1
|
Henry WS, Müller S, Yang JS, Innes-Gold S, Das S, Reinhardt F, Sigmund K, Phadnis VV, Wan Z, Eaton E, Sampaio JL, Bell GW, Viravalli A, Hammond PT, Kamm RD, Cohen AE, Boehnke N, Hsu VW, Levental KR, Rodriguez R, Weinberg RA. Ether lipids influence cancer cell fate by modulating iron uptake. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585922. [PMID: 38562716 PMCID: PMC10983928 DOI: 10.1101/2024.03.20.585922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Cancer cell fate has been widely ascribed to mutational changes within protein-coding genes associated with tumor suppressors and oncogenes. In contrast, the mechanisms through which the biophysical properties of membrane lipids influence cancer cell survival, dedifferentiation and metastasis have received little scrutiny. Here, we report that cancer cells endowed with a high metastatic ability and cancer stem cell-like traits employ ether lipids to maintain low membrane tension and high membrane fluidity. Using genetic approaches and lipid reconstitution assays, we show that these ether lipid-regulated biophysical properties permit non-clathrin-mediated iron endocytosis via CD44, leading directly to significant increases in intracellular redox-active iron and enhanced ferroptosis susceptibility. Using a combination of in vitro three-dimensional microvascular network systems and in vivo animal models, we show that loss of ether lipids also strongly attenuates extravasation, metastatic burden and cancer stemness. These findings illuminate a mechanism whereby ether lipids in carcinoma cells serve as key regulators of malignant progression while conferring a unique vulnerability that can be exploited for therapeutic intervention.
Collapse
Affiliation(s)
- Whitney S Henry
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Sebastian Müller
- Institut Curie, CNRS, INSERM, PSL Research University, Equipe Labellisée Ligue Contre le Cancer, Paris 75005, France
| | - Jia-Shu Yang
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, and Dept. of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Sarah Innes-Gold
- Dept. of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Sunny Das
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Ferenc Reinhardt
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Kim Sigmund
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Vaishnavi V Phadnis
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Dept. of Biology, MIT, Cambridge, MA 02139, USA
| | - Zhengpeng Wan
- Dept. of Biological Engineering, MIT, Cambridge, MA 02139, USA
| | - Elinor Eaton
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Julio L Sampaio
- Institut Curie, INSERM, Mines ParisTech, Paris 75005, France
| | - George W Bell
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Amartya Viravalli
- Dept. of Chemical Engineering and Materials Science, University of Minnesota Minneapolis, MN 55455, USA
| | - Paula T Hammond
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA 02139, USA
- Dept. of Chemical Engineering, MIT, Cambridge, MA 02139, USA
- Senior author
| | - Roger D Kamm
- Dept. of Biological Engineering, MIT, Cambridge, MA 02139, USA
- Dept. of Physics, Harvard University, Cambridge, MA 02138, USA
- Senior author
| | - Adam E Cohen
- Dept. of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Dept. of Physics, Harvard University, Cambridge, MA 02138, USA
- Senior author
| | - Natalie Boehnke
- Dept. of Chemical Engineering and Materials Science, University of Minnesota Minneapolis, MN 55455, USA
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA 02139, USA
- Senior author
| | - Victor W Hsu
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, and Dept. of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Senior author
| | - Kandice R Levental
- Dept. of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA 22903, USA
- Senior author
| | - Raphaël Rodriguez
- Institut Curie, CNRS, INSERM, PSL Research University, Equipe Labellisée Ligue Contre le Cancer, Paris 75005, France
- Senior author
| | - Robert A Weinberg
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Dept. of Biology, MIT, Cambridge, MA 02139, USA
- Ludwig Center for Molecular Oncology, Cambridge, MA 02139, USA
- Senior author
| |
Collapse
|
2
|
Chintapula U, Yang S, Nguyen T, Li Y, Jaworski J, Dong H, Nguyen KT. Supramolecular Peptide Nanofiber/PLGA Nanocomposites for Enhancing Pulmonary Drug Delivery. ACS APPLIED MATERIALS & INTERFACES 2022; 14:56498-56509. [PMID: 36475601 DOI: 10.1021/acsami.2c15204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Effective drug delivery to pulmonary sites will benefit from the design and synthesis of novel drug delivery systems that can overcome various tissue and cellular barriers. Cell penetrating peptides (CPPs) have shown promise for intracellular delivery of various imaging probes and therapeutics. Although CPPs improve delivery efficacy to a certain extent, they still lack the scope of engineering to improve the payload capacity and protect the payload from the physiological environment in drug delivery applications. Inspired by recent advances of CPPs and CPP-functionalized nanoparticles, in this work, we demonstrate a novel nanocomposite consisting of fiber-forming supramolecular CPPs that are coated onto polylactic-glycolic acid (PLGA) nanoparticles to enhance pulmonary drug delivery. These nanocomposites show a threefold higher intracellular delivery of nanoparticles in various cells including primary lung epithelial cells, macrophages, and a 10-fold increase in endothelial cells compared to naked PLGA nanoparticles or a twofold increase compared to nanoparticles modified with traditional monomeric CPPs. Cell uptake studies suggest that nanocomposites likely enter cells through mixed macropinocytosis and passive energy-independent mechanisms, which is followed by endosomal escape within 24 h. Nanocomposites also showed potent mucus permeation. More importantly, freeze-drying and nebulizing formulated nanocomposite powder did not affect their physiochemical and biological activity, which further highlights the translative potential for use as a stable drug carrier for pulmonary drug delivery. We expect nanocomposites based on peptide nanofibers, and PLGA nanoparticles can be custom designed to encapsulate and deliver a wide range of therapeutics including nucleic acids, proteins, and small-molecule drugs when employed in inhalable systems to treat various pulmonary diseases.
Collapse
Affiliation(s)
- Uday Chintapula
- Department of Bioengineering, University of Texas at Arlington, Engineering Research Building, Room 226, 500 UTA Blvd., Arlington, Texas 76010, United States
| | - Su Yang
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Chemistry & Physics Building, Room 130, 700 Planetarium Place, Arlington, Texas 76019, United States
| | - Trinh Nguyen
- Department of Bioengineering, University of Texas at Arlington, Engineering Research Building, Room 226, 500 UTA Blvd., Arlington, Texas 76010, United States
| | - Yang Li
- Department of Biophysics, University of Texas at Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Justyn Jaworski
- Department of Bioengineering, University of Texas at Arlington, Engineering Research Building, Room 226, 500 UTA Blvd., Arlington, Texas 76010, United States
| | - He Dong
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Chemistry & Physics Building, Room 130, 700 Planetarium Place, Arlington, Texas 76019, United States
| | - Kytai T Nguyen
- Department of Bioengineering, University of Texas at Arlington, Engineering Research Building, Room 226, 500 UTA Blvd., Arlington, Texas 76010, United States
| |
Collapse
|
3
|
Griffiths G, Gruenberg J, Marsh M, Wohlmann J, Jones AT, Parton RG. Nanoparticle entry into cells; the cell biology weak link. Adv Drug Deliv Rev 2022; 188:114403. [PMID: 35777667 DOI: 10.1016/j.addr.2022.114403] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 12/22/2022]
Abstract
Nanoparticles (NP) are attractive options for the therapeutic delivery of active pharmaceutical drugs, proteins and nucleic acids into cells, tissues and organs. Research into the development and application of NP most often starts with a diverse group of scientists, including chemists, bioengineers and material and pharmaceutical scientists, who design, fabricate and characterize NP in vitro (Stage 1). The next step (Stage 2) generally investigates cell toxicity as well as the processes by which NP bind, are internalized and deliver their cargo to appropriate model tissue culture cells. Subsequently, in Stage 3, selected NP are tested in animal systems, mostly mouse. Whereas the chemistry-based development and analysis in Stage 1 is increasingly sophisticated, the investigations in Stage 2 are not what could be regarded as 'state-of-the-art' for the cell biology field and the quality of research into NP interactions with cells is often sub-standard. In this review we describe our current understanding of the mechanisms by which particles gain entry into mammalian cells via endocytosis. We summarize the most important areas for concern, highlight some of the most common mis-conceptions, and identify areas where NP scientists could engage with trained cell biologists. Our survey of the different mechanisms of uptake into cells makes us suspect that claims for roles for caveolae, as well as macropinocytosis, in NP uptake into cells have been exaggerated, whereas phagocytosis has been under-appreciated.
Collapse
Affiliation(s)
- Gareth Griffiths
- Department Biosciences, University of Oslo, Blindernveien 31, PO Box 1041, 0316 Oslo, Norway.
| | - Jean Gruenberg
- Department of Biochemistry, University of Geneva, 30 quai E. Ansermet, 1211-Geneva-4, Switzerland
| | - Mark Marsh
- Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jens Wohlmann
- Department Biosciences, University of Oslo, Blindernveien 31, PO Box 1041, 0316 Oslo, Norway
| | - Arwyn T Jones
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF103NB, UK
| | - Robert G Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, The University of Queensland, Qld 4072, Australia
| |
Collapse
|
4
|
Matozo T, Kogachi L, de Alencar BC. Myosin motors on the pathway of viral infections. Cytoskeleton (Hoboken) 2022; 79:41-63. [PMID: 35842902 DOI: 10.1002/cm.21718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/25/2022] [Accepted: 07/07/2022] [Indexed: 01/30/2023]
Abstract
Molecular motors are microscopic machines that use energy from adenosine triphosphate (ATP) hydrolysis to generate movement. While kinesins and dynein are molecular motors associated with microtubule tracks, myosins bind to and move on actin filaments. Mammalian cells express several myosin motors. They power cellular processes such as endo- and exocytosis, intracellular trafficking, transcription, migration, and cytokinesis. As viruses navigate through cells, they may take advantage or be hindered by host components and machinery, including the cytoskeleton. This review delves into myosins' cell roles and compares them to their reported functions in viral infections. In most cases, the previously described myosin functions align with their reported role in viral infections, although not in all cases. This opens the possibility that knowledge obtained from studying myosins in viral infections might shed light on new physiological roles for myosins in cells. However, given the high number of myosins expressed and the variety of viruses investigated in the different studies, it is challenging to infer whether the interactions found are specific to a single virus or can be applied to other viruses with the same characteristics. We conclude that the participation of myosins in viral cycles is still a largely unexplored area, especially concerning unconventional myosins.
