accepted: 06/12/2019] [Indexed: 02/08/2023]
Abstract
Tau is a microtubule-associated protein with versatile functions in the dynamic assembly of the neuronal cytoskeleton. Four-repeat (4R-) tauopathies are a group of neurodegenerative diseases defined by cytoplasmic inclusions predominantly composed of tau protein isoforms with four microtubule-binding domains. Progressive supranuclear palsy, corticobasal degeneration, argyrophilic grain disease or glial globular tauopathy belong to the group of 4R-tauopathies. The present review provides an introduction in the current concept of 4R-tauopathies, including an overview of the neuropathological and clinical spectrum of these diseases. It describes the genetic and environmental etiological factors, as well as the contemporary knowledge about the pathophysiological mechanisms, including post-translational modifications, aggregation and fragmentation of tau, as well as the role of protein degradation mechanisms. Furthermore, current theories about disease propagation are discussed, involving different extracellular tau species and their cellular release and uptake mechanisms. Finally, molecular diagnostic tools for 4R-tauopathies, including tau-PET and fluid biomarkers, and investigational therapeutic strategies are presented. In summary, we report on 4R-tauopathies as overarching disease concept based on a shared pathophysiological concept, and highlight the challenges and opportunities on the way towards a causal therapy.
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Affiliation(s)
- Thomas W Rösler
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Amir Tayaranian Marvian
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Matthias Brendel
- Dept. of Nuclear Medicine, University of Munich, 81377 Munich, Germany
| | - Niko-Petteri Nykänen
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Matthias Höllerhage
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Sigrid C Schwarz
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | | | - Thomas Koeglsperger
- Dept. of Neurology, University of Munich, 81377 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Gesine Respondek
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Kerstin Schweyer
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany
| | - Johannes Levin
- Dept. of Neurology, University of Munich, 81377 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Victor L Villemagne
- Dept. of Molecular Imaging and Therapy, Austin Health, Heidelberg, VIC, 3084, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia; Dept. of Medicine, Austin Health, University of Melbourne, Melbourne, VIC, Australia
| | - Henryk Barthel
- Dept. of Nuclear Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Osama Sabri
- Dept. of Nuclear Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Ulrich Müller
- Institute for Human Genetics, University of Giessen, 35392 Giessen, Germany
| | - Wassilios G Meissner
- Service de Neurologie, CHU Bordeaux, 33000 Bordeaux, France; Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; Dept. of Medicine, University of Otago, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand
| | - Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna, 1090 Vienna, Austria; Dept. of Laboratory Medicine and Pathobiology, University of Toronto, Laboratory Medicine Program, University Health Network, Toronto, Canada; Tanz Centre for Research in Neurodegenerative Disease, Krembil Brain Institute, Toronto, Canada
| | - Günter U Höglinger
- Dept. of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany; Dept. of Neurology, Technical University of Munich, School of Medicine, 81675 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany; Dept. of Neurology, Hannover Medical School, 30625 Hannover, Germany.
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Zhao XW, Huang DW, Zhu HL, Pan XC, Wang XX, Qi YX, Cheng GL, Zhao HL, Yang YX. Alterations of the circular RNA profile in the jejunum of neonatal calves in response to colostrum and milk feeding. J Dairy Sci 2019; 102:7038-7048. [PMID: 31178190 DOI: 10.3168/jds.2018-15942] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/10/2019] [Indexed: 12/25/2022]
Abstract
Circular RNA (circRNA) have been suggested to contribute to regulating gene expression in various tissues and cells of eukaryotes. However, little is known regarding the expression pattern of circRNA and their potential function in the small intestine of neonatal calves that receive colostrum. In the current study, jejunum tissue samples were collected from control calves (2 h after birth; CT; n = 3) and neonatal calves that ingested colostrum (24 h after birth; CO; n = 3) or milk (24 h after birth; MK; n = 3) to compare the circRNA expression patterns using a high-throughput RNA sequencing approach. A total of 21,213, 17,861, and 21,737 circRNA were identified in the CT, CO, and MK groups, respectively. Only 13,254 of these circRNA were common to the 3 groups, suggesting high specificity of circRNA expression depending on nutrient type. In total, 243, 249, and 283 circRNA were differentially expressed in the CO versus CT, CO versus MK, and MK versus CT comparisons, respectively. Gene ontology analysis showed that the differentially expressed circRNA and their predicted or known target genes from the CO and MK groups were mainly involved in macromolecule metabolic process, response to stress, and vesicle-mediated transport. Moreover, pathway analysis showed that the Rap1 signaling pathway, focal adhesion, ubiquitin-mediated proteolysis, and extracellular matrix-receptor interaction were the most significantly enriched pathways. These data collectively indicate that circRNA are abundant and dynamically expressed when calves receive colostrum and act as microRNA sponges to regulate their target genes for jejunum function during the early development of newborn calves.
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Affiliation(s)
- X W Zhao
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - D W Huang
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - H L Zhu
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - X C Pan
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - X X Wang
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Y X Qi
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - G L Cheng
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - H L Zhao
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Y X Yang
- Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, China.
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21
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Syntaxin 6: A novel predictive and prognostic biomarker in papillary renal cell carcinoma. Sci Rep 2019; 9:3146. [PMID: 30816681 PMCID: PMC6395695 DOI: 10.1038/s41598-019-39305-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 01/07/2019] [Indexed: 12/20/2022] Open
Abstract
Syntaxin 6 is a SNARE family protein known to play an important role in intracellular trafficking. Here, we examined the tumorogenic role of syntaxin 6 in renal cell carcinoma (RCC). The Cancer Genome Atlas (TCGA) was queried for clinicopathologic data and syntaxin 6 expression. We found a significant difference in overall survival (OS) between groups, with high syntaxin 6 expression correlating with decreased survival. When stratifying the data based on histological subtype, the papillary RCC subtype exhibited a significant correlation between syntaxin 6 expression and survival. Using ROC curve, we calculated the area under the curve (AUC) to determine the ability of syntaxin 6 to predict 3-year overall survival. The AUC for syntaxin 6 was 0.73, significantly higher compared to 0.52 for T stage. Next, syntaxin 6 expression was evaluated in clear cell (786-O and Caki-1) and papillary (Caki-2 and ACHN) RCC cells. Syntaxin 6 expression was higher in Caki-1 and ACHN RCC cells. Silencing of syntaxin 6 in ACHN cells significantly decreased the cell viability (p < 0.001). Overall, syntaxin 6 could be a prognostic biomarker for patients with papillary RCC and syntaxin 6 inhibitors hold promise as a novel therapy against RCC.
