1
|
Rabino A, Awadia S, Ali N, Edson A, Garcia-Mata R. The Scribble/SGEF/Dlg1 complex regulates the stability of apical junctions in epithelial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.26.586884. [PMID: 38585765 PMCID: PMC10996629 DOI: 10.1101/2024.03.26.586884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
SGEF, a RhoG specific GEF, can form a ternary complex with the Scribble polarity complex proteins Scribble and Dlg1, which regulates the formation and maintenance of adherens junctions and barrier function of epithelial cells. Notably, silencing SGEF results in a dramatic downregulation of the expression of both E-cadherin and ZO-1. However, the molecular mechanisms involved in the regulation of this pathway are not known. Here, we describe a novel signaling pathway governed by the Scribble/SGEF/Dlg1 complex. Our results show that an intact ternary complex is required to maintain the stability of the apical junctions, the expression of ZO-1, and TJ permeability. In contrast, only SGEF is necessary to regulate E-cadherin expression. The absence of SGEF destabilizes the E-cadherin/catenin complex at the membrane, triggering a positive feedback loop that exacerbates the phenotype through the repression of E-cadherin transcription in a process that involves the internalization of E-cadherin by endocytosis, β-catenin signaling and the transcriptional repressor Slug.
Collapse
Affiliation(s)
- Agustin Rabino
- Department of Biological Sciences, University of Toledo, Toledo, OH, USA
| | - Sahezeel Awadia
- Department of Biological Sciences, University of Toledo, Toledo, OH, USA
| | - Nabaa Ali
- Department of Biological Sciences, University of Toledo, Toledo, OH, USA
| | - Amber Edson
- Department of Biological Sciences, University of Toledo, Toledo, OH, USA
| | - Rafael Garcia-Mata
- Department of Biological Sciences, University of Toledo, Toledo, OH, USA
| |
Collapse
|
2
|
Roberts BS, Mitra D, Abishek S, Beher R, Satpute-Krishnan P. The p24-family and COPII subunit SEC24C facilitate the clearance of alpha1-antitrypsin Z from the endoplasmic reticulum to lysosomes. Mol Biol Cell 2024; 35:ar45. [PMID: 38294851 PMCID: PMC10916869 DOI: 10.1091/mbc.e23-06-0257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 01/16/2024] [Accepted: 01/24/2024] [Indexed: 02/01/2024] Open
Abstract
A subpopulation of the alpha-1-antitrypsin misfolding Z mutant (ATZ) is cleared from the endoplasmic reticulum (ER) via an ER-to-lysosome-associated degradation (ERLAD) pathway. Here, we report that the COPII subunit SEC24C and the p24-family of proteins facilitate the clearance of ATZ via ERLAD. In addition to the previously reported ERLAD components calnexin and FAM134B, we discovered that ATZ coimmunoprecipitates with the p24-family members TMP21 and TMED9. This contrasts with wild type alpha1-antitrypsin, which did not coimmunoprecipitate with FAM134B, calnexin or the p24-family members. Live-cell imaging revealed that ATZ and the p24-family members traffic together from the ER to lysosomes. Using chemical inhibitors to block ER exit or autophagy, we demonstrated that p24-family members and ATZ co-accumulate at SEC24C marked ER-exit sites or in ER-derived compartments, respectively. Furthermore, depletion of SEC24C, TMP21, or TMED9 inhibited lysosomal trafficking of ATZ and resulted in the increase of intracellular ATZ levels. Conversely, overexpression of these p24-family members resulted in the reduction of ATZ levels. Intriguingly, the p24-family members coimmunoprecipitate with ATZ, FAM134B, and SEC24C. Thus, we propose a model in which the p24-family functions in an adaptor complex linking SEC24C with the ERLAD machinery for the clearance of ATZ.
Collapse
Affiliation(s)
| | - Debashree Mitra
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Sudhanshu Abishek
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Richa Beher
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | | |
Collapse
|
3
|
Kovács D, Gay AS, Debayle D, Abélanet S, Patel A, Mesmin B, Luton F, Antonny B. Lipid exchange at ER-trans-Golgi contact sites governs polarized cargo sorting. J Cell Biol 2024; 223:e202307051. [PMID: 37991810 PMCID: PMC10664280 DOI: 10.1083/jcb.202307051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/18/2023] [Accepted: 10/30/2023] [Indexed: 11/23/2023] Open
Abstract
Oxysterol binding protein (OSBP) extracts cholesterol from the ER to deliver it to the TGN via counter exchange and subsequent hydrolysis of the phosphoinositide PI(4)P. Here, we show that this pathway is essential in polarized epithelial cells where it contributes not only to the proper subcellular distribution of cholesterol but also to the trans-Golgi sorting and trafficking of numerous plasma membrane cargo proteins with apical or basolateral localization. Reducing the expression of OSBP, blocking its activity, or inhibiting a PI4Kinase that fuels OSBP with PI(4)P abolishes the epithelial phenotype. Waves of cargo enrichment in the TGN in phase with OSBP and PI(4)P dynamics suggest that OSBP promotes the formation of lipid gradients along the TGN, which helps cargo sorting. During their transient passage through the trans-Golgi, polarized plasma membrane proteins get close to OSBP but fail to be sorted when OSBP is silenced. Thus, OSBP lipid exchange activity is decisive for polarized cargo sorting and distribution in epithelial cells.
Collapse
Affiliation(s)
- Dávid Kovács
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Anne-Sophie Gay
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Delphine Debayle
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Sophie Abélanet
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Amanda Patel
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Bruno Mesmin
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Frédéric Luton
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Bruno Antonny
- Université Côte d’Azur and CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| |
Collapse
|
4
|
Balakrishnan M, Kenworthy AK. Lipid peroxidation drives liquid-liquid phase separation and disrupts raft protein partitioning in biological membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557355. [PMID: 37745342 PMCID: PMC10515805 DOI: 10.1101/2023.09.12.557355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The peroxidation of membrane lipids by free radicals contributes to aging, numerous diseases, and ferroptosis, an iron-dependent form of cell death. Peroxidation changes the structure, conformation and physicochemical properties of lipids, leading to major membrane alterations including bilayer thinning, altered fluidity, and increased permeability. Whether and how lipid peroxidation impacts the lateral organization of proteins and lipids in biological membranes, however, remains poorly understood. Here, we employ cell-derived giant plasma membrane vesicles (GPMVs) as a model to investigate the impact of lipid peroxidation on ordered membrane domains, often termed membrane rafts. We show that lipid peroxidation induced by the Fenton reaction dramatically enhances phase separation propensity of GPMVs into co-existing liquid ordered (raft) and liquid disordered (non-raft) domains and increases the relative abundance of the disordered, non-raft phase. Peroxidation also leads to preferential accumulation of peroxidized lipids and 4-hydroxynonenal (4-HNE) adducts in the disordered phase, decreased lipid packing in both raft and non-raft domains, and translocation of multiple classes of proteins out of rafts. These findings indicate that peroxidation of plasma membrane lipids disturbs many aspects of membrane rafts, including their stability, abundance, packing, and protein and lipid composition. We propose that these disruptions contribute to the pathological consequences of lipid peroxidation during aging and disease, and thus serve as potential targets for therapeutic intervention.
Collapse
Affiliation(s)
- Muthuraj Balakrishnan
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Anne K. Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| |
Collapse
|
5
|
Shelby SA, Castello-Serrano I, Wisser KC, Levental I, Veatch SL. Membrane phase separation drives responsive assembly of receptor signaling domains. Nat Chem Biol 2023; 19:750-758. [PMID: 36997644 PMCID: PMC10771812 DOI: 10.1038/s41589-023-01268-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 01/17/2023] [Indexed: 04/01/2023]
Abstract
Plasma membrane heterogeneity has been tied to a litany of cellular functions and is often explained by analogy to membrane phase separation; however, models based on phase separation alone fall short of describing the rich organization available within cell membranes. Here we present comprehensive experimental evidence motivating an updated model of plasma membrane heterogeneity in which membrane domains assemble in response to protein scaffolds. Quantitative super-resolution nanoscopy measurements in live B lymphocytes detect membrane domains that emerge upon clustering B cell receptors (BCRs). These domains enrich and retain membrane proteins based on their preference for the liquid-ordered phase. Unlike phase-separated membranes that consist of binary phases with defined compositions, membrane composition at BCR clusters is modulated through the protein constituents in clusters and the composition of the membrane overall. This tunable domain structure is detected through the variable sorting of membrane probes and impacts the magnitude of BCR activation.
Collapse
Affiliation(s)
- Sarah A Shelby
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee Knoxville, Knoxville, TN, USA
| | - Ivan Castello-Serrano
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | | | - Ilya Levental
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Sarah L Veatch
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA.
| |
Collapse
|
6
|
Pereira C, Stalder D, Anderson GS, Shun-Shion AS, Houghton J, Antrobus R, Chapman MA, Fazakerley DJ, Gershlick DC. The exocyst complex is an essential component of the mammalian constitutive secretory pathway. J Cell Biol 2023; 222:e202205137. [PMID: 36920342 PMCID: PMC10041652 DOI: 10.1083/jcb.202205137] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/11/2022] [Accepted: 02/01/2023] [Indexed: 03/16/2023] Open
Abstract
Secreted proteins fulfill a vast array of functions, including immunity, signaling, and extracellular matrix remodeling. In the trans-Golgi network, proteins destined for constitutive secretion are sorted into post-Golgi carriers which fuse with the plasma membrane. The molecular machinery involved is poorly understood. Here, we have used kinetic trafficking assays and transient CRISPR-KO to study biosynthetic sorting from the Golgi to the plasma membrane. Depletion of all canonical exocyst subunits causes cargo accumulation in post-Golgi carriers. Exocyst subunits are recruited to and co-localize with carriers. Exocyst abrogation followed by kinetic trafficking assays of soluble cargoes results in intracellular cargo accumulation. Unbiased secretomics reveals impairment of soluble protein secretion after exocyst subunit knockout. Importantly, in specialized cell types, the loss of exocyst prevents constitutive secretion of antibodies in lymphocytes and of leptin in adipocytes. These data identify exocyst as the functional tether of secretory post-Golgi carriers at the plasma membrane and an essential component of the mammalian constitutive secretory pathway.
