1
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Biton T, Scher N, Carmon S, Elbaz-Alon Y, Schejter ED, Shilo BZ, Avinoam O. Fusion pore dynamics of large secretory vesicles define a distinct mechanism of exocytosis. J Cell Biol 2023; 222:e202302112. [PMID: 37707500 PMCID: PMC10501449 DOI: 10.1083/jcb.202302112] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/06/2023] [Accepted: 08/24/2023] [Indexed: 09/15/2023] Open
Abstract
Exocrine cells utilize large secretory vesicles (LSVs) up to 10 μm in diameter. LSVs fuse with the apical surface, often recruiting actomyosin to extrude their content through dynamic fusion pores. The molecular mechanism regulating pore dynamics remains largely uncharacterized. We observe that the fusion pores of LSVs in the Drosophila larval salivary glands expand, stabilize, and constrict. Arp2/3 is essential for pore expansion and stabilization, while myosin II is essential for pore constriction. We identify several Bin-Amphiphysin-Rvs (BAR) homology domain proteins that regulate fusion pore expansion and stabilization. We show that the I-BAR protein Missing-in-Metastasis (MIM) localizes to the fusion site and is essential for pore expansion and stabilization. The MIM I-BAR domain is essential but not sufficient for localization and function. We conclude that MIM acts in concert with actin, myosin II, and additional BAR-domain proteins to control fusion pore dynamics, mediating a distinct mode of exocytosis, which facilitates actomyosin-dependent content release that maintains apical membrane homeostasis during secretion.
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Affiliation(s)
- Tom Biton
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Nadav Scher
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shari Carmon
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Elbaz-Alon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal D. Schejter
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ben-Zion Shilo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ori Avinoam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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2
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Madarász T, Brunner B, Halász H, Telek E, Matkó J, Nyitrai M, Szabó-Meleg E. Molecular Relay Stations in Membrane Nanotubes: IRSp53 Involved in Actin-Based Force Generation. Int J Mol Sci 2023; 24:13112. [PMID: 37685917 PMCID: PMC10487789 DOI: 10.3390/ijms241713112] [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: 07/04/2023] [Revised: 07/28/2023] [Accepted: 08/12/2023] [Indexed: 09/10/2023] Open
Abstract
Membrane nanotubes are cell protrusions that grow to tens of micrometres and functionally connect cells. Actin filaments are semi-flexible polymers, and their polymerisation provides force for the formation and growth of membrane nanotubes. The molecular bases for the provision of appropriate force through such long distances are not yet clear. Actin filament bundles are likely involved in these processes; however, even actin bundles weaken when growing over long distances, and there must be a mechanism for their regeneration along the nanotubes. We investigated the possibility of the formation of periodic molecular relay stations along membrane nanotubes by describing the interactions of actin with full-length IRSp53 protein and its N-terminal I-BAR domain. We concluded that I-BAR is involved in the early phase of the formation of cell projections, while IRSp53 is also important for the elongation of protrusions. Considering that IRSp53 binds to the membrane along the nanotubes and nucleates actin polymerisation, we propose that, in membrane nanotubes, IRSp53 establishes molecular relay stations for actin polymerisation and, as a result, supports the generation of force required for the growth of nanotubes.
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Affiliation(s)
- Tamás Madarász
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Brigitta Brunner
- Institute of Biology, Faculty of Sciences, University of Pécs, H-7624 Pécs, Hungary
| | - Henriett Halász
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Elek Telek
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - János Matkó
- Department of Immunology, Faculty of Science, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Miklós Nyitrai
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Edina Szabó-Meleg
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
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3
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Feng Z, Lee S, Jia B, Jian T, Kim E, Zhang M. IRSp53 promotes postsynaptic density formation and actin filament bundling. J Cell Biol 2022; 221:213346. [PMID: 35819332 PMCID: PMC9280192 DOI: 10.1083/jcb.202105035] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 11/04/2021] [Accepted: 06/13/2022] [Indexed: 01/14/2023] Open
Abstract
IRSp53 (aka BAIAP2) is a scaffold protein that couples membranes with the cytoskeleton in actin-filled protrusions such as filopodia and lamellipodia. The protein is abundantly expressed in excitatory synapses and is essential for synapse development and synaptic plasticity, although with poorly understood mechanisms. Here we show that specific multivalent interactions between IRSp53 and its binding partners PSD-95 or Shank3 drive phase separation of the complexes in solution. IRSp53 can be enriched to the reconstituted excitatory PSD (ePSD) condensates via bridging to the core and deeper layers of ePSD. Overexpression of a mutant defective in the IRSp53/PSD-95 interaction perturbs synaptic enrichment of IRSp53 in mouse cortical neurons. The reconstituted PSD condensates promote bundled actin filament formation both in solution and on membranes, via IRSp53-mediated actin binding and bundling. Overexpression of mutants that perturb IRSp53-actin interaction leads to defects in synaptic maturation of cortical neurons. Together, our studies provide potential mechanistic insights into the physiological roles of IRSp53 in synapse formation and function.
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Affiliation(s)
- Zhe Feng
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Bowen Jia
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Tao Jian
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea,Correspondence to Eunjoon Kim:
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China,School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
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4
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Wu M, Qiu Q, Zhou Q, Li J, Yang J, Zheng C, Luo A, Li X, Zhang H, Cheng X, Lu W, Liu P, Lu B, Lu Y. circFBXO7/miR-96-5p/MTSS1 axis is an important regulator in the Wnt signaling pathway in ovarian cancer. Mol Cancer 2022; 21:137. [PMID: 35768865 PMCID: PMC9241180 DOI: 10.1186/s12943-022-01611-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND CircRNAs are a novel class of evolutionarily conserved noncoding RNA molecules that form covalently closed continuous loop structures without 5' caps and 3' poly(A) tails. Accumulating evidence suggests that circRNAs play important regulatory roles in cancer and are promising biomarkers for cancer diagnosis and prognosis, as well as targets for cancer therapy. In this study, we identify and explore the role of a novel circRNA, circFBXO7, in ovarian cancer. METHODS rRNA-depleted RNA-sequencing was performed to identify differentially expressed circRNAs between ovarian cancerous and normal tissues. qRT-PCR and single-molecule RNA in-situ hybridization was used to quantify circFBXO7 expression in tumor tissues. The association of circFBXO7 expression with patient prognosis was evaluated by Kaplan-Meier survival analysis. The biological function of circFBXO7 was also investigated using loss-of-function and gain-of-function assays in vivo and in vitro. Luciferase reporter and TOP/FOP-Flash reporter assays were then conducted together with RNA immunoprecipitation and western blot to assess the circFBXO7/miR-96-5p/MTSS1/Wnt/β-catenin axis. RESULTS circFBXO7 was downregulated in ovarian cancer which was associated with poor prognosis. Biologically, circFBXO7 overexpression significantly suppressed ovarian cancer cell proliferation, migration, and invasion in vitro, and inhibited tumor growth and metastasis in vivo, whereas its knockdown exerted an opposite role. Mechanistically, circFBXO7 functioned as a competing endogenous RNA for miR-96-5p to regulate the expression of MTSS1. Consequently, downregulation of MTSS1 led to excessive accumulation of β-catenin and increased phosphorylation of GSK3β, leading to the translocation of β-catenin to the nucleus, thereby activating the Wnt/β-catenin signaling pathway and ultimately promoting ovarian cancer progression. CONCLUSIONS Our findings indicate that circFBXO7 acts as a bone fide tumor suppressor in ovarian cancer and that the circFBXO7/miR-96-5p/MTSS1 axis is an important regulator in the Wnt/β-catenin signaling pathway which may provide a promising target for ovarian cancer therapy.
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Affiliation(s)
- Mengting Wu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Qiongzi Qiu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Qing Zhou
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Jia Li
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Juze Yang
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Chengcai Zheng
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Aoran Luo
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Xufan Li
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Honghe Zhang
- Department of Pathology, Research Unit of Intelligence Classification of Tumor Pathology and Precision Therapy, Chinese Academy of Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China.,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China
| | - Xiaodong Cheng
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China.,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China
| | - Weiguo Lu
- Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.,Women's Reproductive Health Key Laboratory of Zhejiang Province, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Pengyuan Liu
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China. .,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.
| | - Bingjian Lu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.
| | - Yan Lu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.
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5
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Insights into Membrane Curvature Sensing and Membrane Remodeling by Intrinsically Disordered Proteins and Protein Regions. J Membr Biol 2022; 255:237-259. [PMID: 35451616 PMCID: PMC9028910 DOI: 10.1007/s00232-022-00237-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/29/2022] [Indexed: 12/15/2022]
Abstract
Cellular membranes are highly dynamic in shape. They can rapidly and precisely regulate their shape to perform various cellular functions. The protein’s ability to sense membrane curvature is essential in various biological events such as cell signaling and membrane trafficking. As they are bound, these curvature-sensing proteins may also change the local membrane shape by one or more curvature driving mechanisms. Established curvature-sensing/driving mechanisms rely on proteins with specific structural features such as amphipathic helices and intrinsically curved shapes. However, the recent discovery and characterization of many proteins have shattered the protein structure–function paradigm, believing that the protein functions require a unique structural feature. Typically, such structure-independent functions are carried either entirely by intrinsically disordered proteins or hybrid proteins containing disordered regions and structured domains. It is becoming more apparent that disordered proteins and regions can be potent sensors/inducers of membrane curvatures. In this article, we outline the basic features of disordered proteins and regions, the motifs in such proteins that encode the function, membrane remodeling by disordered proteins and regions, and assays that may be employed to investigate curvature sensing and generation by ordered/disordered proteins.
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6
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Mechanism of negative membrane curvature generation by I-BAR domains. Structure 2021; 29:1440-1452.e4. [PMID: 34520736 DOI: 10.1016/j.str.2021.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/16/2021] [Accepted: 07/22/2021] [Indexed: 11/23/2022]
Abstract
The membrane sculpting ability of BAR domains has been attributed to the intrinsic curvature of their banana-shaped dimeric structure. However, there is often a mismatch between this intrinsic curvature and the diameter of the membrane tubules generated. I-BAR domains are especially mysterious since they are almost flat but generate high negative membrane curvature. Here, we use atomistic implicit-solvent computer modeling to show that the membrane bending of the IRSp53 I-BAR domain is dictated by its higher oligomeric structure, whose curvature is completely unrelated to the intrinsic curvature of the dimer. Two other I-BARs give similar results, whereas a flat F-BAR sheet develops a concave membrane-binding interface, consistent with its observed positive membrane curvature generation. Laterally interacting helical spirals of I-BAR dimers on tube interiors are stable and have an enhanced binding energy that is sufficient for membrane bending to experimentally observed tubule diameters at a reasonable surface density.