Collapse
Affiliation(s)
- Tais Matozo
- Departamento de Imunologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Leticia Kogachi
- Departamento de Imunologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Bruna Cunha de Alencar
- Departamento de Imunologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| |
Collapse
|
5
|
Factors Affecting Spontaneous Endocytosis and Survival of Probiotic Lactobacilli in Human Intestinal Epithelial Cells. Microorganisms 2022; 10:microorganisms10061142. [PMID: 35744660 PMCID: PMC9230732 DOI: 10.3390/microorganisms10061142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022] Open
Abstract
Mutualistic bacteria have different forms of interaction with the host. In contrast to the invasion of pathogenic bacteria, naturally occurring internalization of commensal bacteria has not been studied in depth. Three in vitro methods, gentamicin protection, flow cytometry and confocal laser scanning microscopy, have been implemented to accurately assess the internalization of two lactobacillus strains—Lacticaseibacillus paracasei BL23 and Lacticaseibacillus rhamnosus GG—in Caco-2 and T84 intestinal epithelial cells (IECs) under a variety of physiological conditions and with specific inhibitors. First and most interesting, internalization occurred at a variable rate that depends on the bacterial strain and IEC line, and the most efficient was BL23 internalization by T84 and, second, efficient internalization required active IEC proliferation, as it improved naturally at the early confluence stages and by stimulation with epidermal growth factor (EGF). IFN-γ is bound to innate immune responses and autolysis; this cytokine had a significant effect on internalization, as shown by flow cytometry, but increased internalization was not perceived in all conditions, possibly because it was also stimulating autolysis and, as a consequence, the viability of bacteria after uptake could be affected. Bacterial uptake required actin polymerization, as shown by cytochalasin D inhibition, and it was partially bound to clathrin and caveolin dependent endocytosis. It also showed partial inhibition by ML7 indicating the involvement of cholesterol lipid rafts and myosin light chain kinase (MLCK) activation, at least in the LGG uptake by Caco-2. Most interestingly, bacteria remained viable inside the IEC for as long as 72 h without damaging the epithelial cells, and paracellular transcytosis was observed. These results stressed the fact that internalization of commensal and mutualistic bacteria is a natural, nonpathogenic process that may be relevant in crosstalk processes between the intestinal populations and the host, and future studies could determine its connection to processes such as commensal tolerance, resilience of microbial populations or transorganic bacterial migration.
Collapse
|
6
|
Abouelezz A, Almeida-Souza L. The mammalian endocytic cytoskeleton. Eur J Cell Biol 2022; 101:151222. [DOI: 10.1016/j.ejcb.2022.151222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 12/27/2022] Open
|
7
|
Islam MS, Junod SL, Zhang S, Buuh ZY, Guan Y, Zhao M, Kaneria KH, Kafley P, Cohen C, Maloney R, Lyu Z, Voelz VA, Yang W, Wang RE. Unprotected peptide macrocyclization and stapling via a fluorine-thiol displacement reaction. Nat Commun 2022; 13:350. [PMID: 35039490 PMCID: PMC8763920 DOI: 10.1038/s41467-022-27995-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/19/2021] [Indexed: 12/31/2022] Open
Abstract
We report the discovery of a facile peptide macrocyclization and stapling strategy based on a fluorine thiol displacement reaction (FTDR), which renders a class of peptide analogues with enhanced stability, affinity, cellular uptake, and inhibition of cancer cells. This approach enabled selective modification of the orthogonal fluoroacetamide side chains in unprotected peptides in the presence of intrinsic cysteines. The identified benzenedimethanethiol linker greatly promoted the alpha helicity of a variety of peptide substrates, as corroborated by molecular dynamics simulations. The cellular uptake of benzenedimethanethiol stapled peptides appeared to be universally enhanced compared to the classic ring-closing metathesis (RCM) stapled peptides. Pilot mechanism studies suggested that the uptake of FTDR-stapled peptides may involve multiple endocytosis pathways in a distinct pattern in comparison to peptides stapled by RCM. Consistent with the improved cell permeability, the FTDR-stapled lead Axin and p53 peptide analogues demonstrated enhanced inhibition of cancer cells over the RCM-stapled analogues and the unstapled peptides. Strategies capable of stapling unprotected peptides in a straightforward, chemoselective, and clean manner, as well as promoting cellular uptake are of great interest. Here the authors report a peptide macrocyclization and stapling strategy which satisfies those criteria, based on a fluorine thiol displacement reaction.
Collapse
Affiliation(s)
- Md Shafiqul Islam
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Samuel L Junod
- Department of Biology, Temple University, 1900 N. 12th Street, Philadelphia, PA, 19122, USA
| | - Si Zhang
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Zakey Yusuf Buuh
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Yifu Guan
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Mi Zhao
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Kishan H Kaneria
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Parmila Kafley
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Carson Cohen
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Robert Maloney
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Zhigang Lyu
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Vincent A Voelz
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA
| | - Weidong Yang
- Department of Biology, Temple University, 1900 N. 12th Street, Philadelphia, PA, 19122, USA
| | - Rongsheng E Wang
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA, 19122, USA.
| |
Collapse
|
8
|
Gustafsson JK, Davis JE, Rappai T, McDonald KG, Kulkarni DH, Knoop KA, Hogan SP, Fitzpatrick JAJ, Lencer WI, Newberry RD. Intestinal goblet cells sample and deliver lumenal antigens by regulated endocytic uptake and transcytosis. eLife 2021; 10:e67292. [PMID: 34677124 PMCID: PMC8594945 DOI: 10.7554/elife.67292] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 10/20/2021] [Indexed: 12/12/2022] Open
Abstract
Intestinal goblet cells maintain the protective epithelial barrier through mucus secretion and yet sample lumenal substances for immune processing through formation of goblet cell associated antigen passages (GAPs). The cellular biology of GAPs and how these divergent processes are balanced and regulated by goblet cells remains unknown. Using high-resolution light and electron microscopy, we found that in mice, GAPs were formed by an acetylcholine (ACh)-dependent endocytic event remarkable for delivery of fluid-phase cargo retrograde into the trans-golgi network and across the cell by transcytosis - in addition to the expected transport of fluid-phase cargo by endosomes to multi-vesicular bodies and lysosomes. While ACh also induced goblet cells to secrete mucins, ACh-induced GAP formation and mucin secretion were functionally independent and mediated by different receptors and signaling pathways, enabling goblet cells to differentially regulate these processes to accommodate the dynamically changing demands of the mucosal environment for barrier maintenance and sampling of lumenal substances.
Collapse
Affiliation(s)
- Jenny K Gustafsson
- Department of Neuroscience and Physiology, University of GothenburgGothenburgSweden
- Department of Internal Medicine, Washington University School of MedicineSt LouisUnited States
| | - Jazmyne E Davis
- Department of Internal Medicine, Washington University School of MedicineSt LouisUnited States
| | - Tracy Rappai
- Center for Cellular Imaging, Washington University School of MedicineSt LouisUnited States
| | - Keely G McDonald
- Department of Internal Medicine, Washington University School of MedicineSt LouisUnited States
| | - Devesha H Kulkarni
- Department of Internal Medicine, Washington University School of MedicineSt LouisUnited States
| | - Kathryn A Knoop
- Department of Internal Medicine, Washington University School of MedicineSt LouisUnited States
| | - Simon P Hogan
- Mary H. Weiser Food Allergy Center, University of Michigan School of Medicine,Ann ArborUnited States
| | - James AJ Fitzpatrick
- Center for Cellular Imaging, Washington University School of MedicineSt LouisUnited States
- Department of Cell Biology &Physiology, Washington University School of MedicineSt LouisUnited States
- Department of Neuroscience, Washington University School of MedicineSt LouisUnited States
- Department of Biomedical Engineering, Washington University in St. LouisSt. LouisUnited States
| | - Wayne I Lencer
- Department of Pediatrics, Harvard Medical SchoolBostonUnited States
- Division of Gastroenterology, Nutrition and Hepatology, Boston Children’s HospitalBostonUnited States
- Harvard Digestive Disease Center, Harvard Medical SchoolBostonUnited States
| | - Rodney D Newberry
- Department of Internal Medicine, Washington University School of MedicineSt LouisUnited States
| |
Collapse
|
9
|
Liu CCS, Cheung PW, Dinesh A, Baylor N, Paunescu TC, Nair AV, Bouley R, Brown D. Actin-related protein 2/3 complex plays a critical role in the aquaporin-2 exocytotic pathway. Am J Physiol Renal Physiol 2021; 321:F179-F194. [PMID: 34180716 PMCID: PMC8424666 DOI: 10.1152/ajprenal.00015.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The trafficking of proteins such as aquaporin-2 (AQP2) in the exocytotic pathway requires an active actin cytoskeleton network, but the mechanism is incompletely understood. Here, we show that the actin-related protein (Arp)2/3 complex, a key factor in actin filament branching and polymerization, is involved in the shuttling of AQP2 between the trans-Golgi network (TGN) and the plasma membrane. Arp2/3 inhibition (using CK-666) or siRNA knockdown blocks vasopressin-induced AQP2 membrane accumulation and induces the formation of distinct AQP2 perinuclear patches positive for markers of TGN-derived clathrin-coated vesicles. After a 20°C cold block, AQP2 formed perinuclear patches due to continuous endocytosis coupled with inhibition of exit from TGN-associated vesicles. Upon rewarming, AQP2 normally leaves the TGN and redistributes into the cytoplasm, entering the exocytotic pathway. Inhibition of Arp2/3 blocked this process and trapped AQP2 in clathrin-positive vesicles. Taken together, these results suggest that Arp2/3 is essential for AQP2 trafficking, specifically for its delivery into the post-TGN exocytotic pathway to the plasma membrane.NEW & NOTEWORTHY Aquaporin-2 (AQP2) undergoes constitutive recycling between the cytoplasm and plasma membrane, with an intricate balance between endocytosis and exocytosis. By inhibiting the actin-related protein (Arp)2/3 complex, we prevented AQP2 from entering the exocytotic pathway at the post-trans-Golgi network level and blocked AQP2 membrane accumulation. Arp2/3 inhibition, therefore, enables us to separate and target the exocytotic process, while not affecting endocytosis, thus allowing us to envisage strategies to modulate AQP2 trafficking and treat water balance disorders.
Collapse
Affiliation(s)
- Chen-Chung Steven Liu
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Pui Wen Cheung
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Anupama Dinesh
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Noah Baylor
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Theodor C. Paunescu
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Anil V. Nair
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Richard Bouley
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
10
|
Białas N, Müller EK, Epple M, Hilger I. Silica-coated calcium phosphate nanoparticles for gene silencing of NF-κB p65 by siRNA and their impact on cellular players of inflammation. Biomaterials 2021; 276:121013. [PMID: 34252802 DOI: 10.1016/j.biomaterials.2021.121013] [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: 04/07/2021] [Revised: 06/08/2021] [Accepted: 07/04/2021] [Indexed: 12/21/2022]
Abstract
The transcription factor NF-κB and its signaling cascade both play key roles in all inflammatory processes. The most critical member of the NF-κB transcription factor family is p65. We investigated the role of cationic silica-coated calcium phosphate nanoparticles (spherical, diameter by SEM 50-60 nm; zeta potential about +26 mV; stabilized by polyethyleneimine) carrying encapsulated siRNA against NF-κB p65 and their influence on inflamed cells. The nanoparticles were taken up by cells of the blood compartment involved in the inflammatory response, particularly by monocytes, and to a lesser extent by endothelial cells and B-cells, but not by T-cells. The particles were found in endolysosomes where they were dissolved at low pH and released the siRNA into the cytoplasm. This was confirmed by dissolution experiments of model nanoparticles in simulated endolysosomal medium (pH 4.7) and by intracellular co-localization studies of double-labeled nanoparticles (using a negatively charged model peptide for siRNA). The encapsulated functional siRNA reverted the p65 gene and protein expression in inflamed monocytes, the main cells in immune response and surveillance, almost back to the non-inflammatory condition. Additionally, the nanoparticles suppressed the pro-inflammatory cytokine expression profiles (TNF-α, IL-6, IFN-β) in inflamed J774A.1 monocytes. Taken together, such nanoparticles can be applied for the treatment of inflammatory diseases.