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Kinoshita-Kawada M, Hasegawa H, Hongu T, Yanagi S, Kanaho Y, Masai I, Mishima T, Chen X, Tsuboi Y, Rao Y, Yuasa-Kawada J, Wu JY. A crucial role for Arf6 in the response of commissural axons to Slit. Development 2019; 146:dev172106. [PMID: 30674481 PMCID: PMC6382006 DOI: 10.1242/dev.172106] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 01/14/2019] [Indexed: 12/23/2022]
Abstract
A switch in the response of commissural axons to the repellent Slit is crucial for ensuring that they cross the ventral midline only once. However, the underlying mechanisms remain to be elucidated. We have found that both endocytosis and recycling of Robo1 receptor are crucial for modulating Slit sensitivity in vertebrate commissural axons. Robo1 endocytosis and its recycling back to the cell surface maintained the stability of axonal Robo1 during Slit stimulation. We identified Arf6 guanosine triphosphatase and its activators, cytohesins, as previously unknown components in Slit-Robo1 signalling in vertebrate commissural neurons. Slit-Robo1 signalling activated Arf6. The Arf6-deficient mice exhibited marked defects in commissural axon midline crossing. Our data showed that a Robo1 endocytosis-triggered and Arf6-mediated positive-feedback strengthens the Slit response in commissural axons upon their midline crossing. Furthermore, the cytohesin-Arf6 pathways modulated this self-enhancement of the Slit response before and after midline crossing, resulting in a switch that reinforced robust regulation of axon midline crossing. Our study provides insights into endocytic trafficking-mediated mechanisms for spatiotemporally controlled axonal responses and uncovers new players in the midline switch in Slit responsiveness of commissural axons.
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Affiliation(s)
- Mariko Kinoshita-Kawada
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
- Department of Neurology, Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Department of Neurology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Hiroshi Hasegawa
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Tsunaki Hongu
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Shigeru Yanagi
- Laboratory of Molecular Biochemistry, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Yasunori Kanaho
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Ichiro Masai
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Takayasu Mishima
- Department of Neurology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Xiaoping Chen
- Department of Neurology, Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Yoshio Tsuboi
- Department of Neurology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Yi Rao
- State Key Laboratory of Biomembrane and Membrane Biology, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University School of Life Sciences, Beijing 100871, China
| | - Junichi Yuasa-Kawada
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
- Department of Neurology, Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Department of Neurology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
- Center for Advanced Medical Innovation, Kyushu University, Fukuoka 812-8582, Japan
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Jane Y Wu
- Department of Neurology, Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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MFSC: Multi-voting based feature selection for classification of Golgi proteins by adopting the general form of Chou's PseAAC components. J Theor Biol 2019; 463:99-109. [DOI: 10.1016/j.jtbi.2018.12.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 12/02/2018] [Accepted: 12/14/2018] [Indexed: 12/29/2022]
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Hussain S, Fredriksen I, Ringsevjen H, Kavalali ET, Davanger S. Antibodies raised against aldehyde-fixed antigens improve sensitivity for postembedding electron microscopy. J Neurosci Methods 2019; 317:1-10. [PMID: 30703389 DOI: 10.1016/j.jneumeth.2019.01.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Antibodies are one of the most important tools in biological research. High specificity and sensitivity of antibodies are crucial to obtain reliable results. Tissue fixed with glutaraldehyde (GA) is commonly used in electron microscopical investigations. The fixation and embedding routine in preparation of tissue for post-embedding electron microscopy (EM) will mask and structurally alter epitopes, making antibody-antigen interaction inefficient, with low labeling intensities. One of the main factors in this regard is the use of GA as fixative. NEW METHOD To alleviate these technical challenges, we immunized rabbits with antigen pre-fixed with GA. We hypothesized that the resulting antibodies would have stronger affinity to antigens that have been conformationally changed and denatured by GA, the way they are in fixed tissue. COMPARISON WITH EXISTING METHOD AND RESULTS An initial screening with western blotting (WB) showed results consistent with our hypothesis. In-house antibodies raised against GA-fixed SNARE proteins SNAP-25 and VAMP2, binds more strongly to fixed proteins compared to non-fixed proteins, while the pattern is opposite with the commercially available antibodies raised against non-fixed antigens (standard antibodies). Quantitative post-embedding EM of hippocampal synapses gave higher labeling intensities with anti-GA-SNAP-25 and anti-GA-VAMP2 compared to standard antibodies. Importantly, light microscopy (LM) and EM with our antibodies revealed stronger labeling of GA-fixed than formaldehyde (FH) treated brains. CONCLUSION Our results highlight the experimental potential of raising antibodies against GA-treated antigen to improve sensitivity of the antibodies for postembedding immunogold EM.
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Affiliation(s)
- S Hussain
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, Oslo, Norway.
| | - I Fredriksen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - H Ringsevjen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, Oslo, Norway
| | | | - S Davanger
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, Oslo, Norway
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25
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Dingjan I, Linders PTA, Verboogen DRJ, Revelo NH, Ter Beest M, van den Bogaart G. Endosomal and Phagosomal SNAREs. Physiol Rev 2018; 98:1465-1492. [PMID: 29790818 DOI: 10.1152/physrev.00037.2017] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.
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Affiliation(s)
- Ilse Dingjan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Peter T A Linders
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Danielle R J Verboogen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Natalia H Revelo
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Martin Ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
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Amino acids stimulate the endosome-to-Golgi trafficking through Ragulator and small GTPase Arl5. Nat Commun 2018; 9:4987. [PMID: 30478271 PMCID: PMC6255761 DOI: 10.1038/s41467-018-07444-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/31/2018] [Indexed: 11/22/2022] Open
Abstract
The endosome-to-Golgi or endocytic retrograde trafficking pathway is an important post-Golgi recycling route. Here we show that amino acids (AAs) can stimulate the retrograde trafficking and regulate the cell surface localization of certain Golgi membrane proteins. By testing components of the AA-stimulated mTORC1 signaling pathway, we demonstrate that SLC38A9, v-ATPase and Ragulator, but not Rag GTPases and mTORC1, are essential for the AA-stimulated trafficking. Arl5, an ARF-like family small GTPase, interacts with Ragulator in an AA-regulated manner and both Arl5 and its effector, the Golgi-associated retrograde protein complex (GARP), are required for the AA-stimulated trafficking. We have therefore identified a mechanistic connection between the nutrient signaling and the retrograde trafficking pathway, whereby SLC38A9 and v-ATPase sense AA-sufficiency and Ragulator might function as a guanine nucleotide exchange factor to activate Arl5, which, together with GARP, a tethering factor, probably facilitates the endosome-to-Golgi trafficking. Amino acid levels are known to regulate anabolic and catabolic pathways. Here, the authors report that amino acids also affect membrane trafficking by stimulating endosome-to-Golgi retrograde trafficking and regulating cell surface localization of certain Golgi proteins through Ragulator and Arl5.
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27
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Abstract
Antigen cross-presentation is an adaptation of the cellular process of loading MHC-I molecules with endogenous peptides during their biosynthesis within the endoplasmic reticulum. Cross-presented peptides derive from internalized proteins, microbial pathogens, and transformed or dying cells. The physical separation of internalized cargo from the endoplasmic reticulum, where the machinery for assembling peptide-MHC-I complexes resides, poses a challenge. To solve this problem, deliberate rewiring of organelle communication within cells is necessary to prepare for cross-presentation, and different endocytic receptors and vesicular traffic patterns customize the emergent cross-presentation compartment to the nature of the peptide source. Three distinct pathways of vesicular traffic converge to form the ideal cross-presentation compartment, each regulated differently to supply a unique component that enables cross-presentation of a diverse repertoire of peptides. Delivery of centerpiece MHC-I molecules is the critical step regulated by microbe-sensitive Toll-like receptors. Defining the subcellular sources of MHC-I and identifying sites of peptide loading during cross-presentation remain key challenges.
