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Chai YM, Zhou ZB, Liu RZ, Cui YS, Zhang Y. SNX4 Is Correlated With Immune Infiltration and Prognosis in Clear Cell Renal Cell Carcinoma. World J Oncol 2024; 15:809-824. [PMID: 39328330 PMCID: PMC11424112 DOI: 10.14740/wjon1868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 06/18/2024] [Indexed: 09/28/2024] Open
Abstract
Background Clear cell renal cell carcinoma (ccRCC) is known as the most common and malignant histologic subtype of renal carcinoma. Sorting nexin 4 (SNX4) plays a regulatory role in recycling from endosomes to the plasma membrane and promotes autophagosome assembly and transport, which may exert the cancerous growth and progression. This study aimed to assess the biological role of SNX4 in ccRCC and their clinical association via public biological data platforms combined with experimental verification. Methods In our study, we analyzed the mRNA and protein expression of SNX4 in ccRCC under different clinicopathological characteristics through The Cancer Genome Atlas (TCGA), Human Protein Atlas (HPA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) databases. We used the Gene Expression Profiling Interactive Analysis (GEPIA) platform to conduct the survival analysis and figure out the immune cell infiltration level under different expression levels of SNX4 combined with Tumor Immune Estimation Resource (TIMER) database. Furthermore, we predicted competing endogenous RNA (ceRNA) regulatory network using TargetScan, miRDB, starBase and miRTarBase online databases. We totally collected six paired ccRCC tissues and adjacent tissues and applied quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) to detect the expression of SNX4 in the collected clinical specimens. Results The mRNA and protein expression level of SNX4 was significantly lower in ccRCC than those in normal tissues. The results proposed that lower SNX4 was expressed in patients with higher histologic grade and in male patients. Kaplan-Meier analysis demonstrated that lower mRNA expression level of SNX4 was correlated with poorer prognosis. SNX4 had positive correlation with immune cell infiltrating levels and programmed cell death-ligand 1 (PD-L1) expression. Furthermore, we constructed the SNX4/miR-221-3p/miR-222-3p/DHRS4-AS1 axis, which may be the underlying ceRNA interaction network. Finally, we verified the reduced expression of SNX4 in ccRCC by qRT-PCR and WB. Conclusion The expression of SNX4 in ccRCC was lower than adjacent tissues and its downregulated expression was associated with poor prognosis of ccRCC patients. SNX4 may exert critical roles in the tumorigenesis, development and migration of ccRCC via various mechanisms.
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Affiliation(s)
- Yu Meng Chai
- Department of Urology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- These authors contributed equally to this article
| | - Zhong Bao Zhou
- Department of Urology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- These authors contributed equally to this article
| | - Run Ze Liu
- Department of Urology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
| | - Yuan Shan Cui
- Department of Urology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong, China
| | - Yong Zhang
- Department of Urology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
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2
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Lv S, Jiang H, Yu L, Zhang Y, Sun L, Xu J. SNX14 inhibits autophagy via the PI3K/AKT/mTOR signaling cascade in breast cancer cells. J Mol Histol 2024; 55:391-401. [PMID: 38869753 DOI: 10.1007/s10735-024-10209-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 06/01/2024] [Indexed: 06/14/2024]
Abstract
BACKGROUND Sorting nexin 14 (SNX14) is a member of the sorting junction protein family. Its specific roles in cancer development remain unclear. Therefore, in this study, we aimed to determine the effects and underlying mechanisms of SNX14 on autophagy of breast cancer cells to aid in the therapeutic treatment of breast cancer. METHODS In this study, we performed in vitro experiments to determine the effect of SNX14 on breast cancer cell growth. Moreover, we used an MCF7 breast cancer tumor-bearing mouse model to confirm the effect of SNX14 on tumor cell growth in vivo. We also performed western blotting and quantitative polymerase chain reaction to identify the mechanism by which SNX14 affects breast cancer MCF7 cells. RESULTS We found that SNX14 regulated the onset and progression of breast cancer by promoting the proliferation and inhibiting the autophagy of MCF7 breast cancer cells. In vivo experiments further confirmed that SNX14 knockdown inhibited the tumorigenicity and inhibited the growth of tumor cells in tumor tissues of nude mice. In addition, western blotting analysis revealed that SNX14 modulate the autophagy of MCF7 breast cancer cells via the phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin kinase signaling pathway. CONCLUSION Our findings indicate that SNX14 is an essential tumor-promoting factor in the development of breast cancer.
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Affiliation(s)
- Sha Lv
- Department of Pharmacy, Zhejiang Hospital, Hangzhou, 310013, China
| | - Hongyan Jiang
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Lingyan Yu
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Yafei Zhang
- Department of Nuclear Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Liangliang Sun
- Department of Pharmacy, Zhejiang Hospital, Hangzhou, 310013, China
| | - Junjun Xu
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
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3
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Garcia‐Agudo LF, Shi Z, Smith IF, Kramár EA, Tran K, Kawauchi S, Wang S, Collins S, Walker A, Shi K, Neumann J, Liang HY, Da Cunha C, Milinkeviciute G, Morabito S, Miyoshi E, Rezaie N, Gomez‐Arboledas A, Arvilla AM, Ghaemi DI, Tenner AJ, LaFerla FM, Wood MA, Mortazavi A, Swarup V, MacGregor GR, Green KN. BIN1 K358R suppresses glial response to plaques in mouse model of Alzheimer's disease. Alzheimers Dement 2024; 20:2922-2942. [PMID: 38460121 PMCID: PMC11032570 DOI: 10.1002/alz.13767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 03/11/2024]
Abstract
INTRODUCTION The BIN1 coding variant rs138047593 (K358R) is linked to Late-Onset Alzheimer's Disease (LOAD) via targeted exome sequencing. METHODS To elucidate the functional consequences of this rare coding variant on brain amyloidosis and neuroinflammation, we generated BIN1K358R knock-in mice using CRISPR/Cas9 technology. These mice were subsequently bred with 5xFAD transgenic mice, which serve as a model for Alzheimer's pathology. RESULTS The presence of the BIN1K358R variant leads to increased cerebral amyloid deposition, with a dampened response of astrocytes and oligodendrocytes, but not microglia, at both the cellular and transcriptional levels. This correlates with decreased neurofilament light chain in both plasma and brain tissue. Synaptic densities are significantly increased in both wild-type and 5xFAD backgrounds homozygous for the BIN1K358R variant. DISCUSSION The BIN1 K358R variant modulates amyloid pathology in 5xFAD mice, attenuates the astrocytic and oligodendrocytic responses to amyloid plaques, decreases damage markers, and elevates synaptic densities. HIGHLIGHTS BIN1 rs138047593 (K358R) coding variant is associated with increased risk of LOAD. BIN1 K358R variant increases amyloid plaque load in 12-month-old 5xFAD mice. BIN1 K358R variant dampens astrocytic and oligodendrocytic response to plaques. BIN1 K358R variant decreases neuronal damage in 5xFAD mice. BIN1 K358R upregulates synaptic densities and modulates synaptic transmission.
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Affiliation(s)
| | - Zechuan Shi
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Ian F. Smith
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Enikö A. Kramár
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Katelynn Tran
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Shimako Kawauchi
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
| | - Shuling Wang
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
| | - Sherilyn Collins
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
| | - Amber Walker
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
| | - Kai‐Xuan Shi
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
| | - Jonathan Neumann
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
| | - Heidi Yahan Liang
- Department of Developmental and Cell BiologyUniversity of CaliforniaIrvineCaliforniaUSA
- Center for Complex Biological Systems, University of CaliforniaIrvineCaliforniaUSA
| | - Celia Da Cunha
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Giedre Milinkeviciute
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Samuel Morabito
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Emily Miyoshi
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Narges Rezaie
- Department of Developmental and Cell BiologyUniversity of CaliforniaIrvineCaliforniaUSA
- Center for Complex Biological Systems, University of CaliforniaIrvineCaliforniaUSA
| | - Angela Gomez‐Arboledas
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Adrian Mendoza Arvilla
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Daryan Iman Ghaemi
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Andrea J. Tenner
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
- Department of Molecular Biology & BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
- Department of Pathology and Laboratory MedicineUniversity of CaliforniaIrvineCaliforniaUSA
| | - Frank M. LaFerla
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Marcelo A. Wood
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
| | - Ali Mortazavi
- Department of Developmental and Cell BiologyUniversity of CaliforniaIrvineCaliforniaUSA
- Center for Complex Biological Systems, University of CaliforniaIrvineCaliforniaUSA
| | - Vivek Swarup
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
- Center for Complex Biological Systems, University of CaliforniaIrvineCaliforniaUSA
| | - Grant R. MacGregor
- Transgenic Mouse Facility, ULAR, Office of Research, University of CaliforniaIrvineCaliforniaUSA
- Department of Developmental and Cell BiologyUniversity of CaliforniaIrvineCaliforniaUSA
| | - Kim N. Green
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
- Institute for Memory Impairments and Neurological Disorders, University of CaliforniaIrvineCaliforniaUSA
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4
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Kaur I, Behl T, Sundararajan G, Panneerselvam P, Vijayakumar AR, Senthilkumar GP, Venkatachalam T, Jaglan D, Yadav S, Anwer K, Fuloria NK, Sehgal A, Gulati M, Chigurupati S. BIN1 in the Pursuit of Ousting the Alzheimer's Reign: Impact on Amyloid and Tau Neuropathology. Neurotox Res 2023; 41:698-707. [PMID: 37847429 DOI: 10.1007/s12640-023-00670-3] [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: 12/13/2022] [Revised: 09/12/2023] [Accepted: 09/19/2023] [Indexed: 10/18/2023]
Abstract
Alzheimer's disease contributes to 60-70% of all dementia cases in the general population. Belonging to the BIN1/amphiphysin/RVS167 (BAR) superfamily, the bridging integrator (BIN1) has been identified to impact two major pathological hallmarks in Alzheimer's disease (AD), i.e., amyloid beta (Aβ) and tau accumulation. Aβ accumulation is found to increase by BIN1 knockdown in cortical neurons in late-onset AD, due to BACE1 accumulation at enlarged early endosomes. Two BIN1 mutants, KR and PL, were identified to exhibit Aβ accumulation. Furthermore, BIN1 deficiency by BIN1-related polymorphisms impairs the interaction with tau, thus elevating tau phosphorylation, altering synapse structure and tau function. Even though the precise role of BIN1 in the neuronal tissue needs further investigation, the authors aim to throw light on the potential of BIN1 and unfold its implications on tau and Aβ pathology, to aid AD researchers across the globe to examine BIN1, as an appropriate target gene for disease management.
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Affiliation(s)
- Ishnoor Kaur
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Tapan Behl
- School of Health Sciences and Technology, University of Petroleum and Energy Studies, Bidholi, Dehradun, India.
| | - G Sundararajan
- Department of Pharmaceutics, Faculty of Pharmacy, Sree Balaji Medical College and Hospital, Chromepet, Chennai, Tamil Nadu, India
| | - P Panneerselvam
- Faculty of Pharmacy, Sree Balaji Medical College and Hospital Campus, Bharath Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - A R Vijayakumar
- Faculty of Pharmacy, Sree Balaji Medical College and Hospital Campus, Bharath Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - G P Senthilkumar
- Faculty of Pharmacy, Sree Balaji Medical College and Hospital Campus, Bharath Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - T Venkatachalam
- Department of Pharmaceutical Chemistry, JKKMMRFs-Amnai JKK Sampoorani Ammal College of Pharmacy, Komarapalayam, Tamil Nadu, India
| | - Dharmender Jaglan
- Faculty of Pharmaceutical Sciences, DAV University, Jalandhar, Punjab, India
| | - Shivam Yadav
- School of Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Chhatrapti Shahu Ji Maharaj University, Uttar Pradesh, Kanpur, India
| | - Khalid Anwer
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj, Saudi Arabia
| | - Neeraj Kumar Fuloria
- Faculty of Pharmacy, AIMST University, Bedong, Kedah, Malaysia
- Center for Transdisciplinary Research, Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospital, Saveetha University, Chennai, Tamil Nadu, India
| | - Aayush Sehgal
- GHG Khalsa College of Pharmacy, Gurusar Sadhar, Punjab, India
| | - Monica Gulati
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, 1444411, India
- Faculty of Health, ARCCIM, University of Technology Sydney, Ultimo, NSW, 20227, Australia
| | - Sridevi Chigurupati
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Qassim University, Buraydah, 52571, Kingdom of Saudi Arabia.
- Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Saveetha Nagar, Thandalam, Chennai, Tamilnadu, 602105, India.
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5
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Zhou C, Wu Z, Du W, Que H, Wang Y, Ouyang Q, Jian F, Yuan W, Zhao Y, Tian R, Li Y, Chen Y, Gao S, Wong CCL, Rong Y. Recycling of autophagosomal components from autolysosomes by the recycler complex. Nat Cell Biol 2022; 24:497-512. [PMID: 35332264 DOI: 10.1038/s41556-022-00861-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 02/04/2022] [Indexed: 11/09/2022]
Abstract
Autolysosomes contain components from autophagosomes and lysosomes. The contents inside the autolysosomal lumen are degraded during autophagy, while the fate of autophagosomal components on the autolysosomal membrane remains unknown. Here we report that the autophagosomal membrane components are not degraded, but recycled from autolysosomes through a process coined in this study as autophagosomal components recycling (ACR). We further identified a multiprotein complex composed of SNX4, SNX5 and SNX17 essential for ACR, which we termed 'recycler'. In this, SNX4 and SNX5 form a heterodimer that recognizes autophagosomal membrane proteins and is required for generating membrane curvature on autolysosomes, both via their BAR domains, to mediate the cargo sorting process. SNX17 interacts with both the dynein-dynactin complex and the SNX4-SNX5 dimer to facilitate the retrieval of autophagosomal membrane components. Our discovery of ACR and identification of the recycler reveal an important retrieval and recycling pathway on autolysosomes.
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Affiliation(s)
- Chuchu Zhou
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhe Wu
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wanqing Du
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huilin Que
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yufen Wang
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qinqin Ouyang
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Fenglei Jian
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weigang Yuan
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Zhao
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Tian
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Li
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yang Chen
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Peking University, Beijing, China.,School of Basic Medical Sciences, Peking University Health Science Center, Peking University, Beijing, China
| | - Shuaixin Gao
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Peking University, Beijing, China.,School of Basic Medical Sciences, Peking University Health Science Center, Peking University, Beijing, China
| | - Catherine C L Wong
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Peking University, Beijing, China.,School of Basic Medical Sciences, Peking University Health Science Center, Peking University, Beijing, China
| | - Yueguang Rong
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. .,Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, China.
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6
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Schürmanns L, Hamann A, Osiewacz HD. Lifespan Increase of Podospora anserina by Oleic Acid Is Linked to Alterations in Energy Metabolism, Membrane Trafficking and Autophagy. Cells 2022; 11:cells11030519. [PMID: 35159328 PMCID: PMC8834509 DOI: 10.3390/cells11030519] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 12/02/2022] Open
Abstract
The maintenance of cellular homeostasis over time is essential to avoid the degeneration of biological systems leading to aging and disease. Several interconnected pathways are active in this kind of quality control. One of them is autophagy, the vacuolar degradation of cellular components. The absence of the sorting nexin PaATG24 (SNX4 in other organisms) has been demonstrated to result in impairments in different types of autophagy and lead to a shortened lifespan. In addition, the growth rate and the size of vacuoles are strongly reduced. Here, we report how an oleic acid diet leads to longevity of the wild type and a PaAtg24 deletion mutant (ΔPaAtg24). The lifespan extension is linked to altered membrane trafficking, which abrogates the observed autophagy defects in ΔPaAtg24 by restoring vacuole size and the proper localization of SNARE protein PaSNC1. In addition, an oleic acid diet leads to an altered use of the mitochondrial respiratory chain: complex I and II are bypassed, leading to reduced reactive oxygen species (ROS) production. Overall, our study uncovers multiple effects of an oleic acid diet, which extends the lifespan of P. anserina and provides perspectives to explain the positive nutritional effects on human aging.
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7
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Gómez-Oca R, Cowling BS, Laporte J. Common Pathogenic Mechanisms in Centronuclear and Myotubular Myopathies and Latest Treatment Advances. Int J Mol Sci 2021; 22:11377. [PMID: 34768808 PMCID: PMC8583656 DOI: 10.3390/ijms222111377] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 10/18/2021] [Indexed: 01/18/2023] Open
Abstract
Centronuclear myopathies (CNM) are rare congenital disorders characterized by muscle weakness and structural defects including fiber hypotrophy and organelle mispositioning. The main CNM forms are caused by mutations in: the MTM1 gene encoding the phosphoinositide phosphatase myotubularin (myotubular myopathy), the DNM2 gene encoding the mechanoenzyme dynamin 2, the BIN1 gene encoding the membrane curvature sensing amphiphysin 2, and the RYR1 gene encoding the skeletal muscle calcium release channel/ryanodine receptor. MTM1, BIN1, and DNM2 proteins are involved in membrane remodeling and trafficking, while RyR1 directly regulates excitation-contraction coupling (ECC). Several CNM animal models have been generated or identified, which confirm shared pathological anomalies in T-tubule remodeling, ECC, organelle mispositioning, protein homeostasis, neuromuscular junction, and muscle regeneration. Dynamin 2 plays a crucial role in CNM physiopathology and has been validated as a common therapeutic target for three CNM forms. Indeed, the promising results in preclinical models set up the basis for ongoing clinical trials. Another two clinical trials to treat myotubular myopathy by MTM1 gene therapy or tamoxifen repurposing are also ongoing. Here, we review the contribution of the different CNM models to understanding physiopathology and therapy development with a focus on the commonly dysregulated pathways and current therapeutic targets.
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Affiliation(s)
- Raquel Gómez-Oca
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France;
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, 67400 Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, 67400 Illkirch, France
- Strasbourg University, 67081 Strasbourg, France
- Dynacure, 67400 Illkirch, France;
| | | | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France;
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, 67400 Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, 67400 Illkirch, France
- Strasbourg University, 67081 Strasbourg, France
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8
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Perdigão C, Barata MA, Burrinha T, Guimas Almeida C. Alzheimer's disease BIN1 coding variants increase intracellular Aβ levels by interfering with BACE1 recycling. J Biol Chem 2021; 297:101056. [PMID: 34375641 PMCID: PMC8413894 DOI: 10.1016/j.jbc.2021.101056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/29/2021] [Accepted: 08/05/2021] [Indexed: 01/20/2023] Open
Abstract
Genetic studies have identified BIN1 as the second most important risk locus associated with late-onset Alzheimer's disease (LOAD). However, it is unclear how mutation of this locus mechanistically promotes Alzheimer's disease (AD) pathology. Here we show the consequences of two coding variants in BIN1 (rs754834233 and rs138047593), both in terms of intracellular beta-amyloid (iAbeta) accumulation and early endosome enlargement, two interrelated early cytopathological AD phenotypes, supporting their association with LOAD risk. We previously found that Bin1 deficiency potentiates iAbeta production by enabling BACE1 cleavage of the amyloid precursor protein in enlarged early endosomes due to decreased BACE1 recycling. Here, we discovered that the expression of the two LOAD mutant forms of Bin1 does not rescue the iAbeta accumulation and early endosome enlargement induced by Bin1 knockdown and recovered by wild-type Bin1. Moreover, the overexpression of Bin1 mutants, but not wild-type Bin1, increased the iAbeta42 fragment by reducing the recycling of BACE1, which accumulated in early endosomes, recapitulating the phenotype of Bin1 knockdown. We showed that the mutations in Bin1 reduced its interaction with BACE1. The endocytic recycling of transferrin was similarly affected, indicating that Bin1 is a general regulator of endocytic recycling. These data demonstrate that the LOAD-coding variants in Bin1 lead to a loss of function in endocytic recycling, which may be an early causal mechanism of LOAD.
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Affiliation(s)
- Catarina Perdigão
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Mariana A Barata
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Tatiana Burrinha
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Cláudia Guimas Almeida
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Lisboa, Portugal.
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9
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Vieira N, Rito T, Correia-Neves M, Sousa N. Sorting Out Sorting Nexins Functions in the Nervous System in Health and Disease. Mol Neurobiol 2021; 58:4070-4106. [PMID: 33931804 PMCID: PMC8280035 DOI: 10.1007/s12035-021-02388-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022]
Abstract
Endocytosis is a fundamental process that controls protein/lipid composition of the plasma membrane, thereby shaping cellular metabolism, sensing, adhesion, signaling, and nutrient uptake. Endocytosis is essential for the cell to adapt to its surrounding environment, and a tight regulation of the endocytic mechanisms is required to maintain cell function and survival. This is particularly significant in the central nervous system (CNS), where composition of neuronal cell surface is crucial for synaptic functioning. In fact, distinct pathologies of the CNS are tightly linked to abnormal endolysosomal function, and several genome wide association analysis (GWAS) and biochemical studies have identified intracellular trafficking regulators as genetic risk factors for such pathologies. The sorting nexins (SNXs) are a family of proteins involved in protein trafficking regulation and signaling. SNXs dysregulation occurs in patients with Alzheimer’s disease (AD), Down’s syndrome (DS), schizophrenia, ataxia and epilepsy, among others, establishing clear roles for this protein family in pathology. Interestingly, restoration of SNXs levels has been shown to trigger synaptic plasticity recovery in a DS mouse model. This review encompasses an historical and evolutionary overview of SNXs protein family, focusing on its organization, phyla conservation, and evolution throughout the development of the nervous system during speciation. We will also survey SNXs molecular interactions and highlight how defects on SNXs underlie distinct pathologies of the CNS. Ultimately, we discuss possible strategies of intervention, surveying how our knowledge about the fundamental processes regulated by SNXs can be applied to the identification of novel therapeutic avenues for SNXs-related disorders.
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Affiliation(s)
- Neide Vieira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal. .,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Teresa Rito
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Margarida Correia-Neves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
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10
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Silva-Lima AW, Froes AM, Garcia GD, Tonon LAC, Swings J, Cosenza CAN, Medina M, Penn K, Thompson JR, Thompson CC, Thompson FL. Mussismilia braziliensis White Plague Disease Is Characterized by an Affected Coral Immune System and Dysbiosis. MICROBIAL ECOLOGY 2021; 81:795-806. [PMID: 33000311 DOI: 10.1007/s00248-020-01588-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
Infectious diseases are one of the major drivers of coral reef decline worldwide. White plague-like disease (WPL) is a widespread disease with a complex etiology that infects several coral species, including the Brazilian endemic species Mussismilia braziliensis. Gene expression profiles of healthy and WPL-affected M. braziliensis were analyzed in winter and summer seasons. The de novo assembly of the M. braziliensis transcriptome from healthy and white plague samples produced a reference transcriptome containing 119,088 transcripts. WPL-diseased samples were characterized by repression of immune system and cellular defense processes. Autophagy and cellular adhesion transcripts were also repressed in WPL samples, suggesting exhaustion of the coral host defenses. Seasonal variation leads to plasticity in transcription with upregulation of intracellular signal transduction, apoptosis regulation, and oocyte development in the summer. Analysis of the active bacterial rRNA indicated that Pantoea bacteria were more abundant in WPL corals, while Tistlia, Fulvivirga, and Gammaproteobacteria Ga0077536 were more abundant in healthy samples. Cyanobacteria proliferation was also observed in WPL, mostly in the winter. These results indicate a scenario of dysbiosis in WPL-affected M. braziliensis, with the loss of potentially symbiotic bacteria and proliferation of opportunistic microbes after the start of the infection process.
