1
|
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
|
2
|
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
|
3
|
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
|
4
|
Kokkonen N, Khosrowabadi E, Hassinen A, Harrus D, Glumoff T, Kietzmann T, Kellokumpu S. Abnormal Golgi pH Homeostasis in Cancer Cells Impairs Apical Targeting of Carcinoembryonic Antigen by Inhibiting Its Glycosyl-Phosphatidylinositol Anchor-Mediated Association with Lipid Rafts. Antioxid Redox Signal 2019; 30:5-21. [PMID: 29304557 PMCID: PMC6276271 DOI: 10.1089/ars.2017.7389] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIMS Carcinoembryonic antigen (CEACAM5, CEA) is a known tumor marker for colorectal cancer that localizes in a polarized manner to the apical surface in normal colon epithelial cells whereas in cancer cells it is present at both the apical and basolateral surfaces of the cells. Since the Golgi apparatus sorts and transports most proteins to these cell surface domains, we set out here to investigate whether any of the factors commonly associated with tumorigenesis, including hypoxia, generation of reactive oxygen species (ROS), altered redox homeostasis, or an altered Golgi pH, are responsible for mistargeting of CEA to the basolateral surface in cancer cells. RESULTS Using polarized nontumorigenic Madin-Darby canine kidney (MDCK) cells and CaCo-2 colorectal cancer cells as targets, we show that apical delivery of CEA is not affected by hypoxia, ROS, nor changes in the Golgi redox state. Instead, we find that an elevated Golgi pH induces basolateral targeting of CEA and increases its TX-100 solubility, indicating impaired association of CEA with lipid rafts. Moreover, disruption of lipid rafts by methyl-β-cyclodextrin induced accumulation of the CEA protein at the basolateral surface in MDCK cells. Experiments with the glycosylphosphatidylinositol (GPI)-anchorless CEA mutant and CEA-specific GPI-anchored enhanced green fluorescent protein (EGFP-GPI) fusion protein revealed that the GPI-anchor was critical for the pH-dependent apical delivery of the CEA in MDCK cells. Innovation and Conclusion: The findings indicate that an abnormal Golgi pH homeostasis in cancer cells is an important factor that causes mistargeting of CEA to the basolateral surface of cancer cells via inhibiting its GPI-anchor-mediated association with lipid rafts.
Collapse
Affiliation(s)
- Nina Kokkonen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Elham Khosrowabadi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Antti Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Deborah Harrus
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Tuomo Glumoff
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Thomas Kietzmann
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Sakari Kellokumpu
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
- Address correspondence to: Dr. Sakari Kellokumpu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, PO Box 5400, Oulu FI-90014, Finland
| |
Collapse
|
5
|
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
|
6
|
Castillon GA, Burriat‐Couleru P, Abegg D, Criado Santos N, Watanabe R. Clathrin and AP1 are required for apical sorting of glycosyl phosphatidyl inositol‐anchored proteins in biosynthetic and recycling routes in Madin‐Darby canine kidney cells. Traffic 2018; 19:215-228. [DOI: 10.1111/tra.12548] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 01/16/2018] [Accepted: 01/16/2018] [Indexed: 01/12/2023]
Affiliation(s)
| | | | - Daniel Abegg
- Department of Biochemistry, Sciences IIUniversity of Geneva Geneva Switzerland
| | - Nina Criado Santos
- Department of Biochemistry, Sciences IIUniversity of Geneva Geneva Switzerland
| | - Reika Watanabe
- Department of Biochemistry, Sciences IIUniversity of Geneva Geneva Switzerland
| |
Collapse
|
7
|
Ermini L, Ausman J, Melland-Smith M, Yeganeh B, Rolfo A, Litvack ML, Todros T, Letarte M, Post M, Caniggia I. A Single Sphingomyelin Species Promotes Exosomal Release of Endoglin into the Maternal Circulation in Preeclampsia. Sci Rep 2017; 7:12172. [PMID: 28939895 PMCID: PMC5610344 DOI: 10.1038/s41598-017-12491-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 09/11/2017] [Indexed: 11/09/2022] Open
Abstract
Preeclampsia (PE), an hypertensive disorder of pregnancy, exhibits increased circulating levels of a short form of the auxillary TGF-beta (TGFB) receptor endoglin (sENG). Until now, its release and functionality in PE remains poorly understood. Here we show that ENG selectively interacts with sphingomyelin(SM)-18:0 which promotes its clustering with metalloproteinase 14 (MMP14) in SM-18:0 enriched lipid rafts of the apical syncytial membranes from PE placenta where ENG is cleaved by MMP14 into sENG. The SM-18:0 enriched lipid rafts also contain type 1 and 2 TGFB receptors (TGFBR1 and TGFBR2), but not soluble fms-like tyrosine kinase 1 (sFLT1), another protein secreted in excess in the circulation of women with PE. The truncated ENG is then released into the maternal circulation via SM-18:0 enriched exosomes together with TGFBR1 and 2. Such an exosomal TGFB receptor complex could be functionally active and block the vascular effects of TGFB in the circulation of PE women.
