1
|
Silverman JB, Krystofiak EE, Caplan LR, Lau KS, Tyska MJ. Intestinal tuft cells assemble a cytoskeletal superstructure composed of co-aligned actin bundles and microtubules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.19.585757. [PMID: 38562898 PMCID: PMC10983963 DOI: 10.1101/2024.03.19.585757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Background & Aims All tissues consist of a distinct set of cell types, which collectively support organ function and homeostasis. Tuft cells are a rare epithelial cell type found in diverse epithelia, where they play important roles in sensing antigens and stimulating downstream immune responses. Exhibiting a unique polarized morphology, tuft cells are defined by an array of giant actin filament bundles that support ∼2 μm of apical membrane protrusion and extend over 7 μm towards the cell's perinuclear region. Despite their established roles in maintaining intestinal epithelial homeostasis, tuft cells remain understudied due to their rarity (e.g. ∼ 1% in the small intestinal epithelium). Details regarding the ultrastructural organization of the tuft cell cytoskeleton, the molecular components involved in building the array of giant actin bundles, and how these cytoskeletal structures support tuft cell biology remain unclear. Methods To begin to answer these questions, we used advanced light and electron microscopy to perform quantitative morphometry of the small intestinal tuft cell cytoskeleton. Results We found that tuft cell core bundles consist of actin filaments that are crosslinked in a parallel "barbed-end out" configuration. These polarized structures are also supported by a unique group of tuft cell enriched actin-binding proteins that are differentially localized along the giant core bundles. Furthermore, we found that tuft cell actin bundles are co-aligned with a highly ordered network of microtubules. Conclusions Tuft cells assemble a cytoskeletal superstructure that is well positioned to serve as a track for subcellular transport along the apical-basolateral axis and in turn, support the dynamic sensing functions that are critical for intestinal epithelial homeostasis. SYNOPSIS This research leveraged advanced light and electron microscopy to perform quantitative morphometry of the intestinal tuft cell cytoskeleton. Three-dimensional reconstructions of segmented image data revealed a co-aligned actin-microtubule superstructure that may play a fundamental role in tuft cell function.
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Gaeta IM, Tyska MJ. BioID2 screening identifies KIAA1671 as an EPS8 proximal factor that marks sites of microvillus growth. Mol Biol Cell 2023; 34:ar31. [PMID: 36790915 PMCID: PMC10092648 DOI: 10.1091/mbc.e22-11-0498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Microvilli are defining morphological features of the apical surfaces in diverse epithelial tissues. To develop our understanding of microvillus biogenesis, we used a biotin proximity-labeling approach to uncover new molecules enriched near EPS8, a well-studied marker of the microvillus distal tip compartment. Mass spectrometry of biotinylated hits identified KIAA1671, a large (∼200 kDa), disordered, and previously uncharacterized protein. Based on immunofluorescent staining and expression of fluorescent protein-tagged constructs, we found that KIAA1671 localizes to the base of the brush border in native intestinal tissue and polarized epithelial-cell culture models, as well as dynamic actin-rich structures in unpolarized, nonepithelial cell types. Live imaging also revealed that during the early stages of microvillar growth, KIAA1671 colocalizes with EPS8 in diffraction-limited puncta. However, once elongation of the core bundle begins, these two factors separate, with EPS8 tracking the distal end and KIAA1671 remaining behind at the base of the structure. These results suggest that KIAA1671 cooperates with EPS8 and potentially other assembly factors to initiate growth of microvilli on the apical surface. These findings offer new details on how transporting epithelial cells builds the brush border and may inform our understanding of how apical specializations are assembled in other epithelial contexts.
