1
|
Sandegaard SL, Riishede A, Birn H, Damkier HH, Praetorius J. The Cyst Epithelium in Polycystic Kidney Disease Patients Displays Normal Apical-Basolateral Cell Polarity. Int J Mol Sci 2024; 25:1904. [PMID: 38339183 PMCID: PMC10855726 DOI: 10.3390/ijms25031904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
The main characteristic of polycystic kidney disease is the development of multiple fluid-filled renal cysts. The discovery of mislocalized sodium-potassium pump (Na,K-ATPase) in the apical membrane of cyst-lining epithelia alluded to reversal of polarity as a possible explanation for the fluid secretion. The topic of apical Na,K-ATPase in cysts remains controversial. We investigated the localization of the Na,K-ATPase and assessed the apical-basolateral polarization of cyst-lining epithelia by means of immunohistochemistry in kidney tissue from six polycystic kidney disease patients undergoing nephrectomy. The Na,K-ATPase α1 subunit was conventionally situated in the basolateral membrane of all immunoreactive cysts. Proteins of the Crumbs and partitioning defective (Par) complexes were localized to the apical membrane domain in cyst epithelial cells. The apical targeting protein Syntaxin-3 also immunolocalized to the apical domain of cyst-lining epithelial cells. Proteins of the basolateral Scribble complex immunolocalized to the basolateral domain of cysts. Thus, no deviations from the typical epithelial distribution of basic cell polarity proteins were observed in the cysts from the six patients. Furthermore, we confirmed that cysts can originate from virtually any tubular segment with preserved polarity. In conclusion, we find no evidence of a reversal in apical-basolateral polarity in cyst-lining epithelia in polycystic kidney disease.
Collapse
Affiliation(s)
- Samuel Loft Sandegaard
- Department of Biomedicine, Health Faculty, Aarhus University, DK-8000 Aarhus C, Denmark; (S.L.S.); (A.R.); (H.B.); (H.H.D.)
| | - Andreas Riishede
- Department of Biomedicine, Health Faculty, Aarhus University, DK-8000 Aarhus C, Denmark; (S.L.S.); (A.R.); (H.B.); (H.H.D.)
| | - Henrik Birn
- Department of Biomedicine, Health Faculty, Aarhus University, DK-8000 Aarhus C, Denmark; (S.L.S.); (A.R.); (H.B.); (H.H.D.)
- Department of Clinical Medicine, Health Faculty, Aarhus University, DK-8200 Aarhus N, Denmark
| | - Helle Hasager Damkier
- Department of Biomedicine, Health Faculty, Aarhus University, DK-8000 Aarhus C, Denmark; (S.L.S.); (A.R.); (H.B.); (H.H.D.)
| | - Jeppe Praetorius
- Department of Biomedicine, Health Faculty, Aarhus University, DK-8000 Aarhus C, Denmark; (S.L.S.); (A.R.); (H.B.); (H.H.D.)
| |
Collapse
|
2
|
Hayashi K, Nozaki S, Tokushima K, Tanaka F, Hirai Y. Role of syntaxin3 an apical polarity protein in poorly polarized keratinocytes: regulation of asymmetric barrier formations in the skin epidermis. Cell Tissue Res 2023; 393:523-535. [PMID: 37351635 DOI: 10.1007/s00441-023-03798-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023]
Abstract
The skin epidermis exhibits an asymmetric structure composed of multilayered keratinocytes and those in the outer layers form two-way physical barriers, cornified cell envelope (CCE), and tight junctions (TJs). While undifferentiated keratinocytes in the basal layer continuously deliver daughter cells outward, which undergo successive differentiation with losing their polarized characteristics, they retain the expression of several polarity proteins. In the present study, we revealed that the t-SNARE protein syntaxin3, a critical element for the formation of the apical compartment in simple epithelial cells, is required to confer the ability to organize the physical barriers on "poorly polarized" keratinocytes in epidermal outer layers. HaCaT keratinocytes with genetic ablation of syntaxin3 readily succumbed to hydrogen peroxide-induced cell death. Additionally, they lost the ability to organize TJ and CCE structures, accompanied by notable downregulation of transglutaminase1 and caspase14 (a cornification regulator) expression. These syntaxin3-knockout cells appeared to restore oxidative stress tolerance and functional TJ formation ability, in response to the inducible re-expression of exogenous syntaxin3. While plausible mechanisms underlying these phenomena remain unclear, syntaxin3, an apical polarity protein in the simple epithelia, has emerged as a potentially crucial element for barrier formation in poorly polarized keratinocytes in polarized epidermal tissue.
Collapse
Affiliation(s)
- Kaho Hayashi
- Department of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara, Sanda, 669-1330, Japan
| | - Sae Nozaki
- Department of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara, Sanda, 669-1330, Japan
| | - Kanako Tokushima
- Department of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara, Sanda, 669-1330, Japan
| | - Fumika Tanaka
- Department of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara, Sanda, 669-1330, Japan
| | - Yohei Hirai
- Department of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara, Sanda, 669-1330, Japan.
