1
|
Lebreton S, Paladino S, Lelek M, Tramier M, Zimmer C, Zurzolo C. Actin cytoskeleton differently regulates cell surface organization of GPI-anchored proteins in polarized epithelial cells and fibroblasts. Front Mol Biosci 2024; 11:1360142. [PMID: 38774234 PMCID: PMC11106487 DOI: 10.3389/fmolb.2024.1360142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/11/2024] [Indexed: 05/24/2024] Open
Abstract
The spatiotemporal compartmentalization of membrane-associated glycosylphosphatidylinositol-anchored proteins (GPI-APs) on the cell surface regulates their biological activities. These GPI-APs occupy distinct cellular functions such as enzymes, receptors, and adhesion molecules, and they are implicated in several vital cellular processes. Thus, unraveling the mechanisms and regulators of their membrane organization is essential. In polarized epithelial cells, GPI-APs are enriched at the apical surface, where they form small cholesterol-independent homoclusters and larger heteroclusters accommodating multiple GPI-AP species, all confined within areas of approximately 65-70 nm in diameter. Notably, GPI-AP homoclustering occurs in the Golgi apparatus through a cholesterol- and calcium-dependent mechanism that drives their apical sorting. Despite the critical role of Golgi GPI-AP clustering in their cell surface organization and the importance of cholesterol in heterocluster formation, the regulatory mechanisms governing GPI-AP surface organization, particularly in the context of epithelial polarity, remain elusive. Given that the actin cytoskeleton undergoes substantial remodeling during polarity establishment, this study explores whether the actin cytoskeleton regulates the spatiotemporal apical organization of GPI-APs in MDCK cells. Utilizing various imaging techniques (number and brightness, FRET/FLIM, and dSTORM coupled to pair correlation analysis), we demonstrate that the apical organization of GPI-APs, at different scales, does not rely on the actin cytoskeleton, unlike in fibroblastic cells. Interestingly, calcium chelation disrupts the organization of GPI-APs at the apical surface by impairing Golgi GPI-AP clustering, emphasizing the existence of an interplay among Golgi clustering, apical sorting, and surface organization in epithelial cells. In summary, our findings unveil distinct mechanisms regulating the organization of GPI-APs in cell types of different origins, plausibly allowing them to adapt to different external signals and different cellular environments in order to achieve specialized functions.
Collapse
Affiliation(s)
- Stéphanie Lebreton
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, Paris, France
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Mickaël Lelek
- Imaging and Modeling Unit, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Marc Tramier
- Université Rennes, Centre National de la recherche scientifique, IGDR (Genetics and Development Institute of Rennes), Unité mixte de receherche 6290, Rennes, France
| | - Christophe Zimmer
- Imaging and Modeling Unit, Department of Computational Biology, Institut Pasteur, Paris, France
- Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Chiara Zurzolo
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, Paris, France
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| |
Collapse
|
2
|
Liu D, Paladino S, Zurzolo C, Lebreton S. Calcium-binding Cab45 regulates the polarized apical secretion of soluble proteins in epithelial cells. Mol Biol Cell 2023; 34:br12. [PMID: 37163315 PMCID: PMC10398874 DOI: 10.1091/mbc.e22-12-0549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/12/2023] [Accepted: 05/02/2023] [Indexed: 05/11/2023] Open
Abstract
Protein secretion is essential for epithelial tissue homoeostasis and therefore has to be tightly regulated. However, while the mechanisms regulating polarized protein sorting and trafficking have been widely studied in the past decade, those governing polarized secretion remain elusive. The calcium manganese pump SPCA1 and the calcium-binding protein Cab45 were recently shown to regulate the secretion of a subset of soluble cargoes in nonpolarized HeLa cells. Interestingly, we demonstrated that in polarized epithelial cells calcium levels in the trans-Golgi network (TGN), controlled by SPCA1, and Cab45 are critical for the apical sorting of glycosylphosphatidylinositol-anchored proteins (GPI-APs), a class of integral membrane proteins containing a soluble protein attached to the membrane by the GPI anchor, prompting us to investigate the mechanism regulating the polarized secretion of soluble cargoes. By reducing Cab45 expression level or overexpressing an inactive mutant of SPCA1, we found that Cab45 and calcium levels in the TGN drive the polarized apical secretion of a secretory form of placental alkaline phosphatase, exogenously expressed, and the endogenous soluble protein clusterin/Gp80 in Madin-Darby canine kidney (MDCK) cells. These data highlight the critical role of a calcium-dependent Cab45 mechanism regulating apical exocytosis in polarized MDCK cells.
Collapse
Affiliation(s)
- Dandan Liu
- Unité de Trafic Membranaire et Pathogenèse, Institut Pasteur, 75015 Paris, France
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
| | - Chiara Zurzolo
- Unité de Trafic Membranaire et Pathogenèse, Institut Pasteur, 75015 Paris, France
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
| | - Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogenèse, Institut Pasteur, 75015 Paris, France
| |
Collapse
|
3
|
Tutanov OS, Glass SE, Coffey RJ. Emerging connections between GPI-anchored proteins and their extracellular carriers in colorectal cancer. EXTRACELLULAR VESICLES AND CIRCULATING NUCLEIC ACIDS 2023; 4:195-217. [PMID: 37840781 PMCID: PMC10569057 DOI: 10.20517/evcna.2023.17] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Although extracellular vesicles (EVs) were discovered over 40 years ago, there has been a resurgence of interest in secreted vesicles and their attendant cargo as novel modes of intracellular communication. In addition to vesicles, two amembranous nanoparticles, exomeres and supermeres, have been isolated and characterized recently. In this rapidly expanding field, it has been challenging to assign cargo and specific functions to a particular carrier. Refinement of isolation methods, well-controlled studies, and guidelines detailed by Minimal Information for Studies of Extracellular Vesicles (MISEV) are being employed to "bring order to chaos." In this review, we will briefly summarize three types of extracellular carriers - small EVs (sEVs), exomeres, and supermeres - in the context of colorectal cancer (CRC). We found that a number of GPI-anchored proteins (GPI-APs) are overexpressed in CRC, are enriched in exosomes (a distinct subset of sEVs), and can be detected in exomeres and supermeres. This affords the opportunity to elaborate on GPI-AP biogenesis, modifications, and trafficking using DPEP1, a GPI-AP upregulated in CRC, as a prime example. We have cataloged the GPI-anchored proteins secreted in CRC and will highlight features of select CRC-associated GPI-anchored proteins we have detected. Finally, we will discuss the remaining challenges and future opportunities in studying these secreted GPI-APs in CRC.