Collapse
Affiliation(s)
- Isabella M Gaeta
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| |
Collapse
|
4
|
de Poret A, Dibsy R, Merida P, Trausch A, Inamdar K, Muriaux D. Extracellular vesicles containing the I-BAR protein IRSp53 are released from the cell plasma membrane in an Arp2/3 dependent manner. Biol Cell 2022; 114:259-275. [PMID: 35844059 DOI: 10.1111/boc.202100095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 07/08/2022] [Accepted: 07/13/2022] [Indexed: 11/28/2022]
Abstract
Extracellular vesicles (EVs) are nanometric membrane vesicles produced by cells and involved in cell-cell communication. Extracellular vesicle formation can occur in endosomal compartments whose budding depends on the ESCRT machinery (i.e., exosomes), or at the cell plasma membrane (ie., EVs or microvesicles). How these extracellular vesicles (EVs) bud from the cell plasma membrane is not completely understood. Membrane curvatures of the plasma membrane towards the exterior are often generated by I-BAR domain proteins. I-BAR proteins are cytosolic proteins that when activated bind to the cell plasma membrane and are involved in protrusion formation including filopodia and lamellipodia. These proteins contain a conserved I-BAR domain that senses curvature and induces negative membrane curvatures at the plasma membrane. I-BAR proteins, such as IRSp53, also interact with actin co-factors to favor membrane protrusions. Here, we explore whether the I-BAR protein IRSp53 is sorting with EVs and if ectopic GFP-tagged I-BAR proteins, such as IRSp53-GFP, as well as related IRTKS-GFP or Pinkbar proteins, can be found in these EVs originated from the cell plasma membrane. We found that a subpopulation of these I-BAR EVs, which are negative for the CD81 exosomal biomarker, are produced from the cell plasma membrane in a TSG101-independent manner but in an Arp2/3-dependent manner. Our results thus reveal that IRSp53 containing EVs represent a subset of plasma membrane EVs whose production depends on branched actin. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Aurore de Poret
- Institut de Recherche en Infectiologie de Montpellier, UMR9004 CNRS, Montpellier University, Montpellier, France
| | - Rayane Dibsy
- Institut de Recherche en Infectiologie de Montpellier, UMR9004 CNRS, Montpellier University, Montpellier, France
| | - Peggy Merida
- Institut de Recherche en Infectiologie de Montpellier, UMR9004 CNRS, Montpellier University, Montpellier, France
| | | | - Kaushik Inamdar
- Institut de Recherche en Infectiologie de Montpellier, UMR9004 CNRS, Montpellier University, Montpellier, France
| | - Delphine Muriaux
- Institut de Recherche en Infectiologie de Montpellier, UMR9004 CNRS, Montpellier University, Montpellier, France
| |
Collapse
|
5
|
Wilkinson B, Coba MP. Molecular architecture of postsynaptic Interactomes. Cell Signal 2020; 76:109782. [PMID: 32941943 DOI: 10.1016/j.cellsig.2020.109782] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 01/02/2023]
Abstract
The postsynaptic density (PSD) plays an essential role in the organization of the synaptic signaling machinery. It contains a set of core scaffolding proteins that provide the backbone to PSD protein-protein interaction networks (PINs). These core scaffolding proteins can be seen as three principal layers classified by protein family, with DLG proteins being at the top, SHANKs along the bottom, and DLGAPs connecting the two layers. Early studies utilizing yeast two hybrid enabled the identification of direct protein-protein interactions (PPIs) within the multiple layers of scaffolding proteins. More recently, mass-spectrometry has allowed the characterization of whole interactomes within the PSD. This expansion of knowledge has further solidified the centrality of core scaffolding family members within synaptic PINs and provided context for their role in neuronal development and synaptic function. Here, we discuss the scaffolding machinery of the PSD, their essential functions in the organization of synaptic PINs, along with their relationship to neuronal processes found to be impaired in complex brain disorders.