| |
Collapse
|
3
|
Chatterjee R, Nair AV, Singh A, Mehta N, Setty SRG, Chakravortty D. Syntaxin 3 SPI-2 dependent crosstalk facilitates the division of Salmonella containing vacuole. Traffic 2023; 24:270-283. [PMID: 37114883 DOI: 10.1111/tra.12887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023]
Abstract
Intracellular membrane fusion is mediated by membrane-bridging complexes of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). SNARE proteins are one of the key players in vesicular transport. Several reports shed light on intracellular bacteria modulating host SNARE machinery to establish infection successfully. The critical SNAREs in macrophages responsible for phagosome maturation are Syntaxin 3 (STX3) and Syntaxin 4 (STX4). Reports also suggest that Salmonella actively modulates its vacuole membrane composition to escape lysosomal fusion. Salmonella containing vacuole (SCV) harbours recycling endosomal SNARE Syntaxin 12 (STX12). However, the role of host SNAREs in SCV biogenesis and pathogenesis remains unclear. Upon knockdown of STX3, we observed a reduction in bacterial proliferation, which is concomitantly restored upon the overexpression of STX3. Live-cell imaging of Salmonella-infected cells showed that STX3 localises to the SCV membranes and thus might help in the fusion of SCV with intracellular vesicles to acquire membrane for its division. We also found the interaction STX3-SCV was abrogated when we infected with SPI-2 encoded Type 3 secretion system (T3SS) apparatus mutant (STM ∆ssaV) but not with SPI-1 encoded T3SS apparatus mutant (STM ∆invC). These observations were also consistent in the mice model of Salmonella infection. Together, these results shed light on the effector molecules secreted through T3SS encoded by SPI-2, possibly involved in interaction with host SNARE STX3, which is essential to maintain the division of Salmonella in SCV and help to maintain a single bacterium per vacuole.
Collapse
Affiliation(s)
- Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Abhilash Vijay Nair
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Anmol Singh
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Nishi Mehta
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| |
Collapse
|
4
|
Apical-basal polarity and the control of epithelial form and function. Nat Rev Mol Cell Biol 2022; 23:559-577. [PMID: 35440694 DOI: 10.1038/s41580-022-00465-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 02/02/2023]
Abstract
Epithelial cells are the most common cell type in all animals, forming the sheets and tubes that compose most organs and tissues. Apical-basal polarity is essential for epithelial cell form and function, as it determines the localization of the adhesion molecules that hold the cells together laterally and the occluding junctions that act as barriers to paracellular diffusion. Polarity must also target the secretion of specific cargoes to the apical, lateral or basal membranes and organize the cytoskeleton and internal architecture of the cell. Apical-basal polarity in many cells is established by conserved polarity factors that define the apical (Crumbs, Stardust/PALS1, aPKC, PAR-6 and CDC42), junctional (PAR-3) and lateral (Scribble, DLG, LGL, Yurt and RhoGAP19D) domains, although recent evidence indicates that not all epithelia polarize by the same mechanism. Research has begun to reveal the dynamic interactions between polarity factors and how they contribute to polarity establishment and maintenance. Elucidating these mechanisms is essential to better understand the roles of apical-basal polarity in morphogenesis and how defects in polarity contribute to diseases such as cancer.
Collapse
|
5
|
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
|
6
|
Bidaud-Meynard A, Bossard F, Schnúr A, Fukuda R, Veit G, Xu H, Lukacs GL. Transcytosis maintains CFTR apical polarity in the face of constitutive and mutation-induced basolateral missorting. J Cell Sci 2019; 132:jcs.226886. [PMID: 30975917 DOI: 10.1242/jcs.226886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 04/02/2019] [Indexed: 12/22/2022] Open
Abstract
Apical polarity of cystic fibrosis transmembrane conductance regulator (CFTR) is essential for solute and water transport in secretory epithelia and can be impaired in human diseases. Maintenance of apical polarity in the face of CFTR non-polarized delivery and inefficient apical retention of mutant CFTRs lacking PDZ-domain protein (NHERF1, also known as SLC9A3R1) interaction, remains enigmatic. Here, we show that basolateral CFTR delivery originates from biosynthetic (∼35%) and endocytic (∼65%) recycling missorting. Basolateral channels are retrieved via basolateral-to-apical transcytosis (hereafter denoted apical transcytosis), enhancing CFTR apical expression by two-fold and suppressing its degradation. In airway epithelia, CFTR transcytosis is microtubule-dependent but independent of Myo5B, Rab11 proteins and NHERF1 binding to its C-terminal DTRL motif. Increased basolateral delivery due to compromised apical recycling and accelerated internalization upon impaired NHERF1-CFTR association is largely counterbalanced by efficient CFTR basolateral internalization and apical transcytosis. Thus, transcytosis represents a previously unrecognized, but indispensable, mechanism for maintaining CFTR apical polarity that acts by attenuating its constitutive and mutation-induced basolateral missorting.