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Affiliation(s)
- J Magarian Blander
- Jill Roberts Institute for Research in Inflammatory Bowel Disease, Weill Cornell Medicine, Cornell University, New York, NY 10021, USA; .,Joan and Sanford I. Weill Department of Medicine, Department of Microbiology and Immunology, and Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA
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28
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Radif Y, Ndiaye H, Kalantzi V, Jacobs R, Hall A, Minogue S, Waugh MG. The endogenous subcellular localisations of the long chain fatty acid-activating enzymes ACSL3 and ACSL4 in sarcoma and breast cancer cells. Mol Cell Biochem 2018; 448:275-286. [PMID: 29450800 PMCID: PMC6182735 DOI: 10.1007/s11010-018-3332-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 02/09/2018] [Indexed: 12/22/2022]
Abstract
Fatty acid uptake and metabolism are often dysregulated in cancer cells. Fatty acid activation is a critical step that allows these biomolecules to enter cellular metabolic pathways such as mitochondrial β-oxidation for ATP generation or the lipogenic routes that generate bioactive lipids such as the inositol phospholipids. Fatty acid activation by the addition of coenzyme A is catalysed by a family of enzymes called the acyl CoA synthetase ligases (ACSL). Furthermore, enhanced expression of particular ACSL isoforms, such as ACSL4, is a feature of some more aggressive cancers and may contribute to the oncogenic phenotype. This study focuses on ACSL3 and ACSL4, closely related structural homologues that preferentially activate palmitate and arachidonate fatty acids, respectively. In this study, immunohistochemical screening of multiple soft tissue tumour arrays revealed that ACSL3 and ACSL4 were highly, but differentially, expressed in a subset of leiomyosarcomas, fibrosarcomas and rhabdomyosarcomas, with consistent cytoplasmic and granular stainings of tumour cells. The intracellular localisations of endogenously expressed ACSL3 and ACSL4 were further investigated by detailed subcellular fractionation analyses of HT1080 fibrosarcoma and MCF-7 breast cancer cells. ACSL3 distribution closely overlapped with proteins involved in trafficking from the trans-Golgi network and endosomes. In contrast, the ACSL4 localisation pattern more closely followed that of calnexin which is an endoplasmic reticulum resident chaperone. Confocal immunofluorescence imaging of MCF-7 cells confirmed the intracellular localisations of both enzymes. These observations reveal new information regarding the compartmentation of fatty acid metabolism in cancer cells.
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Affiliation(s)
- Yassmeen Radif
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Haarith Ndiaye
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Vasiliki Kalantzi
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Ruth Jacobs
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Andrew Hall
- Sheila Sherlock Liver Centre, Royal Free London NHS Foundation Trust and UCL Institute for Liver and Digestive Health, University College London, London, UK
| | - Shane Minogue
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Mark G Waugh
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK.
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29
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Caronni N, Simoncello F, Stafetta F, Guarnaccia C, Ruiz-Moreno JS, Opitz B, Galli T, Proux-Gillardeaux V, Benvenuti F. Downregulation of Membrane Trafficking Proteins and Lactate Conditioning Determine Loss of Dendritic Cell Function in Lung Cancer. Cancer Res 2018; 78:1685-1699. [PMID: 29363545 DOI: 10.1158/0008-5472.can-17-1307] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/13/2017] [Accepted: 01/18/2018] [Indexed: 11/16/2022]
Abstract
Restoring antigen presentation for efficient and durable activation of tumor-specific CD8+ T-cell responses is pivotal to immunotherapy, yet the mechanisms that cause subversion of dendritic cell (DC) functions are not entirely understood, limiting the development of targeted approaches. In this study, we show that bona fide DCs resident in lung tumor tissues or DCs exposed to factors derived from whole lung tumors become refractory to endosomal and cytosolic sensor stimulation and fail to secrete IL12 and IFNI. Tumor-conditioned DC exhibited downregulation of the SNARE VAMP3, a regulator of endosomes trafficking critical for cross-presentation of tumor antigens and DC-mediated tumor rejection. Dissection of cell-extrinsic suppressive pathways identified lactic acid in the tumor microenvironment as sufficient to inhibit type-I IFN downstream of TLR3 and STING. DC conditioning by lactate also impacted adaptive function, accelerating antigen degradation and impairing cross-presentation. Importantly, DCs conditioned by lactate failed to prime antitumor responses in vivo These findings provide a new mechanistic viewpoint to the concept of DC suppression and hold potential for future therapeutic approaches.Significance: These findings provide insight into the cell-intrinsic and cell-extrinsic mechanisms that cause loss of presentation of tumor-specific antigens in lung cancer tissues. Cancer Res; 78(7); 1685-99. ©2018 AACR.
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Affiliation(s)
- Nicoletta Caronni
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Francesca Stafetta
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Corrado Guarnaccia
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Juan Sebastian Ruiz-Moreno
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité University Medicine, Berlin, Germany
| | - Bastian Opitz
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité University Medicine, Berlin, Germany
| | - Thierry Galli
- Univ Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, Membrane Traffic in Health and Disease, INSERM ERL U950, Paris, France
| | - Veronique Proux-Gillardeaux
- Univ Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, Membrane Traffic in Health and Disease, INSERM ERL U950, Paris, France
| | - Federica Benvenuti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
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30
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Ceder MM, Lekholm E, Hellsten SV, Perland E, Fredriksson R. The Neuronal and Peripheral Expressed Membrane-Bound UNC93A Respond to Nutrient Availability in Mice. Front Mol Neurosci 2017; 10:351. [PMID: 29163028 PMCID: PMC5671512 DOI: 10.3389/fnmol.2017.00351] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 10/13/2017] [Indexed: 12/31/2022] Open
Abstract
Many transporters such as the solute carriers belonging to the Major facilitator superfamily Pfam clan are orphans in that their tissue and cellular localization as well as substrate profile and function are still unknown. Here we have characterized the putative solute carrier UNC93A. We aimed to investigate the expression profile on both protein and mRNA level of UNC93A in mouse since it has not been clarified. UNC93A staining was found in cortex, hippocampus and cerebellum. It was found to be expressed in many neurons, but not all, with staining located in close proximity to the plasma membrane. Furthermore, we aimed to extend the starvation data available for Unc93a in hypothalamic cell cultures from mouse. We investigated the Unc93a alterations with focus on amino acid deprivation in embryonic cortex cells from mice as well as 24 h starvation in adult male mice and compared it to recently studied putative and known solute carriers. Unc93a expression was found both in the brain and peripheral organs, in low to moderate levels in the adult mice and was affected by amino acid deprivation in embryonic cortex cultures and starvation in in vivo samples. In conclusion, the membrane-bound UNC93A is expressed in both the brain and peripheral tissues and responds to nutrient availability in mice.