Collapse
Affiliation(s)
- Nataniel Białas
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117, Essen, Germany
| | - Elena K Müller
- Dept. of Experimental Radiology, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, D-07740, Jena, Germany
| | - Matthias Epple
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117, Essen, Germany.
| | - Ingrid Hilger
- Dept. of Experimental Radiology, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, D-07740, Jena, Germany.
| |
Collapse
|
11
|
Tan W, Zhang Q, Wang J, Yi M, He H, Xu B. Enzymatic Assemblies of Thiophosphopeptides Instantly Target Golgi Apparatus and Selectively Kill Cancer Cells*. Angew Chem Int Ed Engl 2021; 60:12796-12801. [PMID: 33783926 PMCID: PMC8159897 DOI: 10.1002/anie.202102601] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/19/2021] [Indexed: 01/01/2023]
Abstract
Changing an oxygen atom of the phosphoester bond in phosphopeptides by a sulfur atom enables instantly targeting Golgi apparatus (GA) and selectively killing cancer cells by enzymatic self-assembly. Specifically, conjugating cysteamine S-phosphate to the C-terminal of a self-assembling peptide generates a thiophosphopeptide. Being a substrate of alkaline phosphatase (ALP), the thiophosphopeptide undergoes rapid ALP-catalyzed dephosphorylation to form a thiopeptide that self-assembles. The thiophosphopeptide enters cells via caveolin-mediated endocytosis and macropinocytosis and instantly accumulates in GA because of dephosphorylation and formation of disulfide bonds in Golgi by themselves and with Golgi proteins. Moreover, the thiophosphopeptide potently and selectively inhibits cancer cells (HeLa) with the IC50 (about 3 μM), which is an order of magnitude more potent than that of the parent phosphopeptide.
Collapse
Affiliation(s)
- Weiyi Tan
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Qiuxin Zhang
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Jiaqing Wang
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Meihui Yi
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Hongjian He
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Bing Xu
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| |
Collapse
|
12
|
Tan W, Zhang Q, Wang J, Yi M, He H, Xu B. Enzymatic Assemblies of Thiophosphopeptides Instantly Target Golgi Apparatus and Selectively Kill Cancer Cells**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Weiyi Tan
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Qiuxin Zhang
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Jiaqing Wang
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Meihui Yi
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Hongjian He
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Bing Xu
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| |
Collapse
|
13
|
Cortada E, Serradesanferm R, Brugada R, Verges M. The voltage-gated sodium channel β2 subunit associates with lipid rafts by S-palmitoylation. J Cell Sci 2021; 134:jcs.252189. [PMID: 33602743 DOI: 10.1242/jcs.252189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/08/2021] [Indexed: 12/19/2022] Open
Abstract
The voltage-gated sodium channel is critical for cardiomyocyte function. It consists of a protein complex comprising a pore-forming α subunit and associated β subunits. In polarized Madin-Darby canine kidney cells, we show evidence by acyl-biotin exchange that β2 is S-acylated at Cys-182. Interestingly, we found that palmitoylation increases β2 association with detergent-resistant membranes. β2 localizes exclusively to the apical surface. However, depletion of plasma membrane cholesterol, or blocking intracellular cholesterol transport, caused mislocalization of β2, as well as of the non-palmitoylable C182S mutant, to the basolateral domain. Apical β2 did not undergo endocytosis and displayed limited diffusion within the plane of the membrane; such behavior suggests that, at least in part, it is cytoskeleton anchored. Upon acute cholesterol depletion, its mobility was greatly reduced, and a slight reduction was also measured as a result of lack of palmitoylation, supporting β2 association with cholesterol-rich lipid rafts. Indeed, lipid raft labeling confirmed a partial overlap with apical β2. Although β2 palmitoylation was not required to promote surface localization of the α subunit, our data suggest that it is likely implicated in lipid raft association and the polarized localization of β2.
Collapse
Affiliation(s)
- Eric Cortada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain
| | - Robert Serradesanferm
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain.,Medical Sciences Department, University of Girona Medical School, 17071 Girona, Spain.,Cardiology Department, Hospital Josep Trueta - University of Girona Medical School, 17007 Girona, Spain
| | - Marcel Verges
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain .,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain.,Medical Sciences Department, University of Girona Medical School, 17071 Girona, Spain
| |
Collapse
|
14
|
Smoothelin-like 2 Inhibits Coronin-1B to Stabilize the Apical Actin Cortex during Epithelial Morphogenesis. Curr Biol 2021; 31:696-706.e9. [PMID: 33275893 DOI: 10.1016/j.cub.2020.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 09/24/2020] [Accepted: 11/03/2020] [Indexed: 11/22/2022]
Abstract
The actin cortex is involved in many biological processes and needs to be significantly remodeled during cell differentiation. Developing epithelial cells construct a dense apical actin cortex to carry out their barrier and exchange functions. The apical cortex assembles in response to three-dimensional (3D) extracellular cues, but the regulation of this process during epithelial morphogenesis remains unknown. Here, we describe the function of Smoothelin-like 2 (SMTNL2), a member of the smooth-muscle-related Smoothelin protein family, in apical cortex maturation. SMTNL2 is induced during development in multiple epithelial tissues and localizes to the apical and junctional actin cortex in intestinal and kidney epithelial cells. SMTNL2 deficiency leads to membrane herniations in the apical domain of epithelial cells, indicative of cortex abnormalities. We find that SMTNL2 binds to actin filaments and is required to slow down the turnover of apical actin. We also characterize the SMTNL2 proximal interactome and find that SMTNL2 executes its functions partly through inhibition of coronin-1B. Although coronin-1B-mediated actin dynamics are required for early morphogenesis, its sustained activity is detrimental for the mature apical shape. SMTNL2 binds to coronin-1B through its N-terminal coiled-coil region and negates its function to stabilize the apical cortex. In sum, our results unveil a mechanism for regulating actin dynamics during epithelial morphogenesis, providing critical insights on the developmental control of the cellular cortex.
Collapse
|
15
|
Saric A, Freeman SA. Endomembrane Tension and Trafficking. Front Cell Dev Biol 2021; 8:611326. [PMID: 33490077 PMCID: PMC7820182 DOI: 10.3389/fcell.2020.611326] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Eukaryotic cells employ diverse uptake mechanisms depending on their specialized functions. While such mechanisms vary widely in their defining criteria: scale, molecular machinery utilized, cargo selection, and cargo destination, to name a few, they all result in the internalization of extracellular solutes and fluid into membrane-bound endosomes. Upon scission from the plasma membrane, this compartment is immediately subjected to extensive remodeling which involves tubulation and vesiculation/budding of the limiting endomembrane. This is followed by a maturation process involving concomitant retrograde transport by microtubule-based motors and graded fusion with late endosomes and lysosomes, organelles that support the degradation of the internalized content. Here we review an important determinant for sorting and trafficking in early endosomes and in lysosomes; the control of tension on the endomembrane. Remodeling of endomembranes is opposed by high tension (caused by high hydrostatic pressure) and supported by the relief of tension. We describe how the timely and coordinated efflux of major solutes along the endocytic pathway affords the cell control over such tension. The channels and transporters that expel the smallest components of the ingested medium from the early endocytic fluid are described in detail as these systems are thought to enable endomembrane deformation by curvature-sensing/generating coat proteins. We also review similar considerations for the lysosome where resident hydrolases liberate building blocks from luminal macromolecules and transporters flux these organic solutes to orchestrate trafficking events. How the cell directs organellar trafficking based on the luminal contents of organelles of the endocytic pathway is not well-understood, however, we propose that the control over membrane tension by solute transport constitutes one means for this to ensue.
Collapse
Affiliation(s)
- Amra Saric
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Center for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
16
|
Uc PY, Miranda J, Raya-Sandino A, Alarcón L, Roldán ML, Ocadiz-Delgado R, Cortés-Malagón EM, Chávez-Munguía B, Ramírez G, Asomoza R, Shoshani L, Gariglio P, González-Mariscal L. E7 oncoprotein from human papillomavirus 16 alters claudins expression and the sealing of epithelial tight junctions. Int J Oncol 2020; 57:905-924. [PMID: 32945372 PMCID: PMC7473757 DOI: 10.3892/ijo.2020.5105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 04/16/2020] [Indexed: 11/24/2022] Open
Abstract
Tight junctions (TJs) are cell-cell adhesion structures frequently altered by oncogenic transformation. In the present study the role of human papillomavirus (HPV) 16 E7 oncoprotein on the sealing of TJs was investigated and also the expression level of claudins in mouse cervix and in epithelial Madin-Darby Canine Kidney (MDCK) cells. It was found that there was reduced expression of claudins -1 and -10 in the cervix of 7-month-old transgenic K14E7 mice treated with 17β-estradiol (E2), with invasive cancer. In addition, there was also a transient increase in claudin-1 expression in the cervix of 2-month-old K14E7 mice, and claudin-10 accumulated at the border of cells in the upper layer of the cervix in FvB mice treated with E2, and in K14E7 mice treated with or without E2. These changes were accompanied by an augmented paracellular permeability of the cervix in 2- and 7-monthold FvB mice treated with E2, which became more pronounced in K14E7 mice treated with or without E2. In MDCK cells the stable expression of E7 increased the space between adjacent cells and altered the architecture of the monolayers, induced the development of an acute peak of transepithelial electrical resistance accompanied by a reduced expression of claudins -1, -2 and -10, and an increase in claudin-4. Moreover, E7 enhances the ability of MDCK cells to migrate through a 3D matrix and induces cell stiffening and stress fiber formation. These observations revealed that cell transformation induced by HPV16 E7 oncoprotein was accompanied by changes in the pattern of expression of claudins and the degree of sealing of epithelial TJs.
Collapse
Affiliation(s)
- Perla Yaceli Uc
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Jael Miranda
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Arturo Raya-Sandino
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Lourdes Alarcón
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - María Luisa Roldán
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Rodolfo Ocadiz-Delgado
- Department of Genetics and Molecular Biology, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Enoc Mariano Cortés-Malagón
- Research Unit on Genetics and Cancer, Research Division, Hospital Juárez de México, Mexico City 07760, Mexico
| | - Bibiana Chávez-Munguía
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Georgina Ramírez
- Department of Electrical Engineering, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - René Asomoza
- Department of Electrical Engineering, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Liora Shoshani
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Patricio Gariglio
- Department of Genetics and Molecular Biology, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| | - Lorenza González-Mariscal
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies, Mexico City 07360, Mexico
| |
Collapse
|
17
|
Fong VH, Wong S, Jintaridhi P, Vieira A. Transport of the Thyroid Hormone Carrier Protein Transthyretin into Human Epidermoid Cells. Endocr Res 2020; 45:131-136. [PMID: 31762320 DOI: 10.1080/07435800.2019.1694538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Purpose: Transthyretin (TTR) is a protein with a growing number of biological functions in addition to its well-established binding and circulatory transport of thyroxine, and indirect retinoid transport through interaction with retinol-binding protein. Misfolded and aggregated wild-type and mutant TTRs are involved in amyloid diseases. Several aspects of TTR pathology and physiology remain poorly understood. Receptor-mediated cellular transport of TTR has been described in a few cell types; and such studies suggest the possibility of different TTR receptors and endocytic pathways. Our main objective was to further understand the endocytic pathways for TTR.Methods: In the current study, analyses of TTR endocytic transport were performed in the human A431 cell line. The results of TTR uptake were compared with those of the iron-carrier protein transferrin (Tf, a common stardard for endocytosis studies) in the same cell types.Results: A comparison of TTR and Tf endocytosis suggested similar early, 5-10 min, accumulation kinetics. But at a later time, 30 min, TTR accumulation was 20-30% lower than that of Tf (p < .05), a result that suggests different post-endocytic fates for these two ligands. Through the use of multiple endocytosis inhibitors, biochemical evidence is provided for an internalization pathway that differs from the clathrin-mediated endocytosis of Tf.Conclusions: These results for A431 cells are compared with others reported for different cell types; and it is suggested that this same hormone carrier protein can transit into cells through multiple endocytic pathways.