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Affiliation(s)
- A W Silva-Lima
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil
| | - A M Froes
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil
| | - G D Garcia
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil
- Sage/Coppe, Centro de Gestão Tecnológica-CT2, Rua Moniz de Aragão, no. 360-Bloco 2, Ilha do Fundão-Cidade Universitária, Rio de Janeiro, 21941-972, Brazil
| | - L A C Tonon
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil
- Sage/Coppe, Centro de Gestão Tecnológica-CT2, Rua Moniz de Aragão, no. 360-Bloco 2, Ilha do Fundão-Cidade Universitária, Rio de Janeiro, 21941-972, Brazil
| | - J Swings
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil
- Sage/Coppe, Centro de Gestão Tecnológica-CT2, Rua Moniz de Aragão, no. 360-Bloco 2, Ilha do Fundão-Cidade Universitária, Rio de Janeiro, 21941-972, Brazil
| | - C A N Cosenza
- Sage/Coppe, Centro de Gestão Tecnológica-CT2, Rua Moniz de Aragão, no. 360-Bloco 2, Ilha do Fundão-Cidade Universitária, Rio de Janeiro, 21941-972, Brazil
| | - M Medina
- Pennsylvania State University, 324 Mueller Lab, University Park, PA, 16802, USA
| | - K Penn
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - J R Thompson
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - C C Thompson
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil
- Sage/Coppe, Centro de Gestão Tecnológica-CT2, Rua Moniz de Aragão, no. 360-Bloco 2, Ilha do Fundão-Cidade Universitária, Rio de Janeiro, 21941-972, Brazil
| | - F L Thompson
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Fo. S/N-CCS-IB-Lab de Microbiologia-BLOCO A (Anexo) A3-sl 102, Cidade Universitária, Rio de Janeiro, RJ, 21941-599, Brazil.
- Sage/Coppe, Centro de Gestão Tecnológica-CT2, Rua Moniz de Aragão, no. 360-Bloco 2, Ilha do Fundão-Cidade Universitária, Rio de Janeiro, 21941-972, Brazil.
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11
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Osiewacz HD, Schürmanns L. A Network of Pathways Controlling Cellular Homeostasis Affects the Onset of Senescence in Podospora anserina. J Fungi (Basel) 2021; 7:jof7040263. [PMID: 33807190 PMCID: PMC8065454 DOI: 10.3390/jof7040263] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/28/2021] [Indexed: 01/07/2023] Open
Abstract
Research on Podospora anserina unraveled a network of molecular pathways affecting biological aging. In particular, a number of pathways active in the control of mitochondria were identified on different levels. A long-known key process active during aging of P. anserina is the age-related reorganization of the mitochondrial DNA (mtDNA). Mechanisms involved in the stabilization of the mtDNA lead to lifespan extension. Another critical issue is to balance mitochondrial levels of reactive oxygen species (ROS). This is important because ROS are essential signaling molecules, but at increased levels cause molecular damage. At a higher level of the network, mechanisms are active in the repair of damaged compounds. However, if damage passes critical limits, the corresponding pathways are overwhelmed and impaired molecules as well as those present in excess are degraded by specific enzymes or via different forms of autophagy. Subsequently, degraded units need to be replaced by novel functional ones. The corresponding processes are dependent on the availability of intact genetic information. Although a number of different pathways involved in the control of cellular homeostasis were uncovered in the past, certainly many more exist. In addition, the signaling pathways involved in the control and coordination of the underlying pathways are only initially understood. In some cases, like the induction of autophagy, ROS are active. Additionally, sensing and signaling the energetic status of the organism plays a key role. The precise mechanisms involved are elusive and remain to be elucidated.
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12
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Ravussin A, Brech A, Tooze SA, Stenmark H. The phosphatidylinositol 3-phosphate-binding protein SNX4 controls ATG9A recycling and autophagy. J Cell Sci 2021; 134:jcs250670. [PMID: 33468622 PMCID: PMC7888711 DOI: 10.1242/jcs.250670] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
Late endosomes and lysosomes (endolysosomes) receive proteins and cargo from the secretory, endocytic and autophagic pathways. Although these pathways and the degradative processes of endolysosomes are well characterized, less is understood about protein traffic from these organelles. In this study, we demonstrate the direct involvement of the phosphatidylinositol 3-phosphate (PI3P)-binding SNX4 protein in membrane protein recycling from endolysosomes, and show that SNX4 is required for proper autophagic flux. We show that SNX4 mediates recycling of the lipid scramblase ATG9A, which drives expansion of nascent autophagosome membranes, from endolysosomes to early endosomes, from where ATG9A is recycled to the trans-Golgi network in a retromer-dependent manner. Upon siRNA-mediated depletion of SNX4 or the retromer component VPS35, we observed accumulation of ATG9A on endolysosomes and early endosomes, respectively. Moreover, starvation-induced autophagosome biogenesis and autophagic flux were inhibited when SNX4 was downregulated. We propose that proper ATG9A recycling by SNX4 sustains autophagy by preventing exhaustion of the available ATG9A pool.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Anthony Ravussin
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Andreas Brech
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Sharon A Tooze
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway
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13
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Abstract
Flotillins 1 and 2 are two ubiquitous, highly conserved homologous proteins that assemble to form heterotetramers at the cytoplasmic face of the plasma membrane in cholesterol- and sphingolipid-enriched domains. Flotillin heterotetramers can assemble into large oligomers to form molecular scaffolds that regulate the clustering of at the plasma membrane and activity of several receptors. Moreover, flotillins are upregulated in many invasive carcinomas and also in sarcoma, and this is associated with poor prognosis and metastasis formation. When upregulated, flotillins promote plasma membrane invagination and induce an endocytic pathway that allows the targeting of cargo proteins in the late endosomal compartment in which flotillins accumulate. These late endosomes are not degradative, and participate in the recycling and secretion of protein cargos. The cargos of this Upregulated Flotillin–Induced Trafficking (UFIT) pathway include molecules involved in signaling, adhesion, and extracellular matrix remodeling, thus favoring the acquisition of an invasive cellular behavior leading to metastasis formation. Thus, flotillin presence from the plasma membrane to the late endosomal compartment influences the activity, and even modifies the trafficking and fate of key protein cargos, favoring the development of diseases, for instance tumors. This review summarizes the current knowledge on flotillins and their role in cancer development focusing on their function in cellular membrane remodeling and vesicular trafficking regulation.
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14
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Cheung TT, Geda AC, Ware AW, Rasulov SR, Tenci P, Hamilton KL, McDonald FJ. Retromer is involved in epithelial Na+ channel trafficking. Am J Physiol Renal Physiol 2020; 319:F895-F907. [DOI: 10.1152/ajprenal.00198.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The epithelial Na+ channel (ENaC) located at the apical membrane in many epithelia is the rate-limiting step for Na+ reabsorption. Tight regulation of the plasma membrane population of ENaC is required, as hypertension or hypotension may result if too many or too few ENaCs are present. Endocytosed ENaC travels to the early endosome and is then either trafficked to the lysosome for degradation or recycled back to the plasma membrane. Recently, the retromer recycling complex, located at the early endosome, has been implicated in plasma membrane protein recycling pathways. We hypothesized that the retromer is required for recycling of ENaC. Stabilization of retromer function with the retromer stabilizing chaperone R55 increased ENaC current, whereas knockdown or overexpression of individual retromer and associated proteins altered ENaC current and cell surface population of ENaC. KIBRA was identified as an ENaC-binding protein allowing ENaC to link to sorting nexin 4 to alter ENaC trafficking. Knockdown of the retromer-associated cargo-binding sorting nexin 27 protein did not alter ENaC current, whereas CCDC22, a CCC-complex protein, coimmunoprecipitated with ENaC, and CCDC22 knockdown decreased ENaC current and population at the cell surface. Together, our results confirm that retromer and the CCC complex play a role in recycling of ENaC to the plasma membrane.
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Affiliation(s)
- Tanya T. Cheung
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Anna C. Geda
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Adam W. Ware
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sahib R. Rasulov
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Polly Tenci
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Kirk L. Hamilton
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Fiona J. McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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15
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The endosomal protein sorting nexin 4 is a synaptic protein. Sci Rep 2020; 10:18239. [PMID: 33106523 PMCID: PMC7588491 DOI: 10.1038/s41598-020-74694-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/29/2020] [Indexed: 12/14/2022] Open
Abstract
Sorting nexin 4 (SNX4) is an evolutionary conserved protein that mediates recycling from endosomes back to the plasma membrane in yeast and mammalian cells. SNX4 is expressed in the brain. Altered protein levels are associated with Alzheimer's disease, but the neuronal localization and function of SNX4 have not been addressed. Using a new antibody, endogenous neuronal SNX4 co-localized with both early and recycling endosome markers, similar to the reported localization of SNX4 in non-neuronal cells. Neuronal SNX4 accumulated specifically in synaptic areas, with a predominant localization to presynaptic terminals. Acute depletion of neuronal SNX4 using independent short hairpin RNAs did not affect the levels of the transferrin receptor, a canonical SNX4 cargo. Quantitative mass spectrometry revealed that upon SNX4 knockdown the class of proteins involved in neurotransmission was the most dysregulated. This included integral membrane proteins at both the presynaptic and postsynaptic side of the synapse that participate in diverse synaptic processes such as synapse assembly, neurotransmission and the synaptic vesicle cycle. These data suggest that SNX4 is implicated in a variety of synaptic processes.
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16
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The Mechanistic Role of Bridging Integrator 1 (BIN1) in Alzheimer's Disease. Cell Mol Neurobiol 2020; 41:1431-1440. [PMID: 32719966 DOI: 10.1007/s10571-020-00926-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/17/2020] [Indexed: 01/18/2023]
Abstract
Alzheimer's disease (AD) is the leading cause of dementia. The majority of AD cases are late-onset, multifactorial cases. Genome-wide association studies have identified more than 30 loci associated with sporadic AD (SAD), one of which is Bridging integrator 1 (BIN1). For the past few years, there has been a consensus that BIN1 is second only to APOE as the strongest genetic risk factor for SAD. Therefore, many researchers have put great effort into studying the mechanism by which BIN1 might be involved in the pathogenetic process of AD. To date, plenty of evidence has shown that BIN1 may participate in several pathways in AD, including tau and amyloid pathology. In addition, BIN1 has been indicated to take part in other relevant pathways such as inflammation, apoptosis, and calcium homeostasis. In this review, we systemically summarize the research progress on how BIN1 participates in the development of AD, with the expectation of providing promising perspectives for future research.