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7
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Grandits AM, Nguyen CH, Schlerka A, Hackl H, Sill H, Etzler J, Heyes E, Stoiber D, Grebien F, Heller G, Wieser R. Downregulation of MTSS1 in acute myeloid leukemia is associated with a poor prognosis, chemotherapy resistance, and disease aggressiveness. Leukemia 2021; 35:2827-2839. [PMID: 33782537 PMCID: PMC8478650 DOI: 10.1038/s41375-021-01224-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 02/19/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023]
Abstract
Despite recent approval of targeted drugs for acute myeloid leukemia (AML) therapy, chemotherapy with cytosine arabinoside and anthracyclines remains an important pillar of treatment. Both primary and secondary resistance are frequent and associated with poor survival, yet the underlying molecular mechanisms are incompletely understood. In previous work, we identified genes deregulated between diagnosis and relapse of AML, corresponding to therapy naïve and resistant states, respectively. Among them was MTSS1, whose downregulation is known to enhance aggressiveness of solid tumors. Here we show that low MTSS1 expression at diagnosis was associated with a poor prognosis in AML. MTSS1 expression was regulated by promoter methylation, and reduced by cytosine arabinoside and the anthracycline daunorubicin. Experimental downregulation of MTSS1 affected the expression of numerous genes. It induced the DNA damage response kinase WEE1, and rendered human AML cell lines more resistant to cytosine arabinoside, daunorubicin, and other anti-cancer drugs. Mtss1 knockdown in murine MLL-AF9-driven AML substantially decreased disease latency, and increased leukemic burden and ex vivo chemotherapy resistance. In summary, low MTSS1 expression represents a novel factor contributing to disease aggressiveness, therapy resistance, and poor outcome in AML.
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MESH Headings
- Animals
- Anthracyclines/administration & dosage
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cytarabine/administration & dosage
- Daunorubicin/administration & dosage
- Drug Resistance, Neoplasm
- Female
- Gene Expression Regulation, Leukemic
- Humans
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Mice, Inbred C57BL
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Prognosis
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Survival Rate
- Mice
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Affiliation(s)
- Alexander Michael Grandits
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Vienna, Austria
| | - Chi Huu Nguyen
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Vienna, Austria
| | - Angela Schlerka
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Vienna, Austria
| | - Hubert Hackl
- Institute of Bioinformatics, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Heinz Sill
- Division of Hematology, Medical University of Graz, Graz, Austria
| | - Julia Etzler
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Vienna, Austria
| | - Elizabeth Heyes
- Institute for Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
| | - Dagmar Stoiber
- Division of Pharmacology, Department of Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Florian Grebien
- Institute for Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
| | - Gerwin Heller
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Vienna, Austria
| | - Rotraud Wieser
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria.
- Comprehensive Cancer Center, Vienna, Austria.
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8
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Yan K, Zong W, Du H, Zhai X, Ren R, Liu S, Xiong W, Wang Y, Xu Z. BAIAP2L2 is required for the maintenance of mechanotransducing stereocilia of cochlear hair cells. J Cell Physiol 2021; 237:774-788. [PMID: 34346063 DOI: 10.1002/jcp.30545] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 01/05/2023]
Abstract
Stereocilia are actin-based cell protrusions of inner ear hair cells that play an essential role in mechano-electrical transduction (MET). Stereocilia are organized into several rows of increasing heights with the MET protein complex localized at the tips of shorter row stereocilia. At the tips of shorter row mechanotransducing stereocilia also resides a so-called "row 2 protein complex" whose dysfunction causes degeneration of the mechanotransducing stereocilia. In the present work, we show that BAIAP2L2 is localized at the tips of shorter row stereocilia in neonatal and adult mouse cochlear hair cells. Baiap2l2 inactivation causes degeneration of the mechanotransducing stereocilia, which eventually leads to profound hearing loss in mice of either sex. Consistently, electrophysiology and FM 1-43FX dye uptake results confirm that MET currents are compromised in Baiap2l2 knockout mice. Moreover, BAIAP2L2 binds to known row 2 complex components EPS8L2, TWF2, and CAPZB2, and the stereociliary tip localization of CAPZB2 is dependent on functional BAIAP2L2. Interestingly, BAIAP2L2 also binds to CIB2, a known MET complex component, and the stereociliary tip localization of BAIAP2L2 is abolished in Cib2 knockout mice. In conclusion, our present data suggest that BAIAP2L2 is a row 2 complex component, and is required for the maintenance of mechanotransducing stereocilia. Meanwhile, specific MET components such as CIB2 might play a direct role in stereocilia maintenance through binding to BAIAP2L2.
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Affiliation(s)
- Keji Yan
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Wen Zong
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong, China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Xiaoyan Zhai
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Rui Ren
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Shuang Liu
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Wei Xiong
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China.,Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, Shandong, China
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9
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Grandits AM, Wieser R. Gene expression changes contribute to stemness and therapy resistance of relapsed acute myeloid leukemia: roles of SOCS2, CALCRL, MTSS1, and KDM6A. Exp Hematol 2021; 99:1-11. [PMID: 34029637 PMCID: PMC7612147 DOI: 10.1016/j.exphem.2021.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/18/2022]
Abstract
Relapse is associated with therapy resistance and is a major cause of death in acute myeloid leukemia (AML). It is thought to result from the accretion of therapy-refractory leukemic stem cells. Genetic and transcriptional changes that are recurrently gained at relapse are likely to contribute to the increased stemness and decreased therapy responsiveness at this disease stage. Despite the recent approval of several targeted drugs, chemotherapy with cytosine arabinoside and anthracyclines is still the mainstay of AML therapy. Accordingly, a number of studies have investigated genetic and gene expression changes between diagnosis and relapse of patients subjected to such treatment. Genetic alterations recurrently acquired at relapse were identified, but were restricted to small proportions of patients, and their functional characterization is still largely pending. In contrast, the expression of a substantial number of genes was altered consistently between diagnosis and recurrence of AML. Recent studies corroborated the roles of the upregulation of SOCS2 and CALCRL and of the downregulation of MTSS1 and KDM6A in therapy resistance and/or stemness of AML. These findings spur the assumption that functional investigations of genes consistently altered at recurrence of AML have the potential to promote the development of novel targeted drugs that may help to improve the outcome of this currently often fatal disease.
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Affiliation(s)
- Alexander M Grandits
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria; Comprehensive Cancer Center, Vienna, Austria
| | - Rotraud Wieser
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna, Austria; Comprehensive Cancer Center, Vienna, Austria.
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10
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Mesarec L, Drab M, Penič S, Kralj-Iglič V, Iglič A. On the Role of Curved Membrane Nanodomains, and Passive and Active Skeleton Forces in the Determination of Cell Shape and Membrane Budding. Int J Mol Sci 2021; 22:2348. [PMID: 33652934 PMCID: PMC7956631 DOI: 10.3390/ijms22052348] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/18/2021] [Accepted: 02/20/2021] [Indexed: 02/03/2023] Open
Abstract
Biological membranes are composed of isotropic and anisotropic curved nanodomains. Anisotropic membrane components, such as Bin/Amphiphysin/Rvs (BAR) superfamily protein domains, could trigger/facilitate the growth of membrane tubular protrusions, while isotropic curved nanodomains may induce undulated (necklace-like) membrane protrusions. We review the role of isotropic and anisotropic membrane nanodomains in stability of tubular and undulated membrane structures generated or stabilized by cyto- or membrane-skeleton. We also describe the theory of spontaneous self-assembly of isotropic curved membrane nanodomains and derive the critical concentration above which the spontaneous necklace-like membrane protrusion growth is favorable. We show that the actin cytoskeleton growth inside the vesicle or cell can change its equilibrium shape, induce higher degree of segregation of membrane nanodomains or even alter the average orientation angle of anisotropic nanodomains such as BAR domains. These effects may indicate whether the actin cytoskeleton role is only to stabilize membrane protrusions or to generate them by stretching the vesicle membrane. Furthermore, we demonstrate that by taking into account the in-plane orientational ordering of anisotropic membrane nanodomains, direct interactions between them and the extrinsic (deviatoric) curvature elasticity, it is possible to explain the experimentally observed stability of oblate (discocyte) shapes of red blood cells in a broad interval of cell reduced volume. Finally, we present results of numerical calculations and Monte-Carlo simulations which indicate that the active forces of membrane skeleton and cytoskeleton applied to plasma membrane may considerably influence cell shape and membrane budding.
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Affiliation(s)
- Luka Mesarec
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (L.M.); (M.D.); (S.P.)
| | - Mitja Drab
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (L.M.); (M.D.); (S.P.)
| | - Samo Penič
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (L.M.); (M.D.); (S.P.)
| | - Veronika Kralj-Iglič
- Faculty of Health Sciences, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
- Institute of Biosciences and Bioresources, National Research Council, 80131 Napoli, Italy
| | - Aleš Iglič
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (L.M.); (M.D.); (S.P.)
- Institute of Biosciences and Bioresources, National Research Council, 80131 Napoli, Italy
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11
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Carlton AJ, Halford J, Underhill A, Jeng J, Avenarius MR, Gilbert ML, Ceriani F, Ebisine K, Brown SDM, Bowl MR, Barr‐Gillespie PG, Marcotti W. Loss of Baiap2l2 destabilizes the transducing stereocilia of cochlear hair cells and leads to deafness. J Physiol 2021; 599:1173-1198. [PMID: 33151556 PMCID: PMC7898316 DOI: 10.1113/jp280670] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/27/2020] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Mechanoelectrical transduction at auditory hair cells requires highly specialized stereociliary bundles that project from their apical surface, forming a characteristic graded 'staircase' structure. The morphogenesis and maintenance of these stereociliary bundles is a tightly regulated process requiring the involvement of several actin-binding proteins, many of which are still unidentified. We identify a new stereociliary protein, the I-BAR protein BAIAP2L2, which localizes to the tips of the shorter transducing stereocilia in both inner and outer hair cells (IHCs and OHCs). We find that Baiap2l2 deficient mice lose their second and third rows of stereocilia, their mechanoelectrical transducer current, and develop progressive hearing loss, becoming deaf by 8 months of age. We demonstrate that BAIAP2L2 localization to stereocilia tips is dependent on the motor protein MYO15A and its cargo EPS8. We propose that BAIAP2L2 is a new key protein required for the maintenance of the transducing stereocilia in mature cochlear hair cells. ABSTRACT The transduction of sound waves into electrical signals depends upon mechanosensitive stereociliary bundles that project from the apical surface of hair cells within the cochlea. The height and width of these actin-based stereocilia is tightly regulated throughout life to establish and maintain their characteristic staircase-like structure, which is essential for normal mechanoelectrical transduction. Here, we show that BAIAP2L2, a member of the I-BAR protein family, is a newly identified hair bundle protein that is localized to the tips of the shorter rows of transducing stereocilia in mouse cochlear hair cells. BAIAP2L2 was detected by immunohistochemistry from postnatal day 2.5 (P2.5) throughout adulthood. In Baiap2l2 deficient mice, outer hair cells (OHCs), but not inner hair cells (IHCs), began to lose their third row of stereocilia and showed a reduction in the size of the mechanoelectrical transducer current from just after P9. Over the following post-hearing weeks, the ordered staircase structure of the bundle progressively deteriorates, such that, by 8 months of age, both OHCs and IHCs of Baiap2l2 deficient mice have lost most of the second and third rows of stereocilia and become deaf. We also found that BAIAP2L2 interacts with other key stereociliary proteins involved in normal hair bundle morphogenesis, such as CDC42, RAC1, EPS8 and ESPNL. Furthermore, we show that BAIAP2L2 localization to the stereocilia tips depends on the motor protein MYO15A and its cargo EPS8. We propose that BAIAP2L2 is key to maintenance of the normal actin structure of the transducing stereocilia in mature mouse cochlear hair cells.