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Affiliation(s)
- Mikaela M Ceder
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Emilia Lekholm
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Sofie V Hellsten
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Emelie Perland
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Robert Fredriksson
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
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31
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Gomi H, Osawa H, Uno R, Yasui T, Hosaka M, Torii S, Tsukise A. Canine Salivary Glands: Analysis of Rab and SNARE Protein Expression and SNARE Complex Formation With Diverse Tissue Properties. J Histochem Cytochem 2017; 65:637-653. [PMID: 28914590 DOI: 10.1369/0022155417732527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The comparative structure and expression of salivary components and vesicular transport proteins in the canine major salivary glands were investigated. Histochemical analysis revealed that the morphology of the five major salivary glands-parotid, submandibular, polystomatic sublingual, monostomatic sublingual, and zygomatic glands-was greatly diverse. Immunoblot analysis revealed that expression levels of α-amylase and antimicrobial proteins, such as lysozyme, lactoperoxidase, and lactoferrin, differed among the different glands. Similarly, Rab proteins (Rab3d, Rab11a, Rab11b, Rab27a, and Rab27b) and soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins VAMP4, VAMP8, syntaxin-2, syntaxin-3, syntaxin-4, and syntaxin-6 were expressed at various levels in individual glands. mmunohistochemistry of Rab3d, Rab11b, Rab27b, VAMP4, VAMP8, syntaxin-4, and syntaxin-6 revealed their predominant expression in serous acinar cells, demilunes, and ductal cells. The VAMP4/syntaxin-6 SNARE complex, which is thought to be involved in the maturation of secretory granules in the Golgi field, was found more predominantly in the monostomatic sublingual gland than in the parotid gland. These results suggest that protein expression profiles in canine salivary glands differ among individual glands and reflect the properties of their specialized functions.
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Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Hiromi Osawa
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Rie Uno
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
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Cooperative Repression of Insulin-Like Growth Factor Type 2 Receptor Translation by MicroRNA 195 and RNA-Binding Protein CUGBP1. Mol Cell Biol 2017; 37:MCB.00225-17. [PMID: 28716948 DOI: 10.1128/mcb.00225-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/06/2017] [Indexed: 12/14/2022] Open
Abstract
Insulin-like growth factor type 2 (IGF2) receptor (IGF2R) recognizes mannose 6-phosphate-containing molecules and IGF2 and plays an important role in many pathophysiological processes, including gut mucosal adaptation. However, the mechanisms that control cellular IGF2R abundance are poorly known. MicroRNAs (miRNAs) and RNA-binding proteins (RBPs) critically regulate gene expression programs in mammalian cells by modulating the stability and translation of target mRNAs. Here we report that miRNA 195 (miR-195) and RBP CUG-binding protein 1 (CUGBP1) jointly regulate IGF2R expression at the posttranscriptional level in intestinal epithelial cells. Both miR-195 and CUGBP1 interacted with the 3' untranslated region (3'-UTR) of Igf2r mRNA, and the association of CUGBP1 with Igf2r mRNA enhanced miR-195 binding to Igf2r mRNA. Ectopically expressed CUGBP1 and miR-195 repressed IGF2R translation cooperatively without altering the stability of Igf2r mRNA. Importantly, the miR-195- and CUGBP1-repressed levels of cellular IGF2R led to a disruption in the structure of the trans-Golgi network. These findings indicate that IGF2R expression is controlled posttranscriptionally by two factors that associate with Igf2r mRNA and suggest that miR-195 and CUGBP1 dampen IGF signaling by inhibiting IGF2R translation.
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Zhao J, Wang M, Deng W, Zhong D, Jiang Y, Liao Y, Chen B, Zhang X. ADP-ribosylation factor-like GTPase 15 enhances insulin-induced AKT phosphorylation in the IR/IRS1/AKT pathway by interacting with ASAP2 and regulating PDPK1 activity. Biochem Biophys Res Commun 2017; 486:865-871. [PMID: 28322786 DOI: 10.1016/j.bbrc.2017.03.079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 03/16/2017] [Indexed: 10/19/2022]
Abstract
Decreased phosphorylation in the insulin signalling pathway is a hallmark of insulin resistance. The causes of this phenomenon are complicated and multifactorial. Recently, genomic analyses have identified ARL15 as a new candidate gene related to diabetes. However, the ARL15 protein function remains unclear. Here, we show that ARL15 is upregulated by insulin stimulation. This effect was impaired in insulin-resistant pathophysiology in TNF-α-treated C2C12 myotubes and in the skeletal muscles of leptin knockout mice. In addition, ARL15 localized to the cytoplasm in the resting state and accumulated in the Golgi apparatus around the nucleus upon insulin stimulation. ARL15 overexpression can enhance the phosphorylation of the key insulin signalling pathway molecules IR, IRS1 and AKT in C2C12 myotubes. Moreover, ARL15 knockdown can also specifically inhibit the phosphorylation of PDPK1 Ser241, thereby reducing PDPK1 activity and its downstream phosphorylation of AKT Thr308. Co-immunoprecipitation assays identified ASAP2 as an ARL15-interacting protein. In conclusion, we have identified that ARL15 acts as an insulin-sensitizing effector molecule to upregulate the phosphorylation of members of the canonical IR/IRS1/PDPK1/AKT insulin pathway by interacting with its GAP ASAP2 and activating PDPK1. This research may provide new insights into GTPase-mediated insulin signalling regulation and facilitate the development of new pharmacotherapeutic targets for insulin sensitization.
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Affiliation(s)
- Jie Zhao
- Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Min Wang
- Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Wuquan Deng
- Department of Endocrinology and Nephrology, Emergency Medical Center, Chongqing 400014, China
| | - Daping Zhong
- Department of Endocrinology, 324th Hospital of the People's Liberation Army (No. 324 Hospital of PLA), Chongqing 400020, China
| | - Youzhao Jiang
- Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Yong Liao
- Department of Endocrinology, 169th Hospital of the People's Liberation Army (No. 169 Hospital of PLA), Hengyang, Hunan Province, 421002, China
| | - Bing Chen
- Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
| | - Xiaoli Zhang
- Department of Clinical Laboratory, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
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Klink VP, Sharma K, Pant SR, McNeece B, Niraula P, Lawrence GW. Components of the SNARE-containing regulon are co-regulated in root cells undergoing defense. PLANT SIGNALING & BEHAVIOR 2017; 12:e1274481. [PMID: 28010187 PMCID: PMC5351740 DOI: 10.1080/15592324.2016.1274481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/14/2016] [Accepted: 12/15/2016] [Indexed: 05/23/2023]
Abstract
The term regulon has been coined in the genetic model plant Arabidopsis thaliana, denoting a structural and physiological defense apparatus defined genetically through the identification of the penetration (pen) mutants. The regulon is composed partially by the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) syntaxin PEN1. PEN1 has homology to a Saccharomyces cerevisae gene that regulates a Secretion (Sec) protein, Suppressor of Sec 1 (Sso1p). The regulon is also composed of the β-glucosidase (PEN2) and an ATP binding cassette (ABC) transporter (PEN3). While important in inhibiting pathogen infection, limited observations have been made regarding the transcriptional regulation of regulon genes until now. Experiments made using the model agricultural Glycine max (soybean) have identified co-regulated gene expression of regulon components. The results explain the observation of hundreds of genes expressed specifically in the root cells undergoing the natural process of defense. Data regarding additional G. max genes functioning within the context of the regulon are presented here, including Sec 14, Sec 4 and Sec 23. Other examined G. max homologs of membrane fusion genes include an endosomal bromo domain-containing protein1 (Bro1), syntaxin6 (SYP6), SYP131, SYP71, SYP8, Bet1, coatomer epsilon (ϵ-COP), a coatomer zeta (ζ-COP) paralog and an ER to Golgi component (ERGIC) protein. Furthermore, the effectiveness of biochemical pathways that would function within the context of the regulon ave been examined, including xyloglucan xylosyltransferase (XXT), reticuline oxidase (RO) and galactinol synthase (GS). The experiments have unveiled the importance of the regulon during defense in the root and show how the deposition of callose relates to the process.