Collapse
Affiliation(s)
| | - Florian Bossard
- Department of Physiology, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Andrea Schnúr
- Department of Physiology, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Ryosuke Fukuda
- Department of Physiology, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Guido Veit
- Department of Physiology, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Haijin Xu
- Department of Physiology, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montréal, QC, H3G 1Y6, Canada .,Department of Biochemistry, McGill University, Montréal, QC, H3G 1Y6, Canada
| |
Collapse
|
7
|
Distinct segregation patterns of yeast cell-peripheral proteins uncovered by a method for protein segregatome analysis. Proc Natl Acad Sci U S A 2019; 116:8909-8918. [PMID: 30975753 DOI: 10.1073/pnas.1819715116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Protein segregation contributes to various cellular processes such as polarization, differentiation, and aging. However, the difficulty in global determination of protein segregation hampers our understanding of its mechanisms and physiological roles. Here, by developing a quantitative proteomics technique, we globally monitored segregation of preexisting and newly synthesized proteins during cell division of budding yeast, and identified crucial domains that determine the segregation of cell-peripheral proteins. Remarkably, the proteomic and subsequent microscopic analyses demonstrated that the flow through the bud neck of the proteins that harbor both endoplasmic reticulum (ER) membrane-spanning and plasma membrane (PM)-binding domains is not restricted by the previously suggested ER membrane or PM diffusion barriers but by septin-mediated partitioning of the PM-associated ER (pmaER). Furthermore, the proteomic analysis revealed that although the PM-spanning t-SNARE Sso2 was retained in mother cells, its paralog Sso1 unexpectedly showed symmetric localization. We found that the transport of Sso1 to buds was required for enhancement of polarized cell growth and resistance to cell-wall stress. Taken together, these data resolve long-standing questions about septin-mediated compartmentalization of the cell periphery, and provide new mechanistic insights into the segregation of cell-periphery proteins and their cellular functions.
Collapse
|
8
|
Pelaseyed T, Bretscher A. Regulation of actin-based apical structures on epithelial cells. J Cell Sci 2018; 131:131/20/jcs221853. [PMID: 30333133 DOI: 10.1242/jcs.221853] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cells of transporting epithelia are characterized by the presence of abundant F-actin-based microvilli on their apical surfaces. Likewise, auditory hair cells have highly reproducible rows of apical stereocilia (giant microvilli) that convert mechanical sound into an electrical signal. Analysis of mutations in deaf patients has highlighted the critical components of tip links between stereocilia, and related structures that contribute to the organization of microvilli on epithelial cells have been found. Ezrin/radixin/moesin (ERM) proteins, which are activated by phosphorylation, provide a critical link between the plasma membrane and underlying actin cytoskeleton in surface structures. Here, we outline recent insights into how microvilli and stereocilia are built, and the roles of tip links. Furthermore, we highlight how ezrin is locally regulated by phosphorylation, and that this is necessary to maintain polarity. Localized phosphorylation is achieved through an intricate coincidence detection mechanism that requires the membrane lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the apically localized ezrin kinase, lymphocyte-oriented kinase (LOK, also known as STK10) or Ste20-like kinase (SLK). We also discuss how ezrin-binding scaffolding proteins regulate microvilli and how, despite these significant advances, it remains to be discovered how the cell polarity program ultimately interfaces with these processes.
Collapse
Affiliation(s)
- Thaher Pelaseyed
- Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden
| | - Anthony Bretscher
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
9
|
Naydenov NG, Joshi S, Feygin A, Saini S, Litovchick L, Ivanov AI. A membrane fusion protein, Ykt6, regulates epithelial cell migration via microRNA-mediated suppression of Junctional Adhesion Molecule A. Cell Cycle 2018; 17:1812-1831. [PMID: 30010460 DOI: 10.1080/15384101.2018.1496755] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Vesicle trafficking regulates epithelial cell migration by remodeling matrix adhesions and delivering signaling molecules to the migrating leading edge. Membrane fusion, which is driven by soluble N-ethylmaleimide-sensitive factor associated receptor (SNARE) proteins, is an essential step of vesicle trafficking. Mammalian SNAREs represent a large group of proteins, but few have been implicated in the regulation of cell migration. Ykt6 is a unique SNARE existing in equilibrium between active membrane-bound and inactive cytoplasmic pools, and mediating vesicle trafficking between different intracellular compartments. The biological functions of this protein remain poorly understood. In the present study, we found that Ykt6 acts as a negative regulator of migration and invasion of human prostate epithelial cells. Furthermore, Ykt6 regulates the integrity of epithelial adherens and tight junctions. The observed anti-migratory activity of Ykt6 is mediated by a unique mechanism involving the expressional upregulation of microRNA 145, which selectively decreases the cellular level of Junctional Adhesion Molecule (JAM) A. This decreased JAM-A expression limits the activity of Rap1 and Rac1 small GTPases, thereby attenuating cell spreading and motility. The described novel functions of Ykt6 could be essential for the regulation of epithelial barriers, epithelial repair, and metastatic dissemination of cancer cells.