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Affiliation(s)
- Adam J. Carlton
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Julia Halford
- Oregon Hearing Research Center & Vollum InstituteOregon Health & Science UniversityPortlandORUSA
| | - Anna Underhill
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Jing‐Yi Jeng
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Matthew R. Avenarius
- Oregon Hearing Research Center & Vollum InstituteOregon Health & Science UniversityPortlandORUSA
- Present address: Department of Pathology Wexner Medical CenterThe Ohio State UniversityColumbusOHUSA
| | - Merle L. Gilbert
- Oregon Hearing Research Center & Vollum InstituteOregon Health & Science UniversityPortlandORUSA
- Present address: US Army Medical Department Activity‐KoreaCamp HumphreysRepublic of Korea
| | - Federico Ceriani
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | | | - Steve D. M. Brown
- Mammalian Genetics UnitMRC Harwell InstituteHarwell CampusOxfordshireUK
| | - Michael R. Bowl
- Mammalian Genetics UnitMRC Harwell InstituteHarwell CampusOxfordshireUK
- Present address: UCL Ear InstituteUniversity College LondonLondonUK
| | - Peter G. Barr‐Gillespie
- Oregon Hearing Research Center & Vollum InstituteOregon Health & Science UniversityPortlandORUSA
- Oregon Hearing Research CenterOregon Health & Science UniversityPortlandORUSA
| | - Walter Marcotti
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
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12
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Zimmet A, Van Eeuwen T, Boczkowska M, Rebowski G, Murakami K, Dominguez R. Cryo-EM structure of NPF-bound human Arp2/3 complex and activation mechanism. SCIENCE ADVANCES 2020; 6:6/23/eaaz7651. [PMID: 32917641 PMCID: PMC7274804 DOI: 10.1126/sciadv.aaz7651] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 04/16/2020] [Indexed: 05/12/2023]
Abstract
Actin-related protein (Arp) 2/3 complex nucleates branched actin networks that drive cell motility. It consists of seven proteins, including two actin-related subunits (Arp2 and Arp3). Two nucleation-promoting factors (NPFs) bind Arp2/3 complex during activation, but the order, specific interactions, and contribution of each NPF to activation are unresolved. Here, we report the cryo-electron microscopy structure of recombinantly expressed human Arp2/3 complex with two WASP family NPFs bound and address the mechanism of activation. A cross-linking assay that captures the transition of the Arps into the activated filament-like conformation shows that actin binding to NPFs favors this transition. Actin-NPF binding to Arp2 precedes binding to Arp3 and is sufficient to promote the filament-like conformation but not activation. Structure-guided mutagenesis of the NPF-binding sites reveals their distinct roles in activation and shows that, contrary to budding yeast Arp2/3 complex, NPF-mediated delivery of actin at the barbed end of both Arps is required for activation of human Arp2/3 complex.
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Affiliation(s)
- Austin Zimmet
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Trevor Van Eeuwen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Grzegorz Rebowski
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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13
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Chen PW, Billington N, Maron BY, Sload JA, Chinthalapudi K, Heissler SM. The BAR domain of the Arf GTPase-activating protein ASAP1 directly binds actin filaments. J Biol Chem 2020; 295:11303-11315. [PMID: 32444496 DOI: 10.1074/jbc.ra119.009903] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 05/13/2020] [Indexed: 12/11/2022] Open
Abstract
The Arf GTPase-activating protein (Arf GAP) with SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) establishes a connection between the cell membrane and the cortical actin cytoskeleton. The formation, maintenance, and turnover of actin filaments and bundles in the actin cortex are important for cell adhesion, invasion, and migration. Here, using actin cosedimentation, polymerization, and depolymerization assays, along with total internal reflection fluorescence (TIRF), confocal, and EM analyses, we show that the N-terminal N-BAR domain of ASAP1 directly binds to F-actin. We found that ASAP1 homodimerization aligns F-actin in predominantly unipolar bundles and stabilizes them against depolymerization. Furthermore, the ASAP1 N-BAR domain moderately reduced the spontaneous polymerization of G-actin. The overexpression of the ASAP1 BAR-PH tandem domain in fibroblasts induced the formation of actin-filled projections more effectively than did full-length ASAP1. An ASAP1 construct that lacked the N-BAR domain failed to induce cellular projections. Our results suggest that ASAP1 regulates the dynamics and the formation of higher-order actin structures, possibly through direct binding to F-actin via its N-BAR domain. We propose that ASAP1 is a hub protein for dynamic protein-protein interactions in mechanosensitive structures, such as focal adhesions, invadopodia, and podosomes, that are directly implicated in oncogenic events. The effect of ASAP1 on actin dynamics puts a spotlight on its function as a central signaling molecule that regulates the dynamics of the actin cytoskeleton by transmitting signals from the plasma membrane.
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Affiliation(s)
- Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Neil Billington
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
| | - Ben Y Maron
- Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Jeffrey A Sload
- Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Krishna Chinthalapudi
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Sarah M Heissler
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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14
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Sarapulov AV, Petrov P, Hernández-Pérez S, Šuštar V, Kuokkanen E, Cords L, Samuel RVM, Vainio M, Fritzsche M, Carrasco YR, Mattila PK. Missing-in-Metastasis/Metastasis Suppressor 1 Regulates B Cell Receptor Signaling, B Cell Metabolic Potential, and T Cell-Independent Immune Responses. Front Immunol 2020; 11:599. [PMID: 32373113 PMCID: PMC7176992 DOI: 10.3389/fimmu.2020.00599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/16/2020] [Indexed: 11/13/2022] Open
Abstract
Efficient generation of antibodies by B cells is one of the prerequisites of protective immunity. B cell activation by cognate antigens via B cell receptors (BCRs), or pathogen-associated molecules through pattern-recognition receptors, such as Toll-like receptors (TLRs), leads to transcriptional and metabolic changes that ultimately transform B cells into antibody-producing plasma cells or memory cells. BCR signaling and a number of steps downstream of it rely on coordinated action of cellular membranes and the actin cytoskeleton, tightly controlled by concerted action of multiple regulatory proteins, some of them exclusive to B cells. Here, we dissect the role of Missing-In-Metastasis (MIM), or Metastasis suppressor 1 (MTSS1), a cancer-associated membrane and actin cytoskeleton regulating protein, in B cell-mediated immunity by taking advantage of MIM knockout mouse strain. We show undisturbed B cell development and largely normal composition of B cell compartments in the periphery. Interestingly, we found that MIM-/- B cells are defected in BCR signaling in response to surface-bound antigens but, on the other hand, show increased metabolic activity after stimulation with LPS or CpG. In vivo, MIM knockout animals exhibit impaired IgM antibody responses to immunization with T cell-independent antigen. This study provides the first comprehensive characterization of MIM in B cells, demonstrates its regulatory role for B cell-mediated immunity, as well as proposes new functions for MIM in tuning receptor signaling and cellular metabolism, processes, which may also contribute to the poorly understood functions of MIM in cancer.
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Affiliation(s)
- Alexey V. Sarapulov
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
- Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Petar Petrov
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
- Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Sara Hernández-Pérez
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
- Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Vid Šuštar
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Elina Kuokkanen
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Lena Cords
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Rufus V. M. Samuel
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Marika Vainio
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
- Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Marco Fritzsche
- Kennedy Institute for Rheumatology, University of Oxford, Oxford, United Kingdom
- Rosalind Franklin Institute, Didcot, United Kingdom
| | - Yolanda R. Carrasco
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)-CSIC, Madrid, Spain
| | - Pieta K. Mattila
- Institute of Biomedicine and MediCity Research Laboratories, University of Turku, Turku, Finland
- Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
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15
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Zeno WF, Snead WT, Thatte AS, Stachowiak JC. Structured and intrinsically disordered domains within Amphiphysin1 work together to sense and drive membrane curvature. SOFT MATTER 2019; 15:8706-8717. [PMID: 31621751 PMCID: PMC6934260 DOI: 10.1039/c9sm01495k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Cellular membranes undergo remodeling during many cellular processes including endocytosis, cytoskeletal protrusion, and organelle biogenesis. During these events, specialized proteins sense and amplify fluctuations in membrane curvature to create stably curved architectures. Amphiphysin1 is a multi-domain protein containing an N-terminal crescent-shaped BAR (Bin/Amphiphysin/Rvs) domain and a C-terminal domain that is largely disordered. When studied in isolation, the BAR domain of Amphiphysin1 senses membrane curvature and generates membrane tubules. However, the disordered domain has been largely overlooked in these studies. Interestingly, our recent work has demonstrated that the disordered domain is capable of substantially amplifying the membrane remodeling ability of the BAR domain. However, the physical mechanisms responsible for these effects are presently unclear. Here we elucidated the functional role of the disordered domain by gradually truncating it, creating a family of mutant proteins, each of which contained the BAR domain and a fraction of the disordered domain. Using quantitative fluorescence and electron microscopy, our results indicate that the disordered domain contributes to membrane remodeling by making it more difficult for the protein to bind to and assemble on flat membrane surfaces. Specifically, we found that the disordered domain began to significantly impact membrane remodeling when its projected area exceeded that of the BAR domain. Once this threshold was crossed, steric interactions with the membrane surface and with neighboring disordered domains gave rise to increased curvature sensing and membrane vesiculation, respectively. These findings provide insight into the synergy between structured and disordered domains, each of which play important biophysical roles in membrane remodeling.
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Affiliation(s)
- Wade F Zeno
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Wilton T Snead
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Ajay S Thatte
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA. and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
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16
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Gasilina A, Vitali T, Luo R, Jian X, Randazzo PA. The ArfGAP ASAP1 Controls Actin Stress Fiber Organization via Its N-BAR Domain. iScience 2019; 22:166-180. [PMID: 31785555 PMCID: PMC6889188 DOI: 10.1016/j.isci.2019.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/30/2019] [Accepted: 11/06/2019] [Indexed: 12/11/2022] Open
Abstract
ASAP1 is a multi-domain ArfGAP that controls cell migration, spreading, and focal adhesion dynamics. Although its GAP activity contributes to remodeling of the actin cytoskeleton, it does not fully explain all cellular functions of ASAP1. Here we find that ASAP1 regulates actin filament assembly directly through its N-BAR domain and controls stress fiber maintenance. ASAP1 depletion caused defects in stress fiber organization. Conversely, overexpression of ASAP1 enhanced actin remodeling. The BAR-PH fragment was sufficient to affect actin. ASAP1 with the BAR domain replaced with the BAR domain of the related ACAP1 did not affect actin. The BAR-PH tandem of ASAP1 bound and bundled actin filaments directly, whereas the presence of the ArfGAP and the C-terminal linker/SH3 domain reduced binding and bundling of filaments by BAR-PH. Together these data provide evidence that ASAP1 may regulate the actin cytoskeleton through direct interaction of the BAR-PH domain with actin filaments.
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Affiliation(s)
- Anjelika Gasilina
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA; Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Teresa Vitali
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Ruibai Luo
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Xiaoying Jian
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA.