Collapse
Affiliation(s)
- Vai Hong Fong
- Biomedical Physiology BPK, Simon Fraser University, Burnaby, BC, Canada
- Department of Neurology, Far Eastern Memorial University Hospital, New Taipei City, Taiwan
| | - Shaun Wong
- Biomedical Physiology BPK, Simon Fraser University, Burnaby, BC, Canada
| | | | - Amandio Vieira
- Biomedical Physiology BPK, Simon Fraser University, Burnaby, BC, Canada
| |
Collapse
|
18
|
Amato C, Thomason PA, Davidson AJ, Swaminathan K, Ismail S, Machesky LM, Insall RH. WASP Restricts Active Rac to Maintain Cells' Front-Rear Polarization. Curr Biol 2019; 29:4169-4182.e4. [PMID: 31786060 PMCID: PMC6926487 DOI: 10.1016/j.cub.2019.10.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 10/01/2019] [Accepted: 10/18/2019] [Indexed: 12/20/2022]
Abstract
Efficient motility requires polarized cells, with pseudopods at the front and a retracting rear. Polarization is maintained by restricting the pseudopod catalyst, active Rac, to the front. Here, we show that the actin nucleation-promoting factor Wiskott-Aldrich syndrome protein (WASP) contributes to maintenance of front-rear polarity by controlling localization and cellular levels of active Rac. Dictyostelium cells lacking WASP inappropriately activate Rac at the rear, which affects their polarity and speed. WASP's Cdc42 and Rac interacting binding ("CRIB") motif has been thought to be essential for its activation. However, we show that the CRIB motif's biological role is unexpectedly complex. WASP CRIB mutants are no longer able to restrict Rac activity to the front, and cannot generate new pseudopods when SCAR/WAVE is absent. Overall levels of Rac activity also increase when WASP is unable to bind to Rac. However, WASP without a functional CRIB domain localizes normally at clathrin pits during endocytosis, and activates Arp2/3 complex. Similarly, chemical inhibition of Rac does not affect WASP localization or activation at sites of endocytosis. Thus, the interaction between small GTPases and WASP is more complex than previously thought-Rac regulates a subset of WASP functions, but WASP reciprocally restricts active Rac through its CRIB motif.
Collapse
Affiliation(s)
- Clelia Amato
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
| | - Peter A Thomason
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Andrew J Davidson
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Karthic Swaminathan
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Shehab Ismail
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Laura M Machesky
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Robert H Insall
- CRUK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| |
Collapse
|
19
|
Polyhistidine facilitates direct membrane translocation of cell-penetrating peptides into cells. Sci Rep 2019; 9:9398. [PMID: 31253836 PMCID: PMC6599048 DOI: 10.1038/s41598-019-45830-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 06/14/2019] [Indexed: 12/27/2022] Open
Abstract
The bovine lactoferricin L6 (RRWQWR) has been previously identified as a novel cell-penetrating peptide (CPP) that is able to efficiently internalize into human cells. L6 interacts with quantum dots (QDs) noncovalently to generate stable L6/QD complexes that enter cells by endocytosis. In this study, we demonstrate a modified L6 (HL6; CHHHHHRRWQWRHHHHHC), in which short polyhistidine peptides are introduced into both flanks of L6, has enhanced cell-penetrating ability in human bronchoalveolar carcinoma A549 cells. The mechanism of cellular uptake of HL6/QD complexes is primarily direct membrane translocation rather than endocytosis. Dimethyl sulfoxide (DMSO), but not pyrenebutyrate (PB), ethanol, oleic acid, or 1,2-benzisothiazol-3(2 H)-one (BIT), slightly enhances HL6-mediated protein transduction efficiency. Neither HL6 nor HL6/QD complexes are cytotoxic to A549 or HeLa cells. These results indicate that HL6 could be a more efficient drug carrier than L6 for biomedical as well as biotechnological applications, and that the function of polyhistidine peptides is critical to CPP-mediated protein transduction.
Collapse
|
20
|
Shi X, Duan F, Lin L, Xu Q, Xu T, Zhang R. WIP-1 and DBN-1 promote scission of endocytic vesicles by bridging actin and Dynamin-1 in the C. elegans intestine. J Cell Sci 2019; 132:jcs.228023. [PMID: 31118234 DOI: 10.1242/jcs.228023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/13/2019] [Indexed: 01/13/2023] Open
Abstract
There has been a consensus that actin plays an important role in scission of the clathrin-coated pits (CCPs) together with large GTPases of the dynamin family in metazoan cells. However, the recruitment, regulation and functional interdependence of actin and dynamin during this process remain inadequately understood. Here, based on small-scale screening and in vivo live-imaging techniques, we identified a novel set of molecules underlying CCP scission in the multicellular organism Caenorhabditis elegans We found that loss of Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP-1) impaired CCP scission in a manner that is independent of the C. elegans homolog of WASP/N-WASP (WSP-1) and is mediated by direct binding to G-actin. Moreover, the cortactin-binding domain of WIP-1 serves as the binding interface for DBN-1 (also known in other organisms as Abp1), another actin-binding protein. We demonstrate that the interaction between DBN-1 and F-actin is essential for Dynamin-1 (DYN-1) recruitment at endocytic sites. In addition, the recycling regulator RME-1, a homolog of mammalian Eps15 homology (EH) domain-containing proteins, is increasingly recruited at the arrested endocytic intermediates induced by F-actin loss or DYN-1 inactivation, which further stabilizes the tubular endocytic intermediates. Our study provides new insights into the molecular network underlying F-actin participation in the scission of CCPs.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Xuemeng Shi
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Fengyun Duan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Long Lin
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Qifeng Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tao Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China .,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| |
Collapse
|
21
|
Riggi M, Bourgoint C, Macchione M, Matile S, Loewith R, Roux A. TORC2 controls endocytosis through plasma membrane tension. J Cell Biol 2019; 218:2265-2276. [PMID: 31123183 PMCID: PMC6605812 DOI: 10.1083/jcb.201901096] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/11/2019] [Accepted: 05/06/2019] [Indexed: 12/27/2022] Open
Abstract
Target of rapamycin complex 2 (TORC2) is a conserved protein kinase that regulates multiple plasma membrane (PM)-related processes, including endocytosis. Direct, chemical inhibition of TORC2 arrests endocytosis but with kinetics that is relatively slow and therefore inconsistent with signaling being mediated solely through simple phosphorylation cascades. Here, we show that in addition to and independently from regulation of the phosphorylation of endocytic proteins, TORC2 also controls endocytosis by modulating PM tension. Elevated PM tension, upon TORC2 inhibition, impinges on endocytosis at two different levels by (1) severing the bonds between the PM adaptor proteins Sla2 and Ent1 and the actin cytoskeleton and (2) hindering recruitment of Rvs167, an N-BAR-containing protein important for vesicle fission to endocytosis sites. These results underline the importance of biophysical cues in the regulation of cellular and molecular processes.
Collapse
Affiliation(s)
- Margot Riggi
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland.,Department of Biochemistry, University of Geneva, Geneva, Switzerland.,iGE3 Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.,Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland
| | - Clélia Bourgoint
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Mariano Macchione
- Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland.,Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Stefan Matile
- Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland.,Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Robbie Loewith
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland .,iGE3 Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.,Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, Geneva, Switzerland .,Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland
| |
Collapse
|
22
|
Lahiani MH, Khare S, Cerniglia CE, Boy R, Ivanov IN, Khodakovskaya M. The impact of tomato fruits containing multi-walled carbon nanotube residues on human intestinal epithelial cell barrier function and intestinal microbiome composition. NANOSCALE 2019; 11:3639-3655. [PMID: 30741296 DOI: 10.1039/c8nr08604d] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Carbon nanomaterials (CNMs) can positively regulate seed germination and enhance plant growth. However, clarification of the impact of plant organs containing absorbed CNMs on animal and human health is a critical step of risk assessment for new nano-agro-technology. In this study, we have taken a comprehensive approach to studying the effect tomato fruits derived from plants exposed to multi-walled carbon nanotubes (CNTs) have on gastrointestinal epithelial barrier integrity and their impact on the human commensal intestinal microbiota using an in vitro cell culture and batch human fecal suspension models. The effects of CNTs on selected pure cultures of Salmonella enterica Typhimurium and Lactobacillus acidophilus were also evaluated. This study demonstrated that CNT-containing fruits or the corresponding residual level of pure CNTs (0.001 μg ml-1) was not sufficient to initiate a significant change in transepithelial resistance and on gene expression of the model T-84 human intestinal epithelial cells. However, at 10 μg ml-1 concentration CNTs were able to penetrate the cell membrane and change the gene expression profile of exposed cells. Moreover, extracts from CNT-containing fruits had minimal to no effect on human intestinal microbiota as revealed by culture-based analysis and 16S rRNA sequencing.
Collapse
MESH Headings
- Cell Line
- Feces/microbiology
- Fruit/chemistry
- Fruit/metabolism
- Gastrointestinal Microbiome/drug effects
- Humans
- Intestinal Mucosa/cytology
- Intestinal Mucosa/drug effects
- Intestinal Mucosa/metabolism
- Lactobacillus acidophilus/drug effects
- Lactobacillus acidophilus/genetics
- Solanum lycopersicum/chemistry
- Solanum lycopersicum/metabolism
- Nanotubes, Carbon/chemistry
- Nanotubes, Carbon/toxicity
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- Salmonella typhimurium/drug effects
- Salmonella typhimurium/genetics
- Sequence Analysis, DNA
- Spectrum Analysis, Raman
Collapse
Affiliation(s)
- Mohamed H Lahiani
- Department of Biology, University of Arkansas at Little Rock, Little Rock, AR 72204, USA.
| | | | | | | | | | | |
Collapse
|
23
|
Cardiomyocytes cultured on mechanically compliant substrates, but not on conventional culture devices, exhibit prominent mitochondrial dysfunction due to reactive oxygen species and insulin resistance under high glucose. PLoS One 2018; 13:e0201891. [PMID: 30138395 PMCID: PMC6107143 DOI: 10.1371/journal.pone.0201891] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/24/2018] [Indexed: 12/18/2022] Open
Abstract
Rationale Diabetes causes cardiac dysfunction, and understanding of its mechanism is still incomplete. One reason could be limitations in modeling disease conditions by current in vitro cardiomyocyte culture. Emerging evidence suggests that the mechanical properties of the microenvironment affect cardiomyocyte function. Nevertheless, the impact of high glucose on cardiomyocytes cultured on substrates whose stiffness matches that of the heart (approximately 15 kPa) is untested. Objective To test the hypothesis that cardiomyocytes cultured in microenvironments that mimic the mechanical properties of those for cardiomyocytes in vivo may reproduce the pathophysiology characteristics of diabetic cardiomyocytes ex vivo, such as the morphological appearance, ROS accumulation, mitochondrial dysfunction, apoptosis and insulin-stimulated glucose uptake. Methods and results Isolated neonatal rat cardiomyocytes were seeded on 15 kPa polyacrylamide (PAA) gels, whose stiffness mimics that of heart tissues, or on glass coverslips, which represent conventional culture devices but are unphysiologically stiff. Cells were then cultured at 5 mM glucose, corresponding to the normal blood glucose level, or at high glucose levels (10 to 25 mM). Cytoskeletal disorganization, ROS accumulation, attenuated mitochondrial membrane potential and attenuated ATP level caused by high glucose and their reversal by a ROS scavenger were prominent in cells on gels, but not in cells on coverslips. The lack of response to ROS scavenging could be attributable to enhanced apoptosis in cells on glass, shown by enhanced DNA fragmentation and higher caspase 3/7 activity in cells on glass coverslips. High-glucose treatment also downregulated GLUT4 expression and attenuated insulin-stimulated glucose uptake only in cells on 15 kPa gels. Conclusion Our data suggest that a mechanically compliant microenvironment increases the susceptibility of primary cardiomyocytes to elevated glucose levels, which enables these cells to serve as an innovative model for diabetic heart research.