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Affiliation(s)
- Vincent P. Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Keshav Sharma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Shankar R. Pant
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Brant McNeece
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Prakash Niraula
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Gary W. Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, USA
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Priya A, Sugatha J, Parveen S, Lacas-gervais S, Raj P, Gilleron J, Datta S. Essential and selective role of SNX12 in transport of endocytic and retrograde cargo. J Cell Sci 2017; 130:2707-2721. [DOI: 10.1242/jcs.201905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/05/2017] [Indexed: 12/28/2022] Open
Abstract
The endosomal protein sorting machineries play vital roles in diverse physiologically important cellular processes. Much of the core membrane sorting apparatus are conserved in evolution, such as retromer, involved in the recycling of a diverse set of cargoes via retrograde trafficking route. Here, using a RNAi based loss of function study, we identified that SNX12 when suppressed, leads to severe blockage in CIM6PR transport and alters the morphology of the endocytic compartments. We demonstrate that SNX12 is involved in the early phase of CIM6PR transport and mediates receptor recycling upstream of the other well established SNX components of retromer. Ultra-structural analysis revealed that SNX12 resides on tubulo-vesicular structures, inspite of lacking a BAR domain. Further, we illustrate that SNX12 plays a key role in intraluminal vesicle formation and in the maturation of a sub-population of early endosomes to late endosomes thereby regulating selective endocytic transport of cargo for degradation. This study therefore provides evidence for the existence of early endosomal sub-populations, which have differential roles in sorting of the cargoes along endocytic degradative pathways.
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Affiliation(s)
- Amulya Priya
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
| | - Jini Sugatha
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
| | - Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
| | - Sandra Lacas-gervais
- Centre Commun de Microscopie Appliquée, Université Nice-Sophia Antipolis, 06108 Nice Cedex 2, France
| | - Prateek Raj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Jérôme Gilleron
- INSERM U1065, Centre Méditerranéen de Médecine Moléculaire C3M, Nice, France
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
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Topalidou I, Cattin-Ortolá J, Pappas AL, Cooper K, Merrihew GE, MacCoss MJ, Ailion M. The EARP Complex and Its Interactor EIPR-1 Are Required for Cargo Sorting to Dense-Core Vesicles. PLoS Genet 2016; 12:e1006074. [PMID: 27191843 PMCID: PMC4871572 DOI: 10.1371/journal.pgen.1006074] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/30/2016] [Indexed: 12/15/2022] Open
Abstract
The dense-core vesicle is a secretory organelle that mediates the regulated release of peptide hormones, growth factors, and biogenic amines. Dense-core vesicles originate from the trans-Golgi of neurons and neuroendocrine cells, but it is unclear how this specialized organelle is formed and acquires its specific cargos. To identify proteins that act in dense-core vesicle biogenesis, we performed a forward genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We previously reported the identification of two conserved proteins that interact with the small GTPase RAB-2 to control normal dense-core vesicle cargo-sorting. Here we identify several additional conserved factors important for dense-core vesicle cargo sorting: the WD40 domain protein EIPR-1 and the endosome-associated recycling protein (EARP) complex. By assaying behavior and the trafficking of dense-core vesicle cargos, we show that mutants that lack EIPR-1 or EARP have defects in dense-core vesicle cargo-sorting similar to those of mutants in the RAB-2 pathway. Genetic epistasis data indicate that RAB-2, EIPR-1 and EARP function in a common pathway. In addition, using a proteomic approach in rat insulinoma cells, we show that EIPR-1 physically interacts with the EARP complex. Our data suggest that EIPR-1 is a new interactor of the EARP complex and that dense-core vesicle cargo sorting depends on the EARP-dependent trafficking of cargo through an endosomal sorting compartment. Animal cells package and store many important signaling molecules in specialized compartments called dense-core vesicles. Molecules stored in dense-core vesicles include peptide hormones like insulin and small molecule neurotransmitters like dopamine. Defects in the release of these compounds can lead to a wide range of metabolic and mental disorders in humans, including diabetes, depression, and drug addiction. However, it is not well understood how dense-core vesicles are formed in cells and package the appropriate molecules. Here we use a genetic screen in the microscopic worm C. elegans to identify proteins that are important for early steps in the generation of dense-core vesicles, such as packaging the correct molecular cargos in the vesicles. We identify several factors that are conserved between worms and humans and point to a new role for a protein complex that had previously been shown to be important for controlling trafficking in other cellular compartments. The identification of this complex suggests new cellular trafficking events that may be important for the generation of dense-core vesicles.
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Affiliation(s)
- Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Jérôme Cattin-Ortolá
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Andrea L. Pappas
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Kirsten Cooper
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Gennifer E. Merrihew
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael J. MacCoss
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Li YX, Huang Y, Liu S, Mao Y, Yuan CY, Yang X, Yao LJ. Glycogen Synthase Kinase-3 Modulates Hyperosmotic-Induced Urea Transporter A1 Relocation in the Inner Medullary Collecting Duct Cells. Nephron Clin Pract 2016; 133:71-9. [PMID: 27161213 DOI: 10.1159/000446158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 03/28/2016] [Indexed: 11/19/2022] Open
Abstract
AIM Glycogen synthase kinase 3 (GSK3) regulates urine concentration by mediating the vasopressin-induced aquaporin 2 expression and water permeability, although it is unknown whether GSK3 also mediates the accumulation of the urea transporter A1 (UT-A1). The aim of this study is to investigate the effect of GSK3 on UT-A1 distribution. METHODS Mouse inner medullary collecting duct 3 cells were transfected with UT-A1-GFP construct. The stable transfected cells were cultured under hypertonic conditions, treated with GSK3 inhibitor lithium chloride, GSK3 activator, lysosome or proteasome inhibitor. The expression levels of UT-A1, GSK3, and phospho-GSK3 were analyzed using western blot. The interaction between UT-A1 and the Golgi apparatus was examined using confocal immunofluorescence microscope. The UT-A1 trafficking was examined using the biotinylation of surface membranes. RESULTS UT-A1 dissociated away from the Golgi apparatus and translocated to the plasma membrane under hypertonic-NaCl and NaCl plus urea stimulation. This movement was accompanied by the increased phosphorylation of GSK3 and its localization on the cellular membrane. Moreover, these results were duplicated by treating the cells with the GSK3 inhibitor, and by contrast, were partially reversed by the GSK3 activator. Treating cells with a lysosome or proteasome inhibitor failed to attenuate the effects of hypertonic stimulus, indicating that the loss of UT-A1 from the Golgi was not due to degradation. CONCLUSION Our results suggest that GSK3 may in part modulate the hypertonic-induced intracellular UT-A1 redistribution and its accumulation on the plasma membrane, which may constitute another mechanism by which GSK3 modulates urine concentration.