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17
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Kast DJ, Dominguez R. IRSp53 coordinates AMPK and 14-3-3 signaling to regulate filopodia dynamics and directed cell migration. Mol Biol Cell 2019; 30:1285-1297. [PMID: 30893014 PMCID: PMC6724608 DOI: 10.1091/mbc.e18-09-0600] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Filopodia are actin-filled membrane protrusions that play essential roles in cell motility and cell–cell communication and act as precursors of dendritic spines. IRSp53 is an essential regulator of filopodia formation, which couples Rho-GTPase signaling to actin cytoskeleton and membrane remodeling. IRSp53 has three major domains: an N-terminal inverse-BAR (I-BAR) domain, a Cdc42- and SH3-binding CRIB-PR domain, and an SH3 domain that binds downstream cytoskeletal effectors. Phosphorylation sites in the region between the CRIB-PR and SH3 domains mediate the binding of 14-3-3. Yet the mechanism by which 14-3-3 regulates filopodia formation and dynamics and its role in cell migration are poorly understood. Here, we show that phosphorylation-dependent inhibition of IRSp53 by 14-3-3 counters activation by Cdc42 and cytoskeletal effectors, resulting in down-regulation of filopodia dynamics and cancer cell migration. In serum-starved cells, increased IRSp53 phosphorylation triggers 14-3-3 binding, which inhibits filopodia formation and dynamics, irrespective of whether IRSp53 is activated by Cdc42 or downstream effectors (Eps8, Ena/VASP). Pharmacological activation or inhibition of AMPK, respectively, increases or decreases the phosphorylation of two of three sites in IRSp53 implicated in 14-3-3 binding. Mutating these phosphorylation sites reverses 14-3-3-dependent inhibition of filopodia dynamics and cancer cell chemotaxis.
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Affiliation(s)
- David J Kast
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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18
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Petrov P, Sarapulov AV, Eöry L, Scielzo C, Scarfò L, Smith J, Burt DW, Mattila PK. Computational analysis of the evolutionarily conserved Missing In Metastasis/Metastasis Suppressor 1 gene predicts novel interactions, regulatory regions and transcriptional control. Sci Rep 2019; 9:4155. [PMID: 30858428 PMCID: PMC6411742 DOI: 10.1038/s41598-019-40697-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 02/21/2019] [Indexed: 12/25/2022] Open
Abstract
Missing in Metastasis (MIM), or Metastasis Suppressor 1 (MTSS1), is a highly conserved protein, which links the plasma membrane to the actin cytoskeleton. MIM has been implicated in various cancers, however, its modes of action remain largely enigmatic. Here, we performed an extensive in silico characterisation of MIM to gain better understanding of its function. We detected previously unappreciated functional motifs including adaptor protein (AP) complex interaction site and a C-helix, pointing to a role in endocytosis and regulation of actin dynamics, respectively. We also identified new functional regions, characterised with phosphorylation sites or distinct hydrophilic properties. Strong negative selection during evolution, yielding high conservation of MIM, has been combined with positive selection at key sites. Interestingly, our analysis of intra-molecular co-evolution revealed potential regulatory hotspots that coincided with reduced potentially pathogenic polymorphisms. We explored databases for the mutations and expression levels of MIM in cancer. Experimentally, we focused on chronic lymphocytic leukaemia (CLL), where MIM showed high overall expression, however, downregulation on poor prognosis samples. Finally, we propose strong conservation of MTSS1 also on the transcriptional level and predict novel transcriptional regulators. Our data highlight important targets for future studies on the role of MIM in different tissues and cancers.
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Affiliation(s)
- Petar Petrov
- Institute of Biomedicine, and MediCity Research Laboratories, University of Turku, Tykistökatu 6A, 20520, Turku, Finland.
| | - Alexey V Sarapulov
- Institute of Biomedicine, and MediCity Research Laboratories, University of Turku, Tykistökatu 6A, 20520, Turku, Finland
| | - Lel Eöry
- Division of Genetics and Genomics, The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Easter Bush campus, Midlothian, EH25 9RG, United Kingdom
| | - Cristina Scielzo
- Unit of B Cell Neoplasia, Division of Molecular Oncology, IRCCS, San Raffaele Scientific Institute, Milano, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Lydia Scarfò
- Unit of B Cell Neoplasia, Division of Molecular Oncology, IRCCS, San Raffaele Scientific Institute, Milano, Italy.,Università Vita-Salute San Raffaele, Milan, Italy.,Strategic Research Program on CLL, Division of Experimental Oncology, IRCCS, San Raffaele Scientific Institute, Milano, Italy
| | - Jacqueline Smith
- Division of Genetics and Genomics, The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Easter Bush campus, Midlothian, EH25 9RG, United Kingdom
| | - David W Burt
- University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Pieta K Mattila
- Institute of Biomedicine, and MediCity Research Laboratories, University of Turku, Tykistökatu 6A, 20520, Turku, Finland.
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19
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Li L, Baxter SS, Zhao P, Gu N, Zhan X. Differential interactions of missing in metastasis and insulin receptor tyrosine kinase substrate with RAB proteins in the endocytosis of CXCR4. J Biol Chem 2019; 294:6494-6505. [PMID: 30808710 DOI: 10.1074/jbc.ra118.006071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/15/2019] [Indexed: 12/26/2022] Open
Abstract
Missing in metastasis (MIM), an inverse Bin-Amphiphysin-Rvs (I-BAR) domain protein, promotes endocytosis of C-X-C chemokine receptor 4 (CXCR4) in mammalian cells. In response to the CXCR4 ligand stromal cell-derived factor 1 (SDF-1 or CXCL12), MIM associates with RAS-related GTP-binding protein 7 (RAB7) 30 min after stimulation. However, RAB7's role in MIM function remains undefined. Here we show that RNAi-mediated suppression of RAB7 expression in human HeLa cells has little effect on the binding of MIM to RAB5 and on the recruitment of CXCR4 to early endosomes but effectively abolishes MIM-mediated CXCR4 degradation, chemotactic response, and sorting into late endosomes and lysosomes. To determine whether I-BAR domain proteins interact with RAB7, we examined cells expressing insulin receptor tyrosine kinase substrate (IRTKS), an I-BAR domain protein bearing an Src homology 3 (SH3) domain. We observed that both MIM and IRTKS interact with RAB5 at an early response to SDF-1 and that IRTKS binds poorly to RAB7 but strongly to RAB11 at a later time point. Moreover, IRTKS overexpression reduced CXCR4 internalization and enhanced the chemotactic response to SDF-1. Interestingly, deletion of the SH3 domain in IRTKS abolished the IRTKS-RAB11 interaction and promoted CXCR4 degradation. Furthermore, the SH3 domain was required for selective targeting of MIM-IRTKS fusion proteins by both RAB7 and RAB11. Hence, to the best of our knowledge, our results provide first evidence that the SH3 domain is critical in the regulation of specific endocytic pathways by I-BAR domain proteins.
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Affiliation(s)
- Lushen Li
- From the Center for Vascular and Inflammatory Diseases
| | | | - Peng Zhao
- the State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Ning Gu
- the State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xi Zhan
- From the Center for Vascular and Inflammatory Diseases, .,Department of Pathology, and.,University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
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20
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Tzelepi K, Espinosa Garcia C, Williams P, Golding J. Galactose:PEGamine coated gold nanoparticles adhere to filopodia and cause extrinsic apoptosis. NANOSCALE ADVANCES 2019; 1:807-816. [PMID: 36132240 PMCID: PMC9473179 DOI: 10.1039/c8na00270c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 11/09/2018] [Indexed: 06/15/2023]
Abstract
Ultra-small gold nanoparticles, surface functionalised with a 50 : 50 ratio of a thiolated α-galactose derivative and a thiolated hexaethylene glycol amine, are toxic to HSC-3 oral squamous carcinoma cells. Differences in nanoparticle toxicity were found to be related to the synthesis duration, with 1 h reaction nanoparticles being less toxic than 5 h reaction nanoparticles. The ligand density decreased with longer reaction time, although the size, charge and ligand ratio remained similar. The concentration of sodium borohydride in the reaction decreased logarithmically over 5 h but remained within a concentration range sufficient to desorb weakly bound ligands, possibly explaining the observed gradual decrease in ligand density. Nanoparticle toxicity was abrogated by inhibition of either caspase 3/7 or caspase 8, but not by inhibition of caspase 9, consistent with extrinsic apoptosis. Electron microscopic analysis of cellular uptake demonstrated predominantly cytoplasmic localization. However, when energy-dependent transport was inhibited, by lowering the temperature to 4 °C, a remarkable adhesion of nanoparticles to filopodia was observed. Inhibition of filopodial assembly with a fascin inhibitor prevented nanoparticle adhesion to HSC-3 cells at 4 °C, while fascin inhibition at 37 °C resulted in less cytoplasmic uptake. More adhesion to HSC-3 filopodia was seen with the higher toxicity 5 h reaction time nanoparticles than with the 1 h nanoparticles. By including two further cell types (HaCaT keratinocytes and hCMEC/D3 endothelial cells), a pattern of increasing toxicity with filopodial binding of 5 h reaction nanoparticles became apparent.
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Affiliation(s)
- Konstantina Tzelepi
- School of Life, Health and Chemical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK +44 (0)1908 653748
| | | | - Phil Williams
- Midatech Pharma 65 Innovation Drive, Milton Park Abingdon OX14 4RQ UK
| | - Jon Golding
- School of Life, Health and Chemical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK +44 (0)1908 653748
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21
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Alqassim SS, Lee IG, Dominguez R. Rickettsia Sca2 Recruits Two Actin Subunits for Nucleation but Lacks WH2 Domains. Biophys J 2019; 116:540-550. [PMID: 30638962 DOI: 10.1016/j.bpj.2018.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/07/2018] [Accepted: 12/12/2018] [Indexed: 11/16/2022] Open
Abstract
The Rickettsia ∼1800-amino-acid autotransporter protein surface cell antigen 2 (Sca2) promotes actin polymerization on the surface of the bacterium to drive its movement using an actin comet-tail mechanism. Sca2 mimics eukaryotic formins in that it promotes both actin filament nucleation and elongation and competes with capping protein to generate filaments that are long and unbranched. However, despite these functional similarities, Sca2 is structurally unrelated to eukaryotic formins and achieves these functions through an entirely different mechanism. Thus, while formins are dimeric, Sca2 functions as a monomer. However, Sca2 displays intramolecular interactions and functional cooperativity between its N- and C-terminal domains that are crucial for actin nucleation and elongation. Here, we map the interaction of N- and C- terminal fragments of Sca2 and their contribution to actin binding and nucleation. We find that both the N- and C-terminal regions of Sca2 interact with actin monomers but only weakly, whereas the full-length protein binds two actin monomers with high affinity. Moreover, deletions at both ends of the N- and C-terminal regions disrupt their ability to interact with each other, suggesting that they form a contiguous ring-like structure that wraps around two actin subunits, analogous to the formin homology-2 domain. The discovery of Sca2 as an actin nucleator followed the identification of what appeared to be a repeat of three Wiskott-Aldrich syndrome homology 2 (WH2) domains in the middle of the molecule, consistent with the presence of WH2 domains in most actin nucleators. However, we show here that contrary to previous assumptions, Sca2 does not contain WH2 domains. Instead, our analysis indicates that the region containing the putative WH2 domains is folded as a globular domain that cooperates with other parts of the Sca2 molecule for actin binding and nucleation.