Collapse
Affiliation(s)
- Conceição Pereira
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Amber S. Shun-Shion
- Metabolic Research Laboratory, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Jack Houghton
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Daniel J. Fazakerley
- Metabolic Research Laboratory, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - David C. Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| |
Collapse
|
7
|
Structure Composition and Intracellular Transport of Clathrin-Mediated Intestinal Transmembrane Tight Junction Protein. Inflammation 2023; 46:18-34. [PMID: 36050591 DOI: 10.1007/s10753-022-01724-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/20/2022] [Accepted: 07/27/2022] [Indexed: 11/05/2022]
Abstract
Tight junctions (TJs) are located in the apical region of the junctions between epithelial cells and are widely found in organs such as the brain, retina, intestinal epithelium, and endothelial system. As a mechanical barrier of the intestinal mucosa, TJs can not only maintain the integrity of intestinal epithelial cells but also maintain intestinal mucosal permeability by regulating the entry of ions and molecules into paracellular channels. Therefore, the formation disorder or integrity destruction of TJs can induce damage to the intestinal epithelial barrier, ultimately leading to the occurrence of various gastrointestinal diseases, such as inflammatory bowel disease (IBD), gastroesophageal reflux disease (GERD), and irritable bowel syndrome (IBS). However, a large number of studies have shown that TJs protein transport disorder from the endoplasmic reticulum to the apical membrane can lead to TJs formation disorder, in addition to disruption of TJs integrity caused by external pathological factors and reduction of TJs protein synthesis. In this review, we focus on the structural composition of TJs, the formation of clathrin-coated vesicles containing transmembrane TJs from the Golgi apparatus, and the transport process from the Golgi apparatus to the plasma membrane via microtubules and finally fusion with the plasma membrane. At present, the mechanism of the intracellular transport of TJ proteins remains unclear. More studies are needed in the future to focus on the sorting of TJs protein vesicles, regulation of transport processes, and recycling of TJ proteins, etc.
Collapse
|
8
|
Tran ML, Kim Y, von Blume J. Quantification of Protein Exit at the Trans-Golgi Network. Methods Mol Biol 2023; 2557:583-594. [PMID: 36512239 DOI: 10.1007/978-1-0716-2639-9_35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
With one-third of all newly synthesized proteins entering the secretory pathway, correct protein sorting is essential for cellular homeostasis. In the last three decades, researchers have developed numerous biochemical, genetic, and cell biological approaches to study protein export and sorting from the trans-Golgi network (TGN). However, accurately quantifying protein transport from one compartment to the next in the secretory pathway has been challenging. The Retention Using Selective Hooks (RUSH) system is a method that allows monitoring trafficking of a protein of interest in real time, similar to a pulse-chase experiment but without the need of radiolabeling. Accurate calculations, however, are necessary and currently lacking. Here, we combine the RUSH system with live cell imaging to quantify and calculate half lives. We exemplify our approach using a soluble secreted protein (LyzC). This system will benefit membrane trafficking researchers by adding numbers to protein export and comparing the export kinetics of different cargoes and variating conditions.
Collapse
Affiliation(s)
- Mai Ly Tran
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Yeongho Kim
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Julia von Blume
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
| |
Collapse
|
9
|
Li RS, Wen C, Huang CZ, Li N. Functional molecules and nano-materials for the Golgi apparatus-targeted imaging and therapy. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
10
|
Xu H, Zhang J, Zhou Y, Zhao G, Cai M, Gao J, Shao L, Shi Y, Li H, Ji H, Zhao Y, Wang H. Mechanistic Insights into Membrane Protein Clustering Revealed by Visualizing EGFR Secretion. Research (Wash D C) 2022; 2022:9835035. [PMID: 36340505 PMCID: PMC9620640 DOI: 10.34133/2022/9835035] [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: 05/03/2022] [Accepted: 09/22/2022] [Indexed: 11/19/2022] Open
Abstract
Most plasmalemmal proteins are organized into clusters to modulate various cellular functions. However, the machineries that regulate protein clustering remain largely unclear. Here, with EGFR as an example, we directly and in detail visualized the entire process of EGFR from synthesis to secretion onto the plasma membrane (PM) using a high-speed, high-resolution spinning-disk confocal microscope. First, colocalization imaging revealed that EGFR secretory vesicles underwent transport from the ER to the Golgi to the PM, eventually forming different distribution forms on the apical and basal membranes; that is, most EGFR formed larger clusters on the apical membrane than the basal membrane. A dynamic tracking image and further siRNA interference experiment confirmed that fusion of secretory vesicles with the plasma membrane led to EGFR clusters, and we showed that EGFR PM clustering may be intimately related to EGFR signaling and cell proliferation. Finally, we found that the size and origin of the secretory vesicles themselves may determine the difference in the distribution patterns of EGFR on the PM. More importantly, we showed that actin influenced the EGFR distribution by controlling the fusion of secretory vesicles with the PM. Collectively, a comprehensive understanding of the EGFR secretion process helps us to unravel the EGFR clustering process and elucidate the key factors determining the differences in the spatial distribution of EGFR PM, highlighting the correlation between EGFR secretion and its PM distribution pattern.
Collapse
Affiliation(s)
- Haijiao Xu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
| | - Jinrui Zhang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
| | - Yijia Zhou
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Guanfang Zhao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
- University of Science and Technology of China, Hefei, 230026 Anhui, China
| | - Mingjun Cai
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
| | - Jing Gao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
| | - Lina Shao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
| | - Yan Shi
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
| | - Hongru Li
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
- University of Science and Technology of China, Hefei, 230026 Anhui, China
| | - Hongbin Ji
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 130102, China
| | - Yikai Zhao
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hongda Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, China
- University of Science and Technology of China, Hefei, 230026 Anhui, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 Shandong, China
| |
Collapse
|
11
|
Chaoudhary S, Dewasi A, S RP, Rastogi V, Pereira RN, Sinopoli A, Aïssa B, Mitra A. Laser ablation fabrication of a p-NiO/ n-Si heterojunction for broadband and self-powered UV-Visible-NIR photodetection. NANOTECHNOLOGY 2022; 33:255202. [PMID: 35272274 DOI: 10.1088/1361-6528/ac5ca6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
We report on the optoelectronic characteristics ofp-NiO/n-Si heterojunction photodiode for broadband photodetection, fabricated by depositing ap-type NiO thin film onto a commercialn-type silicon substrate using pulsed laser deposition (PLD) technique. The structural properties of the PLD-grownp-NiO material were analysed by means of x-ray diffraction and x-ray photoelectron spectroscopy, confirming its crystalline nature and revealing the presence of Ni vacancies, respectively. Hall measurements confirmed thep-type semiconducting nature of the NiO thin film having a carrier concentration of 8.4 × 1016cm-3. The current-voltage (I-V) characteristics of thep-NiO/n-Si heterojunction photodevice were investigated under different wavelengths ranging from UV to NIR. The self-bias properties under different illuminations of light were also explored systematically. Under self-bias condition, the photodiode exhibits excellent responsivities of 12.5 mA W-1, 24.6 mA W-1and 30.8 mA W-1with illumination under 365 nm, 485 nm, and 850 nm light, respectively. In addition, the time dependency of the photoresponse of the fabricated photodevice has also been investigated and discussed thoroughly.
Collapse
Affiliation(s)
- Savita Chaoudhary
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Avijit Dewasi
- Institute for Plasma Research, Gandhinagar-382428, Bhat, Gujarat, India
| | - Ram Prakash S
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Vipul Rastogi
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Rui N Pereira
- Department of Physics and i3N-Institute for Nanostructures, Nanomodelling and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Alessandro Sinopoli
- Qatar Environment & Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, PO Box 34110, Doha, Qatar
| | - Brahim Aïssa
- Qatar Environment & Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, PO Box 34110, Doha, Qatar
| | - Anirban Mitra
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| |
Collapse
|
12
|
Kang M. Regression Analysis of Confocal FRAP and its Application to Diffusion in Membranes. J Fluoresc 2022; 32:1031-1038. [DOI: 10.1007/s10895-022-02926-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/01/2022] [Indexed: 11/29/2022]
|
13
|
Levic DS, Bagnat M. Self-organization of apical membrane protein sorting in epithelial cells. FEBS J 2022; 289:659-670. [PMID: 33864720 PMCID: PMC8522177 DOI: 10.1111/febs.15882] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/25/2021] [Accepted: 04/14/2021] [Indexed: 02/03/2023]
Abstract
Polarized epithelial cells are characterized by the asymmetric distribution of proteins between apical and basolateral domains of the plasma membrane. This asymmetry is highly conserved and is fundamental to epithelial cell physiology, development, and homeostasis. How proteins are segregated for apical or basolateral delivery, a process known as sorting, has been the subject of considerable investigation for decades. Despite these efforts, the rules guiding apical sorting are poorly understood and remain controversial. Here, we consider mechanisms of apical membrane protein sorting and argue that they are largely driven by self-organization and biophysical principles. The preponderance of data to date is consistent with the idea that apical sorting is not ruled by a dedicated protein-based sorting machinery and relies instead on the concerted effects of oligomerization, phase separation of lipids and proteins in membranes, and pH-dependent glycan interactions.
Collapse
Affiliation(s)
- Daniel S. Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA,Correspondence to Michel Bagnat: or Dan Levic:
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA,Correspondence to Michel Bagnat: or Dan Levic:
| |
Collapse
|
14
|
Yu Y, Wang W, Li W, Wang G, Wang Y, Lu Z, Li S, Zhao W, Li Y, Liu T, Yan X. Photodetectors Based on Micro-nano Structure Material. Front Chem 2022; 9:832028. [PMID: 35096783 PMCID: PMC8790564 DOI: 10.3389/fchem.2021.832028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 12/24/2021] [Indexed: 01/18/2023] Open
Abstract
Photodetectors converting optical signals into electrical signals have been widely utilized and have received more and more attention in scientific research and industrial fields including optical interconnection, optical communication, and environmental monitoring. Herein, we summarize the latest development of photodetectors with different micro-nano structures and different materials and the performance indicators of photodetectors. Several photodetectors, such as flexible, ultraviolet two-dimensional (2D) microscale, and dual-band photodetectors, are listed in this minireview. Meanwhile, the current bottleneck and future development prospects of the photodetector are discussed.