Collapse
Affiliation(s)
- Nayden G Naydenov
- a Department of Inflammation and Immunity , Lerner Research Institute of Cleveland Clinic Foundation , Cleveland , OH , USA.,b Department of Human and Molecular Genetics , Virginia Commonwealth University , Richmond , VA , USA
| | - Supriya Joshi
- b Department of Human and Molecular Genetics , Virginia Commonwealth University , Richmond , VA , USA
| | - Alex Feygin
- b Department of Human and Molecular Genetics , Virginia Commonwealth University , Richmond , VA , USA
| | - Siddharth Saini
- c Department of Internal Medicine , Virginia Commonwealth University , Richmond , VA , USA
| | - Larisa Litovchick
- c Department of Internal Medicine , Virginia Commonwealth University , Richmond , VA , USA
| | - Andrei I Ivanov
- a Department of Inflammation and Immunity , Lerner Research Institute of Cleveland Clinic Foundation , Cleveland , OH , USA.,b Department of Human and Molecular Genetics , Virginia Commonwealth University , Richmond , VA , USA
| |
Collapse
|
10
|
Schillemans M, Karampini E, van den Eshof BL, Gangaev A, Hofman M, van Breevoort D, Meems H, Janssen H, Mulder AA, Jost CR, Escher JC, Adam R, Carter T, Koster AJ, van den Biggelaar M, Voorberg J, Bierings R. Weibel-Palade Body Localized Syntaxin-3 Modulates Von Willebrand Factor Secretion From Endothelial Cells. Arterioscler Thromb Vasc Biol 2018; 38:1549-1561. [PMID: 29880488 PMCID: PMC6039413 DOI: 10.1161/atvbaha.117.310701] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 05/17/2018] [Indexed: 01/08/2023]
Abstract
Supplemental Digital Content is available in the text. Objective— Endothelial cells store VWF (von Willebrand factor) in rod-shaped secretory organelles, called Weibel-Palade bodies (WPBs). WPB exocytosis is coordinated by a complex network of Rab GTPases, Rab effectors, and SNARE (soluble NSF attachment protein receptor) proteins. We have previously identified STXBP1 as the link between the Rab27A-Slp4-a complex on WPBs and the SNARE proteins syntaxin-2 and -3. In this study, we investigate the function of syntaxin-3 in VWF secretion. Approach and Results— In human umbilical vein endothelial cells and in blood outgrowth endothelial cells (BOECs) from healthy controls, endogenous syntaxin-3 immunolocalized to WPBs. A detailed analysis of BOECs isolated from a patient with variant microvillus inclusion disease, carrying a homozygous mutation in STX3(STX3−/−), showed a loss of syntaxin-3 protein and absence of WPB-associated syntaxin-3 immunoreactivity. Ultrastructural analysis revealed no detectable differences in morphology or prevalence of immature or mature WPBs in control versus STX3−/− BOECs. VWF multimer analysis showed normal patterns in plasma of the microvillus inclusion disease patient, and media from STX3−/− BOECs, together indicating WPB formation and maturation are unaffected by absence of syntaxin-3. However, a defect in basal as well as Ca2+- and cAMP-mediated VWF secretion was found in the STX3−/− BOECs. We also show that syntaxin-3 interacts with the WPB-associated SNARE protein VAMP8 (vesicle-associated membrane protein-8). Conclusions— Our data reveal syntaxin-3 as a novel WPB-associated SNARE protein that controls WPB exocytosis.
Collapse
Affiliation(s)
- Maaike Schillemans
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Ellie Karampini
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Bart L van den Eshof
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Anastasia Gangaev
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Menno Hofman
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Dorothee van Breevoort
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Henriët Meems
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Hans Janssen
- Cell Biology, The Netherlands Cancer Institute, Amsterdam (H.J.)
| | - Aat A Mulder
- Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, The Netherlands (A.A.M., C.R.J., A.J.K.)
| | - Carolina R Jost
- Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, The Netherlands (A.A.M., C.R.J., A.J.K.)
| | - Johanna C Escher
- Pediatric Gastroenterology, Sophia Children's Hospital, Erasmus MC, Rotterdam, The Netherlands (J.C.E.)
| | - Rüdiger Adam
- Pediatric Gastroenterology, University Medical Centre, Mannheim, Germany (R.A.)
| | - Tom Carter
- St George's, University of London, United Kingdom (T.C.)
| | - Abraham J Koster
- Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, The Netherlands (A.A.M., C.R.J., A.J.K.)
| | - Maartje van den Biggelaar
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| | - Jan Voorberg
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.).,Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, The Netherlands (J.V.)
| | - Ruben Bierings
- From the Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands (M.S., E.K., B.L.v.d.E., A.G., M.H., D.v.B., H.M., M.v.d.B., J.V., R.B.)
| |
Collapse
|
11
|
Medelnik JP, Roensch K, Okawa S, Del Sol A, Chara O, Mchedlishvili L, Tanaka EM. Signaling-Dependent Control of Apical Membrane Size and Self-Renewal in Rosette-Stage Human Neuroepithelial Stem Cells. Stem Cell Reports 2018; 10:1751-1765. [PMID: 29779899 PMCID: PMC5993681 DOI: 10.1016/j.stemcr.2018.04.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 12/12/2022] Open
Abstract
In the developing nervous system, neural stem cells are polarized and maintain an apical domain facing a central lumen. The presence of apical membrane is thought to have a profound influence on maintaining the stem cell state. With the onset of neurogenesis, cells lose their polarization, and the concomitant loss of the apical domain coincides with a loss of the stem cell identity. Little is known about the molecular signals controlling apical membrane size. Here, we use two neuroepithelial cell systems, one derived from regenerating axolotl spinal cord and the other from human embryonic stem cells, to identify a molecular signaling pathway initiated by lysophosphatidic acid that controls apical membrane size and consequently controls and maintains epithelial organization and lumen size in neuroepithelial rosettes. This apical domain size increase occurs independently of effects on proliferation and involves a serum response factor-dependent transcriptional induction of junctional and apical membrane components.