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Affiliation(s)
- Saif S Alqassim
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - In-Gyun Lee
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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22
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Snead WT, Zeno WF, Kago G, Perkins RW, Richter JB, Zhao C, Lafer EM, Stachowiak JC. BAR scaffolds drive membrane fission by crowding disordered domains. J Cell Biol 2018; 218:664-682. [PMID: 30504247 PMCID: PMC6363457 DOI: 10.1083/jcb.201807119] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/12/2018] [Accepted: 11/08/2018] [Indexed: 01/01/2023] Open
Abstract
Cylindrical protein scaffolds are thought to stabilize membrane tubules, preventing membrane fission. In contrast, Snead et al. find that when scaffold proteins assemble, bulky disordered domains within them become acutely concentrated, generating steric pressure that destabilizes tubules, driving fission. Cellular membranes are continuously remodeled. The crescent-shaped bin-amphiphysin-rvs (BAR) domains remodel membranes in multiple cellular pathways. Based on studies of isolated BAR domains in vitro, the current paradigm is that BAR domain–containing proteins polymerize into cylindrical scaffolds that stabilize lipid tubules. But in nature, proteins that contain BAR domains often also contain large intrinsically disordered regions. Using in vitro and live cell assays, here we show that full-length BAR domain–containing proteins, rather than stabilizing membrane tubules, are instead surprisingly potent drivers of membrane fission. Specifically, when BAR scaffolds assemble at membrane surfaces, their bulky disordered domains become crowded, generating steric pressure that destabilizes lipid tubules. More broadly, we observe this behavior with BAR domains that have a range of curvatures. These data suggest that the ability to concentrate disordered domains is a key driver of membrane remodeling and fission by BAR domain–containing proteins.
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Affiliation(s)
- Wilton T Snead
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX
| | - Wade F Zeno
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX
| | - Grace Kago
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX.,Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX
| | - Ryan W Perkins
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX
| | - J Blair Richter
- Department of Biochemistry and Structural Biology, Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Chi Zhao
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX
| | - Eileen M Lafer
- Department of Biochemistry and Structural Biology, Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX .,Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX
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23
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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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24
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Postema MM, Grega-Larson NE, Neininger AC, Tyska MJ. IRTKS (BAIAP2L1) Elongates Epithelial Microvilli Using EPS8-Dependent and Independent Mechanisms. Curr Biol 2018; 28:2876-2888.e4. [PMID: 30197089 DOI: 10.1016/j.cub.2018.07.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 06/05/2018] [Accepted: 07/09/2018] [Indexed: 11/24/2022]
Abstract
Transporting epithelial cells like those that line the gut build large arrays of actin-supported protrusions called microvilli, which extend from the apical surface into luminal spaces to increase functional surface area. Although critical for maintaining physiological homeostasis, mechanisms controlling the formation of microvilli remain poorly understood. Here, we report that the inverse-bin-amphiphysin-Rvs (I-BAR)-domain-containing protein insulin receptor tyrosine kinase substrate (IRTKS) (also known as BAIAP2L1) promotes the growth of epithelial microvilli. Super-resolution microscopy and live imaging of differentiating epithelial cells revealed that IRTKS localizes to the distal tips of actively growing microvilli via a mechanism that requires its N-terminal I-BAR domain. At microvillar tips, IRTKS promotes elongation through a mechanism involving its C-terminal actin-binding WH2 domain. IRTKS can also drive microvillar elongation using its SH3 domain to recruit the bundling protein EPS8 to microvillar tips. These results provide new insight on mechanisms that control microvillar growth during the differentiation of transporting epithelial cells and help explain why IRTKS is targeted by enteric pathogens that disrupt microvillar structure during infection of the intestinal epithelium.
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Affiliation(s)
- Meagan M Postema
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nathan E Grega-Larson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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25
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Lin X, Wang H, Lou Z, Cao M, Zhang Z, Gu N. Roles of
PIP
2 in the membrane binding of
MIM
I‐
BAR
: insights from molecular dynamics simulations. FEBS Lett 2018; 592:2533-2542. [DOI: 10.1002/1873-3468.13186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/01/2018] [Accepted: 06/26/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Xubo Lin
- Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University China
- State Key Laboratory of Bioelectronics Jiangsu Key Laboratory for Biomaterials and Devices School of Biological Sciences & Medical Engineering, Southeast University Nanjing China
| | - Hongyin Wang
- Department of Integrative Biology and Pharmacology McGovern Medical School The University of Texas Health Science Center at Houston TX USA
| | - Zhichao Lou
- State Key Laboratory of Bioelectronics Jiangsu Key Laboratory for Biomaterials and Devices School of Biological Sciences & Medical Engineering, Southeast University Nanjing China
- College of Materials Science and Engineering Nanjing Forestry University China
| | - Meng Cao
- State Key Laboratory of Bioelectronics Jiangsu Key Laboratory for Biomaterials and Devices School of Biological Sciences & Medical Engineering, Southeast University Nanjing China
- Collaborative Innovation Center of Suzhou Nano‐Science and Technology Suzhou Key Laboratory of Biomaterials and Technologies China
| | - Zuoheng Zhang
- State Key Laboratory of Bioelectronics Jiangsu Key Laboratory for Biomaterials and Devices School of Biological Sciences & Medical Engineering, Southeast University Nanjing China
- Collaborative Innovation Center of Suzhou Nano‐Science and Technology Suzhou Key Laboratory of Biomaterials and Technologies China
| | - Ning Gu
- State Key Laboratory of Bioelectronics Jiangsu Key Laboratory for Biomaterials and Devices School of Biological Sciences & Medical Engineering, Southeast University Nanjing China
- Collaborative Innovation Center of Suzhou Nano‐Science and Technology Suzhou Key Laboratory of Biomaterials and Technologies China
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26
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Jiang N, Tu Z, Zhang Y, Li J, Feng Y, Yang N, Sang X, Chen Q. Identification and characterization of DNA endonucleases in Plasmodium falciparum 3D7 clone. Malar J 2018; 17:232. [PMID: 29914511 PMCID: PMC6006590 DOI: 10.1186/s12936-018-2388-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/13/2018] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium falciparum is the most virulent parasite of the five Plasmodium species that cause human malaria, and biological analysis of the parasite is critical for the development of novel strategies for disease control. DNA endonucleases are important for maintaining the biological activity, gene stability of the parasite and interaction with host immune systems. In this study, ten sequences of DNA endonucleases were found in the genome of P. falciparum 3D7 clone, seven of them were predicted to contain an endonuclease/exonuclease/phosphatase (IPR005135) domain which plays an important role in DNA catalytic activity. The seven DNA endonucleases of P. falciparum were systematically investigated. Methods Plasmodium falciparum 3D7 clone was cultured in human O+ RBCs, RNA was extracted at 8, 16, 24, 32, 40, and 48 h post invasion and real-time quantitative PCR was carried out to analyse the transcription of the seven DNA endonuclease genes in asexual stages. Immunofluorescence assay was carried out to confirm the location of the encoded proteins expressed in the erythrocytic stages. Finally, the catalytic activity of the DNA nucleases were tested. Results Of the seven proteins analysed, two proteins were not soluble. Fragments derived from the rest five endonuclease sequences were successfully expressed as soluble proteins, and which were used to generate antisera for protein localization. The proteins were all located in the nucleus at ring and trophozoite stages. While at schizont stage, proteins encoded by PF3D7_1238600, PF3D7_0107200 and PF3D7_0319200 were in the punctuated forms in the parasite most likely around nuclei of the merozoites. But the proteins encoded by PF3D7_0305600 and PF3D7_1363500 were distributed around the infected erythrocyte membrane. The enzymatic activity of the recombinant GST-PF3D7_1238600 was very efficient without divalent iron, while the activity of the rest four enzymes was iron dependent. Further, divalent irons did not show any specific enhancement on the activity of GST-PF3D7_1238600, but the activity of GST-PF3D7_0107200, GST-PF3D7_1363500 and GST-PF3D7_0319200 were Cu2+ dependent. The activity of GST-PF3D7_0305600 was dependent on Mg2+ and Mn2+. Except GST-PF3D7_1363500, four of the GST tagged recombinant proteins hydrolysed the supercoiled circular plasmid DNA with or without divalent metal ions. The GST-PF3D7_1363500 protein only changed the supercoiled circular plasmid DNA into nicked plasmids, even with Cu2+. Conclusions Fragments derived from five of the endonuclease sequences of P. falciparum 3D7 clone were successfully expressed. The proteins displayed diverse cell distribution, biochemical and enzymatic activities, which indicated that they carried different biological function in the development of the parasite in the erythrocytes. The DNA repair and DNA degradation capacity of the DNA endonucleases in the biology of the parasite remained further studied. Electronic supplementary material The online version of this article (10.1186/s12936-018-2388-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ning Jiang
- Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, People's Republic of China
| | - Zhiwei Tu
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun, 130062, People's Republic of China
| | - Yiwei Zhang
- Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, People's Republic of China
| | - Jianping Li
- Blood Center of Liaoning Province, 13 Beihai Street, Shenyang, 110866, People's Republic of China
| | - Ying Feng
- Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, People's Republic of China
| | - Na Yang
- Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, People's Republic of China
| | - Xiaoyu Sang
- Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, People's Republic of China
| | - Qijun Chen
- Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang, 110866, People's Republic of China.
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27
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Xu M, Xu T. Expression and clinical significance of miR-23a and MTSS1 in diffuse large B-cell lymphoma. Oncol Lett 2018; 16:371-377. [PMID: 29928423 PMCID: PMC6006423 DOI: 10.3892/ol.2018.8657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/02/2018] [Indexed: 12/15/2022] Open
Abstract
The present study investigated the expression and clinical significance of micro-ribonucleic acid-23a (miR-23a) and metastasis suppressor 1 (MTSS1) in diffuse large B-cell lymphoma (DLBCL). A total of 70 cases of tumor tissues of patients with DLBCL and 30 cases of reactive lymphoid hyperplasia tissues were collected. OCI-LY10 cell was transfected with miR-23a antisense oligonucleotide (miR-23a ASO). The expression of miR-23a and MTSS1 in tumor tissues of patients with DLBCL and reactive lymphoid hyperplasia tissues were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. Spearmans test was used for correlation analysis was also performed for their expression. The relationship of the expressions of miR-23a and MTSS1 with the pathological parameters of patients with DLBCL was further analyzed. The DLBCL OCI-LY10 cells were cultured in vitro, and gene silencing downregulated the expression of miR-23a in OCI-LY10 cells. The expression of miR-23a was studied via RT-qPCR, and the effect of downregulation of miR-23a on MTSS1 protein expression was determined by western blot analysis. Moreover, the effects of miR-23a on the proliferation, metastasis and invasion capacities of OCI-LY10 cells were observed by both methyl thiazolyl tetrazolium (MTT) assay and Transwell chamber assay. The results of RT-qPCR showed that the mRNA expression of miR-23a in DLBCL tissues was significantly higher than that of reactive hyperplasia tissues. Immunohistochemical results revealed that the positive expression rate of MTSS1 in DLBCL tissues (30.00%) was significantly lower in comparison to reactive hyperplasia tissues (90.00%). Correlation analysis revealed that the miR-23a expression had a significant negative correlation with MTSS1 expression (r=-0.538, p=0.01). The expression of miR-23a and MTSS1 were correlated with the Ann Arbor staging, extranodal invasion and International Prognostic Index (IPI) scores of patients (p<0.05). However, they had no significant correlation with the sex and age of patients (p>0.05). After the downregulation of miR-23a expression, the MTSS1 protein expression in OCI-LY10 cells showed a significant increase. However, the proliferation, metastasis and invasion capacities of OCI-LY10 cells were obviously decreased. In conclusion, miR-23a promoted the proliferation, invasion and metastasis of DLBCL OCI-LY10 cells through the targeted inhibition of MTSS1. The high expression of miR-23a and the low expression of MTSS1 protein could be used as reference indexes for the prognosis of DLBCL.