Collapse
Affiliation(s)
- Yu Yu
- Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China
- Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin, China
- *Correspondence: Yu Yu,
| | - Wuyue Wang
- Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China
- Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin, China
| | - Weihua Li
- Weihai Photonics Information Technology Lab Co., Ltd., Shandong, China
| | - Gong Wang
- Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China
- Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin, China
| | - Yulei Wang
- Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China
- Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin, China
| | - Zhiwei Lu
- Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China
- Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin, China
| | - Sensen Li
- Science and Technology on Electro-Optical Information Security Control Laboratory, Tianjin, China
| | - Wanli Zhao
- Science and Technology on Electro-Optical Information Security Control Laboratory, Tianjin, China
| | - Yuhai Li
- Science and Technology on Electro-Optical Information Security Control Laboratory, Tianjin, China
| | - Tongyu Liu
- Science and Technology on Electro-Optical Information Security Control Laboratory, Tianjin, China
| | - Xiusheng Yan
- Science and Technology on Electro-Optical Information Security Control Laboratory, Tianjin, China
| |
Collapse
|
15
|
Placidi G, Campa CC. Deliver on Time or Pay the Fine: Scheduling in Membrane Trafficking. Int J Mol Sci 2021; 22:11773. [PMID: 34769203 PMCID: PMC8583995 DOI: 10.3390/ijms222111773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 12/12/2022] Open
Abstract
Membrane trafficking is all about time. Automation in such a biological process is crucial to ensure management and delivery of cellular cargoes with spatiotemporal precision. Shared molecular regulators and differential engagement of trafficking components improve robustness of molecular sorting. Sequential recruitment of low affinity protein complexes ensures directionality of the process and, concomitantly, serves as a kinetic proofreading mechanism to discriminate cargoes from the whole endocytosed material. This strategy helps cells to minimize losses and operating errors in membrane trafficking, thereby matching the appealed deadline. Here, we summarize the molecular pathways of molecular sorting, focusing on their timing and efficacy. We also highlight experimental procedures and genetic approaches to robustly probe these pathways, in order to guide mechanistic studies at the interface between biochemistry and quantitative biology.
Collapse
Affiliation(s)
- Giampaolo Placidi
- Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060 Candiolo, Italy;
- Candiolo Cancer Institute, FPO-IRCCS, Str. Prov.le 142, km 3.95, 10060 Candiolo, Italy
| | - Carlo C. Campa
- Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060 Candiolo, Italy;
- Candiolo Cancer Institute, FPO-IRCCS, Str. Prov.le 142, km 3.95, 10060 Candiolo, Italy
| |
Collapse
|
16
|
Capone R, Tiwari A, Hadziselimovic A, Peskova Y, Hutchison JM, Sanders CR, Kenworthy AK. The C99 domain of the amyloid precursor protein resides in the disordered membrane phase. J Biol Chem 2021; 296:100652. [PMID: 33839158 PMCID: PMC8113881 DOI: 10.1016/j.jbc.2021.100652] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 12/11/2022] Open
Abstract
Processing of the amyloid precursor protein (APP) via the amyloidogenic pathway is associated with the etiology of Alzheimer's disease. The cleavage of APP by β-secretase to generate the transmembrane 99-residue C-terminal fragment (C99) and subsequent processing of C99 by γ-secretase to yield amyloid-β (Aβ) peptides are essential steps in this pathway. Biochemical evidence suggests that amyloidogenic processing of C99 occurs in cholesterol- and sphingolipid-enriched liquid-ordered phase membrane rafts. However, direct evidence that C99 preferentially associates with these rafts has remained elusive. Here, we tested this by quantifying the affinity of C99-GFP for raft domains in cell-derived giant plasma membrane vesicles (GPMVs). We found that C99 was essentially excluded from ordered domains in vesicles from HeLa cells, undifferentiated SH-SY5Y cells, or SH-SY5Y-derived neurons; instead, ∼90% of C99 partitioned into disordered domains. The strong association of C99 with disordered domains occurred independently of its cholesterol-binding activity or homodimerization, or of the presence of the familial Alzheimer disease Arctic mutation (APP E693G). Finally, through biochemical studies we confirmed previous results, which showed that C99 is processed in the plasma membrane by α-secretase, in addition to the well-known γ-secretase. These findings suggest that C99 itself lacks an intrinsic affinity for raft domains, implying that either i) amyloidogenic processing of the protein occurs in disordered regions of the membrane, ii) processing involves a marginal subpopulation of C99 found in rafts, or iii) as-yet-unidentified protein-protein interactions with C99 in living cells drive this protein into membrane rafts to promote its cleavage therein.
Collapse
Affiliation(s)
- Ricardo Capone
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Ajit Tiwari
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Yelena Peskova
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
| | - James M Hutchison
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.
| |
Collapse
|
17
|
Levic DS, Ryan S, Marjoram L, Honeycutt J, Bagwell J, Bagnat M. Distinct roles for luminal acidification in apical protein sorting and trafficking in zebrafish. J Cell Biol 2020; 219:133852. [PMID: 32328632 PMCID: PMC7147097 DOI: 10.1083/jcb.201908225] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/20/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
Epithelial cell physiology critically depends on the asymmetric distribution of channels and transporters. However, the mechanisms targeting membrane proteins to the apical surface are still poorly understood. Here, we performed a visual forward genetic screen in the zebrafish intestine and identified mutants with defective apical targeting of membrane proteins. One of these mutants, affecting the vacuolar H+-ATPase gene atp6ap1b, revealed specific requirements for luminal acidification in apical, but not basolateral, membrane protein sorting and transport. Using a low temperature block assay combined with genetic and pharmacologic perturbation of luminal pH, we monitored transport of newly synthesized membrane proteins from the TGN to apical membrane in live zebrafish. We show that vacuolar H+-ATPase activity regulates sorting of O-glycosylated proteins at the TGN, as well as Rab8-dependent post-Golgi trafficking of different classes of apical membrane proteins. Thus, luminal acidification plays distinct and specific roles in apical membrane biogenesis.
Collapse
Affiliation(s)
| | - Sean Ryan
- Department of Cell Biology, Duke University, Durham, NC
| | | | | | | | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC
| |
Collapse
|
18
|
Jin W, Zucker M, Pralle A. Membrane nanodomains homeostasis during propofol anesthesia as function of dosage and temperature. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183511. [PMID: 33245892 DOI: 10.1016/j.bbamem.2020.183511] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/01/2020] [Accepted: 11/12/2020] [Indexed: 12/12/2022]
Abstract
Some anesthetics bind and potentiate γ-aminobutyric-acid-type receptors, but no universal mechanism for general anesthesia is known. Furthermore, often encountered complications such as anesthesia induced amnesia are not understood. General anesthetics are hydrophobic molecules easily dissolving into lipid bilayers. Recently, it was shown that general anesthetics perturb phase separation in vesicles extracted from fixed cells. Unclear is whether under physiological conditions general anesthetics induce perturbation of the lipid bilayer, and whether this contributes to the transient loss of consciousness or anesthesia side effects. Here we show that propofol perturbs lipid nanodomains in the outer and inner leaflet of the plasma membrane in intact cells, affecting membrane nanodomains in a concentration dependent manner: 1 μM to 5 μM propofol destabilize nanodomains; however, propofol concentrations higher than 5 μM stabilize nanodomains with time. Stabilization occurs only at physiological temperature and in intact cells. This process requires ARP2/3 mediated actin nucleation and Myosin II activity. The rate of nanodomain stabilization is potentiated by GABAA receptor activity. Our results show that active nanodomain homeostasis counteracts the initial disruption causing large changes in cortical actin. SIGNIFICANCE STATEMENT: General anesthesia is a routine medical procedure with few complications, yet a small number of patients experience side-effects that persist for weeks and months. Very young children are at risk for effects on brain development. Elderly patients often exhibit subsequent amnesia. Here, we show that the general anesthetic propofol perturbs the ultrastructure of the lipid bilayer of the cell membrane in intact cells. Initially propofol destabilized lipid nanodomains. However, with increasing incubation time and propofol concentration, the effect is reversed and nanodomains are further stabilized. We show that this stabilization is caused by the activation of the actin cortex under the membrane. These perturbations of membrane bilayer and cortical actin may explain how propofol affects neuronal plasticity at synapses.
Collapse
Affiliation(s)
- Weixiang Jin
- Dept. of Physics, University at Buffalo, SUNY, Buffalo, NY 14260-1500, USA
| | - Michael Zucker
- Dept. of Physics, University at Buffalo, SUNY, Buffalo, NY 14260-1500, USA
| | - Arnd Pralle
- Dept. of Physics, University at Buffalo, SUNY, Buffalo, NY 14260-1500, USA.
| |
Collapse
|
19
|
Castillo-Badillo JA, Bandi AC, Harlalka S, Gautam N. SRRF-Stream Imaging of Optogenetically Controlled Furrow Formation Shows Localized and Coordinated Endocytosis and Exocytosis Mediating Membrane Remodeling. ACS Synth Biol 2020; 9:902-919. [PMID: 32155337 DOI: 10.1021/acssynbio.9b00521] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cleavage furrow formation during cytokinesis involves extensive membrane remodeling. In the absence of methods to exert dynamic control over these processes, it has been a challenge to examine the basis of this remodeling. Here we used a subcellular optogenetic approach to induce this at will and found that furrow formation is mediated by actomyosin contractility, retrograde plasma membrane flow, localized decrease in membrane tension, and endocytosis. FRAP, 4-D imaging, and inhibition or upregulation of endocytosis or exocytosis show that ARF6 and Exo70 dependent localized exocytosis supports a potential model for intercellular bridge elongation. TIRF and Super Resolution Radial Fluctuation (SRRF) stream microscopy show localized VAMP2-mediated exocytosis and incorporation of membrane lipids from vesicles into the plasma membrane at the front edge of the nascent daughter cell. Thus, spatially separated but coordinated plasma membrane depletion and addition are likely contributors to membrane remodeling during cytokinetic processes.
Collapse
|
20
|
Stalder D, Gershlick DC. Direct trafficking pathways from the Golgi apparatus to the plasma membrane. Semin Cell Dev Biol 2020; 107:112-125. [PMID: 32317144 PMCID: PMC7152905 DOI: 10.1016/j.semcdb.2020.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/19/2022]
Abstract
In eukaryotic cells, protein sorting is a highly regulated mechanism important for many physiological events. After synthesis in the endoplasmic reticulum and trafficking to the Golgi apparatus, proteins sort to many different cellular destinations including the endolysosomal system and the extracellular space. Secreted proteins need to be delivered directly to the cell surface. Sorting of secreted proteins from the Golgi apparatus has been a topic of interest for over thirty years, yet there is still no clear understanding of the machinery that forms the post-Golgi carriers. Most evidence points to these post-Golgi carriers being tubular pleomorphic structures that bud from the trans-face of the Golgi. In this review, we present the background studies and highlight the key components of this pathway, we then discuss the machinery implicated in the formation of these carriers, their translocation across the cytosol, and their fusion at the plasma membrane.