Collapse
Affiliation(s)
- Oleg S. Tutanov
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Sarah E. Glass
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Robert J. Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| |
Collapse
|
4
|
Refinement of Singer-Nicolson fluid-mosaic model by microscopy imaging: Lipid rafts and actin-induced membrane compartmentalization. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184093. [PMID: 36423676 DOI: 10.1016/j.bbamem.2022.184093] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/22/2022]
Abstract
This year celebrates the 50th anniversary of the Singer-Nicolson fluid mosaic model for biological membranes. The next level of sophistication we have achieved for understanding plasma membrane (PM) structures, dynamics, and functions during these 50 years includes the PM interactions with cortical actin filaments and the partial demixing of membrane constituent molecules in the PM, particularly raft domains. Here, first, we summarize our current knowledge of these two structures and emphasize that they are interrelated. Second, we review the structure, molecular dynamics, and function of raft domains, with main focuses on raftophilic glycosylphosphatidylinositol-anchored proteins (GPI-APs) and their signal transduction mechanisms. We pay special attention to the results obtained by single-molecule imaging techniques and other advanced microscopy methods. We also clarify the limitations of present optical microscopy methods for visualizing raft domains, but emphasize that single-molecule imaging techniques can "detect" raft domains associated with molecules of interest in the PM.
Collapse
|
5
|
Tan W, Zhang Q, Hong P, Xu B. A Self-Assembling Probe for Imaging the States of Golgi Apparatus in Live Single Cells. Bioconjug Chem 2022; 33:1983-1988. [PMID: 35312281 PMCID: PMC9489815 DOI: 10.1021/acs.bioconjchem.2c00084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite the enormous progress in genomics and proteomics, it is still challenging to assess the states of organelles in living cells with high spatiotemporal resolution. Based on our recent finding of enzyme-instructed self-assembly of a thiophosphopeptide that targets the Golgi Apparatus (GA) instantly, we use the thiophosphopeptide, which is enzymatically responsive and redox active, as an integrative probe for revealing the state of the GA of live cells at the single cell level. By imaging the probe in the GA of live cells over time, our results show that the accumulation of the probe at the GA depends on cell types. By comparison to a conventional Golgi probe, this self-assembling probe accumulates at the GA much faster and are sensitive to the expression of alkaline phosphatases. In addition, subtle changes of the fluorophore results in slightly different GA responses. This work illustrates a novel class of active molecular probes that combine enzyme-instructed self-assembly and redox reaction for high-resolution imaging of the states of subcellular organelles over a large area and extended times.
Collapse
Affiliation(s)
- Weiyi Tan
- Department of Chemistry, Brandeis University, 415 South St., Waltham, MA 02454, USA
| | - Qiuxin Zhang
- Department of Chemistry, Brandeis University, 415 South St., Waltham, MA 02454, USA
| | - Pengyu Hong
- Department of Computer Science, Brandeis University, 415 South St., Waltham, MA 02453, USA
| | - Bing Xu
- Department of Chemistry, Brandeis University, 415 South St., Waltham, MA 02454, USA
| |
Collapse
|
6
|
Ford C, Burd CG. GOPC facilitates the sorting of syndecan-1 in polarized epithelial cells. Mol Biol Cell 2022; 33:ar86. [PMID: 35830596 DOI: 10.1091/mbc.e22-05-0165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The trans-Golgi network must coordinate sorting and secretion of proteins and lipids to intracellular organelles and the plasma membrane. During polarization of epithelial cells, changes in the lipidome and the expression and distribution of proteins contribute to the formation of apical and basolateral plasma membrane domains. Previous studies using HeLa cells show that the syndecan-1 transmembrane domain confers sorting within sphingomyelin-rich vesicles in a sphingomyelin secretion pathway. In polarized Madin-Darby canine kidney cells, we reveal differences in the sorting of syndecan-1, whereupon the correct trafficking of the protein is not dependent on its transmembrane domain and changes in sphingomyelin content of cells during polarization. Instead, we reveal that correct basolateral targeting of syndecan-1 requires a full-length PDZ motif in syndecan-1 and the PDZ domain golgin protein GOPC. Moreover, we reveal changes in Golgi morphology elicited by GOPC overexpression. These results suggest that the role of GOPC in sorting syndecan-1 is indirect and likely due to GOPC effects on Golgi organization.
Collapse
Affiliation(s)
- Charlotte Ford
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Christopher G Burd
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| |
Collapse
|
7
|
Chip-Based Sensing of the Intercellular Transfer of Cell Surface Proteins: Regulation by the Metabolic State. Biomedicines 2021; 9:biomedicines9101452. [PMID: 34680568 PMCID: PMC8533487 DOI: 10.3390/biomedicines9101452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 01/08/2023] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are anchored at the surface of mammalian blood and tissue cells through a carboxy-terminal GPI glycolipid. Eventually, they are released into incubation medium in vitro and blood in vivo and subsequently inserted into neighboring cells, potentially leading to inappropriate surface expression or lysis. To obtain first insight into the potential (patho)physiological relevance of intercellular GPI-AP transfer and its biochemical characterization, a cell-free chip- and microfluidic channel-based sensing system was introduced. For this, rat or human adipocyte or erythrocyte plasma membranes (PM) were covalently captured by the TiO2 chip surface operating as the acceptor PM. To measure transfer between PM, donor erythrocyte or adipocyte PM were injected into the channels of a flow chamber, incubated, and washed out, and the type and amount of proteins which had been transferred to acceptor PM evaluated with specific antibodies. Antibody binding was detected as phase shift of horizontal surface acoustic waves propagating over the chip surface. Time- and temperature-dependent transfer, which did not rely on fusion of donor and acceptor PM, was detected for GPI-APs, but not typical transmembrane proteins. Transfer of GPI-APs was found to be prevented by α-toxin, which binds to the glycan core of GPI anchors, and serum proteins in concentration-dependent fashion. Blockade of transfer, which was restored by synthetic phosphoinositolglycans mimicking the glycan core of GPI anchors, led to accumulation in the chip channels of full-length GPI-APs in association with phospholipids and cholesterol in non-membrane structures. Strikingly, efficacy of transfer between adipocytes and erythrocytes was determined by the metabolic state (genotype and feeding state) of the rats, which were used as source for the PM and sera, with upregulation in obese and diabetic rats and counterbalance by serum proteins. The novel chip-based sensing system for GPI-AP transfer may be useful for the prediction and stratification of metabolic diseases as well as elucidation of the putative role of intercellular transfer of cell surface proteins, such as GPI-APs, in (patho)physiological mechanisms.
