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Liu H, Dang R, Zhang W, Hong J, Li X. SNARE proteins: Core engines of membrane fusion in cancer. Biochim Biophys Acta Rev Cancer 2024:189148. [PMID: 38960006 DOI: 10.1016/j.bbcan.2024.189148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 06/23/2024] [Accepted: 06/27/2024] [Indexed: 07/05/2024]
Abstract
Vesicles are loaded with a variety of cargoes, including membrane proteins, secreted proteins, signaling molecules, and various enzymes, etc. Not surprisingly, vesicle transport is essential for proper cellular life activities including growth, division, movement and cellular communication. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) mediate membrane fusion of vesicles with their target compartments that is fundamental for cargo delivery. Recent studies have shown that multiple SNARE family members are aberrantly expressed in human cancers and actively contribute to malignant proliferation, invasion, metastasis, immune evasion and treatment resistance. Here, the localization and function of SNARE proteins in eukaryotic cells are firstly mapped. Then we summarize the expression and regulation of SNAREs in cancer, and describe their contribution to cancer progression and mechanisms, and finally we propose engineering botulinum toxin as a strategy to target SNAREs for cancer treatment.
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Affiliation(s)
- Hongyi Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China; Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, China
| | - Ruiyue Dang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Wei Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China; Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, China
| | - Jidong Hong
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China.
| | - Xuejun Li
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China; Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, China.
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Tan J, Lu Y, Li H, Sun H, Han W, Zhang J. Functional analysis of circSTX8 in chicken macrophages under lipopolysaccharide stimulation. Res Vet Sci 2023; 165:105053. [PMID: 37856945 DOI: 10.1016/j.rvsc.2023.105053] [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: 08/28/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
Circular RNAs (circRNAs) have a regulatory role in gene expression, development, differentiation, and immune response. In a previous study, circular RNA STX8 (circSTX8) exhibited low expression in chicken lungs during lipopolysaccharide (LPS) stimulation. PCR amplification and Sanger sequencing showed that circSTX8 was created by back-splicing of exons 5 to 6 of STX8. RNase R exonuclease treatment indicated that circSTX8 was a stable circular RNA. RT-qPCR showed that circSTX8 was highly expressed in cecum, spleen, harderian gland, stomach, thymus, liver, small intestine, and lung instead of that in muscle, cerebrum, and cerebellum (n = 8). Chicken macrophages were then divided into four groups: control, overexpression of circSTX8 group, LPS group, and overexpression of circSTX8 + LPS group. CCK8 and RT-qPCR showed that circSTX8 can exacerbate the cellular injury induced by LPS, resulting in a reduction of cell viability and an increase of the pro-inflammatory cytokines expression. In addition, four miRNAs were identified to interact with circSTX8, potentially targeting 914 genes, which were significantly enriched in the pathways of Tight junction, mTOR signaling pathway, MAPK signaling pathway, TGF-beta signaling pathway, Notch signaling pathway, ErbB signaling pathway, and Cell adhesion molecules. These findings showed that circSTX8 was able to regulate the LPS induced cellular immune and inflammatory response.
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Affiliation(s)
- Jishuang Tan
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yue Lu
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Huan Li
- School of Biological and Chemical Engineering, Yangzhou Polytechnic College, Yangzhou University, Yangzhou 225009, China
| | - Hongyan Sun
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
| | - Wei Han
- The Poultry Research Institute of Chinese Academy of Agricultural Sciences, Yangzhou, China
| | - Jibin Zhang
- Department of Anatomic Pathology, Comprehensive Cancer Center, City of Hope, Duarte, CA 91010, USA
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Wu J, Zhang H, Yang L, Chen Y, Li J, Yang M, Zhang X, He C, Wang X, Xu X. Syntaxin 7 modulates seizure activity in epilepsy. Neurobiol Dis 2023; 181:106118. [PMID: 37031804 DOI: 10.1016/j.nbd.2023.106118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/18/2023] [Accepted: 04/05/2023] [Indexed: 04/11/2023] Open
Abstract
The exact pathogenesis of epilepsy, one of the most common and devastating diseases of the nervous system, is not fully understood. Syntaxin7 (STX7) is a member of the SNARE superfamily, which mediates membrane fusion events in all cells. However, the role STX7 plays in epilepsy remains unclear. Therefore, this study investigates the role of STX7 in epilepsy. Our study found that the expression of STX7 was reduced in the epileptic brain and that overexpression of STX7 decreased the susceptibility to epileptic seizures and alleviated epileptic activity in a kainic acid-induced model and pentylenetetrazole-induced kindling model of epilepsy, whereas the downregulation of STX7 showed opposite effects. Whole-cell patch-clamp recordings showed that STX7 does not affect the intrinsic excitability of neurons, but rather the excitation/inhibition ratio mediated by affecting the release of presynaptic γ-aminobutyric acid neurotransmitters. Transmission electron microscopy results showed that STX7 did not affect the density of inhibitory synapses but could affect the density of inhibitory vesicles. Taken together, these results reveal a previously unknown function of STX7 in epilepsy and suggest that STX7 may serve as a novel target for epilepsy therapy.
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Affiliation(s)
- Junhong Wu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China
| | - Hui Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China; Department of Neurology, The First Hospital of Shanxi Medical University, No.85 Jiefang South Road, Taiyuan, Shanxi Province, China
| | - Liu Yang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China; Department of Neurology, The First Hospital of Shanxi Medical University, No.85 Jiefang South Road, Taiyuan, Shanxi Province, China
| | - Yuanyuan Chen
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China
| | - Jiyuan Li
- Department of Neurology, The First Hospital of Shanxi Medical University, No.85 Jiefang South Road, Taiyuan, Shanxi Province, China
| | - Min Yang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China
| | - Xiaogang Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China; Department of Neurology, Chongqing General Hospital, Chongqing Key Laboratory of Neurodegenerative Diseases, No.118, Xingguang Avenue, Liangjiang New Area, Chongqing 401147, China
| | - Changlong He
- Department of Laboratory Medicine, People's Hospital of Jiulongpo District, Chongqing 40016, China; Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China.
| | - Xin Xu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China.
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Larionova I, Kiselev A, Kazakova E, Liu T, Patysheva M, Iamshchikov P, Liu Q, Mossel DM, Riabov V, Rakina M, Sergushichev A, Bezgodova N, Vtorushin S, Litviakov N, Denisov E, Koshkin P, Pyankov D, Tsyganov M, Ibragimova M, Cherdyntseva N, Kzhyshkowska J. Tumor-associated macrophages respond to chemotherapy by detrimental transcriptional reprogramming and suppressing stabilin-1 mediated clearance of EGF. Front Immunol 2023; 14:1000497. [PMID: 36960065 PMCID: PMC10028613 DOI: 10.3389/fimmu.2023.1000497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 01/30/2023] [Indexed: 03/09/2023] Open
Abstract
Introduction Tumor resistance to chemotherapy and metastatic relapse account for more than 90% of cancer specific mortality. Tumor-associated macrophages (TAMs) can process chemotherapeutic agents and impair their action. Little is known about the direct effects of chemotherapy on TAMs. Methods The effect of chemotherapeutic platinum agent cisplatin was assessed in the model system of human ex vivo TAMs. Whole-transcriptome sequencing for paired TAMs stimulated and not stimulated by cisplatin was analysed by NGS. Endocytic uptake of EGF was quantified by flow cytometry. Confocal microscopy was used to visualize stabilin-1-mediated internalization and endocytic trafficking of EGF in CHO cells expressing ectopically recombinant stabilin-1 and in stabilin-1+ TAMs. In cohort of patients with breast cancer, the effect of platinum therapy on the transcriptome of TAMs was validated, and differential expression of regulators of endocytosis was identified. Results Here we show that chemotherapeutic agent cisplatin can initiate detrimental transcriptional and functional programs in TAMs, without significant impairment of their viability. We focused on the clearance function of TAMs that controls composition of tumor microenvironment. For the first time we demonstrated that TAMs' scavenger receptor stabilin-1 is responsible for the clearance of epidermal growth factor (EGF), a potent stimulator of tumor growth. Cisplatin suppressed both overall and EGF-specific endocytosis in TAMs by bidirectional mode: suppression of positive regulators and stimulation of negative regulators of endocytosis, with strongest effect on synaptotagmin-11 (SYT11), confirmed in patients with breast cancer. Conclusion Our data demonstrate that synergistic action of cytostatic agents and innovative immunomodulators is required to overcome cancer therapy resistance.
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Affiliation(s)
- Irina Larionova
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
- Laboratory of Genetic Technologies, Siberian State Medical University, Tomsk, Russia
| | - Artem Kiselev
- Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States
| | - Elena Kazakova
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Tengfei Liu
- Institute of Transfusion Medicine and Immunology, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Marina Patysheva
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Pavel Iamshchikov
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Quan Liu
- Institute of Transfusion Medicine and Immunology, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Dieuwertje M. Mossel
- Institute of Transfusion Medicine and Immunology, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Vladimir Riabov
- Institute of Transfusion Medicine and Immunology, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Militsa Rakina
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Alexey Sergushichev
- Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University), Saint Petersburg, Russia
| | - Natalia Bezgodova
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Sergei Vtorushin
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Nikolai Litviakov
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
- Laboratory of Genetic Technologies, Siberian State Medical University, Tomsk, Russia
| | - Evgeny Denisov
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | | | - Denis Pyankov
- Laboratory of Molecular Pathology, Genomed, Moscow, Russia
| | - Matvei Tsyganov
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Marina Ibragimova
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Nadezhda Cherdyntseva
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
- Laboratory of Genetic Technologies, Siberian State Medical University, Tomsk, Russia
| | - Julia Kzhyshkowska
- Laboratory of translational cellular and molecular biomedicine, National Research Tomsk State University, Tomsk, Russia
- Laboratory of Genetic Technologies, Siberian State Medical University, Tomsk, Russia
- Institute of Transfusion Medicine and Immunology, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- German Red Cross Blood Service Baden-Württemberg – Hessen, Mannheim, Germany
- *Correspondence: Julia Kzhyshkowska,
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Hu M, Zhou N, Cai W, Xu H. Lysosomal solute and water transport. J Cell Biol 2022; 221:213536. [PMID: 36219209 PMCID: PMC9559593 DOI: 10.1083/jcb.202109133] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 09/05/2022] [Accepted: 09/22/2022] [Indexed: 11/22/2022] Open
Abstract
Lysosomes mediate hydrolase-catalyzed macromolecule degradation to produce building block catabolites for reuse. Lysosome function requires an osmo-sensing machinery that regulates osmolytes (ions and organic solutes) and water flux. During hypoosmotic stress or when undigested materials accumulate, lysosomes become swollen and hypo-functional. As a membranous organelle filled with cargo macromolecules, catabolites, ions, and hydrolases, the lysosome must have mechanisms that regulate its shape and size while coordinating content exchange. In this review, we discussed the mechanisms that regulate lysosomal fusion and fission as well as swelling and condensation, with a focus on solute and water transport mechanisms across lysosomal membranes. Lysosomal H+, Na+, K+, Ca2+, and Cl- channels and transporters sense trafficking and osmotic cues to regulate both solute flux and membrane trafficking. We also provide perspectives on how lysosomes may adjust the volume of themselves, the cytosol, and the cytoplasm through the control of lysosomal solute and water transport.