Collapse
Key Words
- ATP, adenosine triphosphate
- BFA, Brefeldin A
- CARTS, CARriers of the TGN to the cell Surface
- CI-MPR, cation-independent mannose-6 phosphate receptor
- Constitutive Secretion
- CtBP3/BARS, C-terminus binding protein 3/BFA adenosine diphosphate–ribosylated substrate
- ER, endoplasmic reticulum
- GPI-anchored proteins, glycosylphosphatidylinositol-anchored proteins
- GlcCer, glucosylceramidetol
- Golgi to plasma membrane sorting
- PAUF, pancreatic adenocarcinoma up-regulated factor
- PKD, Protein Kinase D
- RUSH, retention using selective hooks
- SBP, streptavidin-binding peptide
- SM, sphingomyelin
- SNARE, soluble N-ethylmaleimide sensitive fusion protein attachment protein receptor
- SPCA1, secretory pathway calcium ATPase 1
- Secretion
- TGN, trans-Golgi Network
- TIRF, total internal reflection fluorescence
- VSV, vesicular stomatitis virus
- pleomorphic tubular carriers
- post-Golgi carriers
- ts, temperature sensitive
Collapse
Affiliation(s)
- Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - David C Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom.
| |
Collapse
|
21
|
Kong H, Zhang J, Li J, Wang J, Shin HJ, Tai R, Yan Q, Xia K, Hu J, Wang L, Zhu Y, Fan C. Genetically encoded X-ray cellular imaging for nanoscale protein localization. Natl Sci Rev 2020; 7:1218-1227. [PMID: 34692146 PMCID: PMC8288996 DOI: 10.1093/nsr/nwaa055] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/07/2020] [Accepted: 04/02/2020] [Indexed: 12/20/2022] Open
Abstract
Spatial resolution defines the physical limit of microscopes for probing biomolecular localization and interactions in cells. Whereas synchrotron-based X-ray microscopy (XRM) represents a unique approach for imaging a whole cell with nanoscale resolution due to its intrinsic nanoscale resolution and great penetration ability, existing approaches to label biomolecules rely on the use of exogenous tags that are multi-step and error-prone. Here, we repurpose engineered peroxidases as genetically encoded X-ray-sensitive tags (GXET) for site-specific labeling of protein-of-interest in mammalian cells. We find that 3,3′-diaminobenzidine (DAB) polymers that are in-situ catalytically formed by fusion-expressed peroxidases are visible under XRM. Using this new tag, we imaged the protein location associated with the alteration of a DNA-methylation pathway with an ultra-high resolution of 30 nanometers. Importantly, the excellent energy resolution of XRM enables multicolor imaging using different peroxidase tags. The development of GXET enlightens the way to nanoscopic imaging for biological studies.
Collapse
Affiliation(s)
- Huating Kong
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jichao Zhang
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jiang Li
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jian Wang
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, SK S7N 2V3, Canada
| | - Hyun-Joon Shin
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Korea
| | - Renzhong Tai
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Qinglong Yan
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Kai Xia
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jun Hu
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Lihua Wang
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Ying Zhu
- Bioimaging Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, and Shanghai Key Laboratory for Nucleic Acids Chemistry and Nanomedicine, Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| |
Collapse
|
22
|
Ware AW, Rasulov SR, Cheung TT, Lott JS, McDonald FJ. Membrane trafficking pathways regulating the epithelial Na + channel. Am J Physiol Renal Physiol 2019; 318:F1-F13. [PMID: 31657249 DOI: 10.1152/ajprenal.00277.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Renal Na+ reabsorption, facilitated by the epithelial Na+ channel (ENaC), is subject to multiple forms of control to ensure optimal body blood volume and pressure through altering both the ENaC population and activity at the cell surface. Here, the focus is on regulating the number of ENaCs present in the apical membrane domain through pathways of ENaC synthesis and targeting to the apical membrane as well as ENaC removal, recycling, and degradation. Finally, the mechanisms by which ENaC trafficking pathways are regulated are summarized.
Collapse
Affiliation(s)
- Adam W Ware
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sahib R Rasulov
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Tanya T Cheung
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - J Shaun Lott
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| |
Collapse
|
23
|
Martínez-Mármol R, Mohannak N, Qian L, Wang T, Gormal RS, Ruitenberg MJ, Vanhaesebroeck B, Coulson EJ, Meunier FA. p110δ PI3-Kinase Inhibition Perturbs APP and TNFα Trafficking, Reduces Plaque Burden, Dampens Neuroinflammation, and Prevents Cognitive Decline in an Alzheimer's Disease Mouse Model. J Neurosci 2019; 39:7976-7991. [PMID: 31363064 PMCID: PMC6774409 DOI: 10.1523/jneurosci.0674-19.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/26/2019] [Accepted: 07/22/2019] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is associated with the cleavage of the amyloid precursor protein (APP) to produce the toxic amyloid-β (Aβ) peptide. Accumulation of Aβ, together with the concomitant inflammatory response, ultimately leads to neuronal death and cognitive decline. Despite AD progression being underpinned by both neuronal and immunological components, therapeutic strategies based on dual targeting of these systems remains unexplored. Here, we report that inactivation of the p110δ isoform of phosphoinositide 3-kinase (PI3K) reduces anterograde axonal trafficking of APP in hippocampal neurons and dampens secretion of the inflammatory cytokine tumor necrosis factor-alpha by microglial cells in the familial AD APPswe/PS1ΔE9 (APP/PS1) mouse model. Moreover, APP/PS1 mice with kinase-inactive PI3Kδ (δD910A) had reduced Aβ peptides levels and plaques in the brain and an abrogated inflammatory response compared with APP/PS1 littermates. Mechanistic investigations reveal that PI3Kδ inhibition decreases the axonal transport of APP by eliciting the formation of highly elongated tubular-shaped APP-containing carriers, reducing the levels of secreted Aβ peptide. Importantly, APP/PS1/δD910A mice exhibited no spatial learning or memory deficits. Our data highlight inhibition of PI3Kδ as a new approach to protect against AD pathology due to its dual action of dampening microglial-dependent neuroinflammation and reducing plaque burden by inhibition of neuronal APP trafficking and processing.SIGNIFICANCE STATEMENT During Alzheimer's disease (AD), the accumulation of the toxic amyloid-β (Aβ) peptide in plaques is associated with a chronic excessive inflammatory response. Uncovering new drug targets that simultaneously reduce both Aβ plaque load and neuroinflammation holds therapeutic promise. Using a combination of genetic and pharmacological approaches, we found that the p110δ isoform of phosphoinositide 3-kinase (PI3K) is involved in anterograde trafficking of the amyloid precursor protein in neurons and in the secretion of tumor necrosis factor-alpha from microglial cells. Genetic inactivation of PI3Kδ reduces Aβ plaque deposition and abrogates the inflammatory response, resulting in a complete rescue of the life span and spatial memory performance. We conclude that inhibiting PI3Kδ represents a novel therapeutic approach to ameliorate AD pathology by dampening plaque accumulation and microglial-dependent neuroinflammation.
Collapse
Affiliation(s)
- Ramón Martínez-Mármol
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
| | - Nika Mohannak
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
| | - Lei Qian
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane 4072, Australia, and
| | - Tong Wang
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
| | - Rachel S Gormal
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
| | - Marc J Ruitenberg
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane 4072, Australia, and
| | - Bart Vanhaesebroeck
- Cell Signalling, University College London Cancer Institute, London WC1E 6DD, United Kingdom
| | - Elizabeth J Coulson
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia,
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane 4072, Australia, and
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia,
| |
Collapse
|
24
|
Kang M, Day CA, Kenworthy AK. A novel computational framework for D(t) from Fluorescence Recovery after Photobleaching data reveals various anomalous diffusion types in live cell membranes. Traffic 2019; 20:867-880. [PMID: 31452286 DOI: 10.1111/tra.12690] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 08/23/2019] [Accepted: 08/23/2019] [Indexed: 01/20/2023]
Abstract
Diffusion of proteins and lipids in lipid membranes plays a pivotal role in almost all aspects of cellular biology, including motility, exo-/endocytosis and signal transduction. For this reason, gaining a detailed understanding of membrane structure and function has long been a major area of cell biology research. To better elucidate this structure-function relationship, various tools have been developed for diffusion measurements, including Fluorescence Recovery After Photobleaching (FRAP). Because of the complexity of cellular microenvironments, biological diffusion is often correlated over time and described by a time-dependent diffusion coefficient, D(t), although the underlying mechanisms are not fully understood. Since D(t) provides important information regarding cellular structures, such as the existence of subresolution barriers to diffusion, many efforts have been made to quantify D(t) by FRAP assuming a single power law, D(t) = Γt α - 1 where Γ and α are transport coefficient and anomalous exponent. However, straightforward approaches to quantify a general form of D(t) are lacking. In this study, we develop a novel mathematical and computational framework to compute the mean square displacement of diffusing molecules and diffusion coefficient D(t) from each individual time point of confocal FRAP data without the single power law assumption. Additionally, we developed an auxiliary equation for D(t) which can readily distinguish normal diffusion or single power law anomalous diffusion from other types of anomalous diffusion directly from FRAP data. Importantly, by applying this approach to FRAP data from a variety of membrane markers, we demonstrate the single power law anomalous diffusion assumption is not sufficient to describe various types of D(t) of membrane proteins. Lastly, we discuss how our new approaches can be applied to other fluorescence microscopy tools such as Fluorescence Correlation Spectroscopy (FCS) and Single Particle Tracking (SPT).
Collapse
Affiliation(s)
- Minchul Kang
- Department of Mathematics, Texas A&M University-Commerce, Commerce, Texas
| | - Charles A Day
- The Hormel Institute, University of Minnesota, Austin, Minnesota
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Chemical and Physical Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee
| |
Collapse
|
25
|
Lebreton S, Paladino S, Zurzolo C. Clustering in the Golgi apparatus governs sorting and function of GPI‐APs in polarized epithelial cells. FEBS Lett 2019; 593:2351-2365. [DOI: 10.1002/1873-3468.13573] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/29/2019] [Accepted: 08/05/2019] [Indexed: 01/25/2023]
Affiliation(s)
- Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogénèse Institut Pasteur Paris France
| | - Simona Paladino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche Università degli Studi di Napoli Federico II Naples Italy
| | - Chiara Zurzolo
- Unité de Trafic Membranaire et Pathogénèse Institut Pasteur Paris France
| |
Collapse
|
26
|
von Blume J, Hausser A. Lipid-dependent coupling of secretory cargo sorting and trafficking at the trans-Golgi network. FEBS Lett 2019; 593:2412-2427. [PMID: 31344259 PMCID: PMC8048779 DOI: 10.1002/1873-3468.13552] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/10/2019] [Accepted: 07/22/2019] [Indexed: 12/17/2022]
Abstract
In eukaryotic cells, the trans-Golgi network (TGN) serves as a platform for secretory cargo sorting and trafficking. In recent years, it has become evident that a complex network of lipid–lipid and lipid–protein interactions contributes to these key functions. This review addresses the role of lipids at the TGN with a particular emphasis on sphingolipids and diacylglycerol. We further highlight how these lipids couple secretory cargo sorting and trafficking for spatiotemporal coordination of protein transport to the plasma membrane.