Collapse
|
8
|
Cytokine receptor cluster size impacts its endocytosis and signaling. Proc Natl Acad Sci U S A 2021; 118:2024893118. [PMID: 34504012 DOI: 10.1073/pnas.2024893118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2021] [Indexed: 01/08/2023] Open
Abstract
The interleukin-2 receptor (IL-2R) is a cytokine receptor essential for immunity that transduces proliferative signals regulated by its uptake and degradation. IL-2R is a well-known marker of clathrin-independent endocytosis (CIE), a process devoid of any coat protein, raising the question of how the CIE vesicle is generated. Here, we investigated the impact of IL-2Rγ clustering in its endocytosis. Combining total internal reflection fluorescence (TIRF) live imaging of a CRISPR-edited T cell line endogenously expressing IL-2Rγ tagged with green fluorescent protein (GFP), with multichannel imaging, single-molecule tracking, and quantitative analysis, we were able to decipher IL-2Rγ stoichiometry at the plasma membrane in real time. We identified three distinct IL-2Rγ cluster populations. IL-2Rγ is secreted to the cell surface as a preassembled small cluster of three molecules maximum, rapidly diffusing at the plasma membrane. A medium-sized cluster composed of four to six molecules is key for IL-2R internalization and is promoted by interleukin 2 (IL-2) binding, while larger clusters (more than six molecules) are static and inefficiently internalized. Moreover, we identified membrane cholesterol and the branched actin cytoskeleton as key regulators of IL-2Rγ clustering and IL-2-induced signaling. Both cholesterol depletion and Arp2/3 inhibition lead to the assembly of large IL-2Rγ clusters, arising from the stochastic interaction of receptor molecules in close correlation with their enhanced lateral diffusion at the membrane, thus resulting in a default in IL-2R endocytosis. Despite similar clustering outcomes, while cholesterol depletion leads to a sustained IL-2-dependent signaling, Arp2/3 inhibition prevents signal initiation. Taken together, our results reveal the importance of cytokine receptor clustering for CIE initiation and signal transduction.
Collapse
|
9
|
Calcium levels in the Golgi complex regulate clustering and apical sorting of GPI-APs in polarized epithelial cells. Proc Natl Acad Sci U S A 2021; 118:2014709118. [PMID: 34389665 DOI: 10.1073/pnas.2014709118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are lipid-associated luminal secretory cargoes selectively sorted to the apical surface of the epithelia where they reside and play diverse vital functions. Cholesterol-dependent clustering of GPI-APs in the Golgi is the key step driving their apical sorting and their further plasma membrane organization and activity; however, the specific machinery involved in this Golgi event is still poorly understood. In this study, we show that the formation of GPI-AP homoclusters (made of single GPI-AP species) in the Golgi relies directly on the levels of calcium within cisternae. We further demonstrate that the TGN calcium/manganese pump, SPCA1, which regulates the calcium concentration within the Golgi, and Cab45, a calcium-binding luminal Golgi resident protein, are essential for the formation of GPI-AP homoclusters in the Golgi and for their subsequent apical sorting. Down-regulation of SPCA1 or Cab45 in polarized epithelial cells impairs the oligomerization of GPI-APs in the Golgi complex and leads to their missorting to the basolateral surface. Overall, our data reveal an unexpected role for calcium in the mechanism of GPI-AP apical sorting in polarized epithelial cells and identify the molecular machinery involved in the clustering of GPI-APs in the Golgi.
Collapse
|
10
|
Tan W, Zhang Q, Wang J, Yi M, He H, Xu B. Enzymatic Assemblies of Thiophosphopeptides Instantly Target Golgi Apparatus and Selectively Kill Cancer Cells*. Angew Chem Int Ed Engl 2021; 60:12796-12801. [PMID: 33783926 PMCID: PMC8159897 DOI: 10.1002/anie.202102601] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/19/2021] [Indexed: 01/01/2023]
Abstract
Changing an oxygen atom of the phosphoester bond in phosphopeptides by a sulfur atom enables instantly targeting Golgi apparatus (GA) and selectively killing cancer cells by enzymatic self-assembly. Specifically, conjugating cysteamine S-phosphate to the C-terminal of a self-assembling peptide generates a thiophosphopeptide. Being a substrate of alkaline phosphatase (ALP), the thiophosphopeptide undergoes rapid ALP-catalyzed dephosphorylation to form a thiopeptide that self-assembles. The thiophosphopeptide enters cells via caveolin-mediated endocytosis and macropinocytosis and instantly accumulates in GA because of dephosphorylation and formation of disulfide bonds in Golgi by themselves and with Golgi proteins. Moreover, the thiophosphopeptide potently and selectively inhibits cancer cells (HeLa) with the IC50 (about 3 μM), which is an order of magnitude more potent than that of the parent phosphopeptide.
Collapse
Affiliation(s)
- Weiyi Tan
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Qiuxin Zhang
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Jiaqing Wang
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Meihui Yi
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Hongjian He
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| | - Bing Xu
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
| |
Collapse
|
11
|
Tan W, Zhang Q, Wang J, Yi M, He H, Xu B. Enzymatic Assemblies of Thiophosphopeptides Instantly Target Golgi Apparatus and Selectively Kill Cancer Cells**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Weiyi Tan
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Qiuxin Zhang
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Jiaqing Wang
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Meihui Yi
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Hongjian He
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Bing Xu
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| |
Collapse
|
12
|
GM130 regulates pulmonary surfactant protein secretion in alveolar type II cells. SCIENCE CHINA-LIFE SCIENCES 2021; 65:193-205. [PMID: 33740186 DOI: 10.1007/s11427-020-1875-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/05/2021] [Indexed: 12/14/2022]
Abstract
Pulmonary surfactant is a lipid-protein complex secreted by alveolar type II epithelial cells and is essential for the maintenance of the delicate structure of mammalian alveoli to promote efficient gas exchange across the air-liquid barrier. The Golgi apparatus plays an important role in pulmonary surfactant modification and secretory trafficking. However, the physiological function of the Golgi apparatus in the transport of pulmonary surfactants is unclear. In the present study, deletion of GM130, which encodes for a matrix protein of the cis-Golgi cisternae, was shown to induce the disruption of the Golgi structure leading to impaired secretion of lung surfactant proteins and lipids. Specifically, the results of in vitro and in vivo analysis indicated that the loss of GM130 resulted in trapping of Sftpa in the endoplasmic reticulum, Sftpb and Sftpc accumulation in the Golgi apparatus, and an increase in the compensatory secretion of Sftpd. Moreover, global and epithelial-specific GM130 knockout in mice resulted in an enlargement of alveolar airspace and an increase in alveolar epithelial autophagy; however, surfactant repletion partially rescued the enlarged airspace defects in GM130-deficient mice. Therefore, our results demonstrate that GM130 and the mammalian Golgi apparatus play a critical role in the control of surfactant protein secretion in pulmonary epithelial cells.