Collapse
|
24
|
Platelets Enhance Dendritic Cell Responses against Staphylococcus aureus through CD40-CD40L. Infect Immun 2018; 86:IAI.00186-18. [PMID: 29914928 DOI: 10.1128/iai.00186-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/12/2018] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen that can cause mild to severe life-threatening infections in many tissues and organs. Platelets are known to participate in protection against S. aureus by direct killing and by enhancing the activities of neutrophils and macrophages in clearing S. aureus infection. Platelets have also been shown to induce monocyte differentiation into dendritic cells and to enhance activation of dendritic cells. Therefore, in the present study, we explored the role of platelets in enhancing bone marrow-derived dendritic cell (BMDC) function against S. aureus We observed a significant increase in dendritic cell phagocytosis and intracellular killing of a methicillin-resistant Staphylococcus aureus (MRSA) strain (USA300) by thrombin-activated platelets or their releasates. Enhancement of bacterial uptake and killing by DCs is mediated by platelet-derived CD40L. Coculture of USA300 and BMDCs in the presence of thrombin-activated platelet releasates invokes upregulation of the maturation marker CD80 on DCs and enhanced production of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin 12 (IL-12), and IL-6. Overall, these observations support our hypothesis that platelets play a critical role in the host defense against S. aureus infection. Platelets stimulate DCs, leading to direct killing of S. aureus and enhanced DC maturation, potentially leading to adaptive immune responses against S. aureus.
Collapse
|
25
|
Chentouh R, Fitting C, Cavaillon JM. Specific features of human monocytes activation by monophosphoryl lipid A. Sci Rep 2018; 8:7096. [PMID: 29728623 PMCID: PMC5935727 DOI: 10.1038/s41598-018-25367-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/09/2018] [Indexed: 01/01/2023] Open
Abstract
We deciphered the mechanisms of production of pro- and anti-inflammatory cytokines by adherent human blood mononuclear cells (PBMC) activated by lipopolysaccharide (LPS) or monophosphoryl lipid A (MPLA). Both LPS and MPLA induced tumor necrosis factor (TNF) production proved to be dependent on the production of interleukin-1β (IL-1β). Of note, MPLA induced IL-1β release in human adherent PBMCs whereas MPLA was previously reported to not induce this cytokine in murine cells. Both LPS and MPLA stimulatory effects were inhibited by Toll-like receptor-4 (TLR4) antagonists. Only monocytes activation by LPS was dependent on CD14. Other differences were noticed between LPS and MPLA. Among the different donors, a strong correlation existed in terms of the levels of TNF induced by different LPSs. In contrast, there was no correlation between the TNF productions induced by LPS and those induced by MPLA. However, there was a strong correlation when IL-6 production was analyzed. Blocking actin polymerization and internalization of the agonists inhibited MPLA induced TNF production while the effect on LPS induced TNF production depended on the donors (i.e. high TNF producers versus low TNF producers). Finally, conventional LPS, tolerized adherent PBMCs to TLR2 agonists, while MPLA primed cells to further challenge with TLR2 agonists.
Collapse
Affiliation(s)
- Ryme Chentouh
- Unit "Cytokines & Inflammation", Institut Pasteur, Paris, France
| | | | | |
Collapse
|
26
|
Feng G, Mao D, Liu J, Goh CC, Ng LG, Kong D, Tang BZ, Liu B. Polymeric nanorods with aggregation-induced emission characteristics for enhanced cancer targeting and imaging. NANOSCALE 2018; 10:5869-5874. [PMID: 29560485 DOI: 10.1039/c7nr09196f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Polymeric nanorods loaded with AIEgens are synthesized via nano-precipitation under ultrasound sonication, where prolonged sonication time could induce a nanodot-to-nanorod transition. These AIE nanorods, but not the nanodots, could be selectively internalized into cancer cells, which show better tumor accumulation, higher tumor penetration and more efficient in vivo cancer cell uptake.
Collapse
Affiliation(s)
- Guangxue Feng
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
| | - Duo Mao
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
| | - Jie Liu
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
| | - Chi Ching Goh
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, 138648, Singapore
| | - Lai Guan Ng
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, 138648, Singapore
| | - Deling Kong
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Bioactive Materials. Ministry of Education and College of Life Sciences, Nankai University, China
| | - Ben Zhong Tang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Bin Liu
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
| |
Collapse
|
27
|
|
28
|
Wang Q, An B, Hou X, Guo Y, Luo H, He C. Dicer-like Proteins Regulate the Growth, Conidiation, and Pathogenicity of Colletotrichum gloeosporioides from Hevea brasiliensis. Front Microbiol 2018; 8:2621. [PMID: 29403443 PMCID: PMC5777394 DOI: 10.3389/fmicb.2017.02621] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 12/15/2017] [Indexed: 11/17/2022] Open
Abstract
Colletotrichum gloeosporioides from Hevea brasiliensis is the hemibiotrophic fungi which could cause anthracnose in rubber trees. Dicer like proteins (DCL) were the core enzymes for generation of small RNAs. In the present study, the knocking-out mutants of two dicer like proteins encoding genes of C. gloeosporioides were constructed; and functions of two proteins were investigated. The results showed that DCL play important roles in regulating the growth, conidiation and pathogenicity of C. gloeosporioides; and there is a functional redundancy between DCL1 and DCL2. Microscopy analysis and DAB staining revealed that loss of penetration ability into the host cells, instead of the decreased growth rate, was the main cause for the impaired pathogenicity of the ΔDcl1ΔDcl2 double mutant. Proteomics analysis suggested that DCL proteins affected the expression of functional proteins to regulating multiple biological processes of C. gloeosporioides. These data lead to a better understanding of the functions of DCL proteins in regulating the development and pathogenesis of C. gloeosporioides.
Collapse
Affiliation(s)
- Qiannan Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources and College of Biology, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Bang An
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources and College of Biology, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Xingrong Hou
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources and College of Biology, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Yunfeng Guo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources and College of Biology, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Hongli Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources and College of Biology, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources and College of Biology, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| |
Collapse
|
29
|
Bhattacharyya S, Jean-Alphonse FG, Raghavan V, McGarvey JC, Rbaibi Y, Vilardaga JP, Carattino MD, Weisz OA. Cdc42 activation couples fluid shear stress to apical endocytosis in proximal tubule cells. Physiol Rep 2017; 5:5/19/e13460. [PMID: 29038362 PMCID: PMC5641940 DOI: 10.14814/phy2.13460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 08/30/2017] [Accepted: 09/04/2017] [Indexed: 11/24/2022] Open
Abstract
Cells lining the kidney proximal tubule (PT) respond to acute changes in glomerular filtration rate and the accompanying fluid shear stress (FSS) to regulate reabsorption of ions, glucose, and other filtered molecules and maintain glomerulotubular balance. Recently, we discovered that exposure of PT cells to FSS also stimulates an increase in apical endocytic capacity (Raghavan et al. PNAS, 111:8506–8511, 2014). We found that FSS triggered an increase in intracellular Ca2+ concentration ([Ca2+]i) that required release of extracellular ATP and the presence of primary cilia. In this study, we elucidate steps downstream of the increase in [Ca2+]i that link FSS‐induced calcium increase to increased apical endocytic capacity. Using an intramolecular FRET probe, we show that activation of Cdc42 is a necessary step in the FSS‐stimulated apical endocytosis cascade. Cdc42 activation requires the primary cilia and the FSS‐mediated increase in [Ca2+]i. Moreover, Cdc42 activity and FSS‐stimulated endocytosis are coordinately modulated by activators and inhibitors of calmodulin. Together, these data suggest a mechanism by which PT cell exposure to FSS is translated into enhanced endocytic uptake of filtered molecules.
Collapse
Affiliation(s)
- Sohinee Bhattacharyya
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Frédéric G Jean-Alphonse
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Venkatesan Raghavan
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jennifer C McGarvey
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Youssef Rbaibi
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Marcelo D Carattino
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Ora A Weisz
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| |
Collapse
|
30
|
Dallet L, Decossas M, Taveau JC, Lecomte S, Poussard S, Lambert O, Pitard B. Single lipoaminoglycoside promotes efficient intracellular antibody delivery: A comprehensive insight into the mechanism of action. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 14:141-151. [PMID: 28939489 DOI: 10.1016/j.nano.2017.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/07/2017] [Accepted: 09/14/2017] [Indexed: 11/30/2022]
Abstract
Delivery of biologically active proteins into cells is emerging as important strategy for many applications. Previous experiments have shown that lipoaminoglycosides were capable of delivery of the anti-cytokeratin8 antibody (anti-K8) but only when formulated with lipid helpers potentially leading to toxicity from excess lipids. Here, we optimized anti-K8 delivery with various lipoaminoglycosides in the absence of a lipid helper. Results led to the identification of the aminoglycoside lipid dioleyl phosphoramido ribostamycin (DOPRI) as a potent intracellular delivery system for anti-K8. Electron microscopy revealed that delivered anti-K8 molecules were bound to intermediate filaments in cells. Anti-K8 was bound to the surface of DOPRI vesicles without perturbing lipid organization. Macropinocytosis and caveolin mediated endocytosis contributed to anti-K8 internalization and to filament labeling with a major contribution being made by the caveolin pathway. The results showed that the unique properties of DOPRI were sufficient for efficient intracellular protein delivery without requiring lipid helpers.