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Affiliation(s)
- Meiqin Hu
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China
| | - Nan Zhou
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China
| | - Weijie Cai
- Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China.,Department of Neurology, Second Affiliated Hospital of Zhejiang University Medical School, Hangzhou, China
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Wang H, Liu Y, Sun Y, Zhao L, Dong J, Xu X, Wang H, Zhang J, Yao B, Zhao X, Liu S, Zhang K, Peng R. Changes in rat spatial learning and memory as well as serum exosome proteins after simultaneous exposure to 1.5 GHz and 4.3 GHz microwaves. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 243:113983. [PMID: 35985199 DOI: 10.1016/j.ecoenv.2022.113983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 06/22/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
This study aimed to elucidate the effects and biological targets sensitive to simultaneous 1.5 and 4.3 GHz microwave exposure in rats. A total of 120 male Wistar rats were divided randomly into four groups: the sham (S group), 1.5 GHz microwave exposure (L group), 4.3 GHz microwave exposure (C group) and simultaneous 1.5 and 4.3 GHz microwave exposure (LC group) groups. Spatial learning and memory, cortical electrical activity, and hippocampal ultrastructure were assessed by the Morris Water Maze, electroencephalography, and transmission electron microscopy, respectively. Additionally, serum exosomes were isolated by ultracentrifugation and assessed by Western blotting, nanoparticle tracking and transmission electron microscopy. The serum exosome protein content was assessed by label-free quantitative proteomics. Impaired spatial learning and memory decreased cortical excitability, and damage to the hippocampal ultrastructure were observed in groups exposed to microwaves, especially the L and LC groups. A total of 54, 145 and 296 exosomal proteins were differentially expressed between the S group and the L, C and LC groups, respectively. These differentially expressed proteins were involved in the synaptic vesicle cycle and SNARE interactions during vesicular transport. Additionally, VAMP8, Syn7 and VMAT are potential serum markers of simultaneous microwave exposure. Thus, exposure to 1.5 and 4.3 GHz microwaves induced impairments in spatial learning and memory, and simultaneous microwave exposure had the most severe effects.
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Affiliation(s)
- Hui Wang
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Yu Liu
- Beijing Institute of Radiation Medicine, Beijing 100850, China; College of Education, Hebei University, No. 180 of Wusi East Road, Baoding, China
| | - Yunbo Sun
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Li Zhao
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Ji Dong
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Xinping Xu
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Haoyu Wang
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Jing Zhang
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Binwei Yao
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Xuelong Zhao
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Shuchen Liu
- Beijing Institute of Radiation Medicine, Beijing 100850, China.
| | - Ke Zhang
- College of Education, Hebei University, No. 180 of Wusi East Road, Baoding, China.
| | - Ruiyun Peng
- Beijing Institute of Radiation Medicine, Beijing 100850, China.
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Li M, Feng F, Feng H, Hu P, Xue Y, Xu T, Song E. VAMP4 regulates insulin levels by targeting secretory granules to lysosomes. J Cell Biol 2022; 221:213439. [PMID: 36053215 PMCID: PMC9441717 DOI: 10.1083/jcb.202110164] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 06/28/2022] [Accepted: 07/25/2022] [Indexed: 11/22/2022] Open
Abstract
Insulin levels are essential for the maintenance of glucose homeostasis, and deviations lead to pathoglycemia or diabetes. However, the metabolic mechanism controlling insulin quantity and quality is poorly understood. In pancreatic β cells, insulin homeostasis and release are tightly governed by insulin secretory granule (ISG) trafficking, but the required regulators and mechanisms are largely unknown. Here, we identified that VAMP4 controlled the insulin levels in response to glucose challenge. VAMP4 deficiency led to increased blood insulin levels and hyperresponsiveness to glucose. In β cells, VAMP4 is packaged into immature ISGs (iISGs) at trans-Golgi networks and subsequently resorted to clathrin-coated vesicles during granule maturation. VAMP4-positive iISGs and resorted vesicles then fuse with lysosomes facilitated by a SNARE complex consisting of VAMP4, STX7, STX8, and VTI1B, which ensures the breakdown of excess (pro)insulin and obsolete materials and thus maintenance of intracellular insulin homeostasis. Thus, VAMP4 is a key factor regulating the insulin levels and a potential target for the treatment of diabetes.
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Affiliation(s)
- Min Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,Guangzhou Laboratory, Guangzhou, China,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China,Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Fengping Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Han Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Pengkai Hu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yanhong Xue
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Tao Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,Guangzhou Laboratory, Guangzhou, China,Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China,Dr. Tao Xu:
| | - Eli Song
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China,Correspondence to Dr. Eli Song:
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Warner H, Mahajan S, van den Bogaart G. Rerouting trafficking circuits through posttranslational SNARE modifications. J Cell Sci 2022; 135:276344. [PMID: 35972760 DOI: 10.1242/jcs.260112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are membrane-associated trafficking proteins that confer identity to lipid membranes and facilitate membrane fusion. These functions are achieved through the complexing of Q-SNAREs with a specific cognate target R-SNARE, leading to the fusion of their associated membranes. These SNARE complexes then dissociate so that the Q-SNAREs and R-SNAREs can repeat this cycle. Whilst the basic function of SNAREs has been long appreciated, it is becoming increasingly clear that the cell can control the localisation and function of SNARE proteins through posttranslational modifications (PTMs), such as phosphorylation and ubiquitylation. Whilst numerous proteomic methods have shown that SNARE proteins are subject to these modifications, little is known about how these modifications regulate SNARE function. However, it is clear that these PTMs provide cells with an incredible functional plasticity; SNARE PTMs enable cells to respond to an ever-changing extracellular environment through the rerouting of membrane traffic. In this Review, we summarise key findings regarding SNARE regulation by PTMs and discuss how these modifications reprogramme membrane trafficking pathways.
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Affiliation(s)
- Harry Warner
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands
| | - Shweta Mahajan
- Division of Immunobiology, Center for Inflammation and Tolerance, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
| | - Geert van den Bogaart
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands
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Parveen S, Khamari A, Raju J, Coppolino MG, Datta S. Syntaxin 7 contributes to breast cancer cell invasion by promoting invadopodia formation. J Cell Sci 2022; 135:275829. [PMID: 35762511 DOI: 10.1242/jcs.259576] [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] [Received: 11/12/2021] [Accepted: 05/12/2022] [Indexed: 12/15/2022] Open
Abstract
Invasion in various cancer cells requires coordinated delivery of signaling proteins, adhesion proteins, actin-remodeling proteins and proteases to matrix-degrading structures called invadopodia. Vesicular trafficking involving SNAREs plays a crucial role in the delivery of cargo to the target membrane. Screening of 13 SNAREs from the endocytic and recycling route using a gene silencing approach coupled with functional assays identified syntaxin 7 (STX7) as an important player in MDA-MB-231 cell invasion. Total internal reflection fluorescence microscopy (TIRF-M) studies revealed that STX7 resides near invadopodia and co-traffics with MT1-MMP (also known as MMP14), indicating a possible role for this SNARE in protease trafficking. STX7 depletion reduced the number of invadopodia and their associated degradative activity. Immunoprecipitation studies revealed that STX7 forms distinct SNARE complexes with VAMP2, VAMP3, VAMP7, STX4 and SNAP23. Depletion of VAMP2, VAMP3 or STX4 abrogated invadopodia formation, phenocopying what was seen upon lack of STX7. Whereas depletion of STX4 reduced MT1-MMP level at the cell surfaces, STX7 silencing significantly reduced the invadopodia-associated MT1-MMP pool and increased the non-invadosomal pool. This study highlights STX7 as a major contributor towards the invadopodia formation during cancer cell invasion. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Bhopal 462066, India
| | - Amrita Khamari
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Bhopal 462066, India
| | - Jyothikamala Raju
- Thazhathemalayil House, Thodupuzha East PO, Keerikode, Kerala 685585, India
| | - Marc G Coppolino
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Bhopal 462066, India
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Barber CN, Goldschmidt HL, Ma Q, Devine LR, Cole RN, Huganir RL, Raben DM. Identification of Synaptic DGKθ Interactors That Stimulate DGKθ Activity. Front Synaptic Neurosci 2022; 14:855673. [PMID: 35573662 PMCID: PMC9095502 DOI: 10.3389/fnsyn.2022.855673] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/16/2022] [Indexed: 01/16/2023] Open
Abstract
Lipids and their metabolic enzymes are a critical point of regulation for the membrane curvature required to induce membrane fusion during synaptic vesicle recycling. One such enzyme is diacylglycerol kinase θ (DGKθ), which produces phosphatidic acid (PtdOH) that generates negative membrane curvature. Synapses lacking DGKθ have significantly slower rates of endocytosis, implicating DGKθ as an endocytic regulator. Importantly, DGKθ kinase activity is required for this function. However, protein regulators of DGKθ's kinase activity in neurons have never been identified. In this study, we employed APEX2 proximity labeling and mass spectrometry to identify endogenous interactors of DGKθ in neurons and assayed their ability to modulate its kinase activity. Seven endogenous DGKθ interactors were identified and notably, synaptotagmin-1 (Syt1) increased DGKθ kinase activity 10-fold. This study is the first to validate endogenous DGKθ interactors at the mammalian synapse and suggests a coordinated role between DGKθ-produced PtdOH and Syt1 in synaptic vesicle recycling.