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Affiliation(s)
- Mengwei Xu
- Department of Pathology, Xijing Hospital, Xi'an, Shanxi 710000, P.R. China
| | - Tao Xu
- Department of Pathology, Xijing Hospital, Xi'an, Shanxi 710000, P.R. China
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28
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Muthu Krishnan S. Using Chou's general PseAAC to analyze the evolutionary relationship of receptor associated proteins (RAP) with various folding patterns of protein domains. J Theor Biol 2018; 445:62-74. [DOI: 10.1016/j.jtbi.2018.02.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/24/2018] [Accepted: 02/12/2018] [Indexed: 01/31/2023]
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29
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Membrane re-modelling by BAR domain superfamily proteins via molecular and non-molecular factors. Biochem Soc Trans 2018. [PMID: 29540508 DOI: 10.1042/bst20170322] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin-Amphiphysin-Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane. BAR proteins co-operate with various molecular and non-molecular factors. The molecular factors include cytoskeletal proteins such as the regulators of actin filaments and the membrane scission protein dynamin. Lipid composition, including saturated or unsaturated fatty acid tails of phospholipids, also affects the ability of BAR proteins to mould the membrane. Non-molecular factors include the external physical forces applied to the membrane, such as tension and friction. In this mini-review, we will discuss how the BAR proteins orchestrate membrane dynamics together with various molecular and non-molecular factors.
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30
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Piano Mortari E, Folgiero V, Marcellini V, Romania P, Bellacchio E, D'Alicandro V, Bocci C, Carrozzo R, Martinelli D, Petrini S, Axiotis E, Farroni C, Locatelli F, Schara U, Pilz D, Jungbluth H, Dionisi-Vici C, Carsetti R. The Vici syndrome protein EPG5 regulates intracellular nucleic acid trafficking linking autophagy to innate and adaptive immunity. Autophagy 2018; 14:22-37. [PMID: 29130391 PMCID: PMC5846549 DOI: 10.1080/15548627.2017.1389356] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 09/19/2017] [Accepted: 10/03/2017] [Indexed: 10/18/2022] Open
Abstract
Vici syndrome is a human inherited multi-system disorder caused by recessive mutations in EPG5, encoding the EPG5 protein that mediates the fusion of autophagosomes with lysosomes. Immunodeficiency characterized by lack of memory B cells and increased susceptibility to infection is an integral part of the condition, but the role of EPG5 in the immune system remains unknown. Here we show that EPG5 is indispensable for the transport of the TLR9 ligand CpG to the late endosomal-lysosomal compartment, and for TLR9-initiated signaling, a step essential for the survival of human memory B cells and their ultimate differentiation into plasma cells. Moreover, the predicted structure of EPG5 includes a membrane remodeling domain and a karyopherin-like domain, thus explaining its function as a carrier between separate vesicular compartments. Our findings indicate that EPG5, by controlling nucleic acids intracellular trafficking, links macroautophagy/autophagy to innate and adaptive immunity.
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Affiliation(s)
- E. Piano Mortari
- B cell Physiopathology Unit, Immunology Research Area, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - V. Folgiero
- Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - V. Marcellini
- B cell Physiopathology Unit, Immunology Research Area, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - P. Romania
- Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - E. Bellacchio
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - V. D'Alicandro
- Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - C. Bocci
- B cell Physiopathology Unit, Immunology Research Area, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - R. Carrozzo
- Unit for Neuromuscular and Neurodegenerative Diseases, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - D. Martinelli
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - S. Petrini
- Confocal Microscopy core facility, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - E. Axiotis
- B cell Physiopathology Unit, Immunology Research Area, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - C. Farroni
- B cell Physiopathology Unit, Immunology Research Area, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - F. Locatelli
- Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
- Department of Pediatric Science, University of Pavia, Pavia, Italy
| | - U. Schara
- 41 Pediatric Neurology, University Childrens Hospital, University of Duisburg-Essen, Essen, Germany
| | - D.T. Pilz
- West of Scotland Genetics Service, Queen Elizabeth University Hospital, Glasgow G51 4TF, UK
| | - H. Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's and St. Thomas' Hospital NHS Foundation Trust, London, UK
- Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK
- Department of Basic and Clinical Neuroscience, IoPPN, King's College, London, UK
| | - C. Dionisi-Vici
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - R. Carsetti
- B cell Physiopathology Unit, Immunology Research Area, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
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31
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Shuyskiy LS, Levchenko VV, Negulyaev YA, Staruschenko AV, Ilatovskaya DV. Role of the Scaffold Protein MIM in the Actin-Dependent Regulation of Epithelial Sodium Channels (ENaC). Acta Naturae 2018; 10:97-103. [PMID: 30116621 PMCID: PMC6087825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Epithelial Sodium Channels (ENaCs) are expressed in different organs and tissues, particularly in the cortical collecting duct (CCD) in the kidney, where they fine tune sodium reabsorption. Dynamic rearrangements of the cytoskeleton are one of the common mechanisms of ENaC activity regulation. In our previous studies, we showed that the actin-binding proteins cortactin and Arp2/3 complex are involved in the cytoskeleton-dependent regulation of ENaC and that their cooperative work decreases a channel's probability of remaining open; however, the specific mechanism of interaction between actin-binding proteins and ENaC is unclear. In this study, we propose a new component for the protein machinery involved in the regulation of ENaC, the missing-in-metastasis (MIM) protein. The MIM protein contains an IMD domain (for interaction with PIP2 -rich plasma membrane regions and Rac GTPases; this domain also possesses F-actin bundling activity), a PRD domain (for interaction with cortactin), and a WH2 domain (interaction with G-actin). The patch-clamp electrophysiological technique in whole-cell configuration was used to test the involvement of MIM in the actin-dependent regulation of ENaC. Co-transfection of ENaC subunits with the wild-type MIM protein (or its mutant forms) caused a significant reduction in ENaC-mediated integral ion currents. The analysis of the F-actin structure after the transfection of MIM plasmids showed the important role played by the domains PRD and WH2 of the MIM protein in cytoskeletal rearrangements. These results suggest that the MIM protein may be a part of the complex of actin-binding proteins which is responsible for the actin-dependent regulation of ENaC in the CCD.
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Affiliation(s)
- L. S. Shuyskiy
- Institute of Cytology of RAS, Tikhoretskij Ave. 4, St. Petersburg, 194064, Russia , Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - V. V. Levchenko
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Y. A. Negulyaev
- Institute of Cytology of RAS, Tikhoretskij Ave. 4, St. Petersburg, 194064, Russia , Department of Medical Physics, Peter the Great St. Petersburg Polytechnic University, Politekhnicheskaya Str. 2, St. Petersburg, 195251, Russia
| | - A. V. Staruschenko
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - D. V. Ilatovskaya
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA , Medical University of South Carolina, Department of Medicine, Division of Nephrology, 96 Jonathan Lucas St, MSC 629 CSB 822, Charleston, SC 29425, USA
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32
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Huang XY, Huang ZL, Niu T, Wu ZQ, Xu B, Xu YH, Huang XY, Zheng Q, Zhou J, Chen Z, Tang ZY. Missing-in-metastasis B (MIM-B) combined with caveolin-1 promotes metastasis of hepatocellular carcinoma. Oncotarget 2017; 8:95450-95465. [PMID: 29221140 PMCID: PMC5707034 DOI: 10.18632/oncotarget.20735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 08/04/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Increasing amounts of evidence indicate that Missing in metastasis B (MIM-B) promotes cancer metastasis. Here, we sought to better understand the mechanism through which MIM-B promotes tumor metastasis in hepatocellular carcinoma (HCC). METHODS We performed confocal microscopy analysis to determine the distributions of MIM-B and caveolin-1 and conducted co-immunoprecipitation assays to detect the interactions between MIM-B and caveolin-1 in vitro. We performed transwell assays to analyze the invasive ability of HCC cells. Changes in the expression levels of key genes and some molecular makers were detected by immunohistochemistry and western blotting in HCC tissue samples. RESULTS We found that MIM-B co-localizes with caveolin-1 and demonstrated that MIM-B and caveolin-1 interact in vitro. Repressing MIM-B and caveolin-1 expression inhibited the epidermal growth factor receptor signaling pathway. We overexpressed MIM-B and caveolin-1 in Hep3B cells, which enhanced Hep3B cell invasiveness. Furthermore, MHCC97H cell invasiveness was significantly decreased in cells in which MIM-B and caveolin-1 expression was inhibited. Additionally, we found that MIM-B and caveolin-1 were expressed at higher levels in HCC tissues than in paired normal tissues. Moreover, HCC patients with MIM-B and caveolin-1 up-regulation experienced significantly worse outcomes than controls (P < 0.001), and HCC patients with high MIM-B and caveolin-1 expression levels often developed pulmonary metastasis (P < 0.001). CONCLUSIONS MIM-B combined with caveolin-1 promotes metastasis of HCC, and elevated MIM-B and caveolin-1 expression levels are associated with a poor prognosis in HCC patients; therefore, MIM-B and caveolin-1 may represent novel targets for the diagnosis and treatment of HCC.
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Affiliation(s)
- Xiu-Yan Huang
- Department of General Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, P.R. China
| | - Zi-Li Huang
- Department of Radiology, Xuhui Central Hospital, Shanghai, P.R. China
| | - Tao Niu
- Department of General Surgery, People's Hospital of Menghai County, Yunnan Province, P.R. China
| | - Zhen-Qian Wu
- Department of General Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, P.R. China
| | - Bin Xu
- Department of General Surgery, The Tenth People's Hospital of Tongji University, Shanghai, P.R. China
| | - Yong-Hua Xu
- Department of Radiology, Xuhui Central Hospital, Shanghai, P.R. China
| | - Xin-Yu Huang
- Department of General Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, P.R. China
| | - Qi Zheng
- Department of General Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, P.R. China
| | - Jian Zhou
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Zi Chen
- Thayer School of Engineering, Norris Cotton Cancer Center, Dartmouth College, Hanover, NH, USA
| | - Zhao-You Tang
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Shanghai, P.R. China
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Zhang Y, Lou Z, Lin X, Wang Q, Cao M, Gu N. Optimizing purification process of MIM-I-BAR domain by introducing atomic force microscope and dynamics simulations. Colloids Surf B Biointerfaces 2017. [PMID: 28623696 DOI: 10.1016/j.colsurfb.2017.05.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
MIM (missing in metastasis) is a member of I-BAR (inverse BAR) domain protein family, which functions as a putative metastasis suppressor. However, methods of gaining high purity MIM-I-BAR protein are barely reported. Here, by optimizing the purification process including changing the conditions of cell lysate and protein elution, we successfully purified MIM protein. The purity of the obtained protein was up to ∼90%. High-resolution atomic force microscope (AFM) provides more visual images, ensuring that we can observe the microenvironment around the target protein, as well as the conformations of the purification products following each purification process. MIM protein with two different sizes were observed on mica surface with AFM. Combining with molecular dynamics simulations, these molecules were revealed as MIM monomer and dimer. Furthermore, our study attaches importance to the usage of imidazole with suitable concentrations during the affinity chromatography process, as well as the removal of excessive imidazole after the affinity chromatography process. All these results indicate that the method described here was successful in purifying MIM protein and maintaining their natural properties, and is supposed to be used to purify other proteins with low solubility.
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Affiliation(s)
- Yue Zhang
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, China
| | - Zhichao Lou
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, China; College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xubo Lin
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, United States
| | - Qiwei Wang
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, China
| | - Meng Cao
- Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, China
| | - Ning Gu
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, China.