Collapse
|
13
|
Rodriguez-Gallardo S, Kurokawa K, Sabido-Bozo S, Cortes-Gomez A, Ikeda A, Zoni V, Aguilera-Romero A, Perez-Linero AM, Lopez S, Waga M, Araki M, Nakano M, Riezman H, Funato K, Vanni S, Nakano A, Muñiz M. Ceramide chain length-dependent protein sorting into selective endoplasmic reticulum exit sites. SCIENCE ADVANCES 2020; 6:6/50/eaba8237. [PMID: 33310842 PMCID: PMC7732199 DOI: 10.1126/sciadv.aba8237] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 10/30/2020] [Indexed: 05/05/2023]
Abstract
Protein sorting in the secretory pathway is crucial to maintain cellular compartmentalization and homeostasis. In addition to coat-mediated sorting, the role of lipids in driving protein sorting during secretory transport is a longstanding fundamental question that still remains unanswered. Here, we conduct 3D simultaneous multicolor high-resolution live imaging to demonstrate in vivo that newly synthesized glycosylphosphatidylinositol-anchored proteins having a very long chain ceramide lipid moiety are clustered and sorted into specialized endoplasmic reticulum exit sites that are distinct from those used by transmembrane proteins. Furthermore, we show that the chain length of ceramide in the endoplasmic reticulum membrane is critical for this sorting selectivity. Our study provides the first direct in vivo evidence for lipid chain length-based protein cargo sorting into selective export sites of the secretory pathway.
Collapse
Affiliation(s)
- Sofia Rodriguez-Gallardo
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan.
| | - Susana Sabido-Bozo
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Alejandro Cortes-Gomez
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Atsuko Ikeda
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Valeria Zoni
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Auxiliadora Aguilera-Romero
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Ana Maria Perez-Linero
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Sergio Lopez
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Miho Waga
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Misako Araki
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Miyako Nakano
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Howard Riezman
- NCCR Chemical Biology, Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland
| | - Kouichi Funato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Manuel Muñiz
- Department of Cell Biology, Faculty of Biology, University of Seville and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain.
| |
Collapse
|
14
|
Iswanto ABB, Shon JC, Liu KH, Vu MH, Kumar R, Kim JY. Sphingolipids Modulate Secretion of Glycosylphosphatidylinositol-Anchored Plasmodesmata Proteins and Callose Deposition. PLANT PHYSIOLOGY 2020; 184:407-420. [PMID: 32636343 PMCID: PMC7479907 DOI: 10.1104/pp.20.00401] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/25/2020] [Indexed: 05/04/2023]
Abstract
Plasma membranes encapsulated in the symplasmic nanochannels of plasmodesmata (PD) contain abundant lipid rafts, which are enriched with sphingolipids (SLs) and sterols. Reduction of sterols has highlighted the role played by lipid raft integrity in the intercellular trafficking of glycosylphosphatidylinositol (GPI)-anchored PD proteins, particularly in affecting callose enhancement. The presence of callose at PD is strongly attributed to the regulation of callose accumulation and callose degradation by callose synthases and β-1,3-glucanases (BGs), respectively. SLs are implicated in signaling and membrane protein trafficking; however, the underlying processes linking SL composition to the control of symplasmic apertures remain unknown. The wide variety of SLs in plants prompted us to investigate which SL molecules are important for regulating symplasmic apertures in Arabidopsis (Arabidopsis thaliana). We introduced several potential SL pathway inhibitors and genetically modified SL contents using two independent SL pathway mutants. We were able to modulate callose deposition to control symplasmic connectivity through perturbations of SL metabolism. Alteration in glucosylhydroxyceramides or related SL composition particularly disturbed the secretory machinery for the GPI-anchored PdBG2 protein, resulting in an overaccumulation of callose. Moreover, our results revealed that SL-enriched lipid rafts link symplasmic channeling to PD callose homeostasis by controlling the targeting of GPI-anchored PdBG2. This study elevates our understanding of the molecular linkage underlying intracellular trafficking and precise targeting of GPI-anchored PD proteins incorporating glucosyl SLs.
Collapse
Affiliation(s)
- Arya Bagus Boedi Iswanto
- Division of Applied Life Science (BK21 Plus Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Jong Cheol Shon
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
- Environmental Chemistry Research Group, Korea Institute of Toxicology, Jinju 52834, Republic of Korea
| | - Kwang Hyeon Liu
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Minh Huy Vu
- Division of Applied Life Science (BK21 Plus Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Ritesh Kumar
- Division of Applied Life Science (BK21 Plus Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Jae-Yean Kim
- Division of Applied Life Science (BK21 Plus Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
- Division of Life Science, Gyeongsang National University, Jinju 52828, Republic of Korea
| |
Collapse
|
15
|
Abstract
At least 150 human proteins are glycosylphosphatidylinositol-anchored proteins (GPI-APs). The protein moiety of GPI-APs lacking transmembrane domains is anchored to the plasma membrane with GPI covalently attached to the C-terminus. The GPI consists of the conserved core glycan, phosphatidylinositol and glycan side chains. The entire GPI-AP is anchored to the outer leaflet of the lipid bilayer by insertion of fatty chains of phosphatidylinositol. Because of GPI-dependent membrane anchoring, GPI-APs have some unique characteristics. The most prominent feature of GPI-APs is their association with membrane microdomains or membrane rafts. In the polarized cells such as epithelial cells, many GPI-APs are exclusively expressed in the apical surfaces, whereas some GPI-APs are preferentially expressed in the basolateral surfaces. Several GPI-APs act as transcytotic transporters carrying their ligands from one compartment to another. Some GPI-APs are shed from the membrane after cleavage within the GPI by a GPI-specific phospholipase or a glycosidase. In this review, I will summarize the current understanding of GPI-AP biosynthesis in mammalian cells and discuss examples of GPI-dependent functions of mammalian GPI-APs.
Collapse
Affiliation(s)
- Taroh Kinoshita
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, Japan
| |
Collapse
|
16
|
Different spatiotemporal organization of GPI-anchored T-cadherin in response to low-density lipoprotein and adiponectin. Biochim Biophys Acta Gen Subj 2019; 1863:129414. [DOI: 10.1016/j.bbagen.2019.129414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 07/23/2019] [Accepted: 08/07/2019] [Indexed: 01/10/2023]
|
17
|
Emperador-Melero J, Toonen RF, Verhage M. Vti Proteins: Beyond Endolysosomal Trafficking. Neuroscience 2019; 420:32-40. [DOI: 10.1016/j.neuroscience.2018.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 10/27/2022]
|
18
|
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
|
19
|
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
|
20
|
Burke LC, Ezeribe HO, Kwon AY, Dockery D, Lyons PJ. Carboxypeptidase O is a lipid droplet-associated enzyme able to cleave both acidic and polar C-terminal amino acids. PLoS One 2018; 13:e0206824. [PMID: 30388170 PMCID: PMC6214572 DOI: 10.1371/journal.pone.0206824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 10/19/2018] [Indexed: 11/18/2022] Open
Abstract
Carboxypeptidase O (CPO) is a member of the M14 family of metallocarboxypeptidases with a preference for the cleavage of C-terminal acidic amino acids. CPO is largely expressed in the small intestine, although it has been detected in other tissues such as the brain and ovaries. CPO does not contain a prodomain, nor is it strongly regulated by pH, and hence appears to exist as a constitutively active enzyme. The goal of this study was to investigate the intracellular distribution and activity of CPO in order to predict physiological substrates and function. The distribution of CPO, when expressed in MDCK cells, was analyzed by immunofluorescence microscopy. Soon after addition of nutrient-rich media, CPO was found to associate with lipid droplets, causing an increase in lipid droplet quantity. As media became depleted, CPO moved to a broader ER distribution, no longer impacting lipid droplet numbers. Membrane cholesterol levels played a role in the distribution and in vitro enzymatic activity of CPO, with cholesterol enrichment leading to decreased lipid droplet association and enzymatic activity. The ability of CPO to cleave C-terminal amino acids within the early secretory pathway (in vivo) was examined using Gaussia luciferase as a substrate, C-terminally tagged with variants of an ER retention signal. While no effect of cholesterol was observed, these data show that CPO does function as an active enzyme within the ER where it removes C-terminal glutamates and aspartates, as well as a number of polar amino acids.