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Affiliation(s)
- Casey N. Barber
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Hana L. Goldschmidt
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Qianqian Ma
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Lauren R. Devine
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Robert N. Cole
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Richard L. Huganir
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Daniel M. Raben
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States,*Correspondence: Daniel M. Raben,
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11
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Mentrup T, Schröder B. Signal peptide peptidase-like 2 proteases: Regulatory switches or proteasome of the membrane? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119163. [PMID: 34673079 DOI: 10.1016/j.bbamcr.2021.119163] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 10/07/2021] [Accepted: 10/11/2021] [Indexed: 12/30/2022]
Abstract
Signal peptide peptidase-like 2 (SPPL) proteases constitute a subfamily of SPP/SPPL intramembrane proteases which are homologues of the presenilins, the catalytic core of the γ-secretase complex. The three SPPL2 proteases SPPL2a, SPPL2b and SPPL2c proteolyse single-span, type II-oriented transmembrane proteins and/or tail-anchored proteins within their hydrophobic transmembrane segments. We review recent progress in defining substrate spectra and in vivo functions of these proteases. Characterisation of the respective knockout mice has implicated SPPL2 proteases in immune cell differentiation and function, prevention of atherosclerotic plaque development and spermatogenesis. Mechanisms how substrates are selected by these enzymes are still incompletely understood. We will discuss current views on how selective SPPL2-mediated cleavage is or whether these proteases may exhibit a generalised role in the turnover of membrane proteins. This has been suggested previously for the mechanistically related γ-secretase for which the term "proteasome of the membrane" has been coined based on its broad substrate spectrum. With regard to individual substrates, potential signalling functions of the resulting cytosolic cleavage fragments remain a controversial aspect. However, it has been clearly shown that SPPL2 proteases can influence cellular signalling and membrane trafficking by controlling levels of their membrane-bound substrate proteins which highlights these enzymes as regulatory switches. Based on this, regulatory mechanisms controlling activity of SPPL2 proteases would need to be postulated, which are just beginning to emerge. These different questions, which are relevant for other families of intramembrane proteases in a similar way, will be critically discussed based on the current state of knowledge.
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Affiliation(s)
- Torben Mentrup
- Institute for Physiological Chemistry, Technische Universität Dresden, Fiedlerstraße 42, D-01307 Dresden, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Technische Universität Dresden, Fiedlerstraße 42, D-01307 Dresden, Germany.
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12
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Kuo EY, Lee TM. Molecular Mechanisms Underlying the Acclimation of Chlamydomonas reinhardtii Against Nitric Oxide Stress. FRONTIERS IN PLANT SCIENCE 2021; 12:690763. [PMID: 34421944 PMCID: PMC8374494 DOI: 10.3389/fpls.2021.690763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
The acclimation mechanism of Chlamydomonas reinhardtii to nitric oxide (NO) was studied by exposure to S-nitroso-N-acetylpenicillamine (SNAP), a NO donor. Treatment with 0.1 or 0.3 mM SNAP transiently inhibited photosynthesis within 1 h, followed by a recovery, while 1.0 mM SNAP treatment caused irreversible photosynthesis inhibition and mortality. The SNAP effects are avoided in the presence of the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (cPTIO). RNA-seq, qPCR, and biochemical analyses were conducted to decode the metabolic shifts under NO stress by exposure to 0.3 mM SNAP in the presence or absence of 0.4 mM cPTIO. These findings revealed that the acclimation to NO stress comprises a temporally orchestrated implementation of metabolic processes: (1). modulation of NADPH oxidase (respiratory burst oxidase-like 2, RBOL2) and ROS signaling pathways for downstream mechanism regulation, (2). trigger of NO scavenging elements to reduce NO level; (3). prevention of photo-oxidative risk through photosynthesis inhibition and antioxidant defense system induction; (4). acclimation to nitrogen and sulfur shortage; (5). attenuation of transcriptional and translational activity together with degradation of damaged proteins through protein trafficking machinery (ubiquitin, SNARE, and autophagy) and molecular chaperone system for dynamic regulation of protein homeostasis. In addition, the expression of the gene encoding NADPH oxidase, RBOL2, showed a transient increase while that of RBOL1 was slightly decreased after NO challenge. It reflects that NADPH oxidase, a regulator in ROS-mediated signaling pathway, may be involved in the responses of Chlamydomonas to NO stress. In conclusion, our findings provide insight into the molecular events underlying acclimation mechanisms in Chlamydomonas to NO stress.
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Affiliation(s)
- Eva YuHua Kuo
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Tse-Min Lee
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung, Taiwan
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13
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Pesaola F, Quassollo G, Venier AC, De Paul AL, Noher I, Bisbal M. The neuronal ceroid lipofuscinosis-related protein CLN8 regulates endo-lysosomal dynamics and dendritic morphology. Biol Cell 2021; 113:419-437. [PMID: 34021618 DOI: 10.1111/boc.202000016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND INFORMATION The endo-lysosomal system (ELS) comprises a set of membranous organelles responsible for transporting intracellular and extracellular components within cells. Defects in lysosomal proteins usually affect a large variety of processes and underlie many diseases, most of them with a strong neuronal impact. Mutations in the endoplasmic reticulum-resident CLN8 protein cause CLN8 disease. This condition is one of the 14 known neuronal ceroid lipofuscinoses (NCLs), a group of inherited diseases characterised by accumulation of lipofuscin-like pigments within lysosomes. Besides mediating the transport of soluble lysosomal proteins, recent research suggested a role for CLN8 in the transport of vesicles and lipids, and autophagy. However, the consequences of CLN8 deficiency on ELS structure and activity, as well as the potential impact on neuronal development, remain poorly characterised. Therefore, we performed CLN8 knockdown in neuronal and non-neuronal cell models to analyse structural, dynamic and functional changes in the ELS and to assess the impact of CLN8 deficiency on axodendritic development. RESULTS CLN8 knockdown increased the size of the Golgi apparatus, the number of mobile vesicles and the speed of endo-lysosomes. Using the fluorescent fusion protein mApple-LAMP1-pHluorin, we detected significant lysosomal alkalisation in CLN8-deficient cells. In turn, experiments in primary rat hippocampal neurons showed that CLN8 deficiency decreased the complexity and size of the somatodendritic compartment. CONCLUSIONS Our results suggest the participation of CLN8 in vesicular distribution, lysosomal pH and normal development of the dendritic tree. We speculate that the defects triggered by CLN8 deficiency on ELS structure and dynamics underlie morphological alterations in neurons, which ultimately lead to the characteristic neurodegeneration observed in this NCL. SIGNIFICANCE This is, to our knowledge, the first characterisation of the effects of CLN8 dysfunction on the structure and dynamics of the ELS. Moreover, our findings suggest a novel role for CLN8 in somatodendritic development, which may account at least in part for the neuropathological manifestations associated with CLN8 disease.
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Affiliation(s)
- Favio Pesaola
- Programa de Investigación Translacional de Lipofuscinosis Ceroidea Neuronal, Hospital de Niños de Córdoba, Córdoba, 5014, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Médicas "Mercedes y Martin Ferreyra"- IMMF-UNC-CONICET, Laboratorio de Neurobiología, Av. Friuli 2434, 5016 Córdoba, Argentina, Universidad Nacional de Córdoba, Córdoba, 5000, Argentina
| | - Gonzalo Quassollo
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Médicas "Mercedes y Martin Ferreyra"- IMMF-UNC-CONICET, Laboratorio de Neurobiología, Av. Friuli 2434, 5016 Córdoba, Argentina, Universidad Nacional de Córdoba, Córdoba, 5000, Argentina
| | - Ana Clara Venier
- Programa de Investigación Translacional de Lipofuscinosis Ceroidea Neuronal, Hospital de Niños de Córdoba, Córdoba, 5014, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigación en Ciencias de la Salud (INICSA), Bv. de la Reforma y Enfermera Gordillo, Ciudad Universitaria, Córdoba, 5016, Argentina
| | - Ana Lucía De Paul
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigación en Ciencias de la Salud (INICSA), Bv. de la Reforma y Enfermera Gordillo, Ciudad Universitaria, Córdoba, 5016, Argentina.,Universidad Nacional de Córdoba, Facultad de Ciencias Médicas, Centro de Microscopía Electrónica, Bv. de la Reforma y Enfermera Gordillo, Ciudad Universitaria, Córdoba, 5016, Argentina
| | - Ines Noher
- Programa de Investigación Translacional de Lipofuscinosis Ceroidea Neuronal, Hospital de Niños de Córdoba, Córdoba, 5014, Argentina
| | - Mariano Bisbal
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Médicas "Mercedes y Martin Ferreyra"- IMMF-UNC-CONICET, Laboratorio de Neurobiología, Av. Friuli 2434, 5016 Córdoba, Argentina, Universidad Nacional de Córdoba, Córdoba, 5000, Argentina.,Instituto Universitario de Ciencias Biomédicas Córdoba, Córdoba, 5016, Argentina
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14
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Syntaxins 6 and 8 facilitate tau into secretory pathways. Biochem J 2021; 478:1471-1484. [PMID: 33769438 PMCID: PMC8057678 DOI: 10.1042/bcj20200664] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/17/2021] [Accepted: 03/26/2021] [Indexed: 12/04/2022]
Abstract
Tau pathology initiates in defined brain regions and is known to spread along neuronal connections as symptoms progress in Alzheimer's disease (AD) and other tauopathies. This spread requires the release of tau from donor cells, but the underlying molecular mechanisms remained unknown. Here, we established the interactome of the C-terminal tail region of tau and identified syntaxin 8 (STX8) as a mediator of tau release from cells. Similarly, we showed the syntaxin 6 (STX6), part of the same SNARE family as STX8 also facilitated tau release. STX6 was previously genetically linked to progressive supranuclear palsy (PSP), a tauopathy. Finally, we demonstrated that the transmembrane domain of STX6 is required and sufficient to mediate tau secretion. The differential role of STX6 and STX8 in alternative secretory pathways suggests the association of tau with different secretory processes. Taken together, both syntaxins, STX6 and STX8, may contribute to AD and PSP pathogenesis by mediating release of tau from cells and facilitating pathology spreading.
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15
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Shulgin AA, Lebedev TD, Prassolov VS, Spirin PV. Plasmolipin and Its Role in Cell Processes. Mol Biol 2021; 55:773-785. [PMID: 34955555 PMCID: PMC8682038 DOI: 10.1134/s0026893321050113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/26/2021] [Accepted: 04/05/2021] [Indexed: 12/04/2022]
Abstract
The mechanisms involved in the origin and development of malignant and neurodegenerative diseases are an important area of modern biomedicine. A crucial task is to identify new molecular markers that are associated with rearrangements of intracellular signaling and can be used for prognosis and the development of effective treatment approaches. The proteolipid plasmolipin (PLLP) is a possible marker. PLLP is a main component of the myelin sheath and plays an important role in the development and normal function of the nervous system. PLLP is involved in intracellular transport, lipid raft formation, and Notch signaling. PLLP is presumably involved in various disorders, such as cancer, schizophrenia, Alzheimer's disease, and type 2 diabetes mellitus. PLLP and its homologs were identified as possible virus entry receptors. The review summarizes the data on the PLLP structure, normal functions, and role in diseases.