Collapse
Affiliation(s)
- Leonardo Ermini
- Program in Translational Medicine, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Jonathan Ausman
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Megan Melland-Smith
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Behzad Yeganeh
- Program in Translational Medicine, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Alessandro Rolfo
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Michael L Litvack
- Program in Translational Medicine, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Tullia Todros
- Department of Obstetrics and Gynecology, University of Turin, Turin, 10126, Italy
| | - Michelle Letarte
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Martin Post
- Program in Translational Medicine, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada. .,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, M5S 1A8, Canada. .,Department of Physiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada. .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
| | - Isabella Caniggia
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| |
Collapse
|
8
|
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]
|
9
|
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
|
10
|
Paladino S, Lebreton S, Tivodar S, Formiggini F, Ossato G, Gratton E, Tramier M, Coppey-Moisan M, Zurzolo C. Golgi sorting regulates organization and activity of GPI proteins at apical membranes. Nat Chem Biol 2014; 10:350-357. [PMID: 24681536 PMCID: PMC4027978 DOI: 10.1038/nchembio.1495] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 02/19/2014] [Indexed: 01/01/2023]
Abstract
Here we combined classical biochemistry with new biophysical approaches to study the organization of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) with high spatial and temporal resolution at the plasma membrane of polarized epithelial cells. We show that in polarized MDCK cells, after sorting in the Golgi, each GPI-AP reaches the apical surface in homoclusters. Golgi-derived homoclusters are required for their subsequent plasma membrane organization into cholesterol-dependent heteroclusters. By contrast, in nonpolarized MDCK cells, GPI-APs are delivered to the surface as monomers in an unpolarized manner and are not able to form heteroclusters. We further demonstrate that this GPI-AP organization is regulated by the content of cholesterol in the Golgi apparatus and is required to maintain the functional state of the protein at the apical membrane. Thus, in contrast to fibroblasts, in polarized epithelial cells, a selective cholesterol-dependent sorting mechanism in the Golgi regulates both the organization and function of GPI-APs at the apical surface.