Collapse
Affiliation(s)
- Julia von Blume
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA.,Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart, Germany.,Stuttgart Research Center Systems Biology, University of Stuttgart, Germany
| |
Collapse
|
27
|
Endoplasmic Reticulum Export of GPI-Anchored Proteins. Int J Mol Sci 2019; 20:ijms20143506. [PMID: 31319476 PMCID: PMC6678536 DOI: 10.3390/ijms20143506] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/07/2019] [Accepted: 07/15/2019] [Indexed: 12/12/2022] Open
Abstract
Protein export from the endoplasmic reticulum (ER) is an essential process in all eukaryotes driven by the cytosolic coat complex COPII, which forms vesicles at ER exit sites for transport of correctly assembled secretory cargo to the Golgi apparatus. The COPII machinery must adapt to the existing wide variety of different types of cargo proteins and to different cellular needs for cargo secretion. The study of the ER export of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs), a special glycolipid-linked class of cell surface proteins, is contributing to address these key issues. Due to their special biophysical properties, GPI-APs use a specialized COPII machinery to be exported from the ER and their processing and maturation has been recently shown to actively regulate COPII function. In this review, we discuss the regulatory mechanisms by which GPI-APs are assembled and selectively exported from the ER.
Collapse
|
28
|
Funato K, Riezman H, Muñiz M. Vesicular and non-vesicular lipid export from the ER to the secretory pathway. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158453. [PMID: 31054928 DOI: 10.1016/j.bbalip.2019.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 11/26/2022]
Abstract
The endoplasmic reticulum is the site of synthesis of most glycerophospholipids, neutral lipids and the initial steps of sphingolipid biosynthesis of the secretory pathway. After synthesis, these lipids are distributed within the cells to create and maintain the specific compositions of the other secretory organelles. This represents a formidable challenge, particularly while there is a simultaneous and quantitatively important flux of membrane components stemming from the vesicular traffic of proteins through the pathway, which can also vary depending on the cell type and status. To meet this challenge cells have developed an intricate system of interorganellar contacts and lipid transport proteins, functioning in non-vesicular lipid transport, which are able to ensure membrane lipid homeostasis even in the absence of membrane trafficking. Nevertheless, under normal conditions, lipids are transported in cells by both vesicular and non-vesicular mechanisms. In this review we will discuss the mechanism and roles of vesicular and non-vesicular transport of lipids from the ER to other organelles of the secretory pathway.
Collapse
Affiliation(s)
- Kouichi Funato
- Department of Bioresource Science and Technology, Hiroshima University, Japan.
| | - Howard Riezman
- NCCR Chemical Biology and Department of Biochemistry, Sciences II, University of Geneva, Switzerland.
| | - Manuel Muñiz
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
| |
Collapse
|
29
|
Pereira PM, Albrecht D, Culley S, Jacobs C, Marsh M, Mercer J, Henriques R. Fix Your Membrane Receptor Imaging: Actin Cytoskeleton and CD4 Membrane Organization Disruption by Chemical Fixation. Front Immunol 2019; 10:675. [PMID: 31024536 PMCID: PMC6460894 DOI: 10.3389/fimmu.2019.00675] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/12/2019] [Indexed: 12/25/2022] Open
Abstract
Single-molecule localization microscopy (SMLM) techniques allow near molecular scale resolution (~ 20 nm) as well as precise and robust analysis of protein organization at different scales. SMLM hardware, analytics and probes have been the focus of a variety of studies and are now commonly used in laboratories across the world. Protocol reliability and artifact identification are increasingly seen as important aspects of super-resolution microscopy. The reliability of these approaches thus requires in-depth evaluation so that biological findings are based on solid foundations. Here we explore how different fixation approaches that disrupt or preserve the actin cytoskeleton affect membrane protein organization. Using CD4 as a model, we show that fixation-mediated disruption of the actin cytoskeleton correlates with changes in CD4 membrane organization. We highlight how these artifacts are easy to overlook and how careful sample preparation is essential for extracting meaningful results from super-resolution microscopy.
Collapse
Affiliation(s)
- Pedro M. Pereira
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
| | - David Albrecht
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Siân Culley
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Caron Jacobs
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Mark Marsh
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Jason Mercer
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Ricardo Henriques
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| |
Collapse
|
30
|
A lipid-based partitioning mechanism for selective incorporation of proteins into membranes of HIV particles. Nat Cell Biol 2019; 21:452-461. [PMID: 30936472 DOI: 10.1038/s41556-019-0300-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 02/18/2019] [Indexed: 12/14/2022]
Abstract
Particles that bud off from the cell surface, including viruses and microvesicles, typically have a unique membrane protein composition distinct from that of the originating plasma membrane. This selective protein composition enables viruses to evade the immune response and infect other cells. But how membrane proteins sort into budding viruses such as human immunodeficiency virus (HIV) remains unclear. Proteins could passively distribute into HIV-assembly-site membranes producing compositions resembling pre-existing plasma-membrane domains. Here, we demonstrate that proteins instead sort actively into HIV-assembly-site membranes, generating compositions enriched in cholesterol and sphingolipids that undergo continuous remodelling. Proteins are recruited into and removed from the HIV assembly site through lipid-based partitioning, initiated by oligomerization of the HIV structural protein Gag. Changes in membrane curvature at the assembly site further amplify this sorting process. Thus, a lipid-based sorting mechanism, aided by increasing membrane curvature, generates the unique membrane composition of the HIV surface.
Collapse
|
31
|
CD4-Dependent Modulation of HIV-1 Entry by LY6E. J Virol 2019; 93:JVI.01866-18. [PMID: 30674630 DOI: 10.1128/jvi.01866-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/16/2019] [Indexed: 01/06/2023] Open
Abstract
Lymphocyte antigen 6E (LY6E) is a GPI-anchored, interferon-inducible protein that has been shown to modulate viral infection in a cell type-dependent manner. Our recent work showed that LY6E promotes HIV-1 infection in some high-CD4-expressing cells, including human peripheral blood mononuclear cells (PBMCs) and the SupT1 cell line. In this work, we provide evidence that LY6E inhibits HIV-1 entry and spread in low-CD4-expressing Jurkat cells and human monocyte-derived macrophages (MDMs) through downregulation of the viral receptor CD4. We found that knockdown of LY6E in Jurkat cells and MDMs increases HIV-1 infection, yet overexpression of LY6E in Jurkat cells inhibits HIV-1 entry and replication. LY6E was found to be colocalized with CD4 on the plasma membrane of Jurkat cells and MDMs and enhances CD4 internalization. We artificially manipulated the CD4 level in Jurkat and SupT1 cells and found that overexpression of CD4 in Jurkat cells overcomes the inhibitory effect of LY6E; conversely, blocking the function of CD4 in SupT1 with a neutralizing antibody eliminates the enhancement of LY6E on HIV-1 entry. The CD4-dependent inhibitory phenotype of LY6E in low-CD4-expressing human MDMs can be recapitulated for a panel of transmitted founder viruses and laboratory-adapted HIV-1 strains. Given that HIV-1 can target low-CD4-expressing cells during acute infection yet replicates efficiently in high-CD4-expressing T cells at the late stage of disease, our observation that LY6E differentially modulates HIV-1 replication in a CD4-dependent manner has implications for understanding the complex roles of interferon (IFN)-induced proteins in AIDS pathogenesis.IMPORTANCE The role of IFN-induced genes (ISGs) in viral infection remains incompletely understood. While most ISGs are antiviral, some ISGs have been shown to promote viral infection, including HIV-1 infection. We previously showed that IFN-inducible LY6E protein promotes HIV-1 infection in human PMBCs and high-CD4-expressing SupT1 cells. Here we found that LY6E inhibits HIV-1 entry and replication in low-CD4-expressing MDMs and Jurkat cells. Mechanistically, we demonstrated that LY6E downregulates the cell surface receptor CD4, thus impairing the virus binding to target cells. This is in contrast to the situation of high-CD4-expressing cells, where LY6E predominantly promotes viral membrane fusion. The opposing role of IFN-inducible LY6E in modulating HIV-1 infection highlights the complex roles of ISGs in viral infection and viral pathogenesis.
Collapse
|
32
|
Rawangwong A, Khrongyut S, Chomphoo S, Konno K, Yamasaki M, Watanabe M, Kondo H, Hipkaeo W. Heterogeneous localization of muscarinic cholinoceptor M 1 in the salivary ducts of adult mice. Arch Oral Biol 2019; 100:14-22. [PMID: 30743058 DOI: 10.1016/j.archoralbio.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/31/2019] [Accepted: 02/03/2019] [Indexed: 11/24/2022]
Abstract
We hypothesize variation in expression and localization, along the course of the glandular tubule, of muscarinic cholinergic receptor M1 which plays as a distinct contribution, though minor in comparison with M3 receptor, in saliva secretion. Localization of the M1 receptor was examined using immunohistochemistry in three major salivary glands. Although all glandular cells were more or less M1-immunoreactive, acinar cells were weakly immunoreactive, while ductal cells exhibited substantial M1-immunoreactivity. Many ductal cells exhibited clear polarity with higher immunoreactivity in their apical/supra-nuclear domain. However, some exhibited indistinct polarity because of additional higher immunoreactivity in their basal/infra-nuclear domain. A small group of cells with intense immunoreactivity was found, mostly located in the intercalated ducts or in portions of the striated ducts close to the intercalated ducts. In immuno-electron microscopy, the immunoreactive materials were mainly in the cytoplasm including various vesicles and vacuoles. Unexpectedly, distinct immunoreactivity on apical and basal plasma membranes was infrequent in most ductal cells. The heterogeneous localization of M1-immunoreactivity along the gland tubular system is discussed in view of possible modulatory roles of the M1 receptor in saliva secretion.