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Affiliation(s)
- A. A. Shulgin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia ,Moscow Institute of Physics and Technology (State University), 141701 Dolgoprudny, Moscow oblast Russia
| | - T. D. Lebedev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - V. S. Prassolov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - P. V. Spirin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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16
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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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17
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Groener M, Wang Y, Cross E, Tian X, Ebenezer K, Baik E, Pedigo C, Schiffer M, Inoue K, Ishibe S. Identification of Podocyte Cargo Proteins by Proteomic Analysis of Clathrin-Coated Vesicles. KIDNEY360 2020; 1:480-490. [PMID: 35368594 PMCID: PMC8809311 DOI: 10.34067/kid.0000212020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/13/2020] [Indexed: 04/20/2023]
Abstract
Background Clathrin-mediated endocytosis (CME) plays a fundamental role in podocyte health. Genetic ablation of genes implicated in CME has been shown to cause severe proteinuria and foot process effacement in mice. However, little is known about the cargo of clathrin-coated vesicles (CCVs) in podocytes. The goal of this study was to isolate CCVs from podocytes and identify their cargo by proteomic analysis. Methods Glomeruli isolated from Podocin-Cre Rosa-DTRflox mouse kidneys were seeded and treated with diphtheria toxin to obtain pure primary podocyte cultures. CCVs were isolated by differential gradient ultracentrifugation, and enrichment of CCVs was assessed by immunoblotting and electron microscopy (EM). Liquid chromatography-mass spectrometry (LC-MS) was performed for proteomic analysis. Proteins with higher abundance than transferrin receptor protein 1 were evaluated for CCV cargo potential against previously published literature. Immunofluorescence staining of identified cargo proteins and CCVs was performed in podocytes for further verification. Results Immunoblotting for multiple protein markers of CME revealed enrichment in the CCV fraction. Enrichment of CCVs among other small vesicles was observed via EM. Proteomics yielded a total of >1200 significant proteins. Multiple-step data analysis revealed 36 CCV-associated proteins, of which 10 represent novel, highly abundant cargo proteins in podocytes. Colocalization of cargo proteins and CCVs on immunostaining was observed. Conclusions Our identification of podocyte CCV cargo proteins helps to elucidate the importance of endocytic trafficking for podocyte health and maintenance of the glomerular environment.
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Affiliation(s)
- Marwin Groener
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Elizabeth Cross
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Karen Ebenezer
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Eunice Baik
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Christopher Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Mario Schiffer
- Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- Mount Desert Island Biological Laboratories, Salisbury Cove, Maine
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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18
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Coy-Vergara J, Rivera-Monroy J, Urlaub H, Lenz C, Schwappach B. A trap mutant reveals the physiological client spectrum of TRC40. J Cell Sci 2019; 132:jcs.230094. [PMID: 31182645 PMCID: PMC6633398 DOI: 10.1242/jcs.230094] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/31/2019] [Indexed: 12/13/2022] Open
Abstract
The transmembrane recognition complex (TRC) pathway targets tail-anchored (TA) proteins to the membrane of the endoplasmic reticulum (ER). While many TA proteins are known to be able to use this pathway, it is essential for the targeting of only a few. Here, we uncover a large number of TA proteins that engage with TRC40 when other targeting machineries are fully operational. We use a dominant-negative ATPase-impaired mutant of TRC40 in which aspartate 74 was replaced by a glutamate residue to trap TA proteins in the cytoplasm. Manipulation of the hydrophobic TA-binding groove in TRC40 (also known as ASNA1) reduces interaction with most, but not all, substrates suggesting that co-purification may also reflect interactions unrelated to precursor protein targeting. We confirm known TRC40 substrates and identify many additional TA proteins interacting with TRC40. By using the trap approach in combination with quantitative mass spectrometry, we show that Golgi-resident TA proteins such as the golgins golgin-84, CASP and giantin as well as the vesicle-associated membrane-protein-associated proteins VAPA and VAPB interact with TRC40. Thus, our results provide new avenues to assess the essential role of TRC40 in metazoan organisms. This article has an associated First Person interview with the first author of the paper. Summary: A strategy to decipher which tail-anchored proteins do (as opposed to can or must) use the TRC pathway in intact cells generates a comprehensive list of human TRC40 clients.
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Affiliation(s)
- Javier Coy-Vergara
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany
| | - Jhon Rivera-Monroy
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen 37077, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen 37077, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany .,Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
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19
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Abstract
The unusual structure of clathrin, combined with its ability to assemble and disassemble rapidly in cells provides a model system for us to learn about the ways in which proteins can contribute mechanically to a functioning cell. In this article, we discuss the structural properties of clathrin cages and the triskelions which assemble to form them. The function of clathrin depends on the structure of these triskelions and the interactions they make both with each other during assembly and with the adaptor protein network that drives coated vesicle formation. The atomic resolution structure of clathrin domains has been revealed by X-ray crystallography while scattering studies have enabled the shape of a triskelion in solution to be deduced. Cryo-electron microscopy maps have shown the secondary structure of entire cages, how individual triskelion legs are arranged to form a cage and enabled some bound adaptor proteins to be located. Cage formation itself is energetically finely balanced and requires specific interactions between triskelion legs to be productive, as biochemical studies and in silico modeling have shown. Theoretical, structural and cell biological investigations over many years have contributed to our knowledge of clathrin structure and assembly. It now remains to determine the precise nature of the interactions which occur between clathrin triskelions, light chain and heavy chain and the adaptor protein network.
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Affiliation(s)
- Mary Halebian
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Kyle Morris
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Corinne Smith
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
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20
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Abed M, Verschueren E, Budayeva H, Liu P, Kirkpatrick DS, Reja R, Kummerfeld SK, Webster JD, Gierke S, Reichelt M, Anderson KR, Newman RJ, Roose-Girma M, Modrusan Z, Pektas H, Maltepe E, Newton K, Dixit VM. The Gag protein PEG10 binds to RNA and regulates trophoblast stem cell lineage specification. PLoS One 2019; 14:e0214110. [PMID: 30951545 PMCID: PMC6450627 DOI: 10.1371/journal.pone.0214110] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 03/15/2019] [Indexed: 01/03/2023] Open
Abstract
Peg10 (paternally expressed gene 10) is an imprinted gene that is essential for placental development. It is thought to derive from a Ty3-gyspy LTR (long terminal repeat) retrotransposon and retains Gag and Pol-like domains. Here we show that the Gag domain of PEG10 can promote vesicle budding similar to the HIV p24 Gag protein. Expressed in a subset of mouse endocrine organs in addition to the placenta, PEG10 was identified as a substrate of the deubiquitinating enzyme USP9X. Consistent with PEG10 having a critical role in placental development, PEG10-deficient trophoblast stem cells (TSCs) exhibited impaired differentiation into placental lineages. PEG10 expressed in wild-type, differentiating TSCs was bound to many cellular RNAs including Hbegf (Heparin-binding EGF-like growth factor), which is known to play an important role in placentation. Expression of Hbegf was reduced in PEG10-deficient TSCs suggesting that PEG10 might bind to and stabilize RNAs that are critical for normal placental development.
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Affiliation(s)
- Mona Abed
- Physiological Chemistry Department, Genentech, South San Francisco, California, United States of America
| | - Erik Verschueren
- Protein Chemistry Department, Genentech, South San Francisco, California, United States of America
| | - Hanna Budayeva
- Protein Chemistry Department, Genentech, South San Francisco, California, United States of America
| | - Peter Liu
- Protein Chemistry Department, Genentech, South San Francisco, California, United States of America
| | - Donald S. Kirkpatrick
- Protein Chemistry Department, Genentech, South San Francisco, California, United States of America
| | - Rohit Reja
- Bioinformatics and Computational Biology Department, Genentech, South San Francisco, California, United States of America
| | - Sarah K. Kummerfeld
- Bioinformatics and Computational Biology Department, Genentech, South San Francisco, California, United States of America
| | - Joshua D. Webster
- Pathology Department, Genentech, South San Francisco, California, United States of America
| | - Sarah Gierke
- Pathology Department, Genentech, South San Francisco, California, United States of America
| | - Mike Reichelt
- Pathology Department, Genentech, South San Francisco, California, United States of America
| | - Keith R. Anderson
- Molecular Biology Department, Genentech, South San Francisco, California, United States of America
| | - Robert J. Newman
- Molecular Biology Department, Genentech, South San Francisco, California, United States of America
| | - Merone Roose-Girma
- Molecular Biology Department, Genentech, South San Francisco, California, United States of America
| | - Zora Modrusan
- Molecular Biology Department, Genentech, South San Francisco, California, United States of America
| | - Hazal Pektas
- The Center for Reproductive Sciences, Division of Neonatology, University of California, San Francisco, California, United States of America
| | - Emin Maltepe
- The Center for Reproductive Sciences, Division of Neonatology, University of California, San Francisco, California, United States of America
| | - Kim Newton
- Physiological Chemistry Department, Genentech, South San Francisco, California, United States of America
| | - Vishva M. Dixit
- Physiological Chemistry Department, Genentech, South San Francisco, California, United States of America
- * E-mail:
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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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22
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Singh PK, Kapoor A, Lomash RM, Kumar K, Kamerkar SC, Pucadyil TJ, Mukhopadhyay A. Salmonella SipA mimics a cognate SNARE for host Syntaxin8 to promote fusion with early endosomes. J Cell Biol 2018; 217:4199-4214. [PMID: 30309979 PMCID: PMC6279372 DOI: 10.1083/jcb.201802155] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 08/17/2018] [Accepted: 09/18/2018] [Indexed: 01/06/2023] Open
Abstract
Intracellular pathogens can modulate host Rabs and SNAREs to support their replication and immune evasion. Singh et al. show that the Salmonella effector SipA functionally mimics an R-SNARE and recruits host Q-SNAREs to promote membrane fusion. Thus, SNARE mimicry by this intracellular pathogen effector modulates the host trafficking machinery for Salmonella survival. SipA is a major effector of Salmonella, which causes gastroenteritis and enteric fever. Caspase-3 cleaves SipA into two domains: the C-terminal domain regulates actin polymerization, whereas the function of the N terminus is unknown. We show that the cleaved SipA N terminus binds and recruits host Syntaxin8 (Syn8) to Salmonella-containing vacuoles (SCVs). The SipA N terminus contains a SNARE motif with a conserved arginine residue like mammalian R-SNAREs. SipAR204Q and SipA1–435R204Q do not bind Syn8, demonstrating that SipA mimics a cognate R-SNARE for Syn8. Consequently, Salmonella lacking SipA or that express the SipA1–435R204Q SNARE mutant are unable to recruit Syn8 to SCVs. Finally, we show that SipA mimicking an R-SNARE recruits Syn8, Syn13, and Syn7 to the SCV and promotes its fusion with early endosomes to potentially arrest its maturation. Our results reveal that SipA functionally substitutes endogenous SNAREs in order to hijack the host trafficking pathway and promote Salmonella survival.
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Affiliation(s)
| | - Anjali Kapoor
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
| | | | - Kamal Kumar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
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23
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Mosesso N, Bläske T, Nagel MK, Laumann M, Isono E. Preparation of Clathrin-Coated Vesicles From Arabidopsis thaliana Seedlings. FRONTIERS IN PLANT SCIENCE 2018; 9:1972. [PMID: 30687367 PMCID: PMC6334190 DOI: 10.3389/fpls.2018.01972] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/19/2018] [Indexed: 05/22/2023]
Abstract
Clathrin coated vesicles (CCVs) mediate endocytosis of plasma membrane proteins and deliver their content to the endosomes for either subsequent recycling to the plasma membrane or transport to the vacuole for degradation. CCVs assemble also at the trans-Golgi network (TGN) and is responsible for the transport of proteins to other membranes. Oligomerization of clathrin and recruitment of adaptor protein complexes promote the budding and the release of CCVs. However, many of the details during plant CCV formation are not completely elucidated. The analysis of isolated CCVs is therefore important to better understand the formation of plant CCVs, their cargos and the regulation of clathrin-mediated transport processes. In this article, we describe an optimized method to isolate CCVs from Arabidopsis thaliana seedlings.
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Affiliation(s)
- Niccolò Mosesso
- Chair of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Tobias Bläske
- Chair of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Marie-Kristin Nagel
- Chair of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Michael Laumann
- Electron Microscopy Centre, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Erika Isono
- Chair of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
- *Correspondence: Erika Isono,
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24
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Grimm C, Chen CC, Wahl-Schott C, Biel M. Two-Pore Channels: Catalyzers of Endolysosomal Transport and Function. Front Pharmacol 2017; 8:45. [PMID: 28223936 PMCID: PMC5293812 DOI: 10.3389/fphar.2017.00045] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/20/2017] [Indexed: 01/17/2023] Open
Abstract
Two-pore channels (TPCs) have recently emerged as a novel class of non-selective cation channels in the endolysosomal system. There are two members in the human genome, TPC1 and TPC2. Studies with TPC knockout and knockdown models have revealed that these channels participate in the regulation of multiple endolysosomal trafficking pathways which when dysregulated can lead to or influence the development of a range of different diseases such as lysosomal storage, metabolic, or infectious diseases. TPCs have been demonstrated to be activated by different endogenous stimuli, PI(3,5)P2 and NAADP, and ATP has been found to block TPC activation via mTOR. Loss of TPCs can lead to obesity and hypercholesterolemia, and to a slow-down of intracellular virus and bacterial toxin trafficking, it can affect VEGF-induced neoangiogenesis, autophagy, human hair pigmentation or the acrosome reaction in sperm. Moreover, physiological roles of TPCs in cardiac myocytes and pancreatic β cells have been postulated.
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Affiliation(s)
- Christian Grimm
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
| | - Cheng-Chang Chen
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
| | - Christian Wahl-Schott
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
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25
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Abstract
Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells target infected or transformed cells with perforin-containing cytotoxic granules through immune synapses, while platelets secrete several types of granules which contents are essential for thrombosis and hemostasis. Recent work has culminated in the notion that an exocytic SNARE complex, based on a very similar set of components, is primarily responsible for exocytosis of the diverse granules in these different cell types. Granule exocytosis is, in particular, uniquely dependent on the atypical Q-SNARE syntaxin 11, its interacting partners of the Sec/Munc (SM) family, and is regulated by Rab27a. Mutations in these exocytic components underlie disease manifestations of familial hemophagocytic lymphohistiocytosis (FHL) subtypes, characterized by hyperactivation of the immune system, as well as platelet granule secretion defects. Here we discuss the key discoveries that led to the converging notion of the syntaxin 11-based exocytosis machinery for cytotoxic granules and platelet-derived granules.
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Affiliation(s)
- Bor Luen Tang
- a Department of Biochemistry , Yong Loo Lin School of Medicine, National University of Singapore , Singapore and.,b NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , Singapore
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26
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Bhat SS, Friedmann KS, Knörck A, Hoxha C, Leidinger P, Backes C, Meese E, Keller A, Rettig J, Hoth M, Qu B, Schwarz EC. Syntaxin 8 is required for efficient lytic granule trafficking in cytotoxic T lymphocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1653-64. [PMID: 27094127 DOI: 10.1016/j.bbamcr.2016.04.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 03/23/2016] [Accepted: 04/14/2016] [Indexed: 12/21/2022]
Abstract
Cytotoxic T lymphocytes (CTL) eliminate pathogen-infected and cancerous cells mainly by polarized secretion of lytic granules (LG, containing cytotoxic molecules like perforin and granzymes) at the immunological synapse (IS). Members of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) family are involved in trafficking (generation, transport and fusion) of vesicles at the IS. Syntaxin 8 (Stx8) is expressed in LG and colocalizes with the T cell receptor (TCR) upon IS formation. Here, we report the significance of Stx8 for human CTL cytotoxicity. We found that Stx8 mostly localized in late, recycling endosomal and lysosomal compartments with little expression in early endosomal compartments. Down-regulation of Stx8 by siRNA resulted in reduced cytotoxicity. We found that following perforin release of the pre-existing pool upon target cell contact, Stx8 down-regulated CTL regenerate perforin pools less efficiently and thus release less perforin compared to control CTL. CD107a degranulation, real-time and end-point population cytotoxicity assays, and high resolution microscopy support our conclusion that Stx8 is required for proper and timely sorting and trafficking of cytotoxic molecules to functional LG through the endosomal pathway in human CTL.
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Affiliation(s)
- Shruthi S Bhat
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Kim S Friedmann
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Arne Knörck
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Cora Hoxha
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Petra Leidinger
- Human Genetics, School of Medicine, Saarland University, Building 60, 66421 Homburg, Germany.
| | - Christina Backes
- Center for Bioinformatics, Saarland University, Building E2.1, 66123 Saarbrücken, Germany.
| | - Eckart Meese
- Human Genetics, School of Medicine, Saarland University, Building 60, 66421 Homburg, Germany.
| | - Andreas Keller
- Center for Bioinformatics, Saarland University, Building E2.1, 66123 Saarbrücken, Germany.
| | - Jens Rettig
- Physiology, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Markus Hoth
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Bin Qu
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Eva C Schwarz
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
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27
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Vreja IC, Nikić I, Göttfert F, Bates M, Kröhnert K, Outeiro TF, Hell SW, Lemke EA, Rizzoli SO. Super-resolution Microscopy of Clickable Amino Acids Reveals the Effects of Fluorescent Protein Tagging on Protein Assemblies. ACS NANO 2015; 9:11034-11041. [PMID: 26498474 DOI: 10.1021/acsnano.5b04434] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The advent of super-resolution microscopy (nanoscopy) has set high standards for fluorescence tagging. Fluorescent proteins (FPs) are convenient tags in conventional imaging, but their use in nanoscopy has been questioned due to their relatively large size and propensity to form multimers. Here, we compared the nanoscale organization of proteins with or without FP tags by introducing the unnatural amino acid propargyl-L-lysine (PRK) in 26 proteins known to form multimolecular arrangements and into their FP-tagged variants. We revealed the proteins by coupling synthetic fluorophores to PRK via click chemistry and visualized them using ground-state depletion microscopy followed by individual molecule return, as well as stimulated emission depletion microscopy. The arrangements formed by the FP-tagged and nontagged proteins were similar. Mild, but statistically significant differences were observed for only six proteins (23% of all proteins tested). This suggests that FP-based nanoscopy is generally reliable. Unnatural amino acids should be a reliable alternative for the few proteins that are sensitive to FP tagging.
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Affiliation(s)
- Ingrid C Vreja
- International Max Planck Research School for Molecular Biology , Göttingen, Germany
| | - Ivana Nikić
- Structural and Computational Biology Unit, EMBL , 69117 Heidelberg, Germany
| | - Fabian Göttfert
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry , 37077 Göttingen, Germany
| | - Mark Bates
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry , 37077 Göttingen, Germany
| | | | | | - Stefan W Hell
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry , 37077 Göttingen, Germany
| | - Edward A Lemke
- Structural and Computational Biology Unit, EMBL , 69117 Heidelberg, Germany
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28
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Robinson MS. Forty Years of Clathrin-coated Vesicles. Traffic 2015; 16:1210-38. [PMID: 26403691 DOI: 10.1111/tra.12335] [Citation(s) in RCA: 234] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 12/11/2022]
Abstract
The purification of coated vesicles and the discovery of clathrin by Barbara Pearse in 1975 was a landmark in cell biology. Over the past 40 years, work from many labs has uncovered the molecular details of clathrin and its associated proteins, including how they assemble into a coated vesicle and how they select cargo. Unexpected connections have been found with signalling, development, neuronal transmission, infection, immunity and genetic disorders. But there are still a number of unanswered questions, including how clathrin-mediated trafficking is regulated and how the machinery evolved.
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Affiliation(s)
- Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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29
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Danelishvili L, Bermudez LE. Mycobacterium avium MAV_2941 mimics phosphoinositol-3-kinase to interfere with macrophage phagosome maturation. Microbes Infect 2015; 17:628-37. [PMID: 26043821 PMCID: PMC4554883 DOI: 10.1016/j.micinf.2015.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/22/2015] [Indexed: 11/25/2022]
Abstract
Mycobacterium avium subsp hominissuis (M. avium) is a pathogen that infects and survives in macrophages. Previously, we have identified the M. avium MAV_2941 gene encoding a 73 amino acid protein exported by the oligopeptide transporter OppA to the macrophage cytoplasm. Mutations in MAV_2941 were associated with significant impairment of M. avium growth in THP-1 macrophages. In this study, we investigated the molecular mechanism of MAV_2941 action and demonstrated that MAV_2941 interacts with the vesicle trafficking proteins syntaxin-8 (STX8), adaptor-related protein complex 3 (AP-3) complex subunit beta-1 (AP3B1) and Archain 1 (ARCN1) in mononuclear phagocytic cells. Sequencing analysis revealed that the binding site of MAV_2941 is structurally homologous to the human phosphatidylinositol 3-kinase (PI3K) chiefly in the region recognized by vesicle trafficking proteins. The β3A subunit of AP-3, encoded by AP3B1, is essential for trafficking cargo proteins, including lysosomal-associated membrane protein 1 (LAMP-1), to the phagosome and lysosome-related organelles. Here, we show that while the heat-killed M. avium when ingested by macrophages co-localizes with LAMP-1 protein, transfection of MAV_2941 in macrophages results in significant decrease of LAMP-1 co-localization with the heat-killed M. avium phagosomes. Mutated MAV_2941, where the amino acids homologous to the binding region of PI3K were changed, failed to interact with trafficking proteins. Inactivation of the AP3B1 gene led to alteration in the trafficking of LAMP-1. These results suggest that M. avium MAV_2941 interferes with the protein trafficking within macrophages altering the maturation of phagosome.
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Affiliation(s)
- Lia Danelishvili
- Department of Biomedical Sciences, College of Veterinary Medicine, USA
| | - Luiz E Bermudez
- Department of Biomedical Sciences, College of Veterinary Medicine, USA; Department of Microbiology, College of Science, USA; Molecular and Cell Biology Program, Oregon State University, Corvallis, OR 97331, USA.
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30
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Inoue H, Matsuzaki Y, Tanaka A, Hosoi K, Ichimura K, Arasaki K, Wakana Y, Asano K, Tanaka M, Okuzaki D, Yamamoto A, Tani K, Tagaya M. γ-SNAP stimulates disassembly of endosomal SNARE complexes and regulates endocytic trafficking pathways. J Cell Sci 2015; 128:2781-94. [PMID: 26101353 DOI: 10.1242/jcs.158634] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/17/2015] [Indexed: 12/28/2022] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) that reside in the target membranes and transport vesicles assemble into specific SNARE complexes to drive membrane fusion. N-ethylmaleimide-sensitive factor (NSF) and its attachment protein, α-SNAP (encoded by NAPA), catalyze disassembly of the SNARE complexes in the secretory and endocytic pathways to recycle them for the next round of fusion events. γ-SNAP (encoded by NAPG) is a SNAP isoform, but its function in SNARE-mediated membrane trafficking remains unknown. Here, we show that γ-SNAP regulates the endosomal trafficking of epidermal growth factor (EGF) receptor (EGFR) and transferrin. Immunoprecipitation and mass spectrometry analyses revealed that γ-SNAP interacts with a limited range of SNAREs, including endosomal ones. γ-SNAP, as well as α-SNAP, mediated the disassembly of endosomal syntaxin-7-containing SNARE complexes. Overexpression and small interfering (si)RNA-mediated depletion of γ-SNAP changed the morphologies and intracellular distributions of endosomes. Moreover, the depletion partially suppressed the exit of EGFR and transferrin from EEA1-positive early endosomes to delay their degradation and uptake. Taken together, our findings suggest that γ-SNAP is a unique SNAP that functions in a limited range of organelles - including endosomes - and their trafficking pathways.
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Affiliation(s)
- Hiroki Inoue
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Yuka Matsuzaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Ayaka Tanaka
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kaori Hosoi
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kaoru Ichimura
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Yuichi Wakana
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kenichi Asano
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Masato Tanaka
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Daisuke Okuzaki
- Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Akitsugu Yamamoto
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
| | - Katsuko Tani
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Mitsuo Tagaya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
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Expression of syntaxin 8 in visceral adipose tissue is increased in obese patients with type 2 diabetes and related to markers of insulin resistance and inflammation. Arch Med Res 2014; 46:47-53. [PMID: 25523146 DOI: 10.1016/j.arcmed.2014.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 12/09/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND AIMS Obesity is associated with increased adipose tissue inflammation as well as with the development of type 2 diabetes (T2D). Syntaxin 8 (STX8) is a protein required for the transport of endosomes. In this study we analyzed the relationship of STX8 with the presence of T2D in the context of obesity. METHODS With this purpose, 21 subjects (seven lean [LN], eight obese normoglycemic [OB-NG] and six obese with type 2 diabetes [OB-T2D]) were included in the study. Gene and protein expression levels of STX8 and GLUT4 were analyzed in visceral adipose tissue (VAT). RESULTS mRNA (p = 0.008) and protein (p <0.001) expression levels of STX8 were significantly increased in VAT of OB-T2D patients. Moreover, gene expression levels of SLC2A4 (GLUT4) were downregulated (p = 0.002) in VAT of obese patients. We found that STX8 was positively correlated (p <0.05) with fasting glucose concentrations, plasma glucose 2 h after an OGTT and C-reactive protein. Interestingly, the expression of STX8 was negatively correlated (p <0.05) with the expression of SLC2A4 in VAT. CONCLUSIONS Increased STX8 expression in VAT appears to be associated with the presence of T2D in obese patients through a mechanism that may involve GLUT4.
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32
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Grimm C, Holdt LM, Chen CC, Hassan S, Müller C, Jörs S, Cuny H, Kissing S, Schröder B, Butz E, Northoff B, Castonguay J, Luber CA, Moser M, Spahn S, Lüllmann-Rauch R, Fendel C, Klugbauer N, Griesbeck O, Haas A, Mann M, Bracher F, Teupser D, Saftig P, Biel M, Wahl-Schott C. High susceptibility to fatty liver disease in two-pore channel 2-deficient mice. Nat Commun 2014; 5:4699. [DOI: 10.1038/ncomms5699] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/10/2014] [Indexed: 12/15/2022] Open
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33
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Chen B, Zhao L, Li X, Ji YS, Li N, Xu XF, Chen ZY. Syntaxin 8 modulates the post-synthetic trafficking of the TrkA receptor and inflammatory pain transmission. J Biol Chem 2014; 289:19556-69. [PMID: 24872407 DOI: 10.1074/jbc.m114.567925] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Nerve growth factor (NGF) promotes the survival, maintenance, and neurite outgrowth of sensory and sympathetic neurons, and the effects are mediated by TrkA receptor signaling. Thus, the cell surface location of the TrkA receptor is crucial for NGF-mediated functions. However, the regulatory mechanism underlying TrkA cell surface levels remains incompletely understood. In this study, we identified syntaxin 8 (STX8), a Q-SNARE protein, as a novel TrkA-binding protein. Overexpression and knockdown studies showed that STX8 facilitates TrkA transport from the Golgi to the plasma membrane and regulates the surface levels of TrkA but not TrkB receptors. Furthermore, STX8 modulates downstream NGF-induced TrkA signaling and, consequently, the survival of NGF-dependent dorsal root ganglia neurons. Finally, knockdown of STX8 in rat dorsal root ganglia by recombinant adeno-associated virus serotype 6-mediated RNA interference led to analgesic effects on formalin-induced inflammatory pain. These findings demonstrate that STX8 is a modulator of TrkA cell surface levels and biological functions.
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Affiliation(s)
- Bing Chen
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Ling Zhao
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Xian Li
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Yun-Song Ji
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Na Li
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Xu-Feng Xu
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Zhe-Yu Chen
- From the Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Number 44 Wenhua Xi Road, Jinan, Shandong 250012, China
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Gandasi NR, Barg S. Contact-induced clustering of syntaxin and munc18 docks secretory granules at the exocytosis site. Nat Commun 2014; 5:3914. [PMID: 24835618 DOI: 10.1038/ncomms4914] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 04/17/2014] [Indexed: 02/06/2023] Open
Abstract
Docking of secretory vesicles at the plasma membrane is a poorly understood prerequisite for exocytosis. Current models propose raft-like clusters containing syntaxin as docking receptor, but direct evidence for this is lacking. Here we provide quantitative measurements of several exocytosis proteins (syntaxin, SNAP25, munc18, munc13 and rab3) at the insulin granule release site and show that docking coincides with rapid de novo formation of syntaxin1/munc18 clusters at the nascent docking site. Formation of such clusters prevents undocking and is not observed during failed docking attempts. Overexpression of syntaxins' N-terminal Habc-domain competitively interferes with both cluster formation and successful docking. SNAP25 and munc13 are recruited to the docking site more than a minute later, consistent with munc13's reported role in granule priming rather than docking. We conclude that secretory vesicles dock by inducing syntaxin1/munc18 clustering in the target membrane, and find no evidence for preformed docking receptors.
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Affiliation(s)
- Nikhil R Gandasi
- Department of Medical Cell Biology, Uppsala University, BMC 571, 75123 Uppsala, Sweden
| | - Sebastian Barg
- Department of Medical Cell Biology, Uppsala University, BMC 571, 75123 Uppsala, Sweden
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Ikari A, Tonegawa C, Sanada A, Kimura T, Sakai H, Hayashi H, Hasegawa H, Yamaguchi M, Yamazaki Y, Endo S, Matsunaga T, Sugatani J. Tight junctional localization of claudin-16 is regulated by syntaxin 8 in renal tubular epithelial cells. J Biol Chem 2014; 289:13112-23. [PMID: 24659781 DOI: 10.1074/jbc.m113.541193] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Claudin-16 (CLDN16) regulates the paracellular reabsorption of Mg(2+) in the thick ascending limb of Henle's loop. However, the mechanism regulating the tight junctional localization of CLDN16 remains unknown. In yeast two-hybrid systems, we found that CLDN16 bound to syntaxin 8 (STX8), a target soluble N-ethylmaleimide-sensitive factor attachment protein receptor. We have examined the effect of STX8 on the localization and function of CLDN16 using Madin-Darby canine kidney cells expressing FLAG-tagged CLDN16. A pulldown assay showed that the carboxyl cytoplasmic region of human CLDN16 bound to STX8. CLDN16 was localized in the thick ascending limb, whereas STX8 was widely distributed throughout the rat kidney. An association between CLDN16 and STX8 was observed in rat renal homogenates and Madin-Darby canine kidney cells. STX8 siRNA decreased the cell surface localization of CLDN16 and transepithelial electrical resistance and permeability to Mg(2+) but increased the co-localization of CLDN16 with early endosome and lysosome markers. Dephosphorylation of CLDN16 by protein kinase A inhibitors and S217A mutant, a dephosphorylated form, decreased the association with STX8 and the cell surface localization of CLDN16. Recycling assays indicated that STX8 siRNA decreased the trafficking of CLDN16 to the plasma membrane without affecting endocytosis. Dominant negative Rab11 and recycling inhibitor primaquine decreased the cell surface localization of CLDN16, which was similar to that in STX8 siRNA-transfected cells. These results suggest that STX8 mediates the recycling of CLDN16 and constitutes an important component of the CLDN16 trafficking machinery in the kidney.
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Affiliation(s)
- Akira Ikari
- From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan
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Passantino R, Cascio C, Deidda I, Galizzi G, Russo D, Spedale G, Guarneri P. Identifying protein partners of CLN8, an ER-resident protein involved in neuronal ceroid lipofuscinosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:529-40. [DOI: 10.1016/j.bbamcr.2012.10.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 10/29/2012] [Accepted: 10/31/2012] [Indexed: 10/27/2022]
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Segatto O, Anastasi S, Alemà S. Regulation of epidermal growth factor receptor signalling by inducible feedback inhibitors. J Cell Sci 2011; 124:1785-93. [DOI: 10.1242/jcs.083303] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Signalling by the epidermal growth factor receptor (EGFR) controls morphogenesis and/or homeostasis of several tissues from worms to mammals. The correct execution of these programmes requires the generation of EGFR signals of appropriate strength and duration. This is obtained through a complex circuitry of positive and negative feedback regulation. Feedback inhibitory mechanisms restrain EGFR activity in time and space, which is key to ensuring that receptor outputs are commensurate to the cell and tissue needs. Here, we focus on the emerging field of inducible negative feedback regulation of the EGFR in mammals. In mammalian cells, four EGFR inducible feedback inhibitors (IFIs), namely LRIG1, RALT (also known as MIG6 and ERRFI1), SOCS4 and SOCS5, have been discovered recently. EGFR IFIs are expressed de novo in the context of early or delayed transcriptional responses triggered by EGFR activation. They all bind to the EGFR and suppress receptor signalling through several mechanisms, including catalytic inhibition and receptor downregulation. Here, we review the mechanistic basis of IFI signalling and rationalise the function of IFIs in light of gene-knockout studies that assign LRIG1 and RALT an essential role in restricting cell proliferation. Finally, we discuss how IFIs might participate in system control of EGFR signalling and highlight the emerging roles for IFIs in the suppression of EGFR-driven tumorigenesis.
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Affiliation(s)
- Oreste Segatto
- Department of Experimental Oncology, Regina Elena Cancer Institute, 00158 Rome, Italy
| | - Sergio Anastasi
- Department of Experimental Oncology, Regina Elena Cancer Institute, 00158 Rome, Italy
| | - Stefano Alemà
- Institute of Cell Biology, CNR, 00016 Monterotondo, Italy
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Wesolowski J, Paumet F. SNARE motif: a common motif used by pathogens to manipulate membrane fusion. Virulence 2011; 1:319-24. [PMID: 21178463 DOI: 10.4161/viru.1.4.12195] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To penetrate host cells through their membranes, pathogens use a variety of molecular components in which the presence of heptad repeat motifs seems to be a prevailing element. Heptad repeats are characterized by a pattern of seven, generally hydrophobic, residues. In order to initiate membrane fusion, viruses use glycoproteins-containing heptad repeats. These proteins are structurally and functionally similar to the SNARE proteins known to be involved in eukaryotic membrane fusion. SNAREs also display a heptad repeat motif called the "SNARE motif". As bacterial genomes are being sequenced, microorganisms also appear to be carrying membrane proteins resembling eukaryotic SNAREs. This category of SNARE-like proteins might share similar functions and could be used by microorganisms to either promote or block membrane fusion. Such a recurrence across pathogenic organisms suggests that this architectural motif was evolutionarily selected because it most effectively ensures the survival of pathogens within the eukaryotic environment.
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Affiliation(s)
- Jordan Wesolowski
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA, USA
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Akasaki K, Suenobu M, Mukaida M, Michihara A, Wada I. COOH-terminal isoleucine of lysosome-associated membrane protein-1 is optimal for its efficient targeting to dense secondary lysosomes. J Biochem 2010; 148:669-79. [DOI: 10.1093/jb/mvq101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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40
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Balasinor NH, D'Souza R, Nanaware P, Idicula-Thomas S, Kedia-Mokashi N, He Z, Dym M. Effect of high intratesticular estrogen on global gene expression and testicular cell number in rats. Reprod Biol Endocrinol 2010; 8:72. [PMID: 20573204 PMCID: PMC2906496 DOI: 10.1186/1477-7827-8-72] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Accepted: 06/23/2010] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The identification of estrogen receptors alpha and beta and aromatase in the testis has highlighted the important role of estrogens in regulating spermatogenesis. There is a wealth of information on the deleterious effects of fetal and neonatal exposure of estrogens and xenoestrogens in the testis, including spermiation failure and germ cell apoptosis. However, very little is known about gene transcripts affected by exogenous estradiol exposure in the testis. The objective of the present study was to unveil global gene expression profiles and testicular cell number changes in rats after estradiol treatment. METHODS 17beta-estradiol was administered to adult male rats at a dose of 100 micrograms/kg body weight in saline daily for 10 days; male rats receiving only saline were used as controls. Microarray analysis was performed to examine global gene expression profiles with or without estradiol treatment. Real time RT-PCR was conducted to verify the microarray data. In silico promoter and estrogen responsive elements (EREs) analysis was carried out for the differentially expressed genes in response to estradiol. Quantitation of testicular cell number based on ploidy was also performed using flow cytometry in rats with or without estradiol treatment. RESULTS We found that 221 genes and expressed sequence tags (ESTs) were differentially expressed in rat testes treated with estradiol compared to the control; the microarray data were confirmed by real time RT-PCR. Gene Ontology analysis revealed that a number of the differentially expressed genes are involved in androgen and xenobiotic metabolism, maintenance of cell cytoskeleton, endocytosis, and germ cell apoptosis. A total of 33 up-regulated genes and 67 down-regulated genes showed the presence of EREs. Flow cytometry showed that estradiol induced a significant decrease in 2n cells (somatic and germ cells) and 4n cells (pachytene spermatocytes) and a marked increase in the number of elongated and elongating spermatids. CONCLUSIONS This study provides a novel insight into the molecular basis for spermiation failure and apoptosis caused by 17beta-estradiol and it also offers new mechanisms by which adult exposure to environmental estrogens can affect spermatogenesis and fertility.
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Affiliation(s)
- Nafisa H Balasinor
- Neuroendocrinology Division, National Institute for Research in Reproductive Health, Parel, Mumbai, India
| | - Ryan D'Souza
- Neuroendocrinology Division, National Institute for Research in Reproductive Health, Parel, Mumbai, India
| | - Padma Nanaware
- Biomedical Informatics Centre of ICMR, National Institute for Research in Reproductive Health, Parel, Mumbai, India
| | - Susan Idicula-Thomas
- Biomedical Informatics Centre of ICMR, National Institute for Research in Reproductive Health, Parel, Mumbai, India
| | - Neelam Kedia-Mokashi
- Neuroendocrinology Division, National Institute for Research in Reproductive Health, Parel, Mumbai, India
| | - Zuping He
- Georgetown University Medical Center, Department of Biochemistry and Molecular & Cellular Biology, 3900 Reservoir Road, NW, Washington, DC 20057, USA
| | - Martin Dym
- Georgetown University Medical Center, Department of Biochemistry and Molecular & Cellular Biology, 3900 Reservoir Road, NW, Washington, DC 20057, USA
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Mig-6 controls EGFR trafficking and suppresses gliomagenesis. Proc Natl Acad Sci U S A 2010; 107:6912-7. [PMID: 20351267 DOI: 10.1073/pnas.0914930107] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and lethal primary brain cancer that is driven by aberrant signaling of growth factor receptors, particularly the epidermal growth factor receptor (EGFR). EGFR signaling is tightly regulated by receptor endocytosis and lysosome-mediated degradation, although the molecular mechanisms governing such regulation, particularly in the context of cancer, remain poorly delineated. Here, high-resolution genomic profiles of GBM identified a highly recurrent focal 1p36 deletion encompassing the putative tumor suppressor gene, Mig-6. We show that Mig-6 quells the malignant potential of GBM cells and dampens EGFR signaling by driving EGFR into late endosomes and lysosome-mediated degradation upon ligand stimulation. Mechanistically, this effect is mediated by the binding of Mig-6 to a SNARE protein STX8, a protein known to be required for late endosome trafficking. Thus, Mig-6 functions to ensure recruitment of internalized receptor to late endosomes and subsequently the lysosomal degradation compartment through its ability to specifically link EGFR and STX8 during ligand-stimulated EGFR trafficking. In GBM, the highly frequent loss of Mig-6 would therefore serve to sustain aberrant EGFR-mediated oncogenic signaling. Together, these data uncover a unique tumor suppression mechanism involving the regulation of receptor trafficking.
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Xie LX, Calafat J, Janssen H, de la Iglesia-Vicente J, Mollinedo F. Intracellular location of syntaxin 7 in human neutrophils. Immunol Lett 2010; 129:72-7. [PMID: 20170677 DOI: 10.1016/j.imlet.2010.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2009] [Revised: 02/07/2010] [Accepted: 02/09/2010] [Indexed: 11/17/2022]
Abstract
Neutrophils are the first line of defense in the innate immune system. Neutrophils neutralize invading microorganisms mainly by phagocytosis, but the mechanism and molecules involved in this process are not well characterized. Because the endosomal soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein syntaxin 7 regulates vesicle trafficking events in phagocytosis, we investigated the expression and subcellular localization of syntaxin 7 in human neutrophils. Here we have found that human peripheral blood neutrophils and neutrophil-differentiated HL-60 cells express syntaxin 7 at both mRNA and protein levels. Using biochemical and ultrastructural approaches, we found that syntaxin 7 was broadly located in the membranes of the three major cytoplasmic granules of human neutrophils, with a major location in azurophilic granules, which are mainly involved in phagocytosis. A secondary, but extensive, location of syntaxin 7 was in specific and tertiary granules, which resulted translocated to the plasma membrane upon cell activation that promoted mobilization of these organelles. These data reveal the presence of syntaxin 7 in the membranes of exocytosis-prone granules (specific and tertiary granules) and phagocytosis-related granules (azurophilic granules) in human neutrophils, and therefore it might play a role in both exocytosis and phagocytosis in human neutrophils.
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Affiliation(s)
- Li-xin Xie
- Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer, CSIC-Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
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43
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Chaineau M, Danglot L, Galli T. Multiple roles of the vesicular-SNARE TI-VAMP in post-Golgi and endosomal trafficking. FEBS Lett 2009; 583:3817-26. [PMID: 19837067 DOI: 10.1016/j.febslet.2009.10.026] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 10/09/2009] [Accepted: 10/13/2009] [Indexed: 01/13/2023]
Abstract
SNARE (Soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins are the core machinery of membrane fusion. Vesicular SNAREs (v-SNAREs) interact with their target SNAREs (t-SNAREs) to form SNARE complexes which mediate membrane fusion. Here we review the basic properties and functions of the v-SNARE TI-VAMP/VAMP7 (Tetanus neurotoxin insensitive-vesicle associated membrane protein). TI-VAMP interacts with its t-SNARE partners, particularly plasmalemmal syntaxins, to mediate membrane fusion and with several regulatory proteins especially via its amino-terminal regulatory Longin domain. Partners include AP-3, Hrb/(Human immunodeficiency virus Rev binding) protein, and Varp (Vps9 domain and ankyrin repeats containing protein) and regulate TI-VAMP's function and targeting. TI-VAMP is involved both in secretory and endocytic pathways which mediate neurite outgrowth and synaptic transmission, plasma membrane remodeling and lysosomal secretion.
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Affiliation(s)
- Mathilde Chaineau
- Membrane Traffic in Neuronal and Epithelial Morphogenesis', INSERM U950, Paris F-75013, France
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44
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Okayama M, Arakawa T, Tanimura A, Mizoguchi I, Tajima Y, Takuma T. Role of VAMP8/endobrevin in constitutive exocytotic pathway in HeLa cells. Cell Struct Funct 2009; 34:115-25. [PMID: 19738360 DOI: 10.1247/csf.09013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
To evaluate the role of VAMP8/endobrevin in constitutive exocytosis, we have examined the exocytotic pathways of VAMP8 and human growth hormone, both GFP-tagged, by total internal reflection fluorescence microscopy (TIRF-M). Human GH-GFP and VAMP8-GFP were similarly expressed in small round vesicles and elongated tubular vesicles in HeLa cells, and were mostly exocytosed at the peripheral area of the cells. VAMP8-GFP gave 2 types of exocytotic images: a burst type and a non-burst type. The burst type showed a sharp transient increase in the peak fluorescence intensity and a much slower decrease in the average intensity in the active windows, where exocytosis took place, as observed in the "full-fusion" type of exocytosis. The non-burst type showed a relatively long-lasting fusion to the plasma membrane with little transfer of VAMP8-GFP to the plasma membrane, as observed in the so-called "kiss-and-run" type of exocytosis. Endogenous VAMP8 and hGH-GFP were colocalized on the same vesicles at least in part. However, the constitutive exocytosis of hGH-GFP and CLuc, a secreted luciferase from Cypridina noctiluca, was normal, even when siRNAs for VAMP8 and VAMP3 robustly decreased their proteins. These results suggest that VAMP8 is not essential for constitutive exocytosis, although it can be involved in the exocytosis.
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Affiliation(s)
- Miki Okayama
- Department of Orthodontics, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
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Truschel ST, Simoes S, Setty SRG, Harper DC, Tenza D, Thomas PC, Herman KE, Sackett SD, Cowan DC, Theos AC, Raposo G, Marks MS. ESCRT-I function is required for Tyrp1 transport from early endosomes to the melanosome limiting membrane. Traffic 2009; 10:1318-36. [PMID: 19624486 DOI: 10.1111/j.1600-0854.2009.00955.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Melanosomes are lysosome-related organelles that coexist with lysosomes within melanocytes. The pathways by which melanosomal proteins are diverted from endocytic organelles toward melanosomes are incompletely defined. In melanocytes from mouse models of Hermansky-Pudlak syndrome that lack BLOC-1, melanosomal proteins such as tyrosinase-related protein 1 (Tyrp1) accumulate in early endosomes. Whether this accumulation represents an anomalous pathway or an arrested normal intermediate in melanosome protein trafficking is not clear. Here, we show that early endosomes are requisite intermediates in the trafficking of Tyrp1 from the Golgi to late stage melanosomes in normal melanocytic cells. Kinetic analyses show that very little newly synthesized Tyrp1 traverses the cell surface and that internalized Tyrp1 is inefficiently sorted to melanosomes. Nevertheless, nearly all Tyrp1 traverse early endosomes since it becomes trapped within enlarged, modified endosomes upon overexpression of Hrs. Although Tyrp1 localization is not affected by Hrs depletion, depletion of the ESCRT-I component, Tsg101, or inhibition of ESCRT function by dominant-negative approaches results in a dramatic redistribution of Tyrp1 to aberrant endosomal membranes that are largely distinct from those harboring traditional ESCRT-dependent, ubiquitylated cargoes such as MART-1. The lysosomal protein content of some of these membranes and the lack of Tyrp1 recycling to the plasma membrane in Tsg101-depleted cells suggests that ESCRT-I functions downstream of BLOC-1. Our data delineate a novel pathway for Tyrp1 trafficking and illustrate a requirement for ESCRT-I function in controlling protein sorting from vacuolar endosomes to the limiting membrane of a lysosome-related organelle.
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Affiliation(s)
- Steven T Truschel
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Strömberg S, Agnarsdóttir M, Magnusson K, Rexhepaj E, Bolander Å, Lundberg E, Asplund A, Ryan D, Rafferty M, Gallagher WM, Uhlen M, Bergqvist M, Ponten F. Selective Expression of Syntaxin-7 Protein in Benign Melanocytes and Malignant Melanoma. J Proteome Res 2009; 8:1639-46. [DOI: 10.1021/pr800745e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sara Strömberg
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Margrét Agnarsdóttir
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Kristina Magnusson
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Elton Rexhepaj
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Åsa Bolander
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Emma Lundberg
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Anna Asplund
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Denise Ryan
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Mairin Rafferty
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - William M. Gallagher
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Mathias Uhlen
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael Bergqvist
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Fredrik Ponten
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden, Department of Oncology, Uppsala University Hospital, SE-75185 Uppsala Sweden, Department of Proteomics, School of Biotechnology, AlbaNova University Center, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden, and UCD School of Biomolecular and Biomedical Science, UCD, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Hall SL, Hester S, Griffin JL, Lilley KS, Jackson AP. The organelle proteome of the DT40 lymphocyte cell line. Mol Cell Proteomics 2009; 8:1295-305. [PMID: 19181659 DOI: 10.1074/mcp.m800394-mcp200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A major challenge in eukaryotic cell biology is to understand the roles of individual proteins and the subcellular compartments in which they reside. Here, we use the localization of organelle proteins by isotope tagging technique to complete the first proteomic analysis of the major organelles of the DT40 lymphocyte cell line. This cell line is emerging as an important research tool because of the ease with which gene knockouts can be generated. We identify 1090 proteins through the analysis of preparations enriched for integral membrane or soluble and peripherally associated proteins and localize 223 proteins to the endoplasmic reticulum, Golgi, lysosome, mitochondrion, or plasma membrane by matching their density gradient distributions to those of known organelle residents. A striking finding is that within the secretory and endocytic pathway a high proportion of proteins are not uniquely localized to a single organelle, emphasizing the dynamic steady-state nature of intracellular compartments in eukaryotic cells.
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Affiliation(s)
- Stephanie L Hall
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB21QW, United Kingdom
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48
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He Y, Linder ME. Differential palmitoylation of the endosomal SNAREs syntaxin 7 and syntaxin 8. J Lipid Res 2008; 50:398-404. [PMID: 18980942 DOI: 10.1194/jlr.m800360-jlr200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Palmitoylation is a posttranslational modification that regulates protein trafficking and stability. In this study we investigated whether the endosomal soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins syntaxin 7 and syntaxin 8 are modified with palmitate. Using metabolic labeling and site-directed mutagenesis, we show that human syntaxins 7 and 8 are modified with palmitate through a thioester linkage. Palmitoylation is dependent upon cysteine 239 of human syntaxin 7 and cysteine 214 of syntaxin 8, residues that are located on the cytoplasmic face of the transmembrane domain (TMD). Palmitoylation of syntaxin 8 is minimally affected by the Golgi-disturbing agent brefeldin A (BFA), whereas BFA dramatically inhibits palmitoylation of syntaxin7. The differential effect of BFA suggests that palmitoylation of syntaxins 7 and 8 occurs in distinct subcellular compartments. Palmitoylation does not affect the rate of protein turnover of syntaxins 7 and 8 nor does it influence the steady-state localization of syntaxin 8 in late endosomes. Syntaxin 7 actively cycles between endosomes and the plasma membrane. Palmitoylation-defective syntaxin 7 is selectively retained on the plasma membrane, suggesting that palmitoylation is important for intercompartmental transport of syntaxin 7.
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Affiliation(s)
- Yuhong He
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Maurine E Linder
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110.
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Bilan F, Nacfer M, Fresquet F, Norez C, Melin P, Martin-Berge A, Costa de Beauregard MA, Becq F, Kitzis A, Thoreau V. Endosomal SNARE proteins regulate CFTR activity and trafficking in epithelial cells. Exp Cell Res 2008; 314:2199-211. [PMID: 18570918 DOI: 10.1016/j.yexcr.2008.04.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 04/04/2008] [Accepted: 04/22/2008] [Indexed: 01/20/2023]
Abstract
The Cystic Fibrosis Transmembrane conductance Regulator (CFTR) protein is a chloride channel localized at the apical plasma membrane of epithelial cells. We previously described that syntaxin 8, an endosomal SNARE (Soluble N-ethylmaleimide-sensitive factor Attachment protein REceptor) protein, interacts with CFTR and regulates its trafficking to the plasma membrane and hence its channel activity. Syntaxin 8 belongs to the endosomal SNARE complex which also contains syntaxin 7, vti1b and VAMP8. Here, we report that these four endosomal SNARE proteins physically and functionally interact with CFTR. In LLC-PK1 cells transfected with CFTR and in Caco-2 cells endogenously expressing CFTR, we demonstrated that endosomal SNARE protein overexpression inhibits CFTR activity but not swelling- or calcium-activated iodide efflux, indicating a specific effect upon CFTR activity. Moreover, co-immunoprecipitation experiments in LLC-PK1-CFTR cells showed that CFTR and SNARE proteins belong to a same complex and pull-down assays showed that VAMP8 and vti1b preferentially interact with CFTR N-terminus tail. By cell surface biotinylation and immunofluorescence experiments, we evidenced that endosomal SNARE overexpression disturbs CFTR apical targeting. Finally, we found a colocalization of CFTR and endosomal SNARE proteins in Rab11-positive recycling endosomes, suggesting a new role for endosomal SNARE proteins in CFTR trafficking in epithelial cells.
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Affiliation(s)
- Frédéric Bilan
- Institut de Physiologie et de Biologie Cellulaires, CNRS UMR6187, Université de Poitiers, France; CHU de Poitiers, BP577, 86021 Poitiers cedex, France
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Best D, Sahlender DA, Walther N, Peden AA, Adams IR. Sdmg1 is a conserved transmembrane protein associated with germ cell sex determination and germline-soma interactions in mice. Development 2008; 135:1415-25. [PMID: 18321981 PMCID: PMC2584365 DOI: 10.1242/dev.019497] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In mammals, the supporting cell lineage in an embryonic gonad communicates the sex-determining decision to various sexually dimorphic cell types in the developing embryo, including the germ cells. However, the molecular nature of the sex-determining signals that pass from the supporting cells to the germ cells is not well understood. We have identified a conserved transmembrane protein, Sdmg1, owing to its male-specific expression in mouse embryonic gonads. Sdmg1 is expressed in the Sertoli cells of embryonic testes from 12.5 dpc, and in granulosa cells of growing follicles in adult ovaries. In Sertoli cells, Sdmg1 is localised to endosomes, and knock-down of Sdmg1 in Sertoli cell lines causes mis-localisation of the secretory SNARE Stx2 and defects in membrane trafficking. Upregulation of Sdmg1 appears to be part of a larger programme of changes to membrane trafficking pathways in embryonic Sertoli cells, and perturbing secretion in male embryonic gonads in organ culture causes male-to-female germ cell sex reversal. These data suggest that changes that occur in the cell biology of embryonic Sertoli cells may facilitate the communication of male sex-determining decisions to the germ cells during embryonic development.
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Affiliation(s)
- Diana Best
- MRC Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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