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Affiliation(s)
- Yong-Xia Li
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
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Du J, Liu X, Wu Y, Zhu J, Tang Y. Essential role of STX6 in esophageal squamous cell carcinoma growth and migration. Biochem Biophys Res Commun 2016; 472:60-7. [PMID: 26906622 DOI: 10.1016/j.bbrc.2016.02.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/15/2016] [Indexed: 11/15/2022]
Abstract
Abnormalities in endosomes, or dysregulation in their trafficking, play an important role directly in many diseases including oncogenesis. Syntaxin-6 (STX6) is involved in diverse cellular functions in a variety of cell types and has been shown to regulate many intracellular membrane trafficking events such as endocytosis, recycling and anterograde and retrograde trafficking. However, its expression pattern and biological functions in esophageal squamous cell carcinoma (ESCC) remained unknown. Here, we have found that the expression of STX6 was up-regulated in ESCC samples, its expression was significantly correlated with tumor size, histological differentiation, lymph node metastasis and depth. On one hand, STX6 silencing inhibited ESCC cells viability and proliferation in a p53-dependent manner. On the other hand, STX6 effect integrin trafficking and regulate ESCC cells migration. Taken together, our study revealed the oncogenic roles of STX6 in the progression of ESCC, and it might be a valuable target for ESCC therapy.
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Affiliation(s)
- Jin Du
- Department of Cardiothoracic Surgery, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China; Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing 210028, China
| | - Xiang Liu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China
| | - Yanhu Wu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China.
| | - Jinfu Zhu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China
| | - Yihu Tang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China
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Perisa D, Rohrer L, Kaech A, von Eckardstein A. Itinerary of high density lipoproteins in endothelial cells. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:98-107. [DOI: 10.1016/j.bbalip.2015.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 11/02/2015] [Accepted: 11/09/2015] [Indexed: 01/30/2023]
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40
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Venkatareddy M, Verma R, Kalinowski A, Patel SR, Shisheva A, Garg P. Distinct Requirements for Vacuolar Protein Sorting 34 Downstream Effector Phosphatidylinositol 3-Phosphate 5-Kinase in Podocytes Versus Proximal Tubular Cells. J Am Soc Nephrol 2016; 27:2702-19. [PMID: 26825532 DOI: 10.1681/asn.2015050555] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 12/09/2015] [Indexed: 12/16/2022] Open
Abstract
The mechanisms by which the glomerular filtration barrier prevents the loss of large macromolecules and simultaneously, maintains the filter remain poorly understood. Recent studies proposed that podocytes have an active role in both the endocytosis of filtered macromolecules and the maintenance of the filtration barrier. Deletion of a key endosomal trafficking regulator, the class 3 phosphatidylinositol (PtdIns) 3-kinase vacuolar protein sorting 34 (Vps34), in podocytes results in aberrant endosomal membrane morphology and podocyte dysfunction. We recently showed that the vacuolation phenotype in cultured Vps34-deficient podocytes is caused by the absence of a substrate for the Vps34 downstream effector PtdIns 3-phosphate 5-kinase (PIKfyve), which phosphorylates Vps34-generated PtdIns(3)P to produce PtdIns (3,5)P2. PIKfyve perturbation and PtdIns(3,5)P2 reduction result in massive membrane vacuolation along the endosomal system, but the cell-specific functions of PIKfyve in vivo remain unclear. We show here that the genetic deletion of PIKfyve in endocytically active proximal tubular cells resulted in the development of large cytoplasmic vacuoles caused by arrested endocytic traffic progression at a late-endosome stage. In contrast, deletion of PIKfyve in glomerular podocytes did not significantly alter the endosomal morphology, even in age 18-month-old mice. However, on culturing, the PIKfyve-deleted podocytes developed massive cytoplasmic vacuoles. In summary, these data suggest that glomerular podocytes and proximal tubules have different requirements for PIKfyve function, likely related to distinct in vivo needs for endocytic flux.
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Affiliation(s)
- Madhusudan Venkatareddy
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Rakesh Verma
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Anne Kalinowski
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Sanjeevkumar R Patel
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Puneet Garg
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
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Tie HC, Mahajan D, Chen B, Cheng L, VanDongen AMJ, Lu L. A novel imaging method for quantitative Golgi localization reveals differential intra-Golgi trafficking of secretory cargoes. Mol Biol Cell 2016; 27:848-61. [PMID: 26764092 PMCID: PMC4803310 DOI: 10.1091/mbc.e15-09-0664] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/07/2016] [Indexed: 12/02/2022] Open
Abstract
A novel imaging-based method is introduced to quantitatively localize Golgi proteins at nanometer resolution. The method reveals different intra-Golgi trafficking of secretory cargoes. Cellular functions of the Golgi are determined by the unique distribution of its resident proteins. Currently, electron microscopy is required for the localization of a Golgi protein at the sub-Golgi level. We developed a quantitative sub-Golgi localization method based on centers of fluorescence masses of nocodazole-induced Golgi ministacks under conventional optical microscopy. Our method is rapid, convenient, and quantitative, and it yields a practical localization resolution of ∼30 nm. The method was validated by the previous electron microscopy data. We quantitatively studied the intra-Golgi trafficking of synchronized secretory membrane cargoes and directly demonstrated the cisternal progression of cargoes from the cis- to the trans-Golgi. Our data suggest that the constitutive efflux of secretory cargoes could be restricted at the Golgi stack, and the entry of the trans-Golgi network in secretory pathway could be signal dependent.
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Affiliation(s)
- Hieng Chiong Tie
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Divyanshu Mahajan
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Bing Chen
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Li Cheng
- Bioinformatics Institute, Singapore 138671 School of Computing, National University of Singapore, Singapore 117417
| | - Antonius M J VanDongen
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
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Honvo-Houéto E, Truchet S. Indirect Immunofluorescence on Frozen Sections of Mouse Mammary Gland. J Vis Exp 2015. [PMID: 26650781 DOI: 10.3791/53179] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Indirect immunofluorescence is used to detect and locate proteins of interest in a tissue. The protocol presented here describes a complete and simple method for the immune detection of proteins, the mouse lactating mammary gland being taken as an example. A protocol for the preparation of the tissue samples, especially concerning the dissection of mouse mammary gland, tissue fixation and frozen tissue sectioning, are detailed. A standard protocol to perform indirect immunofluorescence, including an optional antigen retrieval step, is also presented. The observation of the labeled tissue sections as well as image acquisition and post-treatments are also stated. This procedure gives a full overview, from the collection of animal tissue to the cellular localization of a protein. Although this general method can be applied to other tissue samples, it should be adapted to each tissue/primary antibody couple studied.