Collapse
Affiliation(s)
- Simona Paladino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Napoli, Italy
- CEINGE Biotecnologie Avanzate, Napoli, Italy
| | - Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
| | - Simona Tivodar
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | | | - Giulia Ossato
- Laboratory for Fluorescence Dynamics, University of California, Irvine, California
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California, Irvine, California
| | - Marc Tramier
- Institut de génétique et dévelopement de Rennes, UMR 6290
| | - Maïté Coppey-Moisan
- Complexes macromoléculaires en cellules vivantes, Institut Jacques Monod, UMR 7592 CNRS, University Paris-Diderot, France
| | - Chiara Zurzolo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Napoli, Italy
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
| |
Collapse
|
11
|
Galmes R, Delaunay JL, Maurice M, Aït-Slimane T. Oligomerization is required for normal endocytosis/transcytosis of a GPI-anchored protein in polarized hepatic cells. J Cell Sci 2013; 126:3409-16. [PMID: 23750006 DOI: 10.1242/jcs.126250] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Targeting of glycosyl-phosphatidylinositol (GPI)-anchored proteins (GPI-APs) in polarized epithelial cells depends on their association with detergent-resistant membrane microdomains called rafts. In MDCK cells, GPI-APs associate with rafts in the trans-Golgi network and are directly delivered to the apical membrane. It has been shown that oligomerization is required for their stabilization in rafts and their apical targeting. In hepatocytes, GPI-APs are first delivered to the basolateral membrane and secondarily reach the apical membrane by transcytosis. We investigated whether oligomerization is required for raft association and apical sorting of GPI-APs in polarized HepG2 cells, and at which step of the pathway oligomerization occurs. Model proteins were wild-type GFP-GPI and a double cysteine GFP-GPI mutant, in which GFP dimerization was impaired. Unlike wild-type GFP-GPI, which was efficiently endocytosed and transcytosed to the apical surface, the double cysteine mutant was basolaterally internalized, but massively accumulated in early endosomes, and reached the bile canaliculi with delayed kinetics. The double cysteine mutant was less resistant to Triton X-100 extraction, and formed fewer high molecular weight complexes. We conclude from these results that, in hepatocytes, oligomerization plays a key role in targeting GPI-APs to the apical membrane, by increasing their affinity for rafts and allowing their transcytosis.
Collapse
Affiliation(s)
- Romain Galmes
- INSERM, UMR_S938, Centre de Recherche Saint-Antoine, Paris, France
| | | | | | | |
Collapse
|
12
|
Castillon GA, Michon L, Watanabe R. Apical sorting of lysoGPI-anchored proteins occurs independent of association with detergent-resistant membranes but dependent on their N-glycosylation. Mol Biol Cell 2013; 24:2021-33. [PMID: 23615438 PMCID: PMC3681704 DOI: 10.1091/mbc.e13-03-0160] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Overexpression of C-terminally tagged PGAP3 causes predominant production of lysoGPI-APs in MDCK cells. In these cells, produced lysoGPI-APs are not incorporated into detergent-resistant membranes but are still delivered apically. The apical transport of both fully remodeled and lysoGPI-APs is sensitive to cholesterol depletion and ablation of N-glycosylation. Most glycosylphosphatidylinositol-anchored proteins (GPI-APs) are located at the apical surface of epithelial cells. The apical delivery of GPI-APs is believed to result from their association with lipid rafts. We find that overexpression of C-terminally tagged PGAP3 caused predominant production of lysoGPI-APs, an intermediate precursor in the GPI lipid remodeling process in Madin–Darby canine kidney cells. In these cells, produced lysoGPI-APs are not incorporated into detergent-resistant membranes (DRMs) but still are delivered apically, suggesting that GPI-AP association with DRMs is not necessary for apical targeting. In contrast, apical transport of both fully remodeled and lyso forms of GPI-APs is dependent on N-glycosylation, confirming a general role of N-glycans in apical protein transport. We also find that depletion of cholesterol causes apical-to-basolateral retargeting not only of fully remodeled GPI-APs, but also of lysoGPI-APs, as well as endogenous soluble and transmembrane proteins that would normally be targeted to the apical membrane. These findings confirm the essential role for cholesterol in the apical protein targeting and further demonstrate that the mechanism of cholesterol-dependent apical sorting is not related to DRM association of GPI-APs.