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Takemura K, Hanawa-Suetsugu K, Suetsugu S, Kitao A. Salt Bridge Formation between the I-BAR Domain and Lipids Increases Lipid Density and Membrane Curvature. Sci Rep 2017; 7:6808. [PMID: 28754893 PMCID: PMC5533756 DOI: 10.1038/s41598-017-06334-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/12/2017] [Indexed: 11/17/2022] Open
Abstract
The BAR domain superfamily proteins sense or induce curvature in membranes. The inverse-BAR domain (I-BAR) is a BAR domain that forms a straight “zeppelin-shaped” dimer. The mechanisms by which IRSp53 I-BAR binds to and deforms a lipid membrane are investigated here by all-atom molecular dynamics simulation (MD), binding energy analysis, and the effects of mutation experiments on filopodia on HeLa cells. I-BAR adopts a curved structure when crystallized, but adopts a flatter shape in MD. The binding of I-BAR to membrane was stabilized by ~30 salt bridges, consistent with experiments showing that point mutations of the interface residues have little effect on the binding affinity whereas multiple mutations have considerable effect. Salt bridge formation increases the local density of lipids and deforms the membrane into a concave shape. In addition, the point mutations that break key intra-molecular salt bridges within I-BAR reduce the binding affinity; this was confirmed by expressing these mutants in HeLa cells and observing their effects. The results indicate that the stiffness of I-BAR is important for membrane deformation, although I-BAR does not act as a completely rigid template.
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Affiliation(s)
- Kazuhiro Takemura
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-0032, Japan
| | - Kyoko Hanawa-Suetsugu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Shiro Suetsugu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Akio Kitao
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-0032, Japan.
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35
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Li L, Baxter SS, Gu N, Ji M, Zhan X. Missing-in-metastasis protein downregulates CXCR4 by promoting ubiquitylation and interaction with small Rab GTPases. J Cell Sci 2017; 130:1475-1485. [PMID: 28264927 DOI: 10.1242/jcs.198937] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 02/27/2017] [Indexed: 01/09/2023] Open
Abstract
Surface expression of chemokine receptor CXCR4 is downregulated by missing-in-metastasis protein (MIM; also known as MTSS1), a member of the inverse BAR (I-BAR)-domain protein family that recognizes and generates membranes with negative curvature. Yet, the mechanism for the regulation is unknown. Here, we show that MIM forms a complex with CXCR4 by binding to E3 ubiquitin ligase AIP4 (also known as ITCH) in response to stromal cell-derived factor 1 (SDF-1; also known as CXCL12). Overexpression of MIM promoted CXCR4 ubiquitylation, inhibited cellular response to SDF-1, caused accumulation and aggregation of multivesicular bodies (MVBs) in the cytoplasm, and promoted CXCR4 sorting into MVBs in a manner depending on binding to AIP4. In response to SDF-1, MIM also bound transiently to the small GTPase Rab5 at 5 min and to Rab7 at 30 min. Binding to Rab7 requires an N-terminal coiled-coil motif, deletion of which abolished MIM-mediated MVB formation and CXCR4 internalization. Our results unveil a previously unknown property of MIM that establishes the linkage of protein ubiquitylation with Rab-guided trafficking of CXCR4 in endocytic vesicles.
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Affiliation(s)
- Lushen Li
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.,Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Shaneen S Baxter
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ning Gu
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Min Ji
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xi Zhan
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA .,Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
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36
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Salzer U, Kostan J, Djinović-Carugo K. Deciphering the BAR code of membrane modulators. Cell Mol Life Sci 2017; 74:2413-2438. [PMID: 28243699 PMCID: PMC5487894 DOI: 10.1007/s00018-017-2478-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 01/06/2023]
Abstract
The BAR domain is the eponymous domain of the “BAR-domain protein superfamily”, a large and diverse set of mostly multi-domain proteins that play eminent roles at the membrane cytoskeleton interface. BAR domain homodimers are the functional units that peripherally associate with lipid membranes and are involved in membrane sculpting activities. Differences in their intrinsic curvatures and lipid-binding properties account for a large variety in membrane modulating properties. Membrane activities of BAR domains are further modified and regulated by intramolecular or inter-subunit domains, by intermolecular protein interactions, and by posttranslational modifications. Rather than providing detailed cell biological information on single members of this superfamily, this review focuses on biochemical, biophysical, and structural aspects and on recent findings that paradigmatically promote our understanding of processes driven and modulated by BAR domains.
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Affiliation(s)
- Ulrich Salzer
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Julius Kostan
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Kristina Djinović-Carugo
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 119, 1000, Ljubljana, Slovenia.
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37
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Stanishneva-Konovalova T, Derkacheva N, Polevova S, Sokolova O. The Role of BAR Domain Proteins in the Regulation of Membrane Dynamics. Acta Naturae 2016; 8:60-69. [PMID: 28050267 PMCID: PMC5199207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Indexed: 11/09/2022] Open
Abstract
Many cellular processes are associated with membrane remodeling. The BAR domain protein family plays a key role in the formation and detection of local membrane curvatures and in attracting other proteins, including the regulators of actin dynamics. Based on their structural and phylogenetic properties, BAR domains are divided into several groups which affect membrane in various ways and perform different functions in cells. However, recent studies have uncovered evidence of functional differences even within the same group. This review discusses the principles underlying the interactions of different groups of BAR domains, and their individual representatives ,with membranes.
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Affiliation(s)
| | - N.I. Derkacheva
- A.I. Evdokimov Moscow State University of Medicine and Dentistry, Department of Biochemistry, Delegatskaya Str. 20, Bld 1, Moscow, 127473, Russia
| | - S.V. Polevova
- Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, Bld 12, Moscow, 119234 , Russia
| | - O.S. Sokolova
- Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, Bld 12, Moscow, 119234 , Russia
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38
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Zhao H, Xue J, Liu J, Liu Y, Cheng Y. Effect of metastasis suppressor 1 on H1299 cells and its clinical significance in non-small cell lung cancer. Oncol Rep 2016; 36:2814-2822. [PMID: 27634022 DOI: 10.3892/or.2016.5081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 05/19/2016] [Indexed: 11/06/2022] Open
Abstract
The present study aimed to investigate the effect of metastasis suppressor 1 (MTSS1) on the proliferation, migration and invasion of human H1299 non-small cell lung cancer cells and its clinical significance in non‑small cell lung cancer. The target gene MTSS1-overexpressing lentivirus (LV-MTSS1) was transfected into H1299 cells and expression of MTSS1 was detected at the mRNA and protein levels. Cell Counting Kit-8, wound healing and Transwell assays revealed that the migration and invasion activities were significantly suppressed by MTSS1, but that it had no effect on cell proliferation. In addition, MTSS1 expression in tissue microarrays including samples from 223 cases of non-small cell lung cancer was tested by immunohistochemistry to explore the correlation between MTSS1 and clinicopathological characteristics and prognosis. MTSS1 suppressed H1299 cell migration and invasion, and its expression level can be used as a new independent factor for determining the prognosis of non-small cell lung cancer.
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Affiliation(s)
- Heyan Zhao
- Department of Anatomy and Neurobiology, The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Jianhua Xue
- Department of Emergency Surgery, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Junhua Liu
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Yifei Liu
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Yinan Cheng
- Department of Anatomy and Neurobiology, The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China
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39
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Actin-Induced Structure in the Beta-Thymosin Family of Intrinsically Disordered Proteins. VITAMINS AND HORMONES 2016; 102:55-71. [PMID: 27450730 DOI: 10.1016/bs.vh.2016.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Thymosin β4 (Tβ4) is a 43-amino acid signature motif peptide that defines the beta-thymosin (βT) family of proteins. βTs are intrinsically unstructured in their free states and undergo disorder-to-order transitions in carrying out their biological functions. This property poses challenges in determining their 3D structures, mainly favoring structural studies on the complexes formed between βTs and their interaction partners. One of the βTs' primary binding partners is monomeric actin, a major component of the cytoskeleton in eukaryotic cells. Tβ4's role in this system is to maintain the highly concentrated pool of monomeric actin that can be accessed through profilin by actin filament nucleating machineries. Here, we give an account of the structures of βTs that have been illuminated by nuclear magnetic resonance (NMR) and X-ray crystallography. NMR has been the method of choice for probing regions that have intrinsic conformational preference within the largely disordered βTs in their native states in solution. X-ray crystallography has demonstrated at atomic detail how βTs interact with actin. Detailed analysis of these structures highlights the disorder-to-order transition of Tβ4 in binding to actin and its isoform specificity.
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40
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Abstract
I-BAR proteins are well-known actin-cytoskeleton adaptors and have been observed to be involved in the formation of plasma membrane protrusions (filopodia). I-BAR proteins contain an all-helical, crescent-shaped IRSp53-MIM domain (IMD) dimer that is believed to be able to couple with a membrane shape. This coupling could involve the sensing and even the generation of negative plasma membrane curvature. Indeed, the in vitro studies have shown that IMDs can induce inward tubulation of liposomes. While N-BAR domains, which generate positive membrane curvature, have received a considerable amount of attention from both theory and experiments, the mechanisms of curvature coupling through IMDs are comparatively less studied and understood. Here we used a membrane-shape stability assay developed recently in our lab to quantitatively characterize IMD-induced membrane-shape transitions. We determined a membrane-shape stability diagram for IMDs that reveals how membrane tension and protein density can comodulate the generation of IMD-induced membrane protrusions. From comparison to analytical theory, we determine three key parameters that characterize the curvature coupling of IMD. We find that the curvature generation capacity of IMDs is significantly stronger compared to that of endophilin, an N-BAR protein known to be involved in plasma membrane shape transitions. Contrary to N-BAR domains, where amphipathic helix insertion is known to promote its membrane curvature generation, for IMDs we find that amphipathic helices inhibit membrane shape transitions, consistent with the inverse curvature that IMDs generate. Importantly, in both of these types of BAR domains, electrostatic interactions affect membrane-binding capacity, but do not appear to affect the curvature generation capacity of the protein. These two types of BAR domain proteins show qualitatively similar membrane shape stability diagrams, suggesting an underlying ubiquitous mechanism by which peripheral proteins regulate membrane curvature.
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41
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The WH2 Domain and Actin Nucleation: Necessary but Insufficient. Trends Biochem Sci 2016; 41:478-490. [PMID: 27068179 DOI: 10.1016/j.tibs.2016.03.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/18/2016] [Accepted: 03/11/2016] [Indexed: 11/22/2022]
Abstract
Two types of sequences, proline-rich domains (PRDs) and the WASP-homology 2 (WH2) domain, are found in most actin filament nucleation and elongation factors discovered thus far. PRDs serve as a platform for protein-protein interactions, often mediating the binding of profilin-actin. The WH2 domain is an abundant actin monomer-binding motif comprising ∼17 amino acids. It frequently occurs in tandem repeats, and functions in nucleation by recruiting actin subunits to form the polymerization nucleus. It is found in Spire, Cordon Bleu (Cobl), Leiomodin (Lmod), Arp2/3 complex activators (WASP, WHAMM, WAVE, etc.), the bacterial nucleators VopL/VopF and Sca2, and some formins. Yet, it is argued here that the WH2 domain plays only an auxiliary role in nucleation, always synergizing with other domains or proteins for this activity.