Collapse
Affiliation(s)
- Brent Wilkinson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Marcelo P Coba
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
| |
Collapse
|
6
|
Bisi S, Marchesi S, Rizvi A, Carra D, Beznoussenko GV, Ferrara I, Deflorian G, Mironov A, Bertalot G, Pisati F, Oldani A, Cattaneo A, Saberamoli G, Pece S, Viale G, Bachi A, Tripodo C, Scita G, Disanza A. IRSp53 controls plasma membrane shape and polarized transport at the nascent lumen in epithelial tubules. Nat Commun 2020; 11:3516. [PMID: 32665580 PMCID: PMC7360740 DOI: 10.1038/s41467-020-17091-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
It is unclear whether the establishment of apical–basal cell polarity during the generation of epithelial lumens requires molecules acting at the plasma membrane/actin interface. Here, we show that the I-BAR-containing IRSp53 protein controls lumen formation and the positioning of the polarity determinants aPKC and podocalyxin. Molecularly, IRSp53 acts by regulating the localization and activity of the small GTPase RAB35, and by interacting with the actin capping protein EPS8. Using correlative light and electron microscopy, we further show that IRSp53 ensures the shape and continuity of the opposing plasma membrane of two daughter cells, leading to the formation of a single apical lumen. Genetic removal of IRSp53 results in abnormal renal tubulogenesis, with altered tubular polarity and architectural organization. Thus, IRSp53 acts as a membrane curvature-sensing platform for the assembly of multi-protein complexes that control the trafficking of apical determinants and the integrity of the luminal plasma membrane. The I-BAR protein IRSp53 senses membrane curvature but its physiological role is unclear. Here, the authors show that during early lumen morphogenesis, IRSp53 controls the shape of the apical plasma membrane and polarized trafficking and ensures the correct epithelial tubular architecture and if deleted, affects renal tubules morphogenesis in various organisms.
Collapse
Affiliation(s)
- Sara Bisi
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Stefano Marchesi
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Abrar Rizvi
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Davide Carra
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Galina V Beznoussenko
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Ines Ferrara
- Department of Health Sciences, Human Pathology Section, University of Palermo School of Medicine, Via del Vespro 129, 90127, Palermo, Italy
| | | | - Alexander Mironov
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Giovanni Bertalot
- European Institute of Oncology (IEO) IRCCS, Via Ripamonti 435, 20141, Milan, Italy
| | | | - Amanda Oldani
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | | | - Ghazaleh Saberamoli
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Salvatore Pece
- European Institute of Oncology (IEO) IRCCS, Via Ripamonti 435, 20141, Milan, Italy.,Department of Oncology and Haemato-Oncology, University of Milan, Via Santa Sofia 9/1, 20122, Milan, Italy
| | - Giuseppe Viale
- European Institute of Oncology (IEO) IRCCS, Via Ripamonti 435, 20141, Milan, Italy
| | - Angela Bachi
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Claudio Tripodo
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy.,Department of Health Sciences, Human Pathology Section, University of Palermo School of Medicine, Via del Vespro 129, 90127, Palermo, Italy
| | - Giorgio Scita
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy. .,Department of Oncology and Haemato-Oncology, University of Milan, Via Santa Sofia 9/1, 20122, Milan, Italy.
| | - Andrea Disanza
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| |
Collapse
|
7
|
Albanesi JP, Barylko B, DeMartino GN, Jameson DM. Palmitoylated Proteins in Dendritic Spine Remodeling. Front Synaptic Neurosci 2020; 12:22. [PMID: 32655390 PMCID: PMC7325885 DOI: 10.3389/fnsyn.2020.00022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/12/2020] [Indexed: 12/14/2022] Open
Abstract
Activity-responsive changes in the actin cytoskeleton are required for the biogenesis, motility, and remodeling of dendritic spines. These changes are governed by proteins that regulate the polymerization, depolymerization, bundling, and branching of actin filaments. Thus, processes that have been extensively characterized in the context of non-neuronal cell shape change and migration are also critical for learning and memory. In this review article, we highlight actin regulatory proteins that associate, at least transiently, with the dendritic plasma membrane. All of these proteins have been shown, either in directed studies or in high-throughput screens, to undergo palmitoylation, a potentially reversible, and stimulus-dependent cysteine modification. Palmitoylation increases the affinity of peripheral proteins for the membrane bilayer and contributes to their subcellular localization and recruitment to cholesterol-rich membrane microdomains.