Collapse
Affiliation(s)
- Atsara Rawangwong
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Suthankamon Khrongyut
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Surang Chomphoo
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Kohtaro Konno
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Miwako Yamasaki
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hisatake Kondo
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Department of Organ Anatomy, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Wiphawi Hipkaeo
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
| |
Collapse
|
33
|
Giacomello E, Ronchi P, Pepperkok R. GM130 and p115 play a key role in the organisation of the early secretory pathway during skeletal muscle differentiation. J Cell Sci 2019; 132:jcs.222083. [DOI: 10.1242/jcs.222083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/20/2018] [Indexed: 12/24/2022] Open
Abstract
ABSTRACT
Skeletal muscle (SKM) differentiation is a highly regulated process leading to the formation of specialised cells with reorganised compartments and organelles, such as those of the early secretory pathway. During SKM differentiation the Golgi complex (GC) redistributes close to the nuclear envelope and in small distinct peripheral structures distributed throughout the myotube. Concurrently, GC elements closely associate with endoplasmic reticulum-exit sites (ERES). The mechanisms underlying this reorganisation and its relevance for SKM differentiation are poorly understood. Here, we show, by time-lapse imaging studies, that the changes in GC organisation involve GC fragmentation and redistribution of ERES with the formation of tightly associated GC–ERES units. We show that knockdown of GM130 (also known as GOLGA2) or p115 (also known as USO1), two regulators of the early secretory pathway, impairs GC and ERES reorganisation. This in turn results in inhibition of myotube fusion and M-cadherin (also known as CDH15) transport to the sarcolemma. Taken together, our data suggest that the correct reorganisation of the early secretory pathway components plays an important role in SKM differentiation and, thus, associated pathologies.
Collapse
Affiliation(s)
- Emiliana Giacomello
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, (EMBL), Meyerhofstraße 1, Heidelberg D-69117, Germany
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste 34149, Italy
| | - Paolo Ronchi
- Electron Microscopy Core Facility, Europen Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, Heidelberg D-69117, Germany
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, (EMBL), Meyerhofstraße 1, Heidelberg D-69117, Germany
| |
Collapse
|
34
|
Wei Z, Liu T, Lei J, Wu Y, Wang S, Liao K. Fam198a, a member of secreted kinase, secrets through caveolae biogenesis pathway. Acta Biochim Biophys Sin (Shanghai) 2018; 50:968-975. [PMID: 30188967 DOI: 10.1093/abbs/gmy105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Indexed: 01/21/2023] Open
Abstract
Fam198a is a member of four-jointed protein kinases, a secreted protein kinase family. It was identified as a caveolae-associated protein and colocalized with cavin-1 and caveolin-1 in both tissues and cells. The newly synthesized Fam198a precursor in endoplasmic reticulum (ER) was transported by caveolae biogenesis vesicles to Golgi apparatus in which it was proteolytically cleaved into the secreted mature form. The amino acid mutation analysis identified Arg 120 and 437 as the proteolytic sites in Fam198a precursor during maturation. In mouse embryo fibroblasts (MEFs) obtained from cavin-1-/- or caveolin-1-/- mice, Fam198a precursor was retained in ER and no mature Fam198a could be formed in these cells. Ectopic expression of exogenous cavin-1 in cavin-1-/- MEFs restored the blocked Fam198a post-translational process and secretion. Cavin-1 was also required for Fam198a secretion after its maturation in Golgi apparatus. Ectopic expression of cavin-1 in A549 cells restored the blocked Fam198a secretion. These results suggest that protein secretion is an important function for caveolae biogenesis pathway and the disruption of caveolae system will affect those functions played by the secreted proteins.
Collapse
Affiliation(s)
- Zhuang Wei
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Tao Liu
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Jigang Lei
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, Tongji University, Shanghai, China
| | - Yuan Wu
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Shilong Wang
- School of Life Science and Technology, Tongji University, Shanghai, China
| | - Kan Liao
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
35
|
Bourke AM, Bowen AB, Kennedy MJ. New approaches for solving old problems in neuronal protein trafficking. Mol Cell Neurosci 2018; 91:48-66. [PMID: 29649542 DOI: 10.1016/j.mcn.2018.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 11/16/2022] Open
Abstract
Fundamental cellular properties are determined by the repertoire and abundance of proteins displayed on the cell surface. As such, the trafficking mechanisms for establishing and maintaining the surface proteome must be tightly regulated for cells to respond appropriately to extracellular cues, yet plastic enough to adapt to ever-changing environments. Not only are the identity and abundance of surface proteins critical, but in many cases, their regulated spatial positioning within surface nanodomains can greatly impact their function. In the context of neuronal cell biology, surface levels and positioning of ion channels and neurotransmitter receptors play essential roles in establishing important properties, including cellular excitability and synaptic strength. Here we review our current understanding of the trafficking pathways that control the abundance and localization of proteins important for synaptic function and plasticity, as well as recent technological advances that are allowing the field to investigate protein trafficking with increasing spatiotemporal precision.
Collapse
Affiliation(s)
- Ashley M Bourke
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Aaron B Bowen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States.
| |
Collapse
|
36
|
Fois G, Winkelmann VE, Bareis L, Staudenmaier L, Hecht E, Ziller C, Ehinger K, Schymeinsky J, Kranz C, Frick M. ATP is stored in lamellar bodies to activate vesicular P2X 4 in an autocrine fashion upon exocytosis. J Gen Physiol 2017; 150:277-291. [PMID: 29282210 PMCID: PMC5806682 DOI: 10.1085/jgp.201711870] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 10/12/2017] [Accepted: 11/17/2017] [Indexed: 12/14/2022] Open
Abstract
P2X4 receptor activation facilitates secretion of pulmonary surfactant from secretory vesicles called lamellar bodies in alveolar epithelial cells. Fois et al. reveal that P2X4 receptors on the lamellar body membranes are activated by ATP stored within the vesicles themselves upon vesicle exocytosis. Vesicular P2X4 receptors are known to facilitate secretion and activation of pulmonary surfactant in the alveoli of the lungs. P2X4 receptors are expressed in the membrane of lamellar bodies (LBs), large secretory lysosomes that store lung surfactant in alveolar type II epithelial cells, and become inserted into the plasma membrane after exocytosis. Subsequent activation of P2X4 receptors by adenosine triphosphate (ATP) results in local fusion-activated cation entry (FACE), facilitating fusion pore dilation, surfactant secretion, and surfactant activation. Despite the importance of ATP in the alveoli, and hence lung function, the origin of ATP in the alveoli is still elusive. In this study, we demonstrate that ATP is stored within LBs themselves at a concentration of ∼1.9 mM. ATP is loaded into LBs by the vesicular nucleotide transporter but does not activate P2X4 receptors because of the low intraluminal pH (5.5). However, the rise in intravesicular pH after opening of the exocytic fusion pore results in immediate activation of vesicular P2X4 by vesicular ATP. Our data suggest a new model in which agonist (ATP) and receptor (P2X4) are located in the same intracellular compartment (LB), protected from premature degradation (ATP) and activation (P2X4), and ideally placed to ensure coordinated and timely receptor activation as soon as fusion occurs to facilitate surfactant secretion.
Collapse
Affiliation(s)
- Giorgio Fois
- Institute of General Physiology, Ulm University, Ulm, Germany
| | | | - Lara Bareis
- Institute of General Physiology, Ulm University, Ulm, Germany
| | | | - Elena Hecht
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Charlotte Ziller
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | | | - Jürgen Schymeinsky
- Immunology and Respiratory Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riß, Germany
| | - Christine Kranz
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
| |
Collapse
|
37
|
Miserey-Lenkei S, Bousquet H, Pylypenko O, Bardin S, Dimitrov A, Bressanelli G, Bonifay R, Fraisier V, Guillou C, Bougeret C, Houdusse A, Echard A, Goud B. Coupling fission and exit of RAB6 vesicles at Golgi hotspots through kinesin-myosin interactions. Nat Commun 2017; 8:1254. [PMID: 29093437 PMCID: PMC5665954 DOI: 10.1038/s41467-017-01266-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/04/2017] [Indexed: 01/08/2023] Open
Abstract
The actin and microtubule cytoskeletons play important roles in Golgi structure and function, but how they are connected remain poorly known. In this study, we investigated whether RAB6 GTPase, a Golgi-associated RAB involved in the regulation of several transport steps at the Golgi level, and two of its effectors, Myosin IIA and KIF20A participate in the coupling between actin and microtubule cytoskeleton. We have previously shown that RAB6–Myosin IIA interaction is critical for the fission of RAB6-positive transport carriers from Golgi/TGN membranes. Here we show that KIF20A is also involved in the fission process and serves to anchor RAB6 on Golgi/TGN membranes near microtubule nucleating sites. We provide evidence that the fission events occur at a limited number of hotspots sites. Our results suggest that coupling between actin and microtubule cytoskeletons driven by Myosin II and KIF20A ensures the spatial coordination between RAB6-positive vesicles fission from Golgi/TGN membranes and their exit along microtubules. Actin and microtubules play important roles in Golgi structure and function but how they are connected is poorly understood. Here the authors show that KIF20A is involved in the fission process and, in association with Myosin II, serves to anchor RAB6 on Golgi/TGN membranes near microtubules nucleating sites.