Collapse
Affiliation(s)
- Linnea C. Burke
- Department of Biology, Andrews University, Berrien Springs, Michigan, United States of America
| | - Hazel O. Ezeribe
- Department of Biology, Andrews University, Berrien Springs, Michigan, United States of America
| | - Anna Y. Kwon
- Department of Biology, Andrews University, Berrien Springs, Michigan, United States of America
| | - Donnel Dockery
- Department of Biology, Andrews University, Berrien Springs, Michigan, United States of America
| | - Peter J. Lyons
- Department of Biology, Andrews University, Berrien Springs, Michigan, United States of America
- * E-mail:
| |
Collapse
|
21
|
Manea E. A step closer in defining glycosylphosphatidylinositol anchored proteins role in health and glycosylation disorders. Mol Genet Metab Rep 2018; 16:67-75. [PMID: 30094187 PMCID: PMC6080220 DOI: 10.1016/j.ymgmr.2018.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/21/2018] [Accepted: 07/21/2018] [Indexed: 12/18/2022] Open
Abstract
Glycosylphosphatidylinositol anchored proteins (GPI-APs) represent a class of soluble proteins attached to the external leaflet of the plasma membrane by a post-translation modification, the GPI anchor. The 28 genes currently involved in the synthesis and remodelling of the GPI anchor add to the ever-growing class of congenital glycosylation disorders. Recent advances in next generation sequencing technology have led to the discovery of Mabry disease and CHIME syndrome genetic aetiology. Moreover, with each described mutation known phenotypes expand and new ones emerge without clear genotype-phenotype correlation. A protein database search was made for human GPI-APs with defined pathology to help building-up a physio-pathological mechanism from a clinical perspective. GPI-APs function in vitamin-B6 and folate transport, nucleotide metabolism and lipid homeostasis. Defining GPI-APs role in disease bears significant clinical implications.
Collapse
|
22
|
Lebreton S, Zurzolo C, Paladino S. Organization of GPI-anchored proteins at the cell surface and its physiopathological relevance. Crit Rev Biochem Mol Biol 2018; 53:403-419. [PMID: 30040489 DOI: 10.1080/10409238.2018.1485627] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of proteins attached to the extracellular leaflet of the plasma membrane via a post-translational modification, the glycolipid anchor. The presence of both glycolipid anchor and protein portion confers them unique features. GPI-APs are expressed in all eukaryotes, from fungi to plants and animals. They display very diverse functions ranging from enzymatic activity, signaling, cell adhesion, cell wall metabolism, neuritogenesis, and immune response. Likewise other plasma membrane proteins, the spatio-temporal organization of GPI-APs is critical for their biological activities in physiological conditions. In this review, we will summarize the latest findings on plasma membrane organization of GPI-APs and the mechanism of its regulation in different cell types. We will also examine the involvement of specific GPI-APs namely the prion protein PrPC, the Folate Receptor alpha and the urokinase plasminogen activator receptor in human diseases focusing on neurodegenerative diseases and cancer.
Collapse
Affiliation(s)
- Stéphanie Lebreton
- a Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur , Paris , France
| | - Chiara Zurzolo
- a Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur , Paris , France
| | - Simona Paladino
- b Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II , Napoli , Italy.,c CEINGE Biotecnologie Avanzate , Napoli , Italy
| |
Collapse
|
23
|
Yeager AN, Weber PK, Kraft ML. Cholesterol is enriched in the sphingolipid patches on the substrate near nonpolarized MDCK cells, but not in the sphingolipid domains in their plasma membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2004-2011. [PMID: 29684331 DOI: 10.1016/j.bbamem.2018.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/15/2018] [Accepted: 04/16/2018] [Indexed: 10/17/2022]
Abstract
Information about the distributions of cholesterol and sphingolipids within the plasma membranes of mammalian cells provides insight into the roles of these molecules in membrane function. In this report, high-resolution secondary ion mass spectrometry was used to image the distributions of metabolically incorporated rare isotope-labeled sphingolipids and cholesterol on the surfaces of nonpolarized epithelial cells. Sphingolipid domains that were not enriched with cholesterol were detected in the plasma membranes of subconfluent Madin-Darby canine kidney cells. Surprisingly, cholesterol-enriched sphingolipid patches were observed on the substrate adjacent to these cells. Based on the shapes of these cholesterol-enriched sphingolipid patches on the substrate and their proximity to cellular projections, we hypothesize that they are deposits of membranous particles released by the cell.
Collapse
Affiliation(s)
- Ashley N Yeager
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, United States
| | - Peter K Weber
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, United States
| | - Mary L Kraft
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, United States.
| |
Collapse
|
24
|
Trafficking and regulation of the NKCC2 cotransporter in the thick ascending limb. Curr Opin Nephrol Hypertens 2018; 26:392-397. [PMID: 28614115 DOI: 10.1097/mnh.0000000000000351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW The kidney Na-K-2Cl cotransporter (NKCC2) is essential for urinary concentration and renal electrolyte handling. Loss of function mutations in the NKCC2 gene cause urinary salt and potassium wasting, whereas excessive NKCC2 function has been linked to high blood pressure. Loop diuretics, targeting the transporter, are instrumental for relieving edema or hypertension. This review focuses on intrinsic mechanisms regulating NKCC2 activity at the posttranslational level, namely its trafficking and phosphorylation. RECENT FINDINGS Protein networks mediating cellular turnover of NKCC2 have recently received major attention. Several key components of its apical trafficking were identified, including respective chaperones, SNARE protein family members and raft-associated proteins. NKCC2 internalization has been characterized qualitatively and quantitatively. Kinase and phosphatase pathways regulating NKCC2 activity have been clarified and links between NKCC2 phosphorylation and trafficking proposed. Constitutive and inducible NKCC2 trafficking and phosphorylation mechanisms have been specified with focus on endocrine control of thick ascending limb (TAL) function by vasopressin. SUMMARY Proper NKCC2 trafficking and phosphorylation are critical to the TAL function in the physiological context of urinary concentration and extracellular volume regulation. Clarification of the underlying mechanisms and respective protein networks may open new therapeutic perspectives for better management of renal electrolyte disorders and blood pressure control.