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42
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Zhan T, Cao C, Li L, Gu N, Civin CI, Zhan X. MIM regulates the trafficking of bone marrow cells via modulating surface expression of CXCR4. Leukemia 2016; 30:1327-34. [PMID: 26965284 PMCID: PMC4889520 DOI: 10.1038/leu.2016.39] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/15/2015] [Accepted: 02/15/2016] [Indexed: 12/21/2022]
Abstract
Missing in metastasis (MIM) is abundantly expressed in hematopoietic cells. Here we characterized the impact of MIM deficiency on murine bone marrow (BM) cells. Although MIM-/- cells proliferated similarly to wild type (WT), they exhibited stronger response to chemokine SDF-1, increase in surface expression of CXCR4, impaired CXCR4 internalization and constitutive activation of Rac, Cdc42 and p38. Transplantation of MIM-/- BM cells into lethally irradiated mice showed enhanced homing to BM, which was abolished when mice were pretreated with a p38 antagonist. Interestingly, MIM-/- BM cells, including hematopoietic stem and progenitor cells (HSPCs), showed 2 to 5-fold increase in mobilization into the peripheral blood upon treatment with AMD3100. In vitro, MIM-/- leukocytes were susceptible to AMD3100 and maintained increased response to AMD3100 for mobilization even after transfer into wild type mice. MIM-/- mice had also a higher level of SDF-1 in the circulation. Our data highlighted an unprecedented role of MIM in the homoeostasis of BM cells, including HSPCs, through modulation of the CXCR4/SDF-1 axis and interactions of BM leukocytes with their microenvironments.
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Affiliation(s)
- T Zhan
- Department of Pathology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
| | - C Cao
- Department of Pathology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - L Li
- Department of Pathology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA.,China Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, China
| | - N Gu
- China Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, China
| | - C I Civin
- Department of Pediatrics, Center for Stem Cell Biology and Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.,Departments of Pediatrics and Physiology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - X Zhan
- Department of Pathology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA.,Departments of Pediatrics and Physiology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
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43
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Mesarec L, Góźdź W, Iglič VK, Kralj S, Iglič A. Closed membrane shapes with attached BAR domains subject to external force of actin filaments. Colloids Surf B Biointerfaces 2016; 141:132-140. [PMID: 26854580 DOI: 10.1016/j.colsurfb.2016.01.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/02/2016] [Accepted: 01/05/2016] [Indexed: 10/22/2022]
Abstract
Membrane deformations induced by attached BAR superfamily domains could trigger or facilitate the growth of plasma membrane protrusions. The BAR domain family consists of BAR, F-BAR and I-BAR domains, each enforcing a different local curvature when attached to the membrane surface. Our theoretical study mainly focuses on the role of I-BAR in the membrane tubular deformations generated or stabilised by actin filaments. The influence of the area density of membrane attached BAR domains and their intrinsic curvature on the closed membrane shapes (vesicles) was investigated numerically. We derived an analytical approximative expression for the critical relative area density of BARs at which the membrane tubular protrusions on vesicles are most prominent. We have shown that the BARs with a higher intrinsic curvature induce thinner and longer cylindrical protrusions. The average orientation of the membrane attached BARs is altered when the vesicle shape is subjected to external force of growing actin rod-like structure inside a vesicle. The average orientation angle of membrane attached BARs may indicate whether the actin filaments are just stabilising the protrusion or generating it by stretching the vesicle.
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Affiliation(s)
- Luka Mesarec
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia.
| | - Wojciech Góźdź
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Veronika Kralj Iglič
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia; Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena 5, SI-1000 Ljubljana, Slovenia
| | - Samo Kralj
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, SI-2000 Maribor, Slovenia; Jožef Stefan Institute, P.O. Box 3000, SI-1000 Ljubljana, Slovenia
| | - Aleš Iglič
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia; Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena 5, SI-1000 Ljubljana, Slovenia
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44
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Zhao P, Cao M, Song L, Wu H, Hu K, Chen B, Wang Q, Gu N. Downregulation of MIM protein inhibits the cellular endocytosis process of magnetic nanoparticles in macrophages. RSC Adv 2016. [DOI: 10.1039/c6ra21530k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
MIM plays a positive role in the RAW 264.7 cellular endocytosis process of iron oxide nanoparticles mainly in clathrin-mediated pathway, which is a meaningful molecular basis for biomedical applications of nanomaterials.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Meng Cao
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Lina Song
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Hao Wu
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Ke Hu
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Bo Chen
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Qiwei Wang
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
| | - Ning Gu
- State Key Laboratory of Bioelectronics
- Jiangsu Key Laboratory for Biomaterials and Devices
- School of Biological Science and Medical Engineering
- Southeast University
- Nanjing 210096
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45
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Tetlow DJ, Winder SJ, Aïssa C. The synthesis and biological evaluation of a kabiramide C fragment modified with a WH2 consensus actin-binding motif as a potential disruptor of the actin cytoskeleton. Chem Commun (Camb) 2016; 52:807-10. [DOI: 10.1039/c5cc06081h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Despite its low affinity for actin monomers, a fragment of kabiramide C disrupts actin filamentsin vitroand in cells.
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Schemionek M, Herrmann O, Reher MM, Chatain N, Schubert C, Costa IG, Hänzelmann S, Gusmao EG, Kintsler S, Braunschweig T, Hamilton A, Helgason GV, Copland M, Schwab A, Müller-Tidow C, Li S, Holyoake TL, Brümmendorf TH, Koschmieder S. Mtss1 is a critical epigenetically regulated tumor suppressor in CML. Leukemia 2015; 30:823-32. [DOI: 10.1038/leu.2015.329] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/23/2015] [Accepted: 11/16/2015] [Indexed: 12/22/2022]
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Structural analysis of the transitional state of Arp2/3 complex activation by two actin-bound WCAs. Nat Commun 2015; 5:3308. [PMID: 24518936 DOI: 10.1038/ncomms4308] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 01/22/2014] [Indexed: 11/08/2022] Open
Abstract
Actin filament nucleation and branching by Arp2/3 complex is activated by nucleation-promoting factors (NPFs), whose C-terminal WCA region contains binding sites for actin (W) and Arp2/3 complex (CA). It is debated whether one or two NPFs are required for activation. Here we present evidence in support of the two-NPF model and show that actin plays a crucial role in the interactions of two mammalian NPFs, N-WASP and WAVE2, with Arp2/3 complex. Competition between actin-WCA and glia maturation factor (GMF) for binding to Arp2/3 complex suggests that during activation the first actin monomer binds at the barbed end of Arp2. Based on distance constraints obtained by time-resolved fluorescence resonance energy transfer, we define the relative position of the two actin-WCAs on Arp2/3 complex and propose an atomic model of the 11-subunit transitional complex.
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Rørvig-Lund A, Bahadori A, Semsey S, Bendix PM, Oddershede LB. Vesicle Fusion Triggered by Optically Heated Gold Nanoparticles. NANO LETTERS 2015; 15:4183-4188. [PMID: 26010468 DOI: 10.1021/acs.nanolett.5b01366] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Membrane fusion can be accelerated by heating that causes membrane melting and expansion. We locally heated the membranes of two adjacent vesicles by laser irradiating gold nanoparticles, thus causing vesicle fusion with associated membrane and cargo mixing. The mixing time scales were consistent with diffusive mixing of the membrane dyes and the aqueous content. This method is useful for nanoscale reactions as demonstrated here by I-BAR protein-mediated membrane tubulation triggered by fusion.
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Affiliation(s)
- Andreas Rørvig-Lund
- †Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - Azra Bahadori
- †Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
- ‡Lundbeck Foundation Center of Excellence for Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Szabolcs Semsey
- †Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - Poul Martin Bendix
- †Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - Lene B Oddershede
- †Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
- ‡Lundbeck Foundation Center of Excellence for Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
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MIM-Induced Membrane Bending Promotes Dendritic Spine Initiation. Dev Cell 2015; 33:644-59. [PMID: 26051541 DOI: 10.1016/j.devcel.2015.04.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/28/2015] [Accepted: 04/21/2015] [Indexed: 11/21/2022]
Abstract
Proper morphogenesis of neuronal dendritic spines is essential for the formation of functional synaptic networks. However, it is not known how spines are initiated. Here, we identify the inverse-BAR (I-BAR) protein MIM/MTSS1 as a nucleator of dendritic spines. MIM accumulated to future spine initiation sites in a PIP2-dependent manner and deformed the plasma membrane outward into a proto-protrusion via its I-BAR domain. Unexpectedly, the initial protrusion formation did not involve actin polymerization. However, PIP2-dependent activation of Arp2/3-mediated actin assembly was required for protrusion elongation. Overexpression of MIM increased the density of dendritic protrusions and suppressed spine maturation. In contrast, MIM deficiency led to decreased density of dendritic protrusions and larger spine heads. Moreover, MIM-deficient mice displayed altered glutamatergic synaptic transmission and compatible behavioral defects. Collectively, our data identify an important morphogenetic pathway, which initiates spine protrusions by coupling phosphoinositide signaling, direct membrane bending, and actin assembly to ensure proper synaptogenesis.
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50
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Numrich J, Péli-Gulli MP, Arlt H, Sardu A, Griffith J, Levine T, Engelbrecht-Vandré S, Reggiori F, De Virgilio C, Ungermann C. The I-BAR protein Ivy1 is an effector of the Rab7 GTPase Ypt7 involved in vacuole membrane homeostasis. J Cell Sci 2015; 128:2278-92. [PMID: 25999476 DOI: 10.1242/jcs.164905] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 05/18/2015] [Indexed: 01/07/2023] Open
Abstract
Membrane fusion at the vacuole depends on a conserved machinery that includes SNAREs, the Rab7 homolog Ypt7 and its effector HOPS. Here, we demonstrate that Ypt7 has an unexpected additional function by controlling membrane homeostasis and nutrient-dependent signaling on the vacuole surface. We show that Ivy1, the yeast homolog of mammalian missing-in-metastasis (MIM), is a vacuolar effector of Ypt7-GTP and interacts with the EGO/ragulator complex, an activator of the target of rapamycin kinase complex 1 (TORC1) on vacuoles. Loss of Ivy1 does not affect EGO vacuolar localization and function. In combination with the deletion of individual subunits of the V-ATPase, however, we observed reduced TORC1 activity and massive enlargement of the vacuole surface. Consistent with this, Ivy1 localizes to invaginations at the vacuole surface and on liposomes in a phosphoinositide- and Ypt7-GTP-controlled manner, which suggests a role in microautophagy. Our data, thus, reveal that Ivy1 is a novel regulator of vacuole membrane homeostasis with connections to TORC1 signaling.
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Affiliation(s)
- Johannes Numrich
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Marie-Pierre Péli-Gulli
- University of Fribourg, Department of Biology, Division of Biochemistry, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Henning Arlt
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Alessandro Sardu
- University of Fribourg, Department of Biology, Division of Biochemistry, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Janice Griffith
- University Medical Centre Utrecht, Center for Molecular Medicine, Department of Cell Biology, Heidelberglaan 100, Utrecht 3584 CX, The Netherlands
| | - Tim Levine
- UCL Institute of Ophthalmology, Department of Cell Biology, 11-43 Bath St., London EC1V 9EL, UK
| | - Siegfried Engelbrecht-Vandré
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Fulvio Reggiori
- University Medical Centre Utrecht, Center for Molecular Medicine, Department of Cell Biology, Heidelberglaan 100, Utrecht 3584 CX, The Netherlands
| | - Claudio De Virgilio
- University of Fribourg, Department of Biology, Division of Biochemistry, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Christian Ungermann
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
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