Collapse
|
13
|
Zimmermann H, Zebisch M, Sträter N. Cellular function and molecular structure of ecto-nucleotidases. Purinergic Signal 2012; 8:437-502. [PMID: 22555564 PMCID: PMC3360096 DOI: 10.1007/s11302-012-9309-4] [Citation(s) in RCA: 768] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/01/2012] [Indexed: 12/12/2022] Open
Abstract
Ecto-nucleotidases play a pivotal role in purinergic signal transmission. They hydrolyze extracellular nucleotides and thus can control their availability at purinergic P2 receptors. They generate extracellular nucleosides for cellular reuptake and salvage via nucleoside transporters of the plasma membrane. The extracellular adenosine formed acts as an agonist of purinergic P1 receptors. They also can produce and hydrolyze extracellular inorganic pyrophosphate that is of major relevance in the control of bone mineralization. This review discusses and compares four major groups of ecto-nucleotidases: the ecto-nucleoside triphosphate diphosphohydrolases, ecto-5'-nucleotidase, ecto-nucleotide pyrophosphatase/phosphodiesterases, and alkaline phosphatases. Only recently and based on crystal structures, detailed information regarding the spatial structures and catalytic mechanisms has become available for members of these four ecto-nucleotidase families. This permits detailed predictions of their catalytic mechanisms and a comparison between the individual enzyme groups. The review focuses on the principal biochemical, cell biological, catalytic, and structural properties of the enzymes and provides brief reference to tissue distribution, and physiological and pathophysiological functions.
Collapse
Affiliation(s)
- Herbert Zimmermann
- Institute of Cell Biology and Neuroscience, Molecular and Cellular Neurobiology, Biologicum, Goethe-University Frankfurt, Max-von-Laue-Str. 13, 60438, Frankfurt am Main, Germany.
| | | | | |
Collapse
|
14
|
Suzuki KGN, Kasai RS, Hirosawa KM, Nemoto YL, Ishibashi M, Miwa Y, Fujiwara TK, Kusumi A. Transient GPI-anchored protein homodimers are units for raft organization and function. Nat Chem Biol 2012; 8:774-83. [DOI: 10.1038/nchembio.1028] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 06/19/2012] [Indexed: 01/08/2023]
|
15
|
Abstract
The polarized distribution of proteins and lipids at the surface membrane of epithelial cells results in the formation of an apical and a basolateral domain, which are separated by tight junctions. The generation and maintenance of epithelial polarity require elaborate mechanisms that guarantee correct sorting and vectorial delivery of cargo molecules. This dynamic process involves the interaction of sorting signals with sorting machineries and the formation of transport carriers. Here we review the recent advances in the field of polarized sorting in epithelial cells. We especially highlight the role of lipid rafts in apical sorting.
Collapse
|
16
|
Surma MA, Klose C, Simons K. Lipid-dependent protein sorting at the trans-Golgi network. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:1059-67. [PMID: 22230596 DOI: 10.1016/j.bbalip.2011.12.008] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 12/02/2011] [Accepted: 12/03/2011] [Indexed: 12/14/2022]
Abstract
In eukaryotic cells, the trans-Golgi network serves as a sorting station for post-Golgi traffic. In addition to coat- and adaptor-mediated mechanisms, studies in mammalian epithelial cells and yeast have provided evidence for lipid-dependent protein sorting as a major delivery mechanism for cargo sorting to the cell surface. The mechanism for lipid-mediated sorting is the generation of raft platforms of sphingolipids, sterols and specific sets of cargo proteins by phase segregation in the TGN. Here, we review the evidence for such lipid-raft-based sorting at the TGN, as well as their involvement in the formation of TGN-to-PM transport carriers. This article is part of a Special Issue entitled Lipids and Vesicular Transport.
Collapse
Affiliation(s)
- Michal A Surma
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | | | | |
Collapse
|
17
|
Imjeti NS, Lebreton S, Paladino S, de la Fuente E, Gonzalez A, Zurzolo C. N-Glycosylation instead of cholesterol mediates oligomerization and apical sorting of GPI-APs in FRT cells. Mol Biol Cell 2011; 22:4621-34. [PMID: 21998201 PMCID: PMC3226479 DOI: 10.1091/mbc.e11-04-0320] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In contrast to MDCK cells, in FRT cells oligomerization and apical sorting of GPI-APs are mediated by N-glycosylation independent of cholesterol and raft association. Sorting of glycosylphosphatidyl-inositol–anchored proteins (GPI-APs) in polarized epithelial cells is not fully understood. Oligomerization in the Golgi complex has emerged as the crucial event driving apical segregation of GPI-APs in two different kind of epithelial cells, Madin–Darby canine kidney (MDCK) and Fisher rat thyroid (FRT) cells, but whether the mechanism is conserved is unknown. In MDCK cells cholesterol promotes GPI-AP oligomerization, as well as apical sorting of GPI-APs. Here we show that FRT cells lack this cholesterol-driven oligomerization as apical sorting mechanism. In these cells both apical and basolateral GPI-APs display restricted diffusion in the Golgi likely due to a cholesterol-enriched membrane environment. It is striking that N-glycosylation is the critical event for oligomerization and apical sorting of GPI-APs in FRT cells but not in MDCK cells. Our data indicate that at least two mechanisms exist to determine oligomerization in the Golgi leading to apical sorting of GPI-APs. One depends on cholesterol, and the other depends on N-glycosylation and is insensitive to cholesterol addition or depletion.