Collapse
Affiliation(s)
- Stéphanie Miserey-Lenkei
- Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport, F-75005, Paris, France.
| | - Hugo Bousquet
- Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport, F-75005, Paris, France
| | - Olena Pylypenko
- Institut Curie, PSL Research University, CNRS, UMR 144, Structural Motility, F-75005, Paris, France
| | - Sabine Bardin
- Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport, F-75005, Paris, France
| | - Ariane Dimitrov
- Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport, F-75005, Paris, France
| | - Gaëlle Bressanelli
- Institut Curie, PSL Research University, CNRS, UMR 144, Structural Motility, F-75005, Paris, France
| | - Raja Bonifay
- Institut Curie, PSL Research University, CNRS, UMR 144, Structural Motility, F-75005, Paris, France
| | - Vincent Fraisier
- Institut Curie, PSL Research University, CNRS, UMR 144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | | | | | - Anne Houdusse
- Institut Curie, PSL Research University, CNRS, UMR 144, Structural Motility, F-75005, Paris, France
| | - Arnaud Echard
- Institut Pasteur, CNRS UMR3691, Membrane Traffic and Cell Division, F-75015, Paris, France
| | - Bruno Goud
- Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport, F-75005, Paris, France.
| |
Collapse
|
38
|
Anandi L, Chakravarty V, Ashiq KA, Bodakuntla S, Lahiri M. DNA-dependent protein kinase plays a central role in transformation of breast epithelial cells following alkylation damage. J Cell Sci 2017; 130:3749-3763. [PMID: 28923836 DOI: 10.1242/jcs.203034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 09/14/2017] [Indexed: 12/25/2022] Open
Abstract
DNA alkylating agents form the first line of cancer chemotherapy. They not only kill cells but also behave as potential carcinogens. MNU, a DNA methylating agent, is well known to induce mammary tumours in rodents. However, the mechanism of tumorigenesis is not well understood. Our study reports a novel role played by DNA-dependent protein kinase (DNA-PK) in methylation damage-induced transformation using three-dimensional breast acinar cultures. Here, we report that exposure of breast epithelial cells to MNU inhibited polarisation at the basolateral domain, increased dispersal of the Golgi at the apical domain and induced an epithelial-to-mesenchymal transition (EMT)-like phenotype as well as invasion. This altered Golgi phenotype correlated with impaired intracellular trafficking. Inhibition of DNA-PK resulted in almost complete reversal of the altered Golgi phenotype and partial rescue of the polarity defect and EMT-like phenotype. The results confirm that methylation damage-induced activation of DNA-PK is a major mechanism in mediating cellular transformation.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Libi Anandi
- Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| | - Vaishali Chakravarty
- Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| | - K A Ashiq
- Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| | - Satish Bodakuntla
- Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India.,Institut Curie, PSL Research University, CNRS UMR3348, F-91405 Orsay, France
| | - Mayurika Lahiri
- Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| |
Collapse
|
39
|
Shashikanth N, Yeruva S, Ong MLDM, Odenwald MA, Pavlyuk R, Turner JR. Epithelial Organization: The Gut and Beyond. Compr Physiol 2017; 7:1497-1518. [DOI: 10.1002/cphy.c170003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
40
|
Two Clathrin Adaptor Protein Complexes Instruct Axon-Dendrite Polarity. Neuron 2017; 90:564-80. [PMID: 27151641 DOI: 10.1016/j.neuron.2016.04.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 03/03/2016] [Accepted: 04/12/2016] [Indexed: 11/23/2022]
Abstract
The cardinal feature of neuronal polarization is the establishment and maintenance of axons and dendrites. How axonal and dendritic proteins are sorted and targeted to different compartments is poorly understood. Here, we identified distinct dileucine motifs that are necessary and sufficient to target transmembrane proteins to either the axon or the dendrite through direct interactions with the clathrin-associated adaptor protein complexes (APs) in C. elegans. Axonal targeting requires AP-3, while dendritic targeting is mediated by AP-1. The axonal dileucine motif binds to AP-3 with higher efficiency than to AP-1. Both AP-3 and AP-1 are localized to the Golgi but occupy adjacent domains. We propose that AP-3 and AP-1 directly select transmembrane proteins and target them to axon and dendrite, respectively, by sorting them into distinct vesicle pools.
Collapse
|
41
|
Liu M, Chung S, Shelness GS, Parks JS. Hepatic ABCA1 deficiency is associated with delayed apolipoprotein B secretory trafficking and augmented VLDL triglyceride secretion. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1035-1043. [PMID: 28694219 DOI: 10.1016/j.bbalip.2017.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 11/30/2022]
Abstract
ATP binding cassette transporter A1 (ABCA1) is a membrane transporter that facilitates nascent HDL formation. Tangier disease subjects with complete ABCA1 deficiency have <5% of normal levels of plasma HDL, elevated triglycerides (TGs), and defective vesicular trafficking in fibroblasts and macrophages. Hepatocyte-specific ABCA1 knockout mice (HSKO) have a similar lipid phenotype with 20% of normal plasma HDL levels and a two-fold elevation of plasma TGs due to hepatic overproduction of large, triglyceride-enriched VLDL. We hypothesized that enhanced VLDL TG secretion in the absence of hepatocyte ABCA1 is due to altered intracellular trafficking of apolipoprotein B (apoB), resulting in augmented TG addition to nascent VLDL. We found that trafficking of newly synthesized apoB through the secretory pathway was delayed in ABCA1-silenced rat hepatoma cells and HSKO primary hepatocytes, relative to controls. Endoglycosidase H treatment of cellular apoB revealed a likely delay in apoB trafficking in post-ER compartments. The reduced rate of protein trafficking was also observed for an adenoviral-expressed GPI-linked fluorescent fusion protein, but not albumin, suggesting a selective delay of secretory cargoes in the absence of hepatocyte ABCA1. Our results suggest an important role for hepatic ABCA1 in regulating secretory trafficking and modulating VLDL expansion during the TG accretion phase of hepatic lipoprotein particle assembly.
Collapse
Affiliation(s)
- Mingxia Liu
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Soonkyu Chung
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Gregory S Shelness
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - John S Parks
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, USA
| |
Collapse
|
42
|
The basolateral vesicle sorting machinery and basolateral proteins are recruited to the site of enteropathogenic E. coli microcolony growth at the apical membrane. PLoS One 2017. [PMID: 28636623 PMCID: PMC5479554 DOI: 10.1371/journal.pone.0179122] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Foodborne Enteropathogenic Escherichia coli (EPEC) infections of the small intestine cause diarrhea especially in children and are a major cause of childhood death in developing countries. EPEC infects the apical membrane of the epithelium of the small intestine by attaching, effacing the microvilli under the bacteria and then forming microcolonies on the cell surface. We first asked the question where on epithelial cells EPEC attaches and grows. Using models of polarized epithelial monolayers, we evaluated the sites of initial EPEC attachment to the apical membrane and found that EPEC preferentially attached over the cell-cell junctions and formed microcolonies preferentially where three cells come together at tricellular tight junctions. The ability of EPEC to adhere increased when host cell polarity was compromised yielding EPEC access to basolateral proteins. EPEC pedestals contain basolateral cytoskeletal proteins. Thus, we asked if attached EPEC causes reorganization the protein composition of the host cell plasma membrane at sites of microcolony formation. We found that EPEC microcolony growth at the apical membrane resulted in a local accumulation of basolateral plasma membrane proteins surrounding the microcolony. Basolateral marker protein aquaporin-3 localized to forming EPEC microcolonies. Components of the basolateral vesicle targeting machinery were re-routed. The Exocyst (Exo70) was recruited to individual EPEC as was the basolateral vesicle SNARE VAMP-3. Moreover, several Rab variants were also recruited to the infection site, and their dominant-negative equivalents were not. To quantitatively study the recruitment of basolateral proteins, we created a pulse of the temperature sensitive basolateral VSVG, VSVG3-SP-GFP, from the trans-Golgi Network. We found that after release from the TGN, significantly more VSVG3-SP-GFP accumulated at the site of microcolony growth than on equivalent membrane regions of uninfected cells. This suggests that trafficking of vesicles destined for the basolateral membrane are redirected to the apical site of microcolony growth. Thus, in addition to disrupting host cell fence function, local host cell plasma membrane protein composition is changed by altered protein trafficking and recruitment of basolateral proteins to the apical microcolony. This may aid EPEC attachment and subsequent microcolony growth.
Collapse
|
43
|
Bottanelli F, Kilian N, Ernst AM, Rivera-Molina F, Schroeder LK, Kromann EB, Lessard MD, Erdmann RS, Schepartz A, Baddeley D, Bewersdorf J, Toomre D, Rothman JE. A novel physiological role for ARF1 in the formation of bidirectional tubules from the Golgi. Mol Biol Cell 2017; 28:1676-1687. [PMID: 28428254 PMCID: PMC5469610 DOI: 10.1091/mbc.e16-12-0863] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/11/2017] [Accepted: 04/14/2017] [Indexed: 11/11/2022] Open
Abstract
Capitalizing on CRISPR/Cas9 gene-editing techniques and super-resolution nanoscopy, we explore the role of the small GTPase ARF1 in mediating transport steps at the Golgi. Besides its well-established role in generating COPI vesicles, we find that ARF1 is also involved in the formation of long (∼3 µm), thin (∼110 nm diameter) tubular carriers. The anterograde and retrograde tubular carriers are both largely free of the classical Golgi coat proteins coatomer (COPI) and clathrin. Instead, they contain ARF1 along their entire length at a density estimated to be in the range of close packing. Experiments using a mutant form of ARF1 affecting GTP hydrolysis suggest that ARF1[GTP] is functionally required for the tubules to form. Dynamic confocal and stimulated emission depletion imaging shows that ARF1-rich tubular compartments fall into two distinct classes containing 1) anterograde cargoes and clathrin clusters or 2) retrograde cargoes and coatomer clusters.
Collapse
Affiliation(s)
- Francesca Bottanelli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
| | - Nicole Kilian
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
| | - Andreas M Ernst
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
| | - Lena K Schroeder
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
| | - Emil B Kromann
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.,Department of Biomedical Engineering, Yale University, New Haven, CT 06520
| | - Mark D Lessard
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
| | - Roman S Erdmann
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.,Department of Chemistry, Yale University, New Haven, CT 06520
| | - Alanna Schepartz
- Department of Chemistry, Yale University, New Haven, CT 06520.,Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520
| | - David Baddeley
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.,Nanobiology Institute, Yale University, West Haven, CT 06516
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.,Department of Biomedical Engineering, Yale University, New Haven, CT 06520.,Nanobiology Institute, Yale University, West Haven, CT 06516
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.,Nanobiology Institute, Yale University, West Haven, CT 06516
| | - James E Rothman
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 .,Nanobiology Institute, Yale University, West Haven, CT 06516
| |
Collapse
|
44
|
Caviglia S, Flores-Benitez D, Lattner J, Luschnig S, Brankatschk M. Rabs on the fly: Functions of Rab GTPases during development. Small GTPases 2017; 10:89-98. [PMID: 28118081 PMCID: PMC6380344 DOI: 10.1080/21541248.2017.1279725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The organization of intracellular transport processes is adapted specifically to different cell types, developmental stages, and physiologic requirements. Some protein traffic routes are universal to all cells and constitutively active, while other routes are cell-type specific, transient, and induced under particular conditions only. Small GTPases of the Rab (Ras related in brain) subfamily are conserved across eukaryotes and regulate most intracellular transit pathways. The complete sets of Rab proteins have been identified in model organisms, and molecular principles underlying Rab functions have been uncovered. Rabs provide intracellular landmarks that define intracellular transport sequences. Nevertheless, it remains a challenge to systematically map the subcellular distribution of all Rabs and their functional interrelations. This task requires novel tools to precisely describe and manipulate the Rab machinery in vivo. Here we discuss recent findings about Rab roles during development and we consider novel approaches to investigate Rab functions in vivo.