Collapse
Affiliation(s)
- Laurence Dallet
- CBMN UMR-CNRS 5248, Université de Bordeaux IPB, Pessac, France; CRCINA, INSERM Université d'Angers, Université de Nantes, France
| | - Marion Decossas
- CBMN UMR-CNRS 5248, Université de Bordeaux IPB, Pessac, France
| | | | - Sophie Lecomte
- CBMN UMR-CNRS 5248, Université de Bordeaux IPB, Pessac, France
| | - Sylvie Poussard
- CBMN UMR-CNRS 5248, Université de Bordeaux IPB, Pessac, France
| | - Olivier Lambert
- CBMN UMR-CNRS 5248, Université de Bordeaux IPB, Pessac, France.
| | | |
Collapse
|
31
|
Neuronal Dysfunction in iPSC-Derived Medium Spiny Neurons from Chorea-Acanthocytosis Patients Is Reversed by Src Kinase Inhibition and F-Actin Stabilization. J Neurosci 2017; 36:12027-12043. [PMID: 27881786 DOI: 10.1523/jneurosci.0456-16.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 09/07/2016] [Accepted: 09/26/2016] [Indexed: 11/21/2022] Open
Abstract
Chorea-acanthocytosis (ChAc) is a fatal neurological disorder characterized by red blood cell acanthocytes and striatal neurodegeneration. Recently, severe cell membrane disturbances based on depolymerized cortical actin and an elevated Lyn kinase activity in erythrocytes from ChAc patients were identified. How this contributes to the mechanism of neurodegeneration is still unknown. To gain insight into the pathophysiology, we established a ChAc patient-derived induced pluripotent stem cell model and an efficient differentiation protocol providing a large population of human striatal medium spiny neurons (MSNs), the main target of neurodegeneration in ChAc. Patient-derived MSNs displayed enhanced neurite outgrowth and ramification, whereas synaptic density was similar to controls. Electrophysiological analysis revealed a pathologically elevated synaptic activity in ChAc MSNs. Treatment with the F-actin stabilizer phallacidin or the Src kinase inhibitor PP2 resulted in the significant reduction of disinhibited synaptic currents to healthy control levels, suggesting a Src kinase- and actin-dependent mechanism. This was underlined by increased G/F-actin ratios and elevated Lyn kinase activity in patient-derived MSNs. These data indicate that F-actin stabilization and Src kinase inhibition represent potential therapeutic targets in ChAc that may restore neuronal function. SIGNIFICANCE STATEMENT Chorea-acanthocytosis (ChAc) is a fatal neurodegenerative disease without a known cure. To gain pathophysiological insight, we newly established a human in vitro model using skin biopsies from ChAc patients to generate disease-specific induced pluripotent stem cells (iPSCs) and developed an efficient iPSC differentiation protocol providing striatal medium spiny neurons. Using patch-clamp electrophysiology, we detected a pathologically enhanced synaptic activity in ChAc neurons. Healthy control levels of synaptic activity could be restored by treatment of ChAc neurons with the F-actin stabilizer phallacidin and the Src kinase inhibitor PP2. Because Src kinases are involved in bridging the membrane to the actin cytoskeleton by membrane protein phosphorylation, our data suggest an actin-dependent mechanism of this dysfunctional phenotype and potential treatment targets in ChAc.
Collapse
|
32
|
Hasdemir B, Mahajan S, Oses-Prieto J, Chand S, Woolley M, Burlingame A, Grammatopoulos DK, Bhargava A. Actin cytoskeleton-dependent regulation of corticotropin-releasing factor receptor heteromers. Mol Biol Cell 2017; 28:2386-2399. [PMID: 28701349 PMCID: PMC5576902 DOI: 10.1091/mbc.e16-11-0778] [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: 11/14/2016] [Revised: 06/30/2017] [Accepted: 07/07/2017] [Indexed: 01/02/2023] Open
Abstract
A physical interaction is shown between CRF1R and CRF2R, two class B G protein–coupled receptors that mediate stress and immune responses. Trafficking of CRF2R but not CRF1R is actin dependent, and coexpression of the two receptors alters actin-independent trafficking. Receptor cross-talk alters agonist binding and signaling. Stress responses are highly nuanced and variable, but how this diversity is achieved by modulating receptor function is largely unknown. Corticotropin-releasing factor receptors (CRFRs), class B G protein–coupled receptors, are pivotal in mediating stress responses. Here we show that the two known CRFRs interact to form heteromeric complexes in HEK293 cells coexpressing both CRFRs and in vivo in mouse pancreas. Coimmunoprecipitation and mass spectrometry confirmed the presence of both CRF1R and CRF2βR, along with actin in these heteromeric complexes. Inhibition of actin filament polymerization prevented the transport of CRF2βR to the cell surface but had no effect on CRF1R. Transport of CRF1R when coexpressed with CRF2βR became actin dependent. Simultaneous stimulation of cells coexpressing CRF1R+CRF2βR with their respective high-affinity agonists, CRF+urocortin2, resulted in approximately twofold increases in peak Ca2+ responses, whereas stimulation with urocortin1 that binds both receptors with 10-fold higher affinity did not. The ability of CRFRs to form heteromeric complexes in association with regulatory proteins is one mechanism to achieve diverse and nuanced function.
Collapse
Affiliation(s)
- Burcu Hasdemir
- Osher Center for Integrative Medicine, University of California, San Francisco, San Francisco, CA 94143.,Department of Obstetrics & Gynecology, University of California, San Francisco, San Francisco, CA 94143
| | - Shilpi Mahajan
- Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Juan Oses-Prieto
- Departments of Pediatrics, Pharmacology, and Chemistry, University of California, San Francisco, San Francisco, CA 94143
| | - Shreya Chand
- Departments of Pediatrics, Pharmacology, and Chemistry, University of California, San Francisco, San Francisco, CA 94143
| | - Michael Woolley
- Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Alma Burlingame
- Departments of Pediatrics, Pharmacology, and Chemistry, University of California, San Francisco, San Francisco, CA 94143
| | - Dimitris K Grammatopoulos
- Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Aditi Bhargava
- Osher Center for Integrative Medicine, University of California, San Francisco, San Francisco, CA 94143 .,Department of Surgery, University of California, San Francisco, San Francisco, CA 94143.,Department of Obstetrics & Gynecology, University of California, San Francisco, San Francisco, CA 94143
| |
Collapse
|
33
|
Pasick J, Diederich S, Berhane Y, Embury-Hyatt C, Xu W. Imbalance between innate antiviral and pro-inflammatory immune responses may contribute to different outcomes involving low- and highly pathogenic avian influenza H5N3 infections in chickens. J Gen Virol 2017. [PMID: 28635590 DOI: 10.1099/jgv.0.000801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In order to gain further insight into the early virus-host interactions associated with highly pathogenic avian influenza virus infections in chickens, genome-wide expression profiling of chicken lung and brain was carried out at 24 and 72 h post-inoculation (h p.i.). For this purpose two recombinant H5N3 viruses were utilized, each possessing a polybasic HA0 cleavage site but differing in pathogenicity. The original rH5N3 P0 virus, which has a low-pathogenic phenotype, was passaged six times through chickens to give rise to the derivative rH5N3 P6 virus, which is highly pathogenic (Diederich S, Berhane Y, Embury-Hyatt C, Hisanaga T, Handel K et al.J Virol 2015;89:10724-10734). The gene-expression profiles in lung were similar for both viruses, although they varied in magnitude. While both viruses produced systemic infections, differences in clinical disease progression and viral tissue loads, particularly in brain, where loads of rH5N3 P6 were three orders of magnitude higher than rH5N3 P0 at 72 .p.i., were observed. Although genes associated with gene ontology (GO) categories INFα and INFβ biosynthesis, regulation of innate immune response, response to exogenous dsRNA, defence response to virus, positive regulation of NF-κB import into the nucleus and positive regulation of immune response were up-regulated in rH5N3 P0 and rH5N3 P6 brains, fold changes were higher for rH5N3 P6. The additional up-regulation of genes associated with cytokine production, inflammasome and leukocyte activation, and cell-cell adhesion detected in rH5N3 P6 versus rH5N3 P0 brains, suggested that the balance between antiviral and pro-inflammatory innate immune responses leading to acute CNS inflammation might explain the observed differences in pathogenicity.
Collapse
Affiliation(s)
- John Pasick
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, Canada.,Present address: 174 Stone Road, Guelph, Ontario, N1G 4S9, Canada
| | - Sandra Diederich
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Yohannes Berhane
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, Canada
| | - Carissa Embury-Hyatt
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, Canada
| | - Wanhong Xu
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, Canada
| |
Collapse
|
34
|
Ferrão FM, Cardoso LHD, Drummond HA, Li XC, Zhuo JL, Gomes DS, Lara LS, Vieyra A, Lowe J. Luminal ANG II is internalized as a complex with AT 1R/AT 2R heterodimers to target endoplasmic reticulum in LLC-PK 1 cells. Am J Physiol Renal Physiol 2017; 313:F440-F449. [PMID: 28468964 DOI: 10.1152/ajprenal.00261.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 04/18/2017] [Accepted: 04/23/2017] [Indexed: 12/28/2022] Open
Abstract
ANG II has many biological effects in renal physiology, particularly in Ca2+ handling in the regulation of fluid and solute reabsorption. It involves the systemic endocrine renin-angiotensin system (RAS), but tissue and intracrine ANG II are also known. We have shown that ANG II induces heterodimerization of its AT1 and AT2 receptors (AT1R and AT2R) to stimulate sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity. Thus, we investigated whether ANG II-AT1R/AT2R complex is formed and internalized, and also examined the intracellular localization of this complex to determine how its effect might be exerted on renal intracrine RAS. Living cell imaging of LLC-PK1 cells, quantification of extracellular ANG II, and use of the receptor antagonists, losartan and PD123319, showed that ANG II is internalized with AT1R/AT2R heterodimers as a complex in a microtubule-dependent and clathrin-independent manner, since colchicine-but not Pitstop2-blocked this process. This result was confirmed by an increase of β-arrestin phosphorylation after ANG II treatment, clathrin-mediated endocytosis being dependent on dephosphorylation of β-arrestin. Internalized ANG II colocalized with an endoplasmic reticulum (ER) marker and increased levels of AT1R, AT2R, and PKCα in ER-enriched membrane fractions. This novel evidence suggests the internalization of an ANG II-AT1/AT2 complex to target ER, where it might trigger intracellular Ca2+ responses.
Collapse
Affiliation(s)
- Fernanda M Ferrão
- Laboratório de Físico-Química Biológica Aída Hassón-Voloch, Instituto de Biofísica Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiza H D Cardoso
- Laboratório de Físico-Química Biológica Aída Hassón-Voloch, Instituto de Biofísica Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Heather A Drummond
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xiao C Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jia L Zhuo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Dayene S Gomes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lucienne S Lara
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adalberto Vieyra
- Laboratório de Físico-Química Biológica Aída Hassón-Voloch, Instituto de Biofísica Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and.,National Institute of Science and Technology for Regenerative Medicine, Rio de Janeiro, Brazil
| | - Jennifer Lowe
- Laboratório de Físico-Química Biológica Aída Hassón-Voloch, Instituto de Biofísica Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; .,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and
| |
Collapse
|
35
|
Tratnjek L, Romih R, Kreft ME. Differentiation-dependent rearrangements of actin filaments and microtubules hinder apical endocytosis in urothelial cells. Histochem Cell Biol 2017; 148:143-156. [DOI: 10.1007/s00418-017-1566-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2017] [Indexed: 01/08/2023]
|
36
|
Inoue K, Balkin DM, Liu L, Nandez R, Wu Y, Tian X, Wang T, Nussbaum R, De Camilli P, Ishibe S. Kidney Tubular Ablation of Ocrl/ Inpp5b Phenocopies Lowe Syndrome Tubulopathy. J Am Soc Nephrol 2016; 28:1399-1407. [PMID: 27895154 DOI: 10.1681/asn.2016080913] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 10/05/2016] [Indexed: 12/26/2022] Open
Abstract
Lowe syndrome and Dent disease are two conditions that result from mutations of the inositol 5-phosphatase oculocerebrorenal syndrome of Lowe (OCRL) and share the feature of impaired kidney proximal tubule function. Genetic ablation of Ocrl in mice failed to recapitulate the human phenotypes, possibly because of the redundant functions of OCRL and its paralog type 2 inositol polyphosphate-5-phosphatase (INPP5B). Germline knockout of both paralogs in mice results in early embryonic lethality. We report that kidney tubule-specific inactivation of Inpp5b on a global Ocrl-knockout mouse background resulted in low molecular weight proteinuria, phosphaturia, and acidemia. At the cellular level, we observed a striking impairment of clathrin-dependent and -independent endocytosis in proximal tubules, phenocopying what has been reported for Dent disease caused by mutations in the gene encoding endosomal proton-chloride exchange transporter 5. These results suggest that the functions of OCRL/INPP5B and proton-chloride exchange transporter 5 converge on shared mechanisms, the impairment of which has a dramatic effect on proximal tubule endocytosis.