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García-Melero A, Reverter M, Hoque M, Meneses-Salas E, Koese M, Conway JRW, Johnsen CH, Alvarez-Guaita A, Morales-Paytuvi F, Elmaghrabi YA, Pol A, Tebar F, Murray RZ, Timpson P, Enrich C, Grewal T, Rentero C. Annexin A6 and Late Endosomal Cholesterol Modulate Integrin Recycling and Cell Migration. J Biol Chem 2015; 291:1320-35. [PMID: 26578516 DOI: 10.1074/jbc.m115.683557] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 01/01/2023] Open
Abstract
Annexins are a family of proteins that bind to phospholipids in a calcium-dependent manner. Earlier studies implicated annexin A6 (AnxA6) to inhibit secretion and participate in the organization of the extracellular matrix. We recently showed that elevated AnxA6 levels significantly reduced secretion of the extracellular matrix protein fibronectin (FN). Because FN is directly linked to the ability of cells to migrate, this prompted us to investigate the role of AnxA6 in cell migration. Up-regulation of AnxA6 in several cell models was associated with reduced cell migration in wound healing, individual cell tracking and three-dimensional migration/invasion assays. The reduced ability of AnxA6-expressing cells to migrate was associated with decreased cell surface expression of αVβ3 and α5β1 integrins, both FN receptors. Mechanistically, we found that elevated AnxA6 levels interfered with syntaxin-6 (Stx6)-dependent recycling of integrins to the cell surface. AnxA6 overexpression caused mislocalization and accumulation of Stx6 and integrins in recycling endosomes, whereas siRNA-mediated AnxA6 knockdown did not modify the trafficking of integrins. Given our recent findings that inhibition of cholesterol export from late endosomes (LEs) inhibits Stx6-dependent integrin recycling and that elevated AnxA6 levels cause LE cholesterol accumulation, we propose that AnxA6 and blockage of LE cholesterol transport are critical for endosomal function required for Stx6-mediated recycling of integrins in cell migration.
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Affiliation(s)
- Ana García-Melero
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Meritxell Reverter
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Monira Hoque
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Elsa Meneses-Salas
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Meryem Koese
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - James R W Conway
- Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Camilla H Johnsen
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Anna Alvarez-Guaita
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Frederic Morales-Paytuvi
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Yasmin A Elmaghrabi
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Albert Pol
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
| | - Francesc Tebar
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
| | - Rachael Z Murray
- Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4095, Australia
| | - Paul Timpson
- Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Carlos Enrich
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia,
| | - Carles Rentero
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
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Hussain S, Davanger S. Postsynaptic VAMP/Synaptobrevin Facilitates Differential Vesicle Trafficking of GluA1 and GluA2 AMPA Receptor Subunits. PLoS One 2015; 10:e0140868. [PMID: 26488171 PMCID: PMC4619507 DOI: 10.1371/journal.pone.0140868] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 10/01/2015] [Indexed: 12/03/2022] Open
Abstract
Vertebrate organisms adapt to a continuously changing environment by regulating the strength of synaptic connections between brain cells. Excitatory synapses are believed to increase their strength by vesicular insertion of transmitter glutamate receptors into the postsynaptic plasma membrane. These vesicles, however, have never been demonstrated or characterized. For the first time, we show the presence of small vesicles in postsynaptic spines, often closely adjacent to the plasma membrane and PSD (postsynaptic density). We demonstrate that they harbor vesicle-associated membrane protein 2 (VAMP2/synaptobrevin-2) and glutamate receptor subunit 1 (GluA1). Disrupting VAMP2 by tetanus toxin treatment reduces the concentration of GluA1 in the postsynaptic plasma membrane. GluA1/VAMP2-containing vesicles, but not GluA2/VAMP2-vesicles, are concentrated in postsynaptic spines relative to dendrites. Our results indicate that small postsynaptic vesicles containing GluA1 are inserted directly into the spine plasma membrane through a VAMP2-dependent mechanism.
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Affiliation(s)
- Suleman Hussain
- Laboratory for Synaptic Plasticity, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, P.O. Box 1105 Blindern, 0317 Oslo, Norway
| | - Svend Davanger
- Laboratory for Synaptic Plasticity, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, P.O. Box 1105 Blindern, 0317 Oslo, Norway
- * E-mail:
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45
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Seko Y, Fujimura T, Yao T, Taka H, Mineki R, Okumura K, Murayama K. Secreted tyrosine sulfated-eIF5A mediates oxidative stress-induced apoptosis. Sci Rep 2015; 5:13737. [PMID: 26348594 PMCID: PMC4562266 DOI: 10.1038/srep13737] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 08/04/2015] [Indexed: 11/11/2022] Open
Abstract
Oxidative stress plays a critical role in ischemia/reperfusion-injury, atherosclerosis, and aging. It causes cell damage that leads to apoptosis via uncertain mechanisms. Because conditioned medium from cardiac myocytes subjected to hypoxia/reoxygenation induces extensive apoptosis of cardiac myocytes under normoxia, we hypothesized that a humoral factor released from the hypoxic/reoxygenated cardiac myocytes mediates apoptosis. We identified an apoptosis-inducing humoral factor in the hypoxia/reoxygenation-conditioned medium. Here, we found that eIF5A undergoes tyrosine sulfation in the trans-Golgi and is rapidly secreted from cardiac myocytes in response to hypoxia/reoxygenation; then, eIF5A induces apoptosis by acting as a pro-apoptotic ligand. The apoptosis of cardiac myocytes induced by hypoxia/reoxygenation or ultraviolet irradiation was suppressed by anti-eIF5A neutralizing monoclonal antibodies (mAbs) in vitro. Myocardial ischemia/reperfusion (but not ischemia alone) markedly increased the plasma levels of eIF5A, and treatment with anti-eIF5A neutralizing mAbs significantly reduced myocardial injury. These results identify an important, novel specific biomarker and a critical therapeutic target for oxidative stress-induced cell injury.