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17
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Antón Z, Betin VMS, Simonetti B, Traer CJ, Attar N, Cullen PJ, Lane JD. A heterodimeric SNX4--SNX7 SNX-BAR autophagy complex coordinates ATG9A trafficking for efficient autophagosome assembly. J Cell Sci 2020; 133:jcs246306. [PMID: 32513819 PMCID: PMC7375690 DOI: 10.1242/jcs.246306] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/02/2020] [Indexed: 11/24/2022] Open
Abstract
The sorting nexins (SNXs) are a family of peripheral membrane proteins that direct protein trafficking decisions within the endocytic network. Emerging evidence in yeast and mammalian cells implicates a subgroup of SNXs in selective and non-selective forms of autophagy. Using siRNA and CRISPR-Cas9, we demonstrate that the SNX-BAR protein SNX4 is needed for efficient LC3 (also known as MAP1LC3) lipidation and autophagosome assembly in mammalian cells. SNX-BARs exist as homo- and hetero-dimers, and we show that SNX4 forms functional heterodimers with either SNX7 or SNX30 that associate with tubulovesicular endocytic membranes. Detailed image-based analysis during the early stages of autophagosome assembly reveals that SNX4-SNX7 is an autophagy-specific SNX-BAR heterodimer, required for efficient recruitment and/or retention of core autophagy regulators at the nascent isolation membrane. SNX4 partially colocalises with juxtanuclear ATG9A-positive membranes, with our data linking the autophagy defect upon SNX4 disruption to the mis-trafficking and/or retention of ATG9A in the Golgi region. Taken together, our findings show that the SNX4-SNX7 heterodimer coordinates ATG9A trafficking within the endocytic network to establish productive autophagosome assembly sites, thus extending knowledge of SNXs as positive regulators of autophagy.
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Affiliation(s)
- Zuriñe Antón
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Virginie M S Betin
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Boris Simonetti
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Colin J Traer
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Naomi Attar
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Peter J Cullen
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Jon D Lane
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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18
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Henkel V, Schürmanns L, Brunner M, Hamann A, Osiewacz HD. Role of sorting nexin PaATG24 in autophagy, aging and development of Podospora anserina. Mech Ageing Dev 2020; 186:111211. [PMID: 32007577 DOI: 10.1016/j.mad.2020.111211] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/12/2019] [Accepted: 01/27/2020] [Indexed: 12/18/2022]
Abstract
Sorting nexins are a conserved protein family involved in vesicle transport, membrane trafficking and protein sorting. The sorting nexin ATG24/SNX4 has been demonstrated to be involved in different autophagy pathways and in endosomal trafficking. However, its impact on cellular quality control and on aging and development is still elusive. Here we report studies analyzing the function of PaATG24 in the aging model Podospora anserina. Ablation of PaATG24 leads to a reduced growth rate, infertility, and to a pronounced lifespan reduction. These characteristics are accompanied by alterations of the morphology and size distribution of vacuoles and severe impairments in non-selective and selective autophagy of peroxisomes (pexophagy) and mitochondria (mitophagy). While general autophagy and pexophagy are almost completely blocked, a PaATG24-independent form of mitophagy is induced during aging. In the ΔPaAtg24 mutant a strong accumulation of peroxisomes occurs while mitochondrial abundance is only slightly increased. These mitochondria are partially affected in function. Most strikingly, although some PaATG24-independent mitophagy exists, it appears that this is not sufficient to remove dysfunctional mitochondria efficiently enough to prevent premature aging. Overall our data emphasize the key role of mitochondria in aging and of mitophagy in quality control to keep a population of "healthy" mitochondria during aging.
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Affiliation(s)
- Vanessa Henkel
- Goethe-University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Lea Schürmanns
- Goethe-University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Miriam Brunner
- Goethe-University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Andrea Hamann
- Goethe-University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Heinz D Osiewacz
- Goethe-University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany.
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19
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Van Acker ZP, Bretou M, Annaert W. Endo-lysosomal dysregulations and late-onset Alzheimer's disease: impact of genetic risk factors. Mol Neurodegener 2019; 14:20. [PMID: 31159836 PMCID: PMC6547588 DOI: 10.1186/s13024-019-0323-7] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 05/10/2019] [Indexed: 12/15/2022] Open
Abstract
Increasing evidence supports that cellular dysregulations in the degradative routes contribute to the initiation and progression of neurodegenerative diseases, including Alzheimer's disease. Autophagy and endolysosomal homeostasis need to be maintained throughout life as they are major cellular mechanisms involved in both the production of toxic amyloid peptides and the clearance of misfolded or aggregated proteins. As such, alterations in endolysosomal and autophagic flux, as a measure of degradation activity in these routes or compartments, may directly impact as well on disease-related mechanisms such as amyloid-β clearance through the blood-brain-barrier and the interneuronal spreading of amyloid-β and/or Tau seeds, affecting synaptic function, plasticity and metabolism. The emerging of several genetic risk factors for late-onset Alzheimer's disease that are functionally related to endocytic transport regulation, including cholesterol metabolism and clearance, supports the notion that in particular the autophagy/lysosomal flux might become more vulnerable during ageing thereby contributing to disease onset. In this review we discuss our current knowledge of the risk genes APOE4, BIN1, CD2AP, PICALM, PLD3 and TREM2 and their impact on endolysosomal (dys)regulations in the light of late-onset Alzheimer's disease pathology.
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Affiliation(s)
- Zoë P. Van Acker
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, Gasthuisberg, O&N4, Rm. 7.159, Herestraat 49, B-3000 Leuven, Belgium
| | - Marine Bretou
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, Gasthuisberg, O&N4, Rm. 7.159, Herestraat 49, B-3000 Leuven, Belgium
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, Gasthuisberg, O&N4, Rm. 7.159, Herestraat 49, B-3000 Leuven, Belgium
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20
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Chen X, Miller NM, Afghah Z, Geiger JD. Development of AD-Like Pathology in Skeletal Muscle. JOURNAL OF PARKINSON'S DISEASE AND ALZHEIMER'S DISEASE 2019; 6:10.13188/2376-922x.1000028. [PMID: 32190732 PMCID: PMC7079679 DOI: 10.13188/2376-922x.1000028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Effective therapeutic strategy against Alzheimer's disease (AD) requires early detection of AD; however, clinical diagnosis of Alzheimer's disease (AD) is not precise and a definitive diagnosis of AD is only possible via postmortem examination for AD pathological hallmarks including senile plaques composed of Aβ and neuro fibrillary tangles composed of phosphorylated tau. Although a variety of biomarker has been developed and used in clinical setting, none of them robustly predicts subsequent clinical course of AD. Thus, it is essential to identify new biomarkers that may facilitate the diagnosis of early stages of AD, prediction of subsequent clinical course, and development of new therapeutic strategies. Given that pathological hallmarks of AD including Aβaccumulation and the presence of phosphorylated tau are also detected in peripheral tissues, AD is considered a systemic disease. Without the protection of blood-brain barrier, systemic factors can affect peripheral tissues much earlier than neurons in brain. Here, we will discuss the development of AD-like pathology in skeletal muscle and the potential use of skeletal muscle biopsy (examination for Aβaccumulation and phosphorylated tau) as a biomarker for AD.
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Affiliation(s)
- X Chen
- Department of Biomedical Sciences, University of North Dakota, USA
| | - NM Miller
- Department of Biomedical Sciences, University of North Dakota, USA
| | - Z Afghah
- Department of Biomedical Sciences, University of North Dakota, USA
| | - JD Geiger
- Department of Biomedical Sciences, University of North Dakota, USA
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21
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BAR domain proteins-a linkage between cellular membranes, signaling pathways, and the actin cytoskeleton. Biophys Rev 2018; 10:1587-1604. [PMID: 30456600 DOI: 10.1007/s12551-018-0467-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/17/2018] [Indexed: 12/23/2022] Open
Abstract
Actin filament assembly typically occurs in association with cellular membranes. A large number of proteins sit at the interface between actin networks and membranes, playing diverse roles such as initiation of actin polymerization, modulation of membrane curvature, and signaling. Bin/Amphiphysin/Rvs (BAR) domain proteins have been implicated in all of these functions. The BAR domain family of proteins comprises a diverse group of multi-functional effectors, characterized by their modular architecture. In addition to the membrane-curvature sensing/inducing BAR domain module, which also mediates antiparallel dimerization, most contain auxiliary domains implicated in protein-protein and/or protein-membrane interactions, including SH3, PX, PH, RhoGEF, and RhoGAP domains. The shape of the BAR domain itself varies, resulting in three major subfamilies: the classical crescent-shaped BAR, the more extended and less curved F-BAR, and the inverse curvature I-BAR subfamilies. Most members of this family have been implicated in cellular functions that require dynamic remodeling of the actin cytoskeleton, such as endocytosis, organelle trafficking, cell motility, and T-tubule biogenesis in muscle cells. Here, we review the structure and function of mammalian BAR domain proteins and the many ways in which they are interconnected with the actin cytoskeleton.
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22
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Structure and function of yeast Atg20, a sorting nexin that facilitates autophagy induction. Proc Natl Acad Sci U S A 2017; 114:E10112-E10121. [PMID: 29114050 DOI: 10.1073/pnas.1708367114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Atg20 and Snx4/Atg24 proteins have been identified in a screen for mutants defective in a type of selective macroautophagy/autophagy. Both proteins are connected to the Atg1 kinase complex, which is involved in autophagy initiation, and bind phosphatidylinositol-3-phosphate. Atg20 and Snx4 contain putative BAR domains, suggesting a possible role in membrane deformation, but they have been relatively uncharacterized. Here we demonstrate that, in addition to its function in selective autophagy, Atg20 plays a critical role in the efficient induction of nonselective autophagy. Atg20 is a dynamic posttranslationally modified protein that engages both structurally stable (PX and BAR) and intrinsically disordered domains for its function. In addition to its PX and BAR domains, Atg20 uses a third membrane-binding module, a membrane-inducible amphipathic helix present in a previously undescribed location in Atg20 within the putative BAR domain. Taken together, these findings yield insights into the molecular mechanism of the autophagy machinery.
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Kim NY, Cho MH, Won SH, Kang HJ, Yoon SY, Kim DH. Sorting nexin-4 regulates β-amyloid production by modulating β-site-activating cleavage enzyme-1. ALZHEIMERS RESEARCH & THERAPY 2017; 9:4. [PMID: 28109317 PMCID: PMC5251330 DOI: 10.1186/s13195-016-0232-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/28/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Amyloid precursor protein (APP) is cleaved by β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) to produce β-amyloid (Aβ), a critical pathogenic peptide in Alzheimer's disease (AD). Aβ generation can be affected by the intracellular trafficking of APP or its related secretases, which is thus important to understanding its pathological alterations. Although sorting nexin (SNX) family proteins regulate this trafficking, the relevance and role of sorting nexin-4 (SNX4) regarding AD has not been studied yet. METHODS In this study, human brain tissue and APP/PS1 mouse brain tissue were used to check the disease relevance of SNX4. To investigate the role of SNX4 in AD pathogenesis, several experiments were done, such as coimmunoprecipitation, Western blotting, immunohistochemistry, and gradient fractionation. RESULTS We found that SNX4 protein levels changed in the brains of patients with AD and of AD model mice. Overexpression of SNX4 significantly increased the levels of BACE1 and Aβ. Downregulation of SNX4 had the opposite effect. SNX4 interacts with BACE1 and prevents BACE1 trafficking to the lysosomal degradation system, resulting in an increased half-life of BACE1 and increased production of Aβ. CONCLUSIONS We show that SNX4 regulates BACE1 trafficking. Our findings suggest novel therapeutic implications of modulating SNX4 to regulate BACE1-mediated β-processing of APP and subsequent Aβ generation.