Collapse
Affiliation(s)
| | - Daniel M Balkin
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut
| | - Lijuan Liu
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut.,Neuroscience, and
| | - Ramiro Nandez
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut
| | - Yumei Wu
- Cell Biology.,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut.,Neuroscience, and
| | | | | | - Robert Nussbaum
- Department of Medicine and.,Institute of Human Genetics, University of California, San Francisco, California; and.,Howard Hughes Medical Institute, and
| | - Pietro De Camilli
- Cell Biology, .,Howard Hughes Medical Institute, and.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut.,Neuroscience, and
| | - Shuta Ishibe
- Departments of Internal Medicine, .,Cellular and Molecular Physiology
| |
Collapse
|
37
|
Liu Z, Ning G, Xu R, Cao Y, Meng A, Wang Q. Fscn1 is required for the trafficking of TGF-β family type I receptors during endoderm formation. Nat Commun 2016; 7:12603. [PMID: 27545838 PMCID: PMC4996939 DOI: 10.1038/ncomms12603] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/15/2016] [Indexed: 01/01/2023] Open
Abstract
Microtubules function in TGF-β signalling by facilitating the cytoplasmic trafficking of internalized receptors and the nucleocytoplasmic shuttling of Smads. However, nothing is known about whether actin filaments are required for these processes. Here we report that zebrafish actin-bundling protein fscn1a is highly expressed in mesendodermal precursors and its expression is directly regulated by the TGF-β superfamily member Nodal. Knockdown or knockout of fscn1a leads to a reduction of Nodal signal transduction and endoderm formation in zebrafish embryos. Fscn1 specifically interacts with TGF-β family type I receptors, and its depletion disrupts the association between receptors and actin filaments and sequesters the internalized receptors into clathrin-coated vesicles. Therefore, Fscn1 acts as a molecular linker between TGF-β family type I receptors and the actin filaments to promote the trafficking of internalized receptors from clathrin-coated vesicles to early endosomes during zebrafish endoderm formation. It is unclear how the cytoskeleton acts to assist in TGF-β signalling downstream of the receptor. Here, in zebrafish, the authors show that the actin-bundling protein FSCN1 interacts with TGF-β type I receptors ALK 4 and 5, enabling actin filament mediated vesicle trafficking and endoderm formation.
Collapse
Affiliation(s)
- Zhaoting Liu
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guozhu Ning
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ranran Xu
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu Cao
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Anming Meng
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Wang
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
38
|
Iowa Mutant Apolipoprotein A-I (ApoA-IIowa) Fibrils Target Lysosomes. Sci Rep 2016; 6:30391. [PMID: 27464946 PMCID: PMC4964564 DOI: 10.1038/srep30391] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/30/2016] [Indexed: 01/01/2023] Open
Abstract
The single amino acid mutation G26R in human apolipoprotein A-I (apoA-IIowa) is the first mutation that was associated with familial AApoA1 amyloidosis. The N-terminal fragments (amino acid residues 1–83) of apoA-I containing this mutation deposit as amyloid fibrils in patients’ tissues and organs, but the mechanisms of cellular degradation and cytotoxicity have not yet been clarified. In this study, we demonstrated degradation of apoA-IIowa fibrils via the autophagy-lysosomal pathway in human embryonic kidney 293 cells. ApoA-IIowa fibrils induced an increase in lysosomal pH and the cytosolic release of the toxic lysosomal protease cathepsin B. The mitochondrial dysfunction caused by apoA-IIowa fibrils depended on cathepsin B and was ameliorated by increasing the degradation of apoA-IIowa fibrils. Thus, although apoA-IIowa fibril transport to lysosomes and fibril degradation in lysosomes may have occurred, the presence of an excess number of apoA-IIowa fibrils, more than the lysosomes could degrade, may be detrimental to cells. Our results thus provide evidence that the target of apoA-IIowa fibrils is lysosomes, and we thereby gained a novel insight into the mechanism of AApoA1 amyloidosis.
Collapse
|
39
|
Briceño MP, Nascimento LAC, Nogueira NP, Barenco PVC, Ferro EAV, Rezende-Oliveira K, Goulart LR, Alves PT, Barbosa BDF, Lima WR, Silva NM. Toxoplasma gondii Infection Promotes Epithelial Barrier Dysfunction of Caco-2 Cells. J Histochem Cytochem 2016; 64:459-69. [PMID: 27370796 DOI: 10.1369/0022155416656349] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022] Open
Abstract
After oral infection, Toxoplasma gondii invades intestinal cells, induces breakdown of intestinal physiology and barrier functions, and causes intestinal pathology in some animal species. Although parasites' invasion into host cells is a known phenomenon, the effects of T. gondii infection in the intestinal barrier are still not well established. To evaluate morphological and physiological modifications on the colorectal adenocarcinoma-derived Caco-2 cell line during T. gondii infection, microvilli, tight junction integrity, and transepithelial electrical resistance (TEER) were investigated under infection. It was observed that the dextran uptake (endocytosis) and distribution were smaller in infected than in noninfected Caco-2 cells. The infection leads to the partial loss of microvilli at the cell surface. Claudin-1, zonula occludens-1 (ZO-1), and occludin expressions were colocalized by immunofluorescence and presented discontinuous net patterns in infected cells. Immunoblotting analysis at 24 hr postinfection revealed decreasing expression of occludin and ZO-1 proteins, whereas claudin-1 presented similar expression level compared with noninfected cells. T. gondii decreased TEER in Caco-2 cells 24 hr after infection. Our results suggest that T. gondii infection may lead to the loss of integrity of intestinal mucosa, resulting in impaired barrier function.
Collapse
Affiliation(s)
- Marisol Pallete Briceño
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| | | | - Nathalia Pires Nogueira
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| | | | - Eloisa Amália Vieira Ferro
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
| | - Karine Rezende-Oliveira
- Laboratory of Biomedical Sciences, Federal University of Uberlândia, Ituiutaba, Minas Gerais, Brazil (KR-O)
| | - Luiz Ricardo Goulart
- Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
| | - Patrícia Terra Alves
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
| | - Bellisa de Freitas Barbosa
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
| | - Wânia Rezende Lima
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, Mato Grosso, Brazil (WRL)
| | - Neide Maria Silva
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| |
Collapse
|
40
|
Hallstrom KN, McCormick BA. The type three secreted effector SipC regulates the trafficking of PERP during Salmonella infection. Gut Microbes 2016; 7:136-45. [PMID: 27078059 PMCID: PMC4856460 DOI: 10.1080/19490976.2015.1128626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Salmonella enterica Typhimurium employs type III secreted effectors to induce cellular invasion and pathogenesis. We previously reported the secreted effector SipA is in part responsible for inducing the apical accumulation of the host membrane protein PERP, a host factor we have shown is key to the inflammatory response induced by Salmonella. We now report that the S. Typhimurium type III secreted effector SipC significantly contributes to PERP redistribution to the apical membrane surface. To our knowledge, this is the first report demonstrating a role for SipC in directing the trafficking of a host membrane protein to the cell surface. In sum, facilitation of PERP trafficking appears to be a result of type III secreted effector-mediated recruitment of vesicles to the apical surface. Our study therefore reveals a new role for SipC, and builds upon previous reports suggesting recruitment of vesicles to the cell surface is important for Salmonella invasion.
Collapse
Affiliation(s)
- Kelly N. Hallstrom
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Beth A. McCormick
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| |
Collapse
|
41
|
Hasdemir B, Mhaske P, Paruthiyil S, Garnett EA, Heyman MB, Matloubian M, Bhargava A. Sex- and corticotropin-releasing factor receptor 2- dependent actions of urocortin 1 during inflammation. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1244-57. [PMID: 27053649 DOI: 10.1152/ajpregu.00445.2015] [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: 10/16/2015] [Accepted: 03/25/2016] [Indexed: 12/20/2022]
Abstract
We investigated whether corticotropin-releasing factor receptor 2 (CRF2) and its high-affinity agonist urocortin 1 (Ucn1) mediate sex-specific signaling and immune responses. Intrarectal trinitrobenzene sulfonic acid was used to induce experimental colitis in wild-type, CRF2 knockout (CRF2KO), and heterozygous (CRF2Ht) mice of both sexes. Changes in plasma extravasation, organ weight, survival, immune cell numbers, inflammatory cytokines, and the MAPK signaling pathway were assessed. Stored intestinal biopsies from patients with Crohn's disease (CD) and age- and sex-matched individuals without inflammatory bowel disease (IBD) were examined by immunofluorescence and confocal microscopy to characterize Ucn1 and CRF receptor expression. CRF2Ht mice of both sexes showed decreased survival during colitis compared with other genotypes. Ucn1 improved survival in male mice alone. Ucn1 restored colon length and spleen and adrenal weight and decreased colonic TNF-α, IL-6, and IL-1β levels in male CRF2Ht mice alone. CRF2Ht mice of both sexes showed decreased phosphorylation of MAPK p38 and heat shock protein 27 (Hsp27) levels. Ucn1 restored p-Hsp27 levels in male CRF2Ht mice alone. Expression of the chaperone protein Hsp90 decreased during colitis, except in male CRF2Ht mice. Taken together, our data indicate that sex shows significant interaction with genotype and Ucn1 during colitis. Human duodenal and colonic biopsies revealed that sex-specific differences exist in levels of CRF receptors and Ucn1 expression in patients with CD compared with the matched non-IBD subjects. To conclude, Ucn1 mediates sex-specific immune and cellular signaling responses via CRF2, emphasizing the need for inclusion of females in preclinical studies.
Collapse
Affiliation(s)
- Burcu Hasdemir
- Department of Surgery, University of California, San Francisco; The Osher Center for Integrative Medicine, University of California, San Francisco
| | - Pallavi Mhaske
- Department of Surgery, University of California, San Francisco
| | | | | | - Melvin B Heyman
- Department of Pediatrics, University of California, San Francisco
| | - Mehrdad Matloubian
- Division of Rheumatology and Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, University of California, San Francisco
| | - Aditi Bhargava
- Department of Surgery, University of California, San Francisco; The Osher Center for Integrative Medicine, University of California, San Francisco;
| |
Collapse
|
42
|
Abstract
PURPOSE OF REVIEW The proximal tubule plays a critical role in the reabsorption of ions, solutes and low molecular weight proteins from the glomerular filtrate. Although the proximal tubule has long been known to acutely modulate ion reabsorption in response to changes in flow rates of the glomerular filtrate, it has only recently been discovered that proximal tubule cells can similarly adjust endocytic capacity in response to flow. This review synthesizes our current understanding of mechanosensitive regulation of endocytic capacity in proximal tubule epithelia and highlights areas of opportunity for future investigations. RECENT FINDINGS Recent studies have reported that the endocytic capacity of proximal tubule cells is dramatically increased upon exposure to flow and the accompanying fluid shear stress. Modulation of this pathway is dependent on increases in intracellular calcium initiated by bending of the primary cilium, and also requires purinergic receptor activation that is mediated by release of extracellular ATP. This article summarizes what is currently known about the signaling cascade that transduces changes in flow into alterations in endocytosis. We discuss the implications of this newly described regulatory pathway with respect to our understanding of protein retrieval by the kidney under normal conditions, and in diseases that present with low molecular weight proteinuria. SUMMARY Primary cilia act as mechanotransducers that modulate apical endocytic capacity in proximal tubule cells in response to changes in fluid shear stress.