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Affiliation(s)
- Yoshinori Seko
- Department of Cardiovascular Medicine, The Institute for Adult Diseases, Asahi Life Foundation, 2-2-6 Nihonbashi-Bakurocho, Chuo-ku, Tokyo 103-0002, Japan
- Department of Immunology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Tsutomu Fujimura
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Takako Yao
- Department of Cardiovascular Medicine, The Institute for Adult Diseases, Asahi Life Foundation, 2-2-6 Nihonbashi-Bakurocho, Chuo-ku, Tokyo 103-0002, Japan
| | - Hikari Taka
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Reiko Mineki
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Ko Okumura
- Department of Immunology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kimie Murayama
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
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46
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Schindler C, Chen Y, Pu J, Guo X, Bonifacino JS. EARP is a multisubunit tethering complex involved in endocytic recycling. Nat Cell Biol 2015; 17:639-50. [PMID: 25799061 PMCID: PMC4417048 DOI: 10.1038/ncb3129] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 01/29/2015] [Indexed: 12/13/2022]
Abstract
Recycling of endocytic receptors to the cell surface involves passage through a series of membrane-bound compartments by mechanisms that are poorly understood. In particular, it is unknown if endocytic recycling requires the function of multisubunit tethering complexes, as is the case for other intracellular trafficking pathways. Herein we describe a tethering complex named Endosome-Associated Recycling Protein (EARP) that is structurally related to the previously described Golgi-Associated Retrograde Protein (GARP) complex. Both complexes share the Ang2, Vps52 and Vps53 subunits, but EARP comprises an uncharacterized protein, Syndetin, in place of the Vps54 subunit of GARP. This change determines differential localization of EARP to recycling endosomes and GARP to the Golgi complex. EARP interacts with the target-SNARE Syntaxin 6 and various cognate SNAREs. Depletion of Syndetin or Syntaxin 6 delays recycling of internalized transferrin to the cell surface. These findings implicate EARP in canonical membrane-fusion events in the process of endocytic recycling.
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Affiliation(s)
- Christina Schindler
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Yu Chen
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jing Pu
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Xiaoli Guo
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Juan S Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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47
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Proteomic analysis of proteins surrounding occludin and claudin-4 reveals their proximity to signaling and trafficking networks. PLoS One 2015; 10:e0117074. [PMID: 25789658 PMCID: PMC4366163 DOI: 10.1371/journal.pone.0117074] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/18/2014] [Indexed: 01/15/2023] Open
Abstract
Tight junctions are complex membrane structures that regulate paracellular movement of material across epithelia and play a role in cell polarity, signaling and cytoskeletal organization. In order to expand knowledge of the tight junction proteome, we used biotin ligase (BioID) fused to occludin and claudin-4 to biotinylate their proximal proteins in cultured MDCK II epithelial cells. We then purified the biotinylated proteins on streptavidin resin and identified them by mass spectrometry. Proteins were ranked by relative abundance of recovery by mass spectrometry, placed in functional categories, and compared not only among the N- and C- termini of occludin and the N-terminus of claudin-4, but also with our published inventory of proteins proximal to the adherens junction protein E-cadherin and the tight junction protein ZO-1. When proteomic results were analyzed, the relative distribution among functional categories was similar between occludin and claudin-4 proximal proteins. Apart from already known tight junction- proteins, occludin and claudin-4 proximal proteins were enriched in signaling and trafficking proteins, especially endocytic trafficking proteins. However there were significant differences in the specific proteins comprising the functional categories near each of the tagging proteins, revealing spatial compartmentalization within the junction complex. Taken together, these results expand the inventory of known and unknown proteins at the tight junction to inform future studies of the organization and physiology of this complex structure.
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48
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Enrich C, Rentero C, Hierro A, Grewal T. Role of cholesterol in SNARE-mediated trafficking on intracellular membranes. J Cell Sci 2015; 128:1071-81. [PMID: 25653390 DOI: 10.1242/jcs.164459] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The cell surface delivery of extracellular matrix (ECM) and integrins is fundamental for cell migration in wound healing and during cancer cell metastasis. This process is not only driven by several soluble NSF attachment protein (SNAP) receptor (SNARE) proteins, which are key players in vesicle transport at the cell surface and intracellular compartments, but is also tightly modulated by cholesterol. Cholesterol-sensitive SNAREs at the cell surface are relatively well characterized, but it is less well understood how altered cholesterol levels in intracellular compartments impact on SNARE localization and function. Recent insights from structural biology, protein chemistry and cell microscopy have suggested that a subset of the SNAREs engaged in exocytic and retrograde pathways dynamically 'sense' cholesterol levels in the Golgi and endosomal membranes. Hence, the transport routes that modulate cellular cholesterol distribution appear to trigger not only a change in the location and functioning of SNAREs at the cell surface but also in endomembranes. In this Commentary, we will discuss how disrupted cholesterol transport through the Golgi and endosomal compartments ultimately controls SNARE-mediated delivery of ECM and integrins to the cell surface and, consequently, cell migration.
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Affiliation(s)
- Carlos Enrich
- Departament de Biologia Cellular, Immunologia i Neurociències, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Facultat de Medicina, Universitat de Barcelona, 08036-Barcelona, Spain
| | - Carles Rentero
- Departament de Biologia Cellular, Immunologia i Neurociències, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Facultat de Medicina, Universitat de Barcelona, 08036-Barcelona, Spain
| | - Aitor Hierro
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
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49
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Marcheva B, Ramsey KM, Bass J. Circadian genes and insulin exocytosis. CELLULAR LOGISTICS 2014; 1:32-36. [PMID: 21686102 DOI: 10.4161/cl.1.1.14426] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 12/07/2010] [Accepted: 12/07/2010] [Indexed: 01/21/2023]
Abstract
The molecular clock controls 24-hour cycles of behavioral and physiological processes across the day-night cycle. Disruption of circadian rhythmicity has been implicated in the pathogenesis of several diseases, including the metabolic syndrome, although the role of clock genes in these disorders is still not well understood. Studies of the etiology of diabetes in circadian mutant mice have revealed a novel role for the clock in pancreatic β-cell insulin secretion, suggesting that a major cellular function of the circadian network involves control of protein exocytosis.
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Affiliation(s)
- Biliana Marcheva
- Department of Medicine; Northwestern University Feinberg School of Medicine; Chicago, IL USA
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50
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Tubulin- and actin-associating GIMAP4 is required for IFN-γ secretion during Th cell differentiation. Immunol Cell Biol 2014; 93:158-66. [PMID: 25287446 PMCID: PMC4355353 DOI: 10.1038/icb.2014.86] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 09/05/2014] [Accepted: 09/06/2014] [Indexed: 12/20/2022]
Abstract
Although GTPase of the immunity-associated protein (GIMAP) family are known to be most highly expressed in the cells of the immune system, their function and role remain still poorly characterized. Small GTPases in general are known to be involved in many cellular processes in a cell type-specific manner and to contribute to specific differentiation processes. Among GIMAP family, GIMAP4 is the only member reported to have true GTPase activity, and its transcription is found to be differentially regulated during early human CD4(+) T helper (Th) lymphocyte differentiation. GIMAP4 has been previously connected mainly with T- and B-cell development and survival and T-cell apoptosis. Here we show GIMAP4 to be localized into cytoskeletal elements and with the component of the trans golgi network, which suggests it to have a function in cellular transport processes. We demonstrate that depletion of GIMAP4 with RNAi results in downregulation of endoplasmic reticulum localizing chaperone VMA21. Most importantly, we discovered that GIMAP4 regulates secretion of cytokines in early differentiating human CD4(+) Th lymphocytes and in particular the secretion of interferon-γ also affecting its downstream targets.
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