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Affiliation(s)
- Na-Young Kim
- Alzheimer's Disease Experts Lab (ADEL), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.,Department of Brain Science, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, SongPa-Gu, Seoul, 05505, Korea.,Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Korea.,Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Korea
| | - Mi-Hyang Cho
- Alzheimer's Disease Experts Lab (ADEL), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.,Department of Brain Science, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, SongPa-Gu, Seoul, 05505, Korea.,Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Korea.,Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Korea
| | - Se-Hoon Won
- Alzheimer's Disease Experts Lab (ADEL), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.,Department of Brain Science, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, SongPa-Gu, Seoul, 05505, Korea.,Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Korea.,Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Korea
| | - Hoe-Jin Kang
- Alzheimer's Disease Experts Lab (ADEL), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.,Department of Brain Science, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, SongPa-Gu, Seoul, 05505, Korea.,Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Korea.,Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Korea
| | - Seung-Yong Yoon
- Alzheimer's Disease Experts Lab (ADEL), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. .,Department of Brain Science, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, SongPa-Gu, Seoul, 05505, Korea. .,Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Korea. .,Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Korea.
| | - Dong-Hou Kim
- Alzheimer's Disease Experts Lab (ADEL), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. .,Department of Brain Science, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, SongPa-Gu, Seoul, 05505, Korea. .,Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Korea. .,Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Korea.
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Ubelmann F, Burrinha T, Salavessa L, Gomes R, Ferreira C, Moreno N, Guimas Almeida C. Bin1 and CD2AP polarise the endocytic generation of beta-amyloid. EMBO Rep 2016; 18:102-122. [PMID: 27895104 DOI: 10.15252/embr.201642738] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/14/2016] [Accepted: 10/19/2016] [Indexed: 01/31/2023] Open
Abstract
The mechanisms driving pathological beta-amyloid (Aβ) generation in late-onset Alzheimer's disease (AD) are unclear. Two late-onset AD risk factors, Bin1 and CD2AP, are regulators of endocytic trafficking, but it is unclear how their endocytic function regulates Aβ generation in neurons. We identify a novel neuron-specific polarisation of Aβ generation controlled by Bin1 and CD2AP We discover that Bin1 and CD2AP control Aβ generation in axonal and dendritic early endosomes, respectively. Both Bin1 loss of function and CD2AP loss of function raise Aβ generation by increasing APP and BACE1 convergence in early endosomes, however via distinct sorting events. When Bin1 levels are reduced, BACE1 is trapped in tubules of early endosomes and fails to recycle in axons. When CD2AP levels are reduced, APP is trapped at the limiting membrane of early endosomes and fails to be sorted for degradation in dendrites. Hence, Bin1 and CD2AP keep APP and BACE1 apart in early endosomes by distinct mechanisms in axon and dendrites. Individuals carrying variants of either factor would slowly accumulate Aβ in neurons increasing the risk for late-onset AD.
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Affiliation(s)
- Florent Ubelmann
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Tatiana Burrinha
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Laura Salavessa
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Ricardo Gomes
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Cláudio Ferreira
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Nuno Moreno
- Advance Imaging Lab, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Cláudia Guimas Almeida
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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25
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Adams SL, Tilton K, Kozubek JA, Seshadri S, Delalle I. Subcellular Changes in Bridging Integrator 1 Protein Expression in the Cerebral Cortex During the Progression of Alzheimer Disease Pathology. J Neuropathol Exp Neurol 2016; 75:779-790. [PMID: 27346750 DOI: 10.1093/jnen/nlw056] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genome-wide association studies have established BIN1 (Bridging Integrator 1) as the most significant late-onset Alzheimer disease (AD) susceptibility locus after APOE We analyzed BIN1 protein expression using automated immunohistochemistry on the hippocampal CA1 region in 19 patients with either no, mild, or moderate-to-marked AD pathology, who had been assessed by Clinical Dementia Rating and CERAD scores. We also examined the amygdala, prefrontal, temporal, and occipital regions in a subset of these patients. In non-demented controls without AD pathology, BIN1 protein was expressed in white matter, glia, particularly oligodendrocytes, and in the neuropil in which the BIN1 signal decorated axons. With increasing severity of AD, BIN1 in the CA1 region showed: 1) sustained expression in glial cells, 2) decreased areas of neuropil expression, and 3) increased cytoplasmic neuronal expression that did not correlate with neurofibrillary tangle load. In patients with AD, both the prefrontal cortex and CA1 showed a decrease in BIN1-immunoreactive (BIN1-ir) neuropil areas and increases in numbers of BIN1-ir neurons. The numbers of CA1 BIN1-ir pyramidal neurons correlated with hippocampal CERAD neuritic plaque scores; BIN1 neuropil signal was absent in neuritic plaques. Our data provide novel insight into the relationship between BIN1 protein expression and the progression of AD-associated pathology and its diagnostic hallmarks.
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Affiliation(s)
- Stephanie L Adams
- From the Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts (SLA, KT, ID); Broad Institute, Cambridge, Massachusetts; Brigham and Women's Hospital, Boston, Massachusetts (JAK) Department of Neurology, Boston University School of Medicine, Boston, Massachusetts (SS)
| | - Kathy Tilton
- From the Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts (SLA, KT, ID); Broad Institute, Cambridge, Massachusetts; Brigham and Women's Hospital, Boston, Massachusetts (JAK) Department of Neurology, Boston University School of Medicine, Boston, Massachusetts (SS)
| | - James A Kozubek
- From the Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts (SLA, KT, ID); Broad Institute, Cambridge, Massachusetts; Brigham and Women's Hospital, Boston, Massachusetts (JAK) Department of Neurology, Boston University School of Medicine, Boston, Massachusetts (SS)
| | - Sudha Seshadri
- From the Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts (SLA, KT, ID); Broad Institute, Cambridge, Massachusetts; Brigham and Women's Hospital, Boston, Massachusetts (JAK) Department of Neurology, Boston University School of Medicine, Boston, Massachusetts (SS)
| | - Ivana Delalle
- From the Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts (SLA, KT, ID); Broad Institute, Cambridge, Massachusetts; Brigham and Women's Hospital, Boston, Massachusetts (JAK) Department of Neurology, Boston University School of Medicine, Boston, Massachusetts (SS).
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Miyagawa T, Ebinuma I, Morohashi Y, Hori Y, Young Chang M, Hattori H, Maehara T, Yokoshima S, Fukuyama T, Tsuji S, Iwatsubo T, Prendergast GC, Tomita T. BIN1 regulates BACE1 intracellular trafficking and amyloid-β production. Hum Mol Genet 2016; 25:2948-2958. [PMID: 27179792 DOI: 10.1093/hmg/ddw146] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 04/13/2016] [Accepted: 05/09/2016] [Indexed: 11/15/2022] Open
Abstract
BIN1 is a genetic risk factor of late-onset Alzheimer disease (AD), which was identified in multiple genome-wide association studies. BIN1 is a member of the amphiphysin family of proteins, and contains N-terminal Bin-Amphiphysin-Rvs and C-terminal Src homology 3 domains. BIN1 is widely expressed in the mouse and human brains, and has been reported to function in the endocytosis and the endosomal sorting of membrane proteins. BACE1 is a type 1 transmembrane aspartyl protease expressed predominantly in neurons of the brain and responsible for the production of amyloid-β peptide (Aβ). Here we report that the depletion of BIN1 increases cellular BACE1 levels through impaired endosomal trafficking and reduces BACE1 lysosomal degradation, resulting in increased Aβ production. Our findings provide a mechanistic role of BIN1 in the pathogenesis of AD as a novel genetic regulator of BACE1 levels and Aβ production.
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Affiliation(s)
- Toji Miyagawa
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences .,Department of Neurology, Graduate School of Medicine, The University of Tokyo, 113-0033 Japan
| | - Ihori Ebinuma
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences
| | - Yuichi Morohashi
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences
| | - Yukiko Hori
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences
| | | | - Haruhiko Hattori
- Laboratory of Natural Products Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya University, 464-8601 Japan
| | - Tomoaki Maehara
- Laboratory of Natural Products Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya University, 464-8601 Japan
| | - Satoshi Yokoshima
- Laboratory of Natural Products Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya University, 464-8601 Japan
| | - Tohru Fukuyama
- Laboratory of Natural Products Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya University, 464-8601 Japan
| | - Shoji Tsuji
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, 113-0033 Japan
| | - Takeshi Iwatsubo
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, 113-0033 Japan
| | | | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences
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27
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Brennand A, Rico E, Rigden DJ, Van Der Smissen P, Courtoy PJ, Michels PAM. ATG24 Represses Autophagy and Differentiation and Is Essential for Homeostasy of the Flagellar Pocket in Trypanosoma brucei. PLoS One 2015; 10:e0130365. [PMID: 26090847 PMCID: PMC4474607 DOI: 10.1371/journal.pone.0130365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/18/2015] [Indexed: 12/30/2022] Open
Abstract
We have previously identified homologs for nearly half of the approximately 30 known yeast Atg’s in the genome database of the human sleeping sickness parasite Trypanosoma brucei. So far, only a few of these homologs have their role in autophagy experimentally confirmed. Among the candidates was the ortholog of Atg24 that is involved in pexophagy in yeast. In T. brucei, the peroxisome-like organelles named glycosomes harbor core metabolic processes, especially glycolysis. In the autotrophic yeast, autophagy is essential for adaptation to different nutritional environments by participating in the renewal of the peroxisome population. We hypothesized that autophagic turnover of the parasite’s glycosomes plays a role in differentiation during its life cycle, which demands adaptation to different host environments and associated dramatic changes in nutritional conditions. We therefore characterized T. brucei ATG24, the T. brucei ortholog of yeast Atg24 and mammalian SNX4, and found it to have a regulatory role in autophagy and differentiation as well as endocytic trafficking. ATG24 partially localized on endocytic membranes where it was recruited via PI3-kinase III/VPS34. ATG24 silencing severely impaired receptor-mediated endocytosis of transferrin, but not adsorptive uptake of a lectin, and caused a major enlargement of the flagellar pocket. ATG24 silencing approximately doubled the number of autophagosomes, suggesting a role in repressing autophagy, and strongly accelerated differentiation, in accordance with a role of autophagy in parasite differentiation. Overexpression of the two isoforms of T. brucei ATG8 fused to GFP slowed down differentiation, possibly by a dominant-negative effect. This was overcome by ATG24 depletion, further supporting its regulatory role.
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Affiliation(s)
- Ana Brennand
- Research Unit for Tropical Diseases, de Duve Institute, and Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
| | - Eva Rico
- Research Unit for Tropical Diseases, de Duve Institute, and Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
- Departamento de Bioquímica y Biología Molecular, Campus Universitario, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - Daniel J. Rigden
- Institute of Integrative Biology, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | | | - Pierre J. Courtoy
- Cell Biology Unit, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Paul A. M. Michels
- Research Unit for Tropical Diseases, de Duve Institute, and Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
- * E-mail:
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28
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Identification and characterization of Rvs162/Rvs167-3, a novel N-BAR heterodimer in the human fungal pathogen Candida albicans. EUKARYOTIC CELL 2014; 14:182-93. [PMID: 25548150 DOI: 10.1128/ec.00282-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Membrane reshaping resides at the core of many important cellular processes, and among its mediators are the BAR (Bin, Amphiphysin, Rvs) domain-containing proteins. We have explored the diversity and function of the Rvs BAR proteins in Candida albicans and identified a novel family member, Rvs167-3 (orf19.1861). We show that Rvs167-3 specifically interacts with Rvs162 to form a stable BAR heterodimer able to bind liposomes in vitro. A second, distinct heterodimer is formed by the canonical BAR proteins Rvs161 and Rvs167. Purified Rvs161/Rvs167 complex also binds liposomes, indicating that C. albicans expresses two functional BAR heterodimers. We used live-cell imaging to localize green fluorescent protein (GFP)-tagged Rvs167-3 and Rvs167 and show that both proteins concentrate in small cortical spots. However, while Rvs167 strictly colocalizes with the endocytic marker protein Abp1, we do not observe any colocalization of Rvs167-3 with sites of endocytosis marked by Abp1. Furthermore, the rvs167-3Δ/Δ mutant is not defective in endocytosis and strains lacking Rvs167-3 or its partner Rvs162 do not display increased sensitivity to high salt concentrations or decreased cell wall integrity, phenotypes which have been observed for rvs167Δ/Δ and rvs161Δ/Δ strains and which are linked to endocytosis defects. Taken together, our results indicate different roles for the two BAR heterodimers in C. albicans: the canonical Rvs161/Rvs167 heterodimer functions in endocytosis, whereas the novel Rvs162/Rvs167-3 heterodimer seems not to be involved in this process. Nevertheless, despite their different roles, our phenotypic analysis revealed a genetic interaction between the two BAR heterodimers, suggesting that they may have related but distinct membrane-associated functions.