Collapse
Affiliation(s)
- Joseph P. Albanesi
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Barbara Barylko
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - George N. DeMartino
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - David M. Jameson
- Department of Cell and Molecular Biology, University of Hawaii, Honolulu, HI, United States
| |
Collapse
|
8
|
Antoine M, Vandenbroere I, Ghosh S, Erneux C, Pirson I. IRSp53 is a novel interactor of SHIP2: A role of the actin binding protein Mena in their cellular localization in breast cancer cells. Cell Signal 2020; 73:109692. [PMID: 32535200 DOI: 10.1016/j.cellsig.2020.109692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 10/24/2022]
Abstract
A tight control of the machineries regulating membrane bending and actin dynamics is very important for the generation of membrane protrusions, which are crucial for cell migration and invasion. Protein/protein and protein/phosphoinositides complexes assemble and disassemble to coordinate these mechanisms, the scaffold properties of the involved proteins playing a prominent role in this organization. The PI 5-phosphatase SHIP2 is a critical enzyme modulating PI(3,4,5)P3, PI(4,5)P2 and PI(3,4)P2 content in the cell. The scaffold properties of SHIP2 contribute to the specific targeting or retention of the protein in particular subcellular domains. Here, we identified IRSp53 as a new binding interactor of SHIP2 proline-rich domain. Both proteins are costained in HEK293T cells protrusions, upon transfection. We showed that the SH3-binding polyproline motif recognized by IRSp53 in SHIP2 is different from the regions targeted by other PRR binding partners i.e., CIN85, ITSN or even Mena a common interactor of both SHIP2 and IRSp53. We presented evidence that IRSp53 phosphorylation on S366 did not influence its interaction with SHIP2 and that Mena is not necessary for the association of SHIP2 with IRSp53 in MDA-MB-231 cells. The absence of Mena in MDA-MB-231 cells decreased the intracellular content in F-actin and modified the subcellular localization of SHIP2 and IRSp53 by increasing their relative content at the plasma membrane. Together our data suggest that SHIP2, through interaction with the cell protrusion regulators IRSp53 and Mena, participate to the formation of multi-protein complexes. This ensures the appropriate modulations of PIs which is important for regulation of membrane dynamics.
Collapse
Affiliation(s)
- Mathieu Antoine
- Institut de Recherche Interdisciplinaire en Biologie Humaine et moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 1070 Brussels, Belgium.
| | - Isabelle Vandenbroere
- Institut de Recherche Interdisciplinaire en Biologie Humaine et moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 1070 Brussels, Belgium
| | - Somadri Ghosh
- Institut de Recherche Interdisciplinaire en Biologie Humaine et moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 1070 Brussels, Belgium
| | - Christophe Erneux
- Institut de Recherche Interdisciplinaire en Biologie Humaine et moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 1070 Brussels, Belgium
| | - Isabelle Pirson
- Institut de Recherche Interdisciplinaire en Biologie Humaine et moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 1070 Brussels, Belgium.
| |
Collapse
|
9
|
Gallop J. Filopodia and their links with membrane traffic and cell adhesion. Semin Cell Dev Biol 2020; 102:81-89. [DOI: 10.1016/j.semcdb.2019.11.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/14/2019] [Accepted: 11/28/2019] [Indexed: 01/24/2023]
|
10
|
Superresolution microscopy reveals distinct localisation of full length IRSp53 and its I-BAR domain protein within filopodia. Sci Rep 2019; 9:2524. [PMID: 30792430 PMCID: PMC6385187 DOI: 10.1038/s41598-019-38851-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 01/04/2019] [Indexed: 11/30/2022] Open
Abstract
Superresolution microscopy offers the advantage of imaging biological structures within cells at the nano-scale. Here we apply two superresolution microscopy techniques, specifically 3D structured illumination microscopy (3D-SIM) and direct stochastic optical reconstruction microscopy (dSTORM), a type of single molecule localisation microscopy, to localise IRSp53 protein and its I-BAR domain in relation to F-actin within filopodia. IRSp53 generates dynamic (extending and retracting) filopodia 300 nm wide with a distinct gap between IRSp53 and F-actin. By contrast, protrusions induced by the I-BAR domain alone are non-dynamic measuring between 100–200 nm in width and exhibit a comparatively closer localisation of the I-BAR domain with the F-actin. The data suggest that IRSp53 membrane localisation is spatially segregated to the lateral edges of filopodia, in contrast to the I-BAR domain is uniformly distributed throughout the membranes of protrusions. Modeling of fluorescence recovery after photobleaching (FRAP) data suggests that a greater proportion of I-BAR domain is associated with membranes when compared to full length IRSp53. The significance of this new data relates to the role filopodia play in cell migration and its importance to cancer.