Collapse
|
25
|
GPI-anchored proteins are confined in subdiffraction clusters at the apical surface of polarized epithelial cells. Biochem J 2017; 474:4075-4090. [PMID: 29046391 PMCID: PMC5712066 DOI: 10.1042/bcj20170582] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/19/2017] [Accepted: 10/17/2017] [Indexed: 11/28/2022]
Abstract
Spatio-temporal compartmentalization of membrane proteins is critical for the regulation of diverse vital functions in eukaryotic cells. It was previously shown that, at the apical surface of polarized MDCK cells, glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are organized in small cholesterol-independent clusters of single GPI-AP species (homoclusters), which are required for the formation of larger cholesterol-dependent clusters formed by multiple GPI-AP species (heteroclusters). This clustered organization is crucial for the biological activities of GPI-APs; hence, understanding the spatio-temporal properties of their membrane organization is of fundamental importance. Here, by using direct stochastic optical reconstruction microscopy coupled to pair correlation analysis (pc-STORM), we were able to visualize and measure the size of these clusters. Specifically, we show that they are non-randomly distributed and have an average size of 67 nm. We also demonstrated that polarized MDCK and non-polarized CHO cells have similar cluster distribution and size, but different sensitivity to cholesterol depletion. Finally, we derived a model that allowed a quantitative characterization of the cluster organization of GPI-APs at the apical surface of polarized MDCK cells for the first time. Experimental FRET (fluorescence resonance energy transfer)/FLIM (fluorescence-lifetime imaging microscopy) data were correlated to the theoretical predictions of the model.
Collapse
|
26
|
Brameshuber M, Sevcsik E, Rossboth BK, Manner C, Deigner HP, Peksel B, Péter M, Török Z, Hermetter A, Schütz GJ. Oxidized Phospholipids Inhibit the Formation of Cholesterol-Dependent Plasma Membrane Nanoplatforms. Biophys J 2016; 110:205-13. [PMID: 26745423 DOI: 10.1016/j.bpj.2015.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 10/14/2015] [Accepted: 11/13/2015] [Indexed: 01/08/2023] Open
Abstract
We previously developed a single-molecule microscopy method termed TOCCSL (thinning out clusters while conserving stoichiometry of labeling), which allows for direct imaging of stable nanoscopic platforms with raft-like properties diffusing in the plasma membrane. As a consensus raft marker, we chose monomeric GFP linked via a glycosylphosphatidylinositol (GPI) anchor to the cell membrane (mGFP-GPI). With this probe, we previously observed cholesterol-dependent homo-association to nanoplatforms diffusing in the plasma membrane of live CHO cells. Here, we report the release of this homo-association upon addition of 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) or 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine, two oxidized phospholipids (oxPLs) that are typically present in oxidatively modified low-density lipoprotein. We found a dose-response relationship for mGFP-GPI nanoplatform disintegration upon addition of POVPC, correlating with the signal of the apoptosis marker Annexin V-Cy3. Similar concentrations of lysolipid showed no effect, indicating that the observed phenomena were not linked to properties of the lipid bilayer itself. Inhibition of acid sphingomyelinase by NB-19 before addition of POVPC completely abolished nanoplatform disintegration by oxPLs. In conclusion, we were able to determine how oxidized lipid species disrupt mGFP-GPI nanoplatforms in the plasma membrane. Our results favor an indirect mechanism involving acid sphingomyelinase activity rather than a direct interaction of oxPLs with nanoplatform constituents.
Collapse
Affiliation(s)
| | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | | | - Hans-Peter Deigner
- Faculty of Medical and Life Sciences, Institute of Precision Medicine, Furtwangen University, Villingen-Schwenningen, Germany; Fraunhofer Institute IZI/EXIM, Furtwangen, Germany
| | - Begüm Peksel
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Mária Péter
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Zsolt Török
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Albin Hermetter
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | | |
Collapse
|
27
|
Arkhipenko A, Syan S, Victoria GS, Lebreton S, Zurzolo C. PrPC Undergoes Basal to Apical Transcytosis in Polarized Epithelial MDCK Cells. PLoS One 2016; 11:e0157991. [PMID: 27389581 PMCID: PMC4936696 DOI: 10.1371/journal.pone.0157991] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 06/08/2016] [Indexed: 01/05/2023] Open
Abstract
The Prion Protein (PrP) is an ubiquitously expressed glycosylated membrane protein attached to the external leaflet of the plasma membrane via a glycosylphosphatidylinositol anchor (GPI). While the misfolded PrPSc scrapie isoform is the infectious agent of prion disease, the cellular isoform (PrPC) is an enigmatic protein with unclear function. Of interest, PrP localization in polarized MDCK cells is controversial and its mechanism of trafficking is not clear. Here we investigated PrP traffic in MDCK cells polarized on filters and in three-dimensional MDCK cysts, a more physiological model of polarized epithelia. We found that, unlike other GPI-anchored proteins (GPI-APs), PrP undergoes basolateral-to-apical transcytosis in fully polarized MDCK cells. Following this event full-length PrP and its cleavage fragments are segregated in different domains of the plasma membrane in polarized cells in both 2D and 3D cultures.
Collapse
Affiliation(s)
- Alexander Arkhipenko
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, 25-28 rue du docteur Roux, 75015, Paris, France
| | - Sylvie Syan
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, 25-28 rue du docteur Roux, 75015, Paris, France
| | - Guiliana Soraya Victoria
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, 25-28 rue du docteur Roux, 75015, Paris, France
| | - Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, 25-28 rue du docteur Roux, 75015, Paris, France
| | - Chiara Zurzolo
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, 25-28 rue du docteur Roux, 75015, Paris, France
| |
Collapse
|
28
|
Zurzolo C, Simons K. Glycosylphosphatidylinositol-anchored proteins: Membrane organization and transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:632-9. [DOI: 10.1016/j.bbamem.2015.12.018] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 12/12/2015] [Accepted: 12/15/2015] [Indexed: 11/17/2022]
|
29
|
Abstract
The fundamental mechanisms of protein and lipid organization at the plasma membrane have continued to engage researchers for decades. Among proposed models, one idea has been particularly successful which assumes that sterol-dependent nanoscopic phases of different lipid chain order compartmentalize proteins, thereby modulating protein functionality. This model of membrane rafts has sustainably sparked the fields of membrane biophysics and biology, and shifted membrane lipids into the spotlight of research; by now, rafts have become an integral part of our terminology to describe a variety of cell biological processes. But is the evidence clear enough to continue supporting a theoretical concept which has resisted direct proof by observation for nearly twenty years? In this essay, we revisit findings that gave rise to and substantiated the raft hypothesis, discuss its impact on recent studies, and present alternative mechanisms to account for plasma membrane heterogeneity.