Collapse
|
43
|
EtpE Binding to DNase X Induces Ehrlichial Entry via CD147 and hnRNP-K Recruitment, Followed by Mobilization of N-WASP and Actin. mBio 2015; 6:e01541-15. [PMID: 26530384 PMCID: PMC4631803 DOI: 10.1128/mbio.01541-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Obligate intracellular bacteria, such as Ehrlichia chaffeensis, perish unless they can enter eukaryotic cells. E. chaffeensis is the etiological agent of human monocytic ehrlichiosis, an emerging infectious disease. To infect cells, Ehrlichia uses the C terminus of the outer membrane invasin entry-triggering protein (EtpE) of Ehrlichia (EtpE-C), which directly binds the mammalian cell surface glycosylphosphatidyl inositol-anchored protein, DNase X. How this binding drives Ehrlichia entry is unknown. Here, using affinity pulldown of host cell lysates with recombinant EtpE-C (rEtpE-C), we identified two new human proteins that interact with EtpE-C: CD147 and heterogeneous nuclear ribonucleoprotein K (hnRNP-K). The interaction of CD147 with rEtpE-C was validated by far-Western blotting and coimmunoprecipitation of native EtpE with endogenous CD147. CD147 was ubiquitous on the cell surface and also present around foci of rEtpE-C-coated-bead entry. Functional neutralization of surface-exposed CD147 with a specific antibody inhibited Ehrlichia internalization and infection but not binding. Downregulation of CD147 by short hairpin RNA (shRNA) impaired E. chaffeensis infection. Functional ablation of cytoplasmic hnRNP-K by a nanoscale intracellular antibody markedly attenuated bacterial entry and infection but not binding. EtpE-C also interacted with neuronal Wiskott-Aldrich syndrome protein (N-WASP), which is activated by hnRNP-K. Wiskostatin, which inhibits N-WASP activation, and cytochalasin D, which inhibits actin polymerization, inhibited Ehrlichia entry. Upon incubation with host cell lysate, EtpE-C but not an EtpE N-terminal fragment stimulated in vitro actin polymerization in an N-WASP- and DNase X-dependent manner. Time-lapse video images revealed N-WASP recruitment at EtpE-C-coated bead entry foci. Thus, EtpE-C binding to DNase X drives Ehrlichia entry by engaging CD147 and hnRNP-K and activating N-WASP-dependent actin polymerization. Ehrlichia chaffeensis, an obligate intracellular bacterium, causes a blood-borne disease called human monocytic ehrlichiosis, one of the most prevalent life-threatening emerging tick-transmitted infectious diseases in the United States. The survival of Ehrlichia bacteria, and hence, their ability to cause disease, depends on their specific mode of entry into eukaryotic host cells. Understanding the mechanism by which E. chaffeensis enters cells will create new opportunities for developing effective therapies to prevent bacterial entry and disease in humans. Our findings reveal a novel cellular signaling pathway triggered by an ehrlichial surface protein called EtpE to induce its infectious entry. The results are also important from the viewpoint of human cell physiology because three EtpE-interacting human proteins, DNase X, CD147, and hnRNP-K, are hitherto unknown partners that drive the uptake of small particles, including bacteria, into human cells.
Collapse
|
44
|
Ball RL, Knapp CM, Whitehead KA. Lipidoid Nanoparticles for siRNA Delivery to the Intestinal Epithelium: In Vitro Investigations in a Caco-2 Model. PLoS One 2015; 10:e0133154. [PMID: 26192592 PMCID: PMC4508104 DOI: 10.1371/journal.pone.0133154] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/24/2015] [Indexed: 02/07/2023] Open
Abstract
Short interfering ribonucleic acid (siRNA) therapeutics show promise for the treatment of intestinal diseases by specifically suppressing the expression of disease relevant proteins. Recently, a class of lipid-like materials termed "lipidoids" have been shown to potently deliver siRNA to the liver and immune cells. Here, we seek to establish the utility of lipidoid nanoparticles (LNPs) in the context of siRNA delivery to the intestinal epithelium. Initial studies demonstrated that the siRNA-loaded LNPs mediated potent, dose dependent, and durable gene silencing in Caco-2 intestinal epithelial cells, with a single 10 nM dose depressing GAPDH mRNA expression for one week. Transfection with siRNA-loaded LNPs did not induce significant cytotoxicity in Caco-2 cells or alter intestinal barrier function. Protein silencing was confirmed by Western blotting, with the lowest levels of GAPDH protein expression observed five days post-transfection. Together, these data underscore the potential of LNPs for the treatment of intestinal disorders.
Collapse
Affiliation(s)
- Rebecca L. Ball
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Christopher M. Knapp
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Kathryn A. Whitehead
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| |
Collapse
|
45
|
Isayenkov SV, Sekan AS, Sorochinsky BV, Blume YB. Molecular aspects of endosomal cellular transport. CYTOL GENET+ 2015. [DOI: 10.3103/s009545271503007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
46
|
Sherrard KM, Fehon RG. The transmembrane protein Crumbs displays complex dynamics during follicular morphogenesis and is regulated competitively by Moesin and aPKC. Development 2015; 142:1869-78. [PMID: 25926360 DOI: 10.1242/dev.115329] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 03/23/2015] [Indexed: 01/05/2023]
Abstract
The transmembrane protein Crumbs (Crb) functions in apical polarity and epithelial integrity. To better understand its role in epithelial morphogenesis, we examined Crb localization and dynamics in the late follicular epithelium of Drosophila. Crb was unexpectedly dynamic during middle-to-late stages of egg chamber development, being lost from the marginal zone (MZ) in stage 9 before abruptly returning at the end of stage 10b, then undergoing a pulse of endocytosis in stage 12. The reappearance of MZ Crb is necessary to maintain an intact adherens junction and MZ. Although Crb has been proposed to interact through its juxtamembrane domain with Moesin (Moe), a FERM domain protein that regulates the cortical actin cytoskeleton, the functional significance of this interaction is poorly understood. We found that whereas the Crb juxtamembrane domain was not required for adherens junction integrity, it was necessary for MZ localization of Moe, aPKC and F-actin. Furthermore, Moe and aPKC functioned antagonistically, suggesting that Moe limits Crb levels by reducing its interactions with the apical Par network. Additionally, Moe mutant cells lost Crb from the apical membrane and accumulated excess Crb at the MZ, suggesting that Moe regulates Crb distribution at the membrane. Together, these studies reveal reciprocal interactions between Crb, Moe and aPKC during cellular morphogenesis.
Collapse
Affiliation(s)
- Kristin M Sherrard
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 E. 58th Street, Chicago, IL 60637, USA
| | - Richard G Fehon
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 E. 58th Street, Chicago, IL 60637, USA
| |
Collapse
|
47
|
Delivery of nucleic acids and nanomaterials by cell-penetrating peptides: opportunities and challenges. BIOMED RESEARCH INTERNATIONAL 2015; 2015:834079. [PMID: 25883975 PMCID: PMC4391616 DOI: 10.1155/2015/834079] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/18/2014] [Accepted: 09/23/2014] [Indexed: 12/20/2022]
Abstract
Many viral and nonviral systems have been developed to aid delivery of biologically active molecules into cells. Among these, cell-penetrating peptides (CPPs) have received increasing attention in the past two decades for biomedical applications. In this review, we focus on opportunities and challenges associated with CPP delivery of nucleic acids and nanomaterials. We first describe the nature of versatile CPPs and their interactions with various types of cargoes. We then discuss in vivo and in vitro delivery of nucleic acids and nanomaterials by CPPs. Studies on the mechanisms of cellular entry and limitations in the methods used are detailed.
Collapse
|
48
|
Aboul Naga SH, Dithmer M, Chitadze G, Kabelitz D, Lucius R, Roider J, Klettner A. Intracellular pathways following uptake of bevacizumab in RPE cells. Exp Eye Res 2015; 131:29-41. [DOI: 10.1016/j.exer.2014.12.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 12/11/2014] [Accepted: 12/17/2014] [Indexed: 12/23/2022]
|
49
|
Abstract
Endocytosis, the process whereby the plasma membrane invaginates to form vesicles, is essential for bringing many substances into the cell and for membrane turnover. The mechanism driving clathrin-mediated endocytosis (CME) involves > 50 different protein components assembling at a single location on the plasma membrane in a temporally ordered and hierarchal pathway. These proteins perform precisely choreographed steps that promote receptor recognition and clustering, membrane remodeling, and force-generating actin-filament assembly and turnover to drive membrane invagination and vesicle scission. Many critical aspects of the CME mechanism are conserved from yeast to mammals and were first elucidated in yeast, demonstrating that it is a powerful system for studying endocytosis. In this review, we describe our current mechanistic understanding of each step in the process of yeast CME, and the essential roles played by actin polymerization at these sites, while providing a historical perspective of how the landscape has changed since the preceding version of the YeastBook was published 17 years ago (1997). Finally, we discuss the key unresolved issues and where future studies might be headed.
Collapse
Affiliation(s)
- Bruce L Goode
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Julian A Eskin
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Beverly Wendland
- The Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218
| |
Collapse
|
50
|
Sattlegger E, Chernova TA, Gogoi NM, Pillai IV, Chernoff YO, Munn AL. Yeast studies reveal moonlighting functions of the ancient actin cytoskeleton. IUBMB Life 2014; 66:538-45. [PMID: 25138357 DOI: 10.1002/iub.1294] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 07/21/2014] [Indexed: 11/12/2022]
Abstract
Classic functions of the actin cytoskeleton include control of cell size and shape and the internal organization of cells. These functions are manifest in cellular processes of fundamental importance throughout biology such as the generation of cell polarity, cell migration, cell adhesion, and cell division. However, studies in the unicellular model eukaryote Saccharomyces cerevisiae (Baker's yeast) are giving insights into other functions in which the actin cytoskeleton plays a critical role. These include endocytosis, control of protein translation, and determination of protein 3-dimensional shape (especially conversion of normal cellular proteins into prions). Here, we present a concise overview of these new "moonlighting" roles for the actin cytoskeleton and how some of these roles might lie at the heart of important molecular switches. This is an exciting time for researchers interested in the actin cytoskeleton. We show here how studies of actin are leading us into many new and exciting realms at the interface of genetics, biochemistry, and cell biology. While many of the pioneering studies have been conducted using yeast, the conservation of the actin cytoskeleton and its component proteins throughout eukaryotes suggests that these new roles for the actin cytoskeleton may not be restricted to yeast cells but rather may reflect new roles for the actin cytoskeleton of all eukaryotes.
Collapse
Affiliation(s)
- Evelyn Sattlegger
- Institute of Natural and Mathematical Sciences, Massey University, Albany, New Zealand
| | | | | | | | | | | |
Collapse
|