Collapse
Affiliation(s)
- Jan-Philip Medelnik
- Research Institute for Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
| | - Kathleen Roensch
- DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Satoshi Okawa
- Computational Biology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 6, Avenue du Swing, Belvaux 4367, Luxembourg
| | - Antonio Del Sol
- Computational Biology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 6, Avenue du Swing, Belvaux 4367, Luxembourg
| | - Osvaldo Chara
- Center for Information Services and High Performance Computing (ZIH), Technische Universität Dresden, 01062 Dresden, Germany; Systems Biology Group (SysBio), Instituto de Física de Líquidos y Sistemas Biológicos (IFLySIB), CONICET, Universidad Nacional de La Plata (UNLP), B1900BTE, La Plata, Argentina
| | - Levan Mchedlishvili
- DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Elly M Tanaka
- Research Institute for Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| |
Collapse
|
12
|
Ribeiro LF, Verpoort B, de Wit J. Trafficking mechanisms of synaptogenic cell adhesion molecules. Mol Cell Neurosci 2018; 91:34-47. [PMID: 29631018 DOI: 10.1016/j.mcn.2018.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 01/01/2023] Open
Abstract
Nearly every aspect of neuronal function, from wiring to information processing, critically depends on the highly polarized architecture of neurons. Establishing and maintaining the distinct molecular composition of axonal and dendritic compartments requires precise control over the trafficking of the proteins that make up these cellular domains. Synaptic cell adhesion molecules (CAMs), membrane proteins with a critical role in the formation, differentiation and plasticity of synapses, require targeting to the correct pre- or postsynaptic compartment for proper functioning of neural circuits. However, the mechanisms that control the polarized trafficking, synaptic targeting, and synaptic abundance of CAMs are poorly understood. Here, we summarize current knowledge about the sequential trafficking events along the secretory pathway that control the polarized surface distribution of synaptic CAMs, and discuss how their synaptic targeting and abundance is additionally influenced by post-secretory determinants. The identification of trafficking-impairing mutations in CAMs associated with various neurodevelopmental disorders underscores the importance of correct protein trafficking for normal brain function.
Collapse
Affiliation(s)
- Luís F Ribeiro
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium
| | - Ben Verpoort
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium.
| |
Collapse
|
13
|
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
|
14
|
Giovannone AJ, Winterstein C, Bhattaram P, Reales E, Low SH, Baggs JE, Xu M, Lalli MA, Hogenesch JB, Weimbs T. Soluble syntaxin 3 functions as a transcriptional regulator. J Biol Chem 2018; 293:5478-5491. [PMID: 29475951 DOI: 10.1074/jbc.ra117.000874] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/20/2018] [Indexed: 01/06/2023] Open
Abstract
Syntaxins are a conserved family of SNARE proteins and contain C-terminal transmembrane anchors required for their membrane fusion activity. Here we show that Stx3 (syntaxin 3) unexpectedly also functions as a nuclear regulator of gene expression. We found that alternative splicing creates a soluble isoform that we termed Stx3S, lacking the transmembrane anchor. Soluble Stx3S binds to the nuclear import factor RanBP5 (RAN-binding protein 5), targets to the nucleus, and interacts physically and functionally with several transcription factors, including ETV4 (ETS variant 4) and ATF2 (activating transcription factor 2). Stx3S is differentially expressed in normal human tissues, during epithelial cell polarization, and in breast cancer versus normal breast tissue. Inhibition of endogenous Stx3S expression alters the expression of cancer-associated genes and promotes cell proliferation. Similar nuclear-targeted, soluble forms of other syntaxins were identified, suggesting that nuclear signaling is a conserved, novel function common among these membrane-trafficking proteins.
Collapse
Affiliation(s)
- Adrian J Giovannone
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Christine Winterstein
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Pallavi Bhattaram
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Elena Reales
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Seng Hui Low
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Julie E Baggs
- the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Mimi Xu
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Matthew A Lalli
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - John B Hogenesch
- the Center for Chronobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Thomas Weimbs
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625,
| |
Collapse
|
15
|
Giovannone AJ, Reales E, Bhattaram P, Fraile-Ramos A, Weimbs T. Tracking Endocytosis and Intracellular Trafficking of Epitope-tagged Syntaxin 3 by Antibody Feeding in Live, Polarized MDCK Cells. Bio Protoc 2018; 8:e2453. [PMID: 29564371 DOI: 10.21769/bioprotoc.2453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The uptake and trafficking of cell surface receptors can be monitored by a technique called 'antibody-feeding' which uses an externally applied antibody to label the receptor on the surface of cultured, live cells. Here, we adapt the traditional antibody-feeding experiment to polarized epithelial cells (Madin-Darby Canine Kidney) grown on permeable Transwell supports. By adding two tandem extracellular Myc epitope tags to the C-terminus of the SNARE protein syntaxin 3 (Stx3), we provided a site where an antibody could bind, allowing us to perform antibody-feeding experiments on cells with distinct apical and basolateral membranes. With this procedure, we observed the endocytosis and intracellular trafficking of Stx3. Specifically, we assessed the internalization rate of Stx3 from the basolateral membrane and observed the ensuing endocytic route in both time and space using immunofluorescence microscopy on cells fixed at different time points. For cell lines that form a polarized monolayer containing distinct apical and basolateral membranes when cultured on permeable supports, e.g., MDCK or Caco-2, this protocol can measure the rate of endocytosis and follow the subsequent trafficking of a target protein from either limiting membrane.