Collapse
|
11
|
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: 79] [Impact Index Per Article: 13.2] [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.
Collapse
|
12
|
Wei Z, Su W, Lou H, Duan S, Chen G. Trafficking pathway between plasma membrane and mitochondria via clathrin-mediated endocytosis. J Mol Cell Biol 2018; 10:539-548. [DOI: 10.1093/jmcb/mjy060] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 10/31/2018] [Indexed: 12/21/2022] Open
Affiliation(s)
- Zhongya Wei
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Neuroregeneration of Jiangsu Province and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Wenfeng Su
- Key Laboratory of Neuroregeneration of Jiangsu Province and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huifang Lou
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Shumin Duan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Gang Chen
- Key Laboratory of Neuroregeneration of Jiangsu Province and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, China
| |
Collapse
|
13
|
Dynamin-2 Stabilizes the HIV-1 Fusion Pore with a Low Oligomeric State. Cell Rep 2017; 18:443-453. [PMID: 28076788 PMCID: PMC5263234 DOI: 10.1016/j.celrep.2016.12.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/14/2016] [Accepted: 12/12/2016] [Indexed: 11/22/2022] Open
Abstract
One of the key research areas surrounding HIV-1 concerns the regulation of the fusion event that occurs between the virus particle and the host cell during entry. Even if it is universally accepted that the large GTPase dynamin-2 is important during HIV-1 entry, its exact role during the first steps of HIV-1 infection is not well characterized. Here, we have utilized a multidisciplinary approach to study the DNM2 role during fusion of HIV-1 in primary resting CD4 T and TZM-bl cells. We have combined advanced light microscopy and functional cell-based assays to experimentally assess the role of dynamin-2 during these processes. Overall, our data suggest that dynamin-2, as a tetramer, might help to establish hemi-fusion and stabilizes the pore during HIV-1 fusion. DNM2 is crucial for HIV-1 fusion in T Cells and reporter cells DNM2 is not necessarily linked with endocytosis DNM2 tetramer stabilizes the HIV-1 fusion pore
Collapse
|
14
|
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: 46] [Impact Index Per Article: 6.6] [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.
Collapse
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.
| |
Collapse
|
15
|
Redundant functions of I-BAR family members, IRSp53 and IRTKS, are essential for embryonic development. Sci Rep 2017; 7:40485. [PMID: 28067313 PMCID: PMC5220365 DOI: 10.1038/srep40485] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/06/2016] [Indexed: 12/29/2022] Open
Abstract
The insulin receptor substrate of 53 kDa, IRSp53, is an adaptor protein that works with activated GTPases, Cdc42 and Rac, to modulate actin dynamics and generate membrane protrusions in response to cell signaling. Adult mice that lack IRSp53 fail to regulate synaptic plasticity and exhibit hippocampus-associated learning deficiencies. Here, we show that 60% of IRSp53 null embryos die at mid to late gestation, indicating a vital IRSp53 function in embryonic development. We find that IRSp53 KO embryos displayed pleiotropic phenotypes such as developmental delay, oligodactyly and subcutaneous edema, and died of severely impaired cardiac and placental development. We further show that double knockout of IRSp53 and its closest family member, IRTKS, resulted in exacerbated placental abnormalities, particularly in spongiotrophoblast differentiation and development, giving rise to complete embryonic lethality. Hence, our findings demonstrate a hitherto under-appreciated IRSp53 function in embryonic development, and further establish an essential genetic interaction between IRSp53 and IRTKS in placental formation.