Collapse
Affiliation(s)
- Eva Sevcsik
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| |
Collapse
|
30
|
Kilbride P, Woodward HJ, Tan KB, Thanh NTK, Chu KME, Minogue S, Waugh MG. Modeling the effects of cyclodextrin on intracellular membrane vesicles from Cos-7 cells prepared by sonication and carbonate treatment. PeerJ 2015; 3:e1351. [PMID: 26528413 PMCID: PMC4627923 DOI: 10.7717/peerj.1351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/05/2015] [Indexed: 01/24/2023] Open
Abstract
Cholesterol has important functions in the organization of membrane structure and this may be mediated via the formation of cholesterol-rich, liquid-ordered membrane microdomains often referred to as lipid rafts. Methyl-beta-cyclodextrin (cyclodextrin) is commonly used in cell biology studies to extract cholesterol and therefore disrupt lipid rafts. However, in this study we reassessed this experimental strategy and investigated the effects of cyclodextrin on the physical properties of sonicated and carbonate-treated intracellular membrane vesicles isolated from Cos-7 fibroblasts. We treated these membranes, which mainly originate from the trans-Golgi network and endosomes, with cyclodextrin and measured the effects on their equilibrium buoyant density, protein content, represented by the palmitoylated protein phosphatidylinositol 4-kinase type IIα, and cholesterol. Despite the reduction in mass stemming from cholesterol removal, the vesicles became denser, indicating a possible large volumetric decrease, and this was confirmed by measurements of hydrodynamic vesicle size. Subsequent mathematical analyses demonstrated that only half of this change in membrane size was attributable to cholesterol loss. Hence, the non-selective desorption properties of cyclodextrin are also involved in membrane size and density changes. These findings may have implications for preceding studies that interpreted cyclodextrin-induced changes to membrane biochemistry in the context of lipid raft disruption without taking into account our finding that cyclodextrin treatment also reduces membrane size.
Collapse
Affiliation(s)
- Peter Kilbride
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Holly J Woodward
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Kuan Boone Tan
- Biophysics Group, Department of Physics & Astronomy, University College London , London , United Kingdom
| | - Nguyễn T K Thanh
- Biophysics Group, Department of Physics & Astronomy, University College London , London , United Kingdom
| | - K M Emily Chu
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Shane Minogue
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Mark G Waugh
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| |
Collapse
|
31
|
Muñiz M, Riezman H. Trafficking of glycosylphosphatidylinositol anchored proteins from the endoplasmic reticulum to the cell surface. J Lipid Res 2015; 57:352-60. [PMID: 26450970 DOI: 10.1194/jlr.r062760] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 11/20/2022] Open
Abstract
In eukaryotes, many cell surface proteins are attached to the plasma membrane via a glycolipid glycosylphosphatidylinositol (GPI) anchor. GPI-anchored proteins (GPI-APs) receive the GPI anchor as a conserved posttranslational modification in the lumen of the endoplasmic reticulum (ER). After anchor attachment, the GPI anchor is structurally remodeled to function as a transport signal that actively triggers the delivery of GPI-APs from the ER to the plasma membrane, via the Golgi apparatus. The structure and composition of the GPI anchor confer a special mode of interaction with membranes of GPI-APs within the lumen of secretory organelles that lead them to be differentially trafficked from other secretory membrane proteins. In this review, we examine the mechanisms by which GPI-APs are selectively transported through the secretory pathway, with special focus on the recent progress made in their actively regulated export from the ER and the trans-Golgi network.
Collapse
Affiliation(s)
- Manuel Muñiz
- Departamento de Biología Celular, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Howard Riezman
- National Centre of Competence in Research (NCCR) Chemical Biology, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| |
Collapse
|
32
|
Prydz K. Determinants of Glycosaminoglycan (GAG) Structure. Biomolecules 2015; 5:2003-22. [PMID: 26308067 PMCID: PMC4598785 DOI: 10.3390/biom5032003] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/17/2015] [Accepted: 08/18/2015] [Indexed: 01/05/2023] Open
Abstract
Proteoglycans (PGs) are glycosylated proteins of biological importance at cell surfaces, in the extracellular matrix, and in the circulation. PGs are produced and modified by glycosaminoglycan (GAG) chains in the secretory pathway of animal cells. The most common GAG attachment site is a serine residue followed by a glycine (-ser-gly-), from which a linker tetrasaccharide extends and may continue as a heparan sulfate, a heparin, a chondroitin sulfate, or a dermatan sulfate GAG chain. Which type of GAG chain becomes attached to the linker tetrasaccharide is influenced by the structure of the protein core, modifications occurring to the linker tetrasaccharide itself, and the biochemical environment of the Golgi apparatus, where GAG polymerization and modification by sulfation and epimerization take place. The same cell type may produce different GAG chains that vary, depending on the extent of epimerization and sulfation. However, it is not known to what extent these differences are caused by compartmental segregation of protein cores en route through the secretory pathway or by differential recruitment of modifying enzymes during synthesis of different PGs. The topic of this review is how different aspects of protein structure, cellular biochemistry, and compartmentalization may influence GAG synthesis.
Collapse
Affiliation(s)
- Kristian Prydz
- Department of Biosciences, University of Oslo, Box 1066, Blindern OSLO 0316, Norway.
| |
Collapse
|
33
|
Paladino S, Lebreton S, Zurzolo C. Trafficking and Membrane Organization of GPI-Anchored Proteins in Health and Diseases. CURRENT TOPICS IN MEMBRANES 2015; 75:269-303. [PMID: 26015286 DOI: 10.1016/bs.ctm.2015.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of lipid-anchored proteins attached to the membranes by a glycolipid anchor that is added, as posttranslation modification, in the endoplasmic reticulum. GPI-APs are expressed at the cell surface of eukaryotes where they play diverse vital functions. Like all plasma membrane proteins, GPI-APs must be correctly sorted along the different steps of the secretory pathway to their final destination. The presence of both a glycolipid anchor and a protein portion confers special trafficking features to GPI-APs. Here, we discuss the recent advances in the field of GPI-AP trafficking, focusing on the mechanisms regulating their biosynthetic pathway and plasma membrane organization. We also discuss how alterations of these mechanisms can result in different diseases. Finally, we will examine the strict relationship between the trafficking and function of GPI-APs in epithelial cells.
Collapse
Affiliation(s)
- Simona Paladino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Napoli, Italy; CEINGE Biotecnologie Avanzate, Napoli, Italy
| | - Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
| | - Chiara Zurzolo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Napoli, Italy; Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
| |
Collapse
|
34
|
Zurzolo C, Sedwick C. Chiara Zurzolo: GPI knows the way to go. J Cell Biol 2015; 208:862-3. [PMID: 25825512 PMCID: PMC4384730 DOI: 10.1083/jcb.2087pi] [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] [Indexed: 11/27/2022] Open
Abstract
Zurzolo studies the trafficking of GPI-anchored proteins and how this links to human disease.