Collapse
Affiliation(s)
- Adrian J Giovannone
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California, USA
| | - Elena Reales
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California, USA
| | - Pallavi Bhattaram
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California, USA
| | - Alberto Fraile-Ramos
- Universidad Complutense de Madrid, Departmento de Biología Celular, Facultad de Medicina, Plaza de Ramoń y Cajal, s/n Ciudad Universitaria, Madrid, Spain
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California, USA
| |
Collapse
|
16
|
Dhekne HS, Pylypenko O, Overeem AW, Zibouche M, Ferreira RJ, van der Velde KJ, Rings EHHM, Posovszky C, van der Sluijs P, Swertz MA, Houdusse A, van IJzendoorn SCD. MYO5B, STX3, and STXBP2 mutations reveal a common disease mechanism that unifies a subset of congenital diarrheal disorders: A mutation update. Hum Mutat 2018; 39:333-344. [PMID: 29266534 PMCID: PMC5838515 DOI: 10.1002/humu.23386] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 12/15/2022]
Abstract
Microvillus inclusion disease (MVID) is a rare but fatal autosomal recessive congenital diarrheal disorder caused by MYO5B mutations. In 2013, we launched an open‐access registry for MVID patients and their MYO5B mutations (www.mvid-central.org). Since then, additional unique MYO5B mutations have been identified in MVID patients, but also in non‐MVID patients. Animal models have been generated that formally prove the causality between MYO5B and MVID. Importantly, mutations in two other genes, STXBP2 and STX3, have since been associated with variants of MVID, shedding new light on the pathogenesis of this congenital diarrheal disorder. Here, we review these additional genes and their mutations. Furthermore, we discuss recent data from cell studies that indicate that the three genes are functionally linked and, therefore, may constitute a common disease mechanism that unifies a subset of phenotypically linked congenital diarrheal disorders. We present new data based on patient material to support this. To congregate existing and future information on MVID geno‐/phenotypes, we have updated and expanded the MVID registry to include all currently known MVID‐associated gene mutations, their demonstrated or predicted functional consequences, and associated clinical information.
Collapse
Affiliation(s)
- Herschel S Dhekne
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Olena Pylypenko
- Structural Motility, Institute Curie, Centre de Reserche, Paris, France
| | - Arend W Overeem
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Malik Zibouche
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Rosaria J Ferreira
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - K Joeri van der Velde
- Genomics Coordination Center, Department of Genetics, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Edmond H H M Rings
- Department of Pediatrics, Erasmus Medical Center Rotterdam, Erasmus University Rotterdam, Rotterdam, The Netherlands.,Department of Pediatrics, Leiden University Medical Center, Leiden University, Leiden, The Netherlands
| | - Carsten Posovszky
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Peter van der Sluijs
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, the Netherlands,Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Morris A Swertz
- Genomics Coordination Center, Department of Genetics, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Anne Houdusse
- Structural Motility, Institute Curie, Centre de Reserche, Paris, France
| | - Sven C D van IJzendoorn
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| |
Collapse
|
17
|
Christensen IB, Mogensen EN, Damkier HH, Praetorius J. Choroid plexus epithelial cells express the adhesion protein P-cadherin at cell-cell contacts and syntaxin-4 in the luminal membrane domain. Am J Physiol Cell Physiol 2018; 314:C519-C533. [PMID: 29351408 DOI: 10.1152/ajpcell.00305.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The choroid plexus epithelial cells (CPECs) belong to a small group of polarized cells, where the Na+-K+-ATPase is expressed in the luminal membrane. The basic polarity of the cells is, therefore, still debated. We investigated the subcellular distribution of an array of proteins known to play fundamental roles either in establishing and maintaining basic cell polarity or in the polarized delivery and recycling of plasma membrane proteins. Immunofluorescence histochemical analysis was applied to determine the subcellular localization of apical and basolateral membrane determinants. Mass spectrometry analysis of CPECs isolated by fluorescence-activated cell sorting was applied to determine the expression of specific forms of the proteins. CPECs mainly express the cell-adhesive P-cadherin, which is localized to the lateral membranes. Proteins belonging to the Crumbs and partitioning defective (Par) protein complexes were all localized to the luminal membrane domain. Par-1 and the Scribble complex were localized to the basolateral membrane domain. Lethal(2) giant larvae homolog 2 (Lgl2) labeling was preferentially observed in the luminal membrane domain. Phosphatidylinositol 3,4,5-trisphosphate (PIP3) was immunolocalized to the basolateral membrane domain, while phosphatidylinositol 4,5-bisphosphate (PIP2) staining was most prominent in the luminal membrane domain along with the PIP3 phosphatase, Pten. The apical target-SNARE syntaxin-3 and the basolateral target-SNARE syntaxin-4 were both localized to the apical membrane domain in CPECs, which lack cellular expression of the clathrin adaptor protein AP-1B for basolateral protein recycling. In conclusion, the CPECs are conventionally polarized, but express P-cadherin at cell-cell contacts, and Lgl2 and syntaxin-4 in the luminal plasma membrane domain.
Collapse
Affiliation(s)
| | | | | | - Jeppe Praetorius
- Department of Biomedicine, Health, Aarhus University , Aarhus, Denmark
| |
Collapse
|
18
|
Wang T, Li L, Hong W. SNARE proteins in membrane trafficking. Traffic 2017; 18:767-775. [PMID: 28857378 DOI: 10.1111/tra.12524] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/25/2017] [Accepted: 08/25/2017] [Indexed: 12/25/2022]
Abstract
SNAREs are the core machinery mediating membrane fusion. In this review, we provide an update on the recent progress on SNAREs regulating membrane fusion events, especially the more detailed fusion processes dissected by well-developed biophysical methods and in vitro single molecule analysis approaches. We also briefly summarize the relevant research from Chinese laboratories and highlight the significant contributions on our understanding of SNARE-mediated membrane trafficking from scientists in China.