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29
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Sakane H, Horii Y, Nogami S, Kawano Y, Kaneko-Kawano T, Shirataki H. α-Taxilin interacts with sorting nexin 4 and participates in the recycling pathway of transferrin receptor. PLoS One 2014; 9:e93509. [PMID: 24690921 PMCID: PMC3972091 DOI: 10.1371/journal.pone.0093509] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/06/2014] [Indexed: 01/09/2023] Open
Abstract
Membrane traffic plays a crucial role in delivering proteins and lipids to their intracellular destinations. We previously identified α-taxilin as a binding partner of the syntaxin family, which is involved in intracellular vesicle traffic. α-Taxilin is overexpressed in tumor tissues and interacts with polymerized tubulin, but the precise function of α-taxilin remains unclear. Receptor proteins on the plasma membrane are internalized, delivered to early endosomes and then either sorted to the lysosome for degradation or recycled back to the plasma membrane. In this study, we found that knockdown of α-taxilin induced the lysosomal degradation of transferrin receptor (TfnR), a well-known receptor which is generally recycled back to the plasma membrane after internalization, and impeded the recycling of transferrin. α-Taxilin was immunoprecipitated with sorting nexin 4 (SNX4), which is involved in the recycling of TfnR. Furthermore, knockdown of α-taxilin decreased the number and length of SNX4-positive tubular structures. We report for the first time that α-taxilin interacts with SNX4 and plays a role in the recycling pathway of TfnR.
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Affiliation(s)
- Hiroshi Sakane
- Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Yukimi Horii
- Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Satoru Nogami
- Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Yoji Kawano
- Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Takako Kaneko-Kawano
- Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Hiromichi Shirataki
- Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
- * E-mail:
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30
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Amphiphysin 2 (BIN1) in physiology and diseases. J Mol Med (Berl) 2014; 92:453-63. [DOI: 10.1007/s00109-014-1138-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 02/11/2014] [Accepted: 02/17/2014] [Indexed: 12/15/2022]
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31
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Tan MS, Yu JT, Tan L. Bridging integrator 1 (BIN1): form, function, and Alzheimer's disease. Trends Mol Med 2013; 19:594-603. [PMID: 23871436 DOI: 10.1016/j.molmed.2013.06.004] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 05/24/2013] [Accepted: 06/21/2013] [Indexed: 12/13/2022]
Abstract
The bridging integrator 1 (BIN1) gene, also known as amphiphysin 2, has recently been identified as the most important risk locus for late onset Alzheimer's disease (LOAD), after apolipoprotein E (APOE). Here, we summarize the known functions of BIN1 and discuss the polymorphisms associated with LOAD, as well as their possible physiological effects. Emerging data suggest that BIN1 affects AD risk primarily by modulating tau pathology, but other affected cellular functions are discussed, including endocytosis/trafficking, inflammation, calcium homeostasis, and apoptosis. Epigenetic modifications are important for AD pathogenesis, and we review data that suggests the possible DNA methylation of the BIN1 promoter. Finally, given the potential contributions of BIN1 to AD pathogenesis, targeting BIN1 might present novel opportunities for AD therapy.
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Affiliation(s)
- Meng-Shan Tan
- College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266003, China; Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
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32
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Dheilly NM, Raftos DA, Haynes PA, Smith LC, Nair SV. Shotgun proteomics of coelomic fluid from the purple sea urchin, Strongylocentrotus purpuratus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 40:35-50. [PMID: 23353016 DOI: 10.1016/j.dci.2013.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 01/03/2013] [Accepted: 01/04/2013] [Indexed: 05/20/2023]
Abstract
The purple sea urchin has a complex immune system that is likely mediated by gene expression in coelomocytes (blood cells). A broad array of potential immune receptors and immune response proteins has been deduced from their gene models. Here we use shotgun mass spectrometry to describe 307 proteins with possible immune function in sea urchins including proteins involved in the complement pathway and numerous SRCRs. The relative abundance of dual oxidase 1, ceruloplasmin, ferritin and transferrin suggests the production of reactive oxygen species in coelomocytes and the sequestration of iron. Proteins such as selectin, cadherin, talin, galectin, amassin and the Von Willebrand factor may be involved in generating a strong clotting reaction. Cell signaling proteins include a guanine nucleotide binding protein, the Rho GDP dissociation factor, calcium storage molecules and a variety of lipoproteins. However, based on this dataset, the expression of TLRs, NLRs and fibrinogen domain containing proteins in coelomic fluid and coelomocytes could not be verified.
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Affiliation(s)
- Nolwenn M Dheilly
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
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33
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Hunt SD, Townley AK, Danson CM, Cullen PJ, Stephens DJ. Microtubule motors mediate endosomal sorting by maintaining functional domain organization. J Cell Sci 2013; 126:2493-501. [PMID: 23549789 PMCID: PMC3679488 DOI: 10.1242/jcs.122317] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Many microtubule motors have been shown to couple to endosomal membranes. These motors include dynein in addition to many different kinesin family members. Sorting nexins (SNXs) are central to the organization and function of endosomes. These proteins can actively shape endosomal membranes and couple directly or indirectly to the minus-end microtubule motor dynein. Motor proteins acting on endosomes drive their motility, dictate their morphology and affect cargo segregation. We have used well-characterized members of the SNX family to elucidate motor coupling using high-resolution light microscopy coupled with depletion of specific microtubule motors. Endosomal domains labelled with SNX1, SNX4 and SNX8 couple to discrete combinations of dynein and kinesin motors. These specific combinations govern the structure and motility of each SNX-coated membrane in addition to the segregation of distinct functional endosomal subdomains. Taken together, our data show that these key features of endosome dynamics are governed by the same set of opposing microtubule motors. Thus, microtubule motors help to define the mosaic layout of endosomes that underpins cargo sorting.
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Affiliation(s)
- Sylvie D Hunt
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
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34
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Heubeck B, Wendler O, Bumm K, Schäfer R, Müller-Vogt U, Häusler M, Meese E, Iro H, Steinhart H. Tumor-associated antigenic pattern in squamous cell carcinomas of the head and neck – Analysed by SEREX. Eur J Cancer 2013; 49:e1-7. [PMID: 16837193 DOI: 10.1016/j.ejca.2005.09.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 09/06/2005] [Indexed: 11/22/2022]
Abstract
Most immuno-therapeutic approaches are based on tumor-associated antigens and many newly identified proteins have led to trials exploiting their possible therapeutic applicability. So far only limited information on the antigenic profile of head and neck squamous cell carcinomas (HNSCC) exists. Serological analysis of tumor antigens by recombinant cDNA expression cloning (SEREX) was used to identify the immunogenic patterns in our HNSCC patient collective. A cDNA expression library derived from a pharynx HNSCC case was screened with autologous and heterologous sera. Thirty-seven positive clones coding for 17 immunoreactive gene products, which elicited an in vivo tumor response, were found. Results were confirmed and extended by expression analysis using RT-PCR and in situ-hybridisation. The protein-sequence of five clones exists so far only hypothetically. Of all identified proteins only KIAA0530 has previously been associated with a HNSCC related immune response. All other proteins have not yet been described in a context with HNSCC antigenic patterns. Antibodies against a heat shock transcription factor 2 (HSF2) were found in 2 out of 10 sera from HNSCC patients. In summary, using the SEREX technique, we isolated 17 immunogenic antigens in HNSCC's and confirmed the clinical relevance of KIAA0530. Further analysis concerning their feasibility as target structures for an immunotherapy approach is currently conducted.
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Affiliation(s)
- Bernd Heubeck
- Department of Otorhinolaryngology Head and Neck Surgery, University of Erlangen-Nuremberg, Waldstrasse 1, 91054 Erlangen, Germany.
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35
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Abstract
The assembly of clathrin/AP (adaptor protein)-1-coated vesicles on the trans-Golgi network and endosomes is much less studied than that of clathrin/AP-2 vesicles at the plasma membrane for endocytosis. In vitro, the association of AP-1 with protein-free liposomes had been shown to require phosphoinositides, Arf1 (ADP-ribosylation factor 1)–GTP and additional cytosolic factor(s). We have purified an active fraction from brain cytosol and found it to contain amphiphysin 1 and 2 and endophilin A1, three proteins known to be involved in the formation of AP-2/clathrin coats at the plasma membrane. Assays with bacterially expressed and purified proteins showed that AP-1 stabilization on liposomes depends on amphiphysin 2 or the amphiphysin 1/2 heterodimer. Activity is independent of the SH3 (Src homology 3) domain, but requires interaction of the WDLW motif with γ-adaptin. Endogenous amphiphysin in neurons and transfected protein in cell lines co-localize perinuclearly with AP-1 at the trans-Golgi network. This localization depends on interaction of clathrin and the adaptor sequence in the amphiphysins and is sensitive to brefeldin A, which inhibits Arf1-dependent AP-1 recruitment. Interaction between AP-1 and amphiphysin 1/2 in vivo was demonstrated by co-immunoprecipitation after cross-linking. These results suggest an involvement of amphiphysins not only with AP-2 at the plasma membrane, but also in AP-1/clathrin coat formation at the trans-Golgi network.
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Shi Y, Stefan CJ, Rue SM, Teis D, Emr SD. Two novel WD40 domain-containing proteins, Ere1 and Ere2, function in the retromer-mediated endosomal recycling pathway. Mol Biol Cell 2011; 22:4093-107. [PMID: 21880895 PMCID: PMC3204071 DOI: 10.1091/mbc.e11-05-0440] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Regulated responses to extracellular signals depend on cell-surface proteins that are internalized and recycled back to the plasma membrane. Two novel WD40 domain proteins, Ere1 and Ere2 (endosomal recycling proteins), are found to mediate cargo-specific recognition by the retromer pathway. Regulated secretion, nutrient uptake, and responses to extracellular signals depend on cell-surface proteins that are internalized and recycled back to the plasma membrane. However, the underlying mechanisms that govern membrane protein recycling to the cell surface are not fully known. Using a chemical-genetic screen in yeast, we show that the arginine transporter Can1 is recycled back to the cell surface via two independent pathways mediated by the sorting nexins Snx4/41/42 and the retromer complex, respectively. In addition, we identify two novel WD40-domain endosomal recycling proteins, Ere1 and Ere2, that function in the retromer pathway. Ere1 is required for Can1 recycling via the retromer-mediated pathway, but it is not required for the transport of other retromer cargoes, such as Vps10 and Ftr1. Biochemical studies reveal that Ere1 physically interacts with internalized Can1. Ere2 is present in a complex containing Ere1 on endosomes and functions as a regulator of Ere1. Taken together, our results suggest that Snx4/41/42 and the retromer comprise two independent pathways for the recycling of internalized cell-surface proteins. Moreover, a complex containing the two novel proteins Ere1 and Ere2 mediates cargo-specific recognition by the retromer pathway.