Collapse
Affiliation(s)
- Naga Salaija Imjeti
- Institut Pasteur, Unité de Traffic Membranaire et Pathogenèse, 75015 Paris, France
| | | | | | | | | | | |
Collapse
|
18
|
Structural remodeling, trafficking and functions of glycosylphosphatidylinositol-anchored proteins. Prog Lipid Res 2011; 50:411-24. [PMID: 21658410 DOI: 10.1016/j.plipres.2011.05.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Glycosylphosphatidylinositol (GPI) is a glycolipid that is covalently attached to proteins as a post-translational modification. Such modification leads to the anchoring of the protein to the outer leaflet of the plasma membrane. Proteins that are decorated with GPIs have unique properties in terms of their physical nature. In particular, these proteins tend to accumulate in lipid rafts, which are critical for the functions and trafficking of GPI-anchored proteins (GPI-APs). Recent studies mainly using mutant cells revealed that various structural remodeling reactions occur to GPIs present in GPI-APs as they are transported from the endoplasmic reticulum to the cell surface. This review examines the recent progress describing the mechanisms of structural remodeling of mammalian GPI-anchors, such as inositol deacylation, glycan remodeling and fatty acid remodeling, with particular focus on their trafficking and functions, as well as the pathogenesis involving GPI-APs and their deficiency.
Collapse
|
19
|
Weisz OA, Rodriguez-Boulan E. Apical trafficking in epithelial cells: signals, clusters and motors. J Cell Sci 2010; 122:4253-66. [PMID: 19923269 DOI: 10.1242/jcs.032615] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In the early days of epithelial cell biology, researchers working with kidney and/or intestinal epithelial cell lines and with hepatocytes described the biosynthetic and recycling routes followed by apical and basolateral plasma membrane (PM) proteins. They identified the trans-Golgi network and recycling endosomes as the compartments that carried out apical-basolateral sorting. They described complex apical sorting signals that promoted association with lipid rafts, and simpler basolateral sorting signals resembling clathrin-coated-pit endocytic motifs. They also noticed that different epithelial cell types routed their apical PM proteins very differently, using either a vectorial (direct) route or a transcytotic (indirect) route. Although these original observations have generally held up, recent studies have revealed interesting complexities in the routes taken by apically destined proteins and have extended our understanding of the machinery required to sustain these elaborate sorting pathways. Here, we critically review the current status of apical trafficking mechanisms and discuss a model in which clustering is required to recruit apical trafficking machineries. Uncovering the mechanisms responsible for polarized trafficking and their epithelial-specific variations will help understand how epithelial functional diversity is generated and the pathogenesis of many human diseases.
Collapse
Affiliation(s)
- Ora A Weisz
- Department of Medicine and Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | | |
Collapse
|
20
|
Abstract
Tissue patterning during development relies on cell communication by secreted proteins and receptors that engage in complex signaling crosstalk to induce distinct cell behaviors in a context-dependent fashion. Here I summarize recent insights into basic mechanisms that control the distribution and activities of transforming growth factor beta, Wnt, Hedgehog, and Notch proteins, by regulating trafficking decisions during secretion and endocytosis.
Collapse
Affiliation(s)
- Daniel B Constam
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) CH 1015 Lausanne, Switzerland USA.
| |
Collapse
|