Collapse
Affiliation(s)
- Tuanlao Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China
| | - Liangcheng Li
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China
| | - Wanjin Hong
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China.,Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
| |
Collapse
|
19
|
Giovannone AJ, Reales E, Bhattaram P, Fraile-Ramos A, Weimbs T. Monoubiquitination of syntaxin 3 leads to retrieval from the basolateral plasma membrane and facilitates cargo recruitment to exosomes. Mol Biol Cell 2017; 28:2843-2853. [PMID: 28814500 PMCID: PMC5638587 DOI: 10.1091/mbc.e17-07-0461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/09/2017] [Accepted: 08/11/2017] [Indexed: 01/02/2023] Open
Abstract
Monoubiquitination of Stx3 leads to efficient endocytosis from the basolateral plasma membrane and trafficking into the multivesicular body/exosomal pathway. Stx3 plays a role in cargo recruitment into exosomes. This pathway is exploited by HCMV for virion excretion. Syntaxin 3 (Stx3), a SNARE protein located and functioning at the apical plasma membrane of epithelial cells, is required for epithelial polarity. A fraction of Stx3 is localized to late endosomes/lysosomes, although how it traffics there and its function in these organelles is unknown. Here we report that Stx3 undergoes monoubiquitination in a conserved polybasic domain. Stx3 present at the basolateral—but not the apical—plasma membrane is rapidly endocytosed, targeted to endosomes, internalized into intraluminal vesicles (ILVs), and excreted in exosomes. A nonubiquitinatable mutant of Stx3 (Stx3-5R) fails to enter this pathway and leads to the inability of the apical exosomal cargo protein GPRC5B to enter the ILV/exosomal pathway. This suggests that ubiquitination of Stx3 leads to removal from the basolateral membrane to achieve apical polarity, that Stx3 plays a role in the recruitment of cargo to exosomes, and that the Stx3-5R mutant acts as a dominant-negative inhibitor. Human cytomegalovirus (HCMV) acquires its membrane in an intracellular compartment and we show that Stx3-5R strongly reduces the number of excreted infectious viral particles. Altogether these results suggest that Stx3 functions in the transport of specific proteins to apical exosomes and that HCMV exploits this pathway for virion excretion.
Collapse
Affiliation(s)
- Adrian J Giovannone
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Elena Reales
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Pallavi Bhattaram
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Alberto Fraile-Ramos
- Departamento de Biología Celular, Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| |
Collapse
|
20
|
Enrich C, Rentero C, Grewal T. Annexin A6 in the liver: From the endocytic compartment to cellular physiology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:933-946. [PMID: 27984093 DOI: 10.1016/j.bbamcr.2016.10.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 12/15/2022]
Abstract
Annexin A6 (AnxA6) belongs to the conserved annexin family - a group of Ca2+-dependent membrane binding proteins. AnxA6 is the largest of all annexins and highly expressed in smooth muscle, hepatocytes, endothelial cells and cardiomyocytes. Upon activation, AnxA6 binds to negatively charged phospholipids in a wide range of intracellular localizations, in particular the plasma membrane, late endosomes/pre-lysosomes, but also synaptic vesicles and sarcolemma. In these cellular sites, AnxA6 is believed to contribute to the organization of membrane microdomains, such as cholesterol-rich lipid rafts and confer multiple regulatory functions, ranging from vesicle fusion, endocytosis and exocytosis to programmed cell death and muscle contraction. Growing evidence supports that Ca2+ and Ca2+-binding proteins control endocytosis and autophagy. Their regulatory role seems to operate at the level of the signalling pathways that initiate autophagy or at later stages, when autophagosomes fuse with endolysosomal compartments. The convergence of the autophagic and endocytic vesicles to lysosomes shares several features that depend on Ca2+ originating from lysosomes/late endosomes and seems to depend on proteins that are subsequently activated by this cation. However, the involvement of Ca2+ and its effector proteins in these autophagic and endocytic stages still remains poorly understood. Although AnxA6 makes up almost 0.25% of total protein in the liver, little is known about its function in hepatocytes. Within the endocytic route, we identified AnxA6 in endosomes and autophagosomes of hepatocytes. Hence, AnxA6 and possibly other annexins might represent new Ca2+ effectors that regulate converging steps of autophagy and endocytic trafficking in hepatocytes. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
Collapse
Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cellular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain.
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cellular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy A15, University of Sydney, Sydney, NSW 2006, Australia
| |
Collapse
|
21
|
Soo Hoo L, Banna CD, Radeke CM, Sharma N, Albertolle ME, Low SH, Weimbs T, Vandenberg CA. The SNARE Protein Syntaxin 3 Confers Specificity for Polarized Axonal Trafficking in Neurons. PLoS One 2016; 11:e0163671. [PMID: 27662481 PMCID: PMC5035089 DOI: 10.1371/journal.pone.0163671] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/12/2016] [Indexed: 11/19/2022] Open
Abstract
Cell polarity and precise subcellular protein localization are pivotal to neuronal function. The SNARE machinery underlies intracellular membrane fusion events, but its role in neuronal polarity and selective protein targeting remain unclear. Here we report that syntaxin 3 is involved in orchestrating polarized trafficking in cultured rat hippocampal neurons. We show that syntaxin 3 localizes to the axonal plasma membrane, particularly to axonal tips, whereas syntaxin 4 localizes to the somatodendritic plasma membrane. Disruption of a conserved N-terminal targeting motif, which causes mislocalization of syntaxin 3, results in coincident mistargeting of the axonal cargos neuron-glia cell adhesion molecule (NgCAM) and neurexin, but not transferrin receptor, a somatodendritic cargo. Similarly, RNAi-mediated knockdown of endogenous syntaxin 3 leads to partial mistargeting of NgCAM, demonstrating that syntaxin 3 plays an important role in its targeting. Additionally, overexpression of syntaxin 3 results in increased axonal growth. Our findings suggest an important role for syntaxin 3 in maintaining neuronal polarity and in the critical task of selective trafficking of membrane protein to axons.