Collapse
|
16
|
Delage E, Cervantes DC, Pénard E, Schmitt C, Syan S, Disanza A, Scita G, Zurzolo C. Differential identity of Filopodia and Tunneling Nanotubes revealed by the opposite functions of actin regulatory complexes. Sci Rep 2016; 6:39632. [PMID: 28008977 PMCID: PMC5180355 DOI: 10.1038/srep39632] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 11/25/2016] [Indexed: 11/09/2022] Open
Abstract
Tunneling Nanotubes (TNTs) are actin enriched filopodia-like protrusions that play a pivotal role in long-range intercellular communication. Different pathogens use TNT-like structures as "freeways" to propagate across cells. TNTs are also implicated in cancer and neurodegenerative diseases, making them promising therapeutic targets. Understanding the mechanism of their formation, and their relation with filopodia is of fundamental importance to uncover their physiological function, particularly since filopodia, differently from TNTs, are not able to mediate transfer of cargo between distant cells. Here we studied different regulatory complexes of actin, which play a role in the formation of both these structures. We demonstrate that the filopodia-promoting CDC42/IRSp53/VASP network negatively regulates TNT formation and impairs TNT-mediated intercellular vesicle transfer. Conversely, elevation of Eps8, an actin regulatory protein that inhibits the extension of filopodia in neurons, increases TNT formation. Notably, Eps8-mediated TNT induction requires Eps8 bundling but not its capping activity. Thus, despite their structural similarities, filopodia and TNTs form through distinct molecular mechanisms. Our results further suggest that a switch in the molecular composition in common actin regulatory complexes is critical in driving the formation of either type of membrane protrusion.
Collapse
Affiliation(s)
- Elise Delage
- Unité Trafic Membranaire et Pathogenèse, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Diégo Cordero Cervantes
- Unité Trafic Membranaire et Pathogenèse, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Esthel Pénard
- Unité Trafic Membranaire et Pathogenèse, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Christine Schmitt
- Ultrapole, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Sylvie Syan
- Unité Trafic Membranaire et Pathogenèse, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Andrea Disanza
- FIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Giorgio Scita
- FIRC Institute of Molecular Oncology, 20139 Milan, Italy.,Dipartimento di Scienze della Salute, Università degli Studi di Milano, 20122 Milan, Italy
| | - Chiara Zurzolo
- Unité Trafic Membranaire et Pathogenèse, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| |
Collapse
|
17
|
Gu C, Lee HW, Garborcauskas G, Reiser J, Gupta V, Sever S. Dynamin Autonomously Regulates Podocyte Focal Adhesion Maturation. J Am Soc Nephrol 2016; 28:446-451. [PMID: 27432739 DOI: 10.1681/asn.2016010008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/01/2016] [Indexed: 12/31/2022] Open
Abstract
Rho family GTPases, the prototypical members of which are Cdc42, Rac1, and RhoA, are molecular switches best known for regulating the actin cytoskeleton. In addition to the canonical small GTPases, the large GTPase dynamin has been implicated in regulating the actin cytoskeleton via direct dynamin-actin interactions. The physiologic role of dynamin in regulating the actin cytoskeleton has been linked to the maintenance of the kidney filtration barrier. Additionally, the small molecule Bis-T-23, which promotes actin-dependent dynamin oligomerization and thus, increases actin polymerization, improved renal health in diverse models of CKD, implicating dynamin as a potential therapeutic target for the treatment of CKD. Here, we show that treating cultured mouse podocytes with Bis-T-23 promoted stress fiber formation and focal adhesion maturation in a dynamin-dependent manner. Furthermore, Bis-T-23 induced the formation of focal adhesions and stress fibers in cells in which the RhoA signaling pathway was downregulated by multiple experimental approaches. Our study suggests that dynamin regulates focal adhesion maturation by a mechanism parallel to and synergistic with the RhoA signaling pathway. Identification of dynamin as one of the essential and autonomous regulators of focal adhesion maturation suggests a molecular mechanism that underlies the beneficial effect of Bis-T-23 on podocyte physiology.