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Affiliation(s)
- Yufeng Shi
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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Meta-analysis for genome-wide association study identifies multiple variants at the BIN1 locus associated with late-onset Alzheimer's disease. PLoS One 2011; 6:e16616. [PMID: 21390209 PMCID: PMC3044719 DOI: 10.1371/journal.pone.0016616] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/02/2011] [Indexed: 12/23/2022] Open
Abstract
Recent GWAS studies focused on uncovering novel genetic loci related to AD have revealed associations with variants near CLU, CR1, PICALM and BIN1. In this study, we conducted a genome-wide association study in an independent set of 1034 cases and 1186 controls using the Illumina genotyping platforms. By coupling our data with available GWAS datasets from the ADNI and GenADA, we replicated the original associations in both PICALM (rs3851179) and CR1 (rs3818361). The PICALM variant seems to be non-significant after we adjusted for APOE e4 status. We further tested our top markers in 751 independent cases and 751 matched controls. Besides the markers close to the APOE locus, a marker (rs12989701) upstream of BIN1 locus was replicated and the combined analysis reached genome-wide significance level (p = 5E-08). We combined our data with the published Harold et al. study and meta-analysis with all available 6521 cases and 10360 controls at the BIN1 locus revealed two significant variants (rs12989701, p = 1.32E-10 and rs744373, p = 3.16E-10) in limited linkage disequilibrium (r2 = 0.05) with each other. The independent contribution of both SNPs was supported by haplotype conditional analysis. We also conducted multivariate analysis in canonical pathways and identified a consistent signal in the downstream pathways targeted by Gleevec (P = 0.004 in Pfizer; P = 0.028 in ADNI and P = 0.04 in GenADA). We further tested variants in CLU, PICALM, BIN1 and CR1 for association with disease progression in 597 AD patients where longitudinal cognitive measures are sufficient. Both the PICALM and CLU variants showed nominal significant association with cognitive decline as measured by change in Clinical Dementia Rating-sum of boxes (CDR-SB) score from the baseline but did not pass multiple-test correction. Future experiments will help us better understand potential roles of these genetic loci in AD pathology.
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38
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Specific amino acids in the BAR domain allow homodimerization and prevent heterodimerization of sorting nexin 33. Biochem J 2011; 433:75-83. [PMID: 20964629 DOI: 10.1042/bj20100709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
SNX33 (sorting nexin 33) is a homologue of the endocytic protein SNX9 and has been implicated in actin polymerization and the endocytosis of the amyloid precursor protein. SNX33 belongs to the large family of BAR (Bin/amphiphysin/Rvs) domain-containing proteins, which alter cellular protein trafficking by modulating cellular membranes and the cytoskeleton. Some BAR domains engage in homodimerization, whereas other BAR domains also mediate heterodimerization between different BAR domain-containing proteins. The molecular basis for this difference is not yet understood. Using co-immunoprecipitations we report that SNX33 forms homodimers, but not heterodimers, with other BAR domain-containing proteins, such as SNX9. Domain deletion analysis revealed that the BAR domain, but not the SH3 (Src homology 3) domain, was required for homodimerization of SNX33. Additionally, the BAR domain prevented the heterodimerization between SNX9 and SNX33, as determined by domain swap experiments. Molecular modelling of the SNX33 BAR domain structure revealed that key amino acids located at the BAR domain dimer interface of the SNX9 homodimer are not conserved in SNX33. Replacing these amino acids in SNX9 with the corresponding amino acids of SNX33 allowed the mutant SNX9 to heterodimerize with SNX33. Taken together, the present study identifies critical amino acids within the BAR domains of SNX9 and SNX33 as determinants for the specificity of BAR domain-mediated interactions and suggests that SNX9 and SNX33 have distinct molecular functions.
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Lenzken SC, Romeo V, Zolezzi F, Cordero F, Lamorte G, Bonanno D, Biancolini D, Cozzolino M, Pesaresi MG, Maracchioni A, Sanges R, Achsel T, Carrì MT, Calogero RA, Barabino SM. Mutant SOD1 and mitochondrial damage alter expression and splicing of genes controlling neuritogenesis in models of neurodegeneration. Hum Mutat 2011; 32:168-82. [DOI: 10.1002/humu.21394] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 09/24/2010] [Indexed: 12/13/2022]
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40
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van Weering JRT, Verkade P, Cullen PJ. SNX-BAR proteins in phosphoinositide-mediated, tubular-based endosomal sorting. Semin Cell Dev Biol 2009; 21:371-80. [PMID: 19914387 DOI: 10.1016/j.semcdb.2009.11.009] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Accepted: 11/06/2009] [Indexed: 12/11/2022]
Abstract
The endocytic network is morphologically characterized by a wide variety of membrane bound compartments that are able to undergo dynamic re-modeling through tubular and vesicular structures. The precise molecular mechanisms governing such re-modeling, and the events that co-ordinated this with the major role of endosomes, cargo sorting, remain unclear. That said, recent work on a protein family of sorting nexins (SNX) - especially a subfamily of SNX that contain a BAR domain (SNX-BARs) - has begun to shed some much needed light on these issues and in particular the process of tubular-based endosomal sorting. SNX-BARs are evolutionary conserved in endosomal protein complexes such as retromer, where they co-ordinate membrane deformation with cargo selection. Furthermore a central theme emerges of SNX-BARs linking the forming membrane carrier to cytoskeletal elements for transport through motor proteins such as dynein. By studying these SNX-BARs, we are gaining an increasingly detailed appreciation of the mechanistic basis of endosomal sorting and how this highly dynamic process functions in health and disease.
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Affiliation(s)
- Jan R T van Weering
- The Henry Wellcome Integrated Signalling Laboratories, Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
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41
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Hartig SM, Ishikura S, Hicklen RS, Feng Y, Blanchard EG, Voelker KA, Pichot CS, Grange RW, Raphael RM, Klip A, Corey SJ. The F-BAR protein CIP4 promotes GLUT4 endocytosis through bidirectional interactions with N-WASp and Dynamin-2. J Cell Sci 2009; 122:2283-91. [PMID: 19509061 DOI: 10.1242/jcs.041343] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
F-BAR proteins are a newly described family of proteins with unknown physiological significance. Because F-BAR proteins, including Cdc42 interacting protein-4 (CIP4), drive membrane deformation and affect endocytosis, we investigated the role of CIP4 in GLUT4 traffic by flow cytometry in GLUT4myc-expressing L6 myoblasts (L6 GLUT4myc). L6 GLUT4myc cells express CIP4a as the predominant F-BAR protein. siRNA knockdown of CIP4 increased insulin-stimulated (14)C-deoxyglucose uptake by elevating cell-surface GLUT4. Enhanced surface GLUT4 was due to decreased endocytosis, which correlated with lower transferrin internalization. Immunoprecipitation of endogenous CIP4 revealed that CIP4 interacted with N-WASp and Dynamin-2 in an insulin-dependent manner. FRET confirmed the insulin-dependent, subcellular properties of these interactions. Insulin exposure stimulated specific interactions in plasma membrane and cytosolic compartments, followed by a steady-state response that underlies the coordination of proteins needed for GLUT4 traffic. Our findings reveal a physiological function for F-BAR proteins, supporting a previously unrecognized role for the F-BAR protein CIP4 in GLUT4 endocytosis, and show that interactions between CIP4 and Dynamin-2 and between CIP4 and NWASp are spatially coordinated to promote function.
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Affiliation(s)
- Sean M Hartig
- Division of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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42
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Meunier B, Quaranta M, Daviet L, Hatzoglou A, Leprince C. The membrane-tubulating potential of amphiphysin 2/BIN1 is dependent on the microtubule-binding cytoplasmic linker protein 170 (CLIP-170). Eur J Cell Biol 2008; 88:91-102. [PMID: 19004523 DOI: 10.1016/j.ejcb.2008.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 08/07/2008] [Accepted: 08/07/2008] [Indexed: 01/02/2023] Open
Abstract
Amphiphysins are BIN-amphiphysin-RVS (BAR) domain-containing proteins that influence membrane curvature in sites such as T-tubules in muscular cells, endocytic pits in neuronal as well as non-neuronal cells, and possibly cytoplasmic endosomes. This effect on lipid membranes is fulfilled by diverse amphiphysin 2/BIN1 isoforms, generated by alternative splicing and showing distinct structural and functional properties. In this study, our goal was to characterize the functional role of a ubiquitously expressed amphiphysin 2/BIN1 by the characterization of new molecular partners. We performed a two-hybrid screen with an isoform of amphiphysin 2/BIN1 expressed in HeLa cells. We identified CLIP-170 as an amphiphysin 2/BIN1-interacting molecule. CLIP-170 is a plus-end tracking protein involved in microtubule (MT) stability and recruitment of dynactin. The binding between amphiphysin 2/BIN1 and CLIP-170 is dependent on the N-terminal part of amphiphysin 2 (mostly the BAR domain) and an internal coiled-coil region of CLIP-170. This partnership was confirmed by GST pull-down assay and by co-immunoprecipitation in HeLa cells that express endogenous amphiphysin 2 (mostly isoforms 6, 9 and 10). When overexpressed in HeLa cells, amphiphysin 2/BIN1 leads to the formation of intracellular tubules which can closely align with MTs. After MT depolymerization by nocodazole, amphiphysin 2-stained tubules disappear, and reappear after nocodazole washout. Furthermore, depletion of CLIP-170 by RNAi induced a decrease in the proportion of cells with amphiphysin 2-stained tubules and an increase in the proportion of cells with no tubules. This result suggests the existence of a mechanistic link between the two types of tubules, which is likely to involve the +TIP protein, CLIP-170. Amphiphysin 2/BIN1 may be an anchoring point on membranes for CLIP-170, and consequently for MT. Then, the pushing force of polymerizing MT could help amphiphysin 2/BIN1 in its tubulation potential. We propose that amphiphysin 2/BIN1 participates in the tubulation of traffic intermediates and intracellular organelles first via its intrinsic tubulating potential and second via its ability to bind CLIP-170 and MT.
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Affiliation(s)
- Brigitte Meunier
- Analysis of Signal Transduction Group, INSERM U830, Institut Curie, Paris, France
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43
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Phan NQ, Kim SJ, Bassham DC. Overexpression of Arabidopsis sorting nexin AtSNX2b inhibits endocytic trafficking to the vacuole. MOLECULAR PLANT 2008; 1:961-976. [PMID: 19825596 DOI: 10.1093/mp/ssn057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Sorting nexins are conserved proteins that function in vesicular trafficking and contain a characteristic phox homology (PX) domain. Here, we characterize the ubiquitously expressed Arabidopsis thaliana sorting nexin AtSNX2b. Sub-cellular fractionation studies indicate that AtSNX2b is peripherally associated with membranes. The AtSNX2b PX domain binds to phosphatidylinositol 3-phosphate in vitro and this association is required for the localization of GFP-AtSNX2b to punctate structures in vivo, identified as the trans-Golgi network, prevacuolar compartment and endosomes. Overexpression of GFP-tagged AtSNX2b produces enlarged GFP-labeled compartments that can also be labeled by the endocytic tracer FM4-64. Endocytic trafficking of FM4-64 to the vacuole is arrested in these GFP-AtSNX2b compartments, and similar FM4-64-accumulating compartments are seen upon overexpression of untagged AtSNX2b. This suggests that exit of membrane components from these enlarged or aggregated endosomes is inhibited. Vacuolar proteins containing an N-terminal propeptide, but not those with a C-terminal propeptide, are also present in these enlarged compartments. We hypothesize that AtSNX2b is involved in vesicular trafficking from endosomes to the vacuole.