Collapse
Affiliation(s)
- Linda Soo Hoo
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Chris D. Banna
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Carolyn M. Radeke
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Nikunj Sharma
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Mary E. Albertolle
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Seng Hui Low
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Carol A. Vandenberg
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
- * E-mail:
| |
Collapse
|
22
|
Doerr N, Wang Y, Kipp KR, Liu G, Benza JJ, Pletnev V, Pavlov TS, Staruschenko A, Mohieldin AM, Takahashi M, Nauli SM, Weimbs T. Regulation of Polycystin-1 Function by Calmodulin Binding. PLoS One 2016; 11:e0161525. [PMID: 27560828 PMCID: PMC4999191 DOI: 10.1371/journal.pone.0161525] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/08/2016] [Indexed: 11/18/2022] Open
Abstract
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common genetic disease that leads to progressive renal cyst growth and loss of renal function, and is caused by mutations in the genes encoding polycystin-1 (PC1) and polycystin-2 (PC2), respectively. The PC1/PC2 complex localizes to primary cilia and can act as a flow-dependent calcium channel in addition to numerous other signaling functions. The exact functions of the polycystins, their regulation and the purpose of the PC1/PC2 channel are still poorly understood. PC1 is an integral membrane protein with a large extracytoplasmic N-terminal domain and a short, ~200 amino acid C-terminal cytoplasmic tail. Most proteins that interact with PC1 have been found to bind via the cytoplasmic tail. Here we report that the PC1 tail has homology to the regulatory domain of myosin heavy chain including a conserved calmodulin-binding motif. This motif binds to CaM in a calcium-dependent manner. Disruption of the CaM-binding motif in PC1 does not affect PC2 binding, cilia targeting, or signaling via heterotrimeric G-proteins or STAT3. However, disruption of CaM binding inhibits the PC1/PC2 calcium channel activity and the flow-dependent calcium response in kidney epithelial cells. Furthermore, expression of CaM-binding mutant PC1 disrupts cellular energy metabolism. These results suggest that critical functions of PC1 are regulated by its ability to sense cytosolic calcium levels via binding to CaM.
Collapse
Affiliation(s)
- Nicholas Doerr
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, United States of America
| | - Yidi Wang
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, United States of America
| | - Kevin R. Kipp
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, United States of America
| | - Guangyi Liu
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, United States of America
- Department of Nephrology, Qilu Hospital, Shandong University, Jinan, China
| | - Jesse J. Benza
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, United States of America
| | - Vladimir Pletnev
- Department of Structural Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Tengis S. Pavlov
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States of America
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States of America
| | - Ashraf M. Mohieldin
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, United States of America
- University of California Irvine, Medical Campus, Orange, CA, United States of America
| | - Maki Takahashi
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, United States of America
- University of California Irvine, Medical Campus, Orange, CA, United States of America
| | - Surya M. Nauli
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, United States of America
- University of California Irvine, Medical Campus, Orange, CA, United States of America
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, United States of America
- * E-mail:
| |
Collapse
|
23
|
Vergés M. Retromer in Polarized Protein Transport. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 323:129-79. [PMID: 26944621 DOI: 10.1016/bs.ircmb.2015.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Retromer is an evolutionary conserved protein complex required for endosome-to-Golgi retrieval of receptors for lysosomal hydrolases. It is constituted by a heterotrimer encoded by the vacuolar protein sorting (VPS) gene products Vps26, Vps35, and Vps29, which selects cargo, and a dimer of phosphoinositide-binding sorting nexins, which deforms the membrane. Recent progress in the mechanism of retromer assembly and functioning has strengthened the link between sorting at the endosome and cytoskeleton dynamics. Retromer is implicated in endosomal sorting of many cargos and plays an essential role in plant and animal development. Although it is best known for endosome sorting to the trans-Golgi network, it also intervenes in recycling to the plasma membrane. In polarized cells, such as epithelial cells and neurons, retromer may also be utilized for transcytosis and long-range transport. Considerable evidence implicates retromer in establishment and maintenance of cell polarity. That includes sorting of the apical polarity module Crumbs; regulation of retromer function by the basolateral polarity module Scribble; and retromer-dependent recycling of various cargoes to a certain surface domain, thus controlling polarized location and cell homeostasis. Importantly, altered retromer function has been linked to neurodegeneration, such as in Alzheimer's or Parkinson's disease. This review will underline how alterations in retromer localization and function may affect polarized protein transport and polarity establishment, thereby causing developmental defects and disease.
Collapse
Affiliation(s)
- Marcel Vergés
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), Girona, Spain; Medical Sciences Department, University of Girona, Girona, Spain.
| |
Collapse
|
24
|
Park S, Bin NR, Rajah M, Kim B, Chou TC, Kang SYA, Sugita K, Parsaud L, Smith M, Monnier PP, Ikura M, Zhen M, Sugita S. Conformational states of syntaxin-1 govern the necessity of N-peptide binding in exocytosis of PC12 cells and Caenorhabditis elegans. Mol Biol Cell 2