Collapse
Affiliation(s)
- Changkyu Gu
- Department of Medicine, Harvard Medical School, Division of Nephrology, Massachusetts General Hospital, Charlestown, Massachusetts; and
| | - Ha Won Lee
- Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | - Garrett Garborcauskas
- Department of Medicine, Harvard Medical School, Division of Nephrology, Massachusetts General Hospital, Charlestown, Massachusetts; and
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | - Vineet Gupta
- Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | - Sanja Sever
- Department of Medicine, Harvard Medical School, Division of Nephrology, Massachusetts General Hospital, Charlestown, Massachusetts; and
| |
Collapse
|
18
|
Sudhaharan T, Sem KP, Liew HF, Yu YH, Goh WI, Chou AM, Ahmed S. Rho GTPase Rif signals through IRTKS, Eps8 and WAVE2 to generate dorsal membrane ruffles and filopodia. J Cell Sci 2016; 129:2829-40. [DOI: 10.1242/jcs.179655] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 05/27/2016] [Indexed: 11/20/2022] Open
Abstract
Rif induces dorsal filopodia but the signalling pathway responsible for this has not been identified. We show here that Rif interacts with the I-BAR family protein IRTKS via its I-BAR domain. Rif also interacts with Pinkbar in N1E-115 mouse neuroblastoma cells. IRTKS and Rif induce dorsal membrane ruffles and filopodia. Dominant negative Rif inhibits the formation of IRTKS-induced morphological structures and Rif activity is blocked in IRTKS KO cells. To further define the Rif-IRTKS signalling pathway, we identify Eps8 and WAVE2 as IRTKS interactors. We find that Eps8 regulates the size and number of dorsal filopodia and membrane ruffles downstream of Rif-IRTKS, while WAVE2 modulates dorsal membrane ruffling. Furthermore, our data suggests that Tir, a protein essential for enterohemorrhagic E.coli infection, may compete for Rif for interaction with the I-BAR domain of IRKS. Based on these evidences we propose a model in which Rho family GTPases use the I-BAR proteins, IRSp53, IRTKS and Pinkbar, as a central mechanism to modulate cell morphology.
Collapse
Affiliation(s)
- Thankiah Sudhaharan
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
| | - Kai Ping Sem
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
| | - Hwi Fen Liew
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
| | - Yuan Hong Yu
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
| | - Wah Ing Goh
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore 117411
| | - Ai Mei Chou
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
| | - Sohail Ahmed
- Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, Singapore 138648
| |
Collapse
|
19
|
Kang J, Park H, Kim E. IRSp53/BAIAP2 in dendritic spine development, NMDA receptor regulation, and psychiatric disorders. Neuropharmacology 2015; 100:27-39. [PMID: 26275848 DOI: 10.1016/j.neuropharm.2015.06.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 06/26/2015] [Accepted: 06/28/2015] [Indexed: 01/08/2023]
Abstract
IRSp53 (also known as BAIAP2) is a multi-domain scaffolding and adaptor protein that has been implicated in the regulation of membrane and actin dynamics at subcellular structures, including filopodia and lamellipodia. Accumulating evidence indicates that IRSp53 is an abundant component of the postsynaptic density at excitatory synapses and an important regulator of actin-rich dendritic spines. In addition, IRSp53 has been implicated in diverse psychiatric disorders, including autism spectrum disorders, schizophrenia, and attention deficit/hyperactivity disorder. Mice lacking IRSp53 display enhanced NMDA (N-methyl-d-aspartate) receptor function accompanied by social and cognitive deficits, which are reversed by pharmacological suppression of NMDA receptor function. These results suggest the hypothesis that defective actin/membrane modulation in IRSp53-deficient dendritic spines may lead to social and cognitive deficits through NMDA receptor dysfunction. This article is part of the Special Issue entitled 'Synaptopathy--from Biology to Therapy'.
Collapse
Affiliation(s)
- Jaeseung Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
| | - Haram Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea; Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon 305-701, South Korea.
| |
Collapse
|