Collapse
|
35
|
Suzuki KG. New Insights into the Organization of Plasma Membrane and Its Role in Signal Transduction. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:67-96. [DOI: 10.1016/bs.ircmb.2015.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
36
|
Maity PC, Yang J, Klaesener K, Reth M. The nanoscale organization of the B lymphocyte membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:830-40. [PMID: 25450974 PMCID: PMC4547082 DOI: 10.1016/j.bbamcr.2014.11.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 10/30/2014] [Accepted: 11/07/2014] [Indexed: 12/13/2022]
Abstract
The fluid mosaic model of Singer and Nicolson correctly predicted that the plasma membrane (PM) forms a lipid bi-layer containing many integral trans-membrane proteins. This model also suggested that most of these proteins were randomly dispersed and freely diffusing moieties. Initially, this view of a dynamic and rather unorganized membrane was supported by early observations of the cell surfaces using the light microscope. However, recent studies on the PM below the diffraction limit of visible light (~250nm) revealed that, at nanoscale dimensions, membranes are highly organized and compartmentalized structures. Lymphocytes are particularly useful to study this nanoscale membrane organization because they grow as single cells and are not permanently engaged in cell:cell contacts within a tissue that can influence membrane organization. In this review, we describe the methods that can be used to better study the protein:protein interaction and nanoscale organization of lymphocyte membrane proteins, with a focus on the B cell antigen receptor (BCR). Furthermore, we discuss the factors that may generate and maintain these membrane structures.
Collapse
Affiliation(s)
- Palash Chandra Maity
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany; Department of Molecular Immunology, Biology III, University of Freiburg, Germany; Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
| | - Jianying Yang
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany; Department of Molecular Immunology, Biology III, University of Freiburg, Germany; Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Kathrin Klaesener
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany; Department of Molecular Immunology, Biology III, University of Freiburg, Germany; Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Michael Reth
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany; Department of Molecular Immunology, Biology III, University of Freiburg, Germany; Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
| |
Collapse
|
37
|
Jaensch N, Corrêa IR, Watanabe R. Stable cell surface expression of GPI-anchored proteins, but not intracellular transport, depends on their fatty acid structure. Traffic 2014; 15:1305-29. [PMID: 25196094 DOI: 10.1111/tra.12224] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 11/28/2022]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are a class of lipid anchored proteins expressed on the cell surface of eukaryotes. The potential interaction of GPI-APs with ordered lipid domains enriched in cholesterol and sphingolipids has been proposed to function in the intracellular transport of these lipid anchored proteins. Here, we examined the biological importance of two saturated fatty acids present in the phosphatidylinositol moiety of GPI-APs. These fatty acids are introduced by the action of lipid remodeling enzymes and required for the GPI-AP association within ordered lipid domains. We found that the fatty acid remodeling is not required for either efficient Golgi-to-plasma membrane transport or selective endocytosis via GPI-enriched early endosomal compartment (GEEC)/ clathrin-independent carrier (CLIC) pathway, whereas cholesterol depletion significantly affects both pathways independent of their fatty acid structure. Therefore, the mechanism of cholesterol dependence does not appear to be related to the interaction with ordered lipid domains mediated by two saturated fatty acids. Furthermore, cholesterol extraction drastically releases the unremodeled GPI-APs carrying an unsaturated fatty acid from the cell surface, but not remodeled GPI-APs carrying two saturated fatty acids. This underscores the essential role of lipid remodeling to ensure a stable membrane association of GPI-APs particularly under potential membrane lipid perturbation.
Collapse
Affiliation(s)
- Nina Jaensch
- Department of Biochemistry, University of Geneva Sciences II, CH1-1211 Geneva, Switzerland
| | | | | |
Collapse
|
38
|
Diaz-Rohrer B, Levental KR, Levental I. Rafting through traffic: Membrane domains in cellular logistics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:3003-3013. [PMID: 25130318 DOI: 10.1016/j.bbamem.2014.07.029] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 01/03/2023]
Abstract
The intricate and tightly regulated organization of eukaryotic cells into spatially and functionally distinct membrane-bound compartments is a defining feature of complex organisms. These compartments are defined by their lipid and protein compositions, with their limiting membrane as the functional interface to the rest of the cell. Thus, proper segregation of membrane proteins and lipids is necessary for the maintenance of organelle identity, and this segregation must be maintained despite extensive, rapid membrane exchange between compartments. Sorting processes of high efficiency and fidelity are required to avoid potentially deleterious mis-targeting and maintain cellular function. Although much molecular machinery associated with membrane traffic (i.e. membrane budding/fusion/fission) has been characterized both structurally and biochemically, the mechanistic details underlying the tightly regulated distribution of membranes between subcellular locations remain to be elucidated. This review presents evidence for the role of ordered lateral membrane domains known as lipid rafts in both biosynthetic sorting in the late secretory pathway, as well as endocytosis and recycling to/from the plasma membrane. Although such evidence is extensive and the involvement of membrane domains in sorting is definitive, specific mechanistic details for raft-dependent sorting processes remain elusive.
Collapse
Affiliation(s)
- Blanca Diaz-Rohrer
- University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, USA
| | - Kandice R Levental
- University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, USA
| | - Ilya Levental
- University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, USA; Cancer Prevention and Research Institute of Texas, USA.
| |
Collapse
|
39
|
Muñiz M, Zurzolo C. Sorting of GPI-anchored proteins from yeast to mammals--common pathways at different sites? J Cell Sci 2014; 127:2793-801. [PMID: 24906797 DOI: 10.1242/jcs.148056] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are luminal secretory cargos that are attached by a post-translational glycolipid modification, the GPI anchor, to the external leaflet of the plasma membrane. GPI-APs are conserved among eukaryotes and possess many diverse and vital functions for which the GPI membrane attachment appears to be essential. The presence of the GPI anchor and its subsequent modifications along the secretory pathway confer to the anchored proteins unique trafficking properties that make GPI-APs an exceptional system to study mechanisms of sorting. In this Commentary, we discuss the recent advances in the field of GPI-AP sorting focusing on the mechanisms operating at the level of the exit from the ER and from the trans-Golgi network (TGN), which take place, respectively, in yeast and in polarized mammalian cells. By considering the similarities and differences between these two sorting events, we present unifying principles that appear to work at different sorting stations and in different organisms.
Collapse
Affiliation(s)
- Manuel Muñiz
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes s/n 41012 Seville, Spain
| | - Chiara Zurzolo
- Institut Pasteur, Unité de Trafic Membranaire et Pathogénèse, 75724 Paris CEDEX 15, France
| |
Collapse
|
40
|
Miyagawa-Yamaguchi A, Kotani N, Honke K. Segregation of Lipid Rafts Revealed by the EMARS Method Using GPI-Anchored HRP Fusion Proteins. TRENDS GLYCOSCI GLYC 2014. [DOI: 10.4052/tigg.26.59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|