Collapse
Affiliation(s)
- Sara Caviglia
- a Danish Stem Cell Center (DanStem), University of Copenhagen , Copenhagen , Denmark.,c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland
| | - David Flores-Benitez
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Johanna Lattner
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Stefan Luschnig
- c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland.,d Institute of Neurobiology and Cluster of Excellence Cells-in-Motion (EXC 1003 - CiM), University of Münster , Münster , Germany
| | - Marko Brankatschk
- e The Biotechnological Center of the TU Dresden (BIOTEC) , Dresden , Germany
| |
Collapse
|
45
|
Liu X, Savy A, Maurin S, Grimaud L, Darchen F, Quinton D, Labbé E, Buriez O, Delacotte J, Lemaître F, Guille-Collignon M. A Dual Functional Electroactive and Fluorescent Probe for Coupled Measurements of Vesicular Exocytosis with High Spatial and Temporal Resolution. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xiaoqing Liu
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Alexandra Savy
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Sylvie Maurin
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Laurence Grimaud
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - François Darchen
- Laboratoire de Neurophotonique, CNRS UMR 8250; Université Paris Descartes; 45, rue des Saints-Pères 75006 Paris France
| | - Damien Quinton
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Eric Labbé
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Olivier Buriez
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Jérôme Delacotte
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Frédéric Lemaître
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| | - Manon Guille-Collignon
- Ecole normale supérieure; PSL Research University, UPMC Univ Paris 06; CNRS; Département de Chimie, PASTEUR; 24, rue Lhomond 75005 Paris France
- Sorbonne Universités; UPMC Univ Paris 06, ENS, CNRS, PASTEUR; 75005 Paris France
| |
Collapse
|
46
|
Liu X, Savy A, Maurin S, Grimaud L, Darchen F, Quinton D, Labbé E, Buriez O, Delacotte J, Lemaître F, Guille-Collignon M. A Dual Functional Electroactive and Fluorescent Probe for Coupled Measurements of Vesicular Exocytosis with High Spatial and Temporal Resolution. Angew Chem Int Ed Engl 2017; 56:2366-2370. [PMID: 28117543 DOI: 10.1002/anie.201611145] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/13/2016] [Indexed: 01/08/2023]
Abstract
In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity. To study secretory behaviors at the single-vesicle level, FFN102 was employed as a new fluorescent/electroactive dual probe in a coupled technique (amperometry and total internal reflection fluorescence microscopy (TIRFM)). We used N13 cells, a stable clone of BON cells, to specifically accumulate FFN102 into their secretory vesicles, and then optical and electrochemical measurements of vesicular exocytosis were experimentally achieved by using indium tin oxide (ITO) transparent electrodes. Upon stimulation, FFN102 started to diffuse out from the acidic intravesicular microenvironment to the neutral extracellular space, leading to fluorescent emissions and to the electrochemical oxidation signals that were simultaneously collected from the ITO electrode surface. The correlation of fluorescence and amperometric signals resulting from the FFN102 probe allows real-time monitoring of single exocytotic events with both high spatial and temporal resolution. This work opens new possibilities in the investigation of exocytotic mechanisms.
Collapse
Affiliation(s)
- Xiaoqing Liu
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Alexandra Savy
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Sylvie Maurin
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Laurence Grimaud
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - François Darchen
- Laboratoire de Neurophotonique, CNRS UMR 8250, Université Paris Descartes, 45, rue des Saints-Pères, 75006, Paris, France
| | - Damien Quinton
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Eric Labbé
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Olivier Buriez
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Jérôme Delacotte
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Frédéric Lemaître
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| | - Manon Guille-Collignon
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France
| |
Collapse
|
47
|
Klayman LM, Wedegaertner PB. Inducible Inhibition of Gβγ Reveals Localization-dependent Functions at the Plasma Membrane and Golgi. J Biol Chem 2016; 292:1773-1784. [PMID: 27994056 DOI: 10.1074/jbc.m116.750430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 12/16/2016] [Indexed: 01/28/2023] Open
Abstract
Heterotrimeric G proteins signal at a variety of endomembrane locations, in addition to their canonical function at the cytoplasmic surface of the plasma membrane (PM), where they are activated by cell surface G protein-coupled receptors. Here we focus on βγ signaling at the Golgi, where βγ activates a signaling cascade, ultimately resulting in vesicle fission from the trans-Golgi network (TGN). To develop a novel molecular tool for inhibiting endogenous βγ in a spatial-temporal manner, we take advantage of a lipid association mutant of the widely used βγ inhibitor GRK2ct (GRK2ct-KERE) and the FRB/FKBP heterodimerization system. We show that GRK2ct-KERE cannot inhibit βγ function when expressed in cells, but recruitment to a specific membrane location recovers the ability of GRK2ct-KERE to inhibit βγ signaling. PM-recruited GRK2ct-KERE inhibits lysophosphatidic acid-induced phosphorylation of Akt, whereas Golgi-recruited GRK2ct-KERE inhibits cargo transport from the TGN to the PM. Moreover, we show that Golgi-recruited GRK2ct-KERE inhibits model basolaterally targeted but not apically targeted cargo delivery, for both PM-destined and secretory cargo, providing the first evidence of selectivity in terms of cargo transport regulated by βγ. Last, we show that Golgi fragmentation induced by ilimaquinone and nocodazole is blocked by βγ inhibition, demonstrating that βγ is a key regulator of multiple pathways that impact Golgi morphology. Thus, we have developed a new molecular tool, recruitable GRK2ct-KERE, to modulate βγ signaling at specific subcellular locations, and we demonstrate novel cargo selectivity for βγ regulation of TGN to PM transport and a novel role for βγ in mediating Golgi fragmentation.
Collapse
Affiliation(s)
- Lauren M Klayman
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Philip B Wedegaertner
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
| |
Collapse
|
48
|
Albrecht D, Winterflood CM, Sadeghi M, Tschager T, Noé F, Ewers H. Nanoscopic compartmentalization of membrane protein motion at the axon initial segment. J Cell Biol 2016; 215:37-46. [PMID: 27697928 PMCID: PMC5057285 DOI: 10.1083/jcb.201603108] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 09/16/2016] [Indexed: 12/31/2022] Open
Abstract
A diffusion barrier impeding membrane molecule motion between the axon and the somatodendritic compartment develops as neurons mature and the axon initial segment (AIS) is enriched in specific molecules. Albrecht et al. analyze the mobility of lipid-anchored molecules in the AIS using single-particle tracking time course experiments and propose a new mechanistic model for the AIS diffusion barrier. The axon initial segment (AIS) is enriched in specific adaptor, cytoskeletal, and transmembrane molecules. During AIS establishment, a membrane diffusion barrier is formed between the axonal and somatodendritic domains. Recently, an axonal periodic pattern of actin, spectrin, and ankyrin forming 190-nm-spaced, ring-like structures has been discovered. However, whether this structure is related to the diffusion barrier function is unclear. Here, we performed single-particle tracking time-course experiments on hippocampal neurons during AIS development. We analyzed the mobility of lipid-anchored molecules by high-speed single-particle tracking and correlated positions of membrane molecules with the nanoscopic organization of the AIS cytoskeleton. We observe a strong reduction in mobility early in AIS development. Membrane protein motion in the AIS plasma membrane is confined to a repetitive pattern of ∼190-nm-spaced segments along the AIS axis as early as day in vitro 4, and this pattern alternates with actin rings. Mathematical modeling shows that diffusion barriers between the segments significantly reduce lateral diffusion along the axon.
Collapse
Affiliation(s)
- David Albrecht
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, England, UK Institute for Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Christian M Winterflood
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, England, UK Institute for Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Mohsen Sadeghi
- Department of Mathematics and Computer Science, Free University Berlin, 14195 Berlin, Germany
| | - Thomas Tschager
- Institute for Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Frank Noé
- Department of Mathematics and Computer Science, Free University Berlin, 14195 Berlin, Germany
| | - Helge Ewers
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, England, UK Institute for Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| |
Collapse
|
49
|
Regulation of intracellular heme trafficking revealed by subcellular reporters. Proc Natl Acad Sci U S A 2016; 113:E5144-52. [PMID: 27528661 DOI: 10.1073/pnas.1609865113] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Heme is an essential prosthetic group in proteins that reside in virtually every subcellular compartment performing diverse biological functions. Irrespective of whether heme is synthesized in the mitochondria or imported from the environment, this hydrophobic and potentially toxic metalloporphyrin has to be trafficked across membrane barriers, a concept heretofore poorly understood. Here we show, using subcellular-targeted, genetically encoded hemoprotein peroxidase reporters, that both extracellular and endogenous heme contribute to cellular labile heme and that extracellular heme can be transported and used in toto by hemoproteins in all six subcellular compartments examined. The reporters are robust, show large signal-to-background ratio, and provide sufficient range to detect changes in intracellular labile heme. Restoration of reporter activity by heme is organelle-specific, with the Golgi and endoplasmic reticulum being important sites for both exogenous and endogenous heme trafficking. Expression of peroxidase reporters in Caenorhabditis elegans shows that environmental heme influences labile heme in a tissue-dependent manner; reporter activity in the intestine shows a linear increase compared with muscle or hypodermis, with the lowest heme threshold in neurons. Our results demonstrate that the trafficking pathways for exogenous and endogenous heme are distinct, with intrinsic preference for specific subcellular compartments. We anticipate our results will serve as a heuristic paradigm for more sophisticated studies on heme trafficking in cellular and whole-animal models.
Collapse
|
50
|
Sphingomyelin is sorted at the trans Golgi network into a distinct class of secretory vesicle. Proc Natl Acad Sci U S A 2016; 113:6677-82. [PMID: 27247384 DOI: 10.1073/pnas.1602875113] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the principal functions of the trans Golgi network (TGN) is the sorting of proteins into distinct vesicular transport carriers that mediate secretion and interorganelle trafficking. Are lipids also sorted into distinct TGN-derived carriers? The Golgi is the principal site of the synthesis of sphingomyelin (SM), an abundant sphingolipid that is transported. To address the specificity of SM transport to the plasma membrane, we engineered a natural SM-binding pore-forming toxin, equinatoxin II (Eqt), into a nontoxic reporter termed Eqt-SM and used it to monitor intracellular trafficking of SM. Using quantitative live cell imaging, we found that Eqt-SM is enriched in a subset of TGN-derived secretory vesicles that are also enriched in a glycophosphatidylinositol-anchored protein. In contrast, an integral membrane secretory protein (CD8α) is not enriched in these carriers. Our results demonstrate the sorting of native SM at the TGN and its transport to the plasma membrane by specific carriers.
Collapse
|