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Affiliation(s)
- Nguyen Q Phan
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
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44
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Prendergast GC, Muller AJ, Ramalingam A, Chang MY. BAR the door: cancer suppression by amphiphysin-like genes. Biochim Biophys Acta Rev Cancer 2008; 1795:25-36. [PMID: 18930786 DOI: 10.1016/j.bbcan.2008.09.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 08/26/2008] [Accepted: 09/03/2008] [Indexed: 11/17/2022]
Abstract
The evolutionarily conserved amphiphysin-like genes Bin1 and Bin3 function in membrane and actin dynamics, cell polarity, and stress signaling. Recent genetic studies in mice discriminate non-essential roles in endocytic processes commonly ascribed to amphiphysins from essential roles in cancer suppression. Bin1 acts in default pathways of apoptosis and senescence that are triggered by the Myc and Raf oncogenes in primary cells, and Bin1 gene products display a 'moonlighting function' in the nucleus where a variety of other 'endocytic' proteins are also found. Together, genetic investigations in yeast, flies, and mice suggest that amphiphysin-like adapter proteins may suppress cancer by helping integrate cell polarity signals generated by actin and vesicle dynamics with central regulators of cell cycle arrest, apoptosis, and immune surveillance.
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45
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SNX4 coordinates endosomal sorting of TfnR with dynein-mediated transport into the endocytic recycling compartment. Nat Cell Biol 2007; 9:1370-80. [PMID: 17994011 DOI: 10.1038/ncb1656] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 09/26/2007] [Indexed: 12/22/2022]
Abstract
SNX-BAR proteins are a sub-family of sorting nexins implicated in endosomal sorting. Here, we establish that through its phox homology (PX) and Bin-Amphiphysin-Rvs (BAR) domains, sorting nexin-4 (SNX4) is associated with tubular and vesicular elements of a compartment that overlaps with peripheral early endosomes and the juxtanuclear endocytic recycling compartment (ERC). Suppression of SNX4 perturbs transport between these compartments and causes lysosomal degradation of the transferrin receptor (TfnR). Through an interaction with KIBRA, a protein previously shown to bind dynein light chain 1, we establish that SNX4 associates with the minus end-directed microtubule motor dynein. Although suppression of KIBRA and dynein perturbs early endosome-to-ERC transport, TfnR sorting is maintained. We propose that by driving membrane tubulation, SNX4 coordinates iterative, geometric-based sorting of the TfnR with the long-range transport of carriers from early endosomes to the ERC. Finally, these data suggest that by associating with molecular motors, SNX-BAR proteins may coordinate sorting with carrier transport between donor and recipient membranes.
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46
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A combinatorial approach to crystallization of PX-BAR unit of the human Sorting Nexin 9. J Struct Biol 2007; 162:356-60. [PMID: 18065239 DOI: 10.1016/j.jsb.2007.10.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 09/21/2007] [Accepted: 10/24/2007] [Indexed: 11/22/2022]
Abstract
Sorting nexins (SNXs) form a family of proteins known to interact with endosomal vesicles and to regulate various steps of vesicle transport. Sorting Nexin 9 (SNX9) is involved in the interface of endocytic, actin polymerizing, and signal transduction events in the cell. Here we report crystallization of the SNX9 PX-BAR domain protein. Initially we used an ordinary protein construct design, and protein crystallization approaches resulted in obtaining granular crystal-like precipitation. SDS-PAGE and MS analysis of the crystal-like precipitation followed by protein construct optimization and using of macro seeding technique resulted in X-ray quality diffracting crystals. The crystals belonged to P2(1)2(1)2(1) space group (a=65.6 A, b=117.5 A, c=145.8 A) with two protein molecules per asymmetric unit. A complete SAD data set from Se-Methionine derived crystal (3.2 A) has been collected to solve the structure.
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47
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Casal E, Federici L, Zhang W, Fernandez-Recio J, Priego EM, Miguel RN, DuHadaway JB, Prendergast GC, Luisi BF, Laue ED. The crystal structure of the BAR domain from human Bin1/amphiphysin II and its implications for molecular recognition. Biochemistry 2006; 45:12917-28. [PMID: 17059209 PMCID: PMC2572078 DOI: 10.1021/bi060717k] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BAR domains are found in proteins that bind and remodel membranes and participate in cytoskeletal and nuclear processes. Here, we report the crystal structure of the BAR domain from the human Bin1 protein at 2.0 A resolution. Both the quaternary and tertiary architectures of the homodimeric Bin1BAR domain are built upon "knobs-into-holes" packing of side chains, like those found in conventional left-handed coiled-coils, and this packing governs the curvature of a putative membrane-engaging concave face. Our calculations indicate that the Bin1BAR domain contains two potential sites for protein-protein interactions on the convex face of the dimer. Comparative analysis of structural features reveals that at least three architectural subtypes of the BAR domain are encoded in the human genome, represented by the Arfaptin, Bin1/Amphiphysin, and IRSp53 BAR domains. We discuss how these principal groups may differ in their potential to form regulatory heterotypic interactions.
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Affiliation(s)
- Eva Casal
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - Luca Federici
- Ce.S.I. Centro Studi sull’Invecchiamento and Dipartimento di Scienze Biomediche, Universita’ di Chieti “G. D’Annunzio”, Via dei Vestini 31, 66013 Chieti, Italy
| | - Wei Zhang
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - Juan Fernandez-Recio
- Institute of Biomedical Research, Barcelona Science Park, Josep Samitier 1–5, 08028 Barcelona, Spain
| | - Eva-Maria Priego
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - Ricardo Nuñez Miguel
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - James B. DuHadaway
- Lankenau Institute for Medical Research, 100 Lancaster Avenue, Wynnewood PA 19096 USA
| | - George C. Prendergast
- Lankenau Institute for Medical Research, 100 Lancaster Avenue, Wynnewood PA 19096 USA
| | - Ben F. Luisi
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
- Correspondence to Ben F. Luisi: , phone 44-1223-766019 FAX 44-1223-766002
| | - Ernest D. Laue
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
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48
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Childress C, Lin Q, Yang W. Dimerization is required for SH3PX1 tyrosine phosphorylation in response to epidermal growth factor signalling and interaction with ACK2. Biochem J 2006; 394:693-8. [PMID: 16316319 PMCID: PMC1383719 DOI: 10.1042/bj20050576] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
SH3PX1 [SNX9 (sorting nexin 9)] is a member of SNX super-family that is recognized by sharing a PX (phox homology) domain. We have previously shown that SH3PX1, phosphorylated by ACK2 (activated Cdc42-associated tyrosine kinase 2), regulates the degradation of EGF (epidermal growth factor) receptor. In mapping the tyrosine phosphorylation region, we found that the C-terminus of SH3PX1 is required for its tyrosine phosphorylation. Further analysis indicates that this region, known as the coiled-coil domain or the BAR (Bin-amphiphysin-Rvs homology) domain, is the dimerization domain of SH3PX1. Truncation of as little as 13 amino acid residues at the very C-terminus in the coiled-coil/BAR domain of SH3PX1 resulted in no dimerization, no ACK2-catalysed and EGF-stimulated tyrosine phosphorylation and no interaction with ACK2. The intracellular localization of SH3PX1 became dysfunctional upon truncation in the BAR domain. Taken together, our results indicate that the dimerization, which is mediated by the BAR domain, is essential for the intracellular function of SH3PX1.
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Affiliation(s)
- Chandra Childress
- Weis Center for Research, Geisinger Clinic, 100 N. Academy Avenue, Danville, PA 17822, U.S.A
| | - Qiong Lin
- Weis Center for Research, Geisinger Clinic, 100 N. Academy Avenue, Danville, PA 17822, U.S.A
| | - Wannian Yang
- Weis Center for Research, Geisinger Clinic, 100 N. Academy Avenue, Danville, PA 17822, U.S.A
- To whom correspondence should be addressed (email )
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Ren G, Vajjhala P, Lee JS, Winsor B, Munn AL. The BAR domain proteins: molding membranes in fission, fusion, and phagy. Microbiol Mol Biol Rev 2006; 70:37-120. [PMID: 16524918 PMCID: PMC1393252 DOI: 10.1128/mmbr.70.1.37-120.2006] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The Bin1/amphiphysin/Rvs167 (BAR) domain proteins are a ubiquitous protein family. Genes encoding members of this family have not yet been found in the genomes of prokaryotes, but within eukaryotes, BAR domain proteins are found universally from unicellular eukaryotes such as yeast through to plants, insects, and vertebrates. BAR domain proteins share an N-terminal BAR domain with a high propensity to adopt alpha-helical structure and engage in coiled-coil interactions with other proteins. BAR domain proteins are implicated in processes as fundamental and diverse as fission of synaptic vesicles, cell polarity, endocytosis, regulation of the actin cytoskeleton, transcriptional repression, cell-cell fusion, signal transduction, apoptosis, secretory vesicle fusion, excitation-contraction coupling, learning and memory, tissue differentiation, ion flux across membranes, and tumor suppression. What has been lacking is a molecular understanding of the role of the BAR domain protein in each process. The three-dimensional structure of the BAR domain has now been determined and valuable insight has been gained in understanding the interactions of BAR domains with membranes. The cellular roles of BAR domain proteins, characterized over the past decade in cells as distinct as yeasts, neurons, and myocytes, can now be understood in terms of a fundamental molecular function of all BAR domain proteins: to sense membrane curvature, to bind GTPases, and to mold a diversity of cellular membranes.
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Affiliation(s)
- Gang Ren
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
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Schöbel S, Neumann S, Seed B, Lichtenthaler SF. Expression cloning screen for modifiers of amyloid precursor protein shedding. Int J Dev Neurosci 2006; 24:141-8. [PMID: 16446073 DOI: 10.1016/j.ijdevneu.2005.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 11/10/2005] [Indexed: 11/22/2022] Open
Abstract
Ectodomain shedding of the amyloid precursor protein (APP) is a key regulatory step in the generation of the amyloid beta peptide (Abeta), which is thought to provoke the pathogenesis of Alzheimer's disease. To better understand the cellular processes that regulate ectodomain shedding of APP we used human embryonic kidney 293 cells and applied a sib-selection expression cloning approach. In addition to a known activator of APP shedding -- protein kinase A -- the following cDNAs were identified: the endocytic proteins endophilin A1 and A3, the metabotropic glutamate receptor 3 (mGluR3), palmitoyl-protein thioesterase 1 (PPT1), Numb-like and the kinase MEKK2. Endophilins A1 and A3, as well as mGluR3 activated APP shedding relatively specifically. They had little or no effect on the shedding of the unrelated membrane proteins TNF receptor 2 and P-selectin glycoprotein ligand-1. In contrast, MEKK2 and PKA also increased shedding of TNF receptor 2, suggesting that these kinases contribute to a general program regulating ectodomain shedding. The strongest activator of APP shedding, endophilin A3, reduced the rate of APP endocytosis and specifically increased APP shedding by the protease alpha-secretase, as measured in an antibody uptake assay and by immunoblot analysis. This suggests that endophilin A3 is a novel modulator of APP trafficking affecting access of APP to alpha-secretase. In summary, this study shows that expression cloning is a suitable way to identify proteins controlling ectodomain shedding of membrane proteins.
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Affiliation(s)
- Susanne Schöbel
- Adolf-Butenandt-Institut, Ludwig-Maximilians-University, Schillerstr. 44, 80336 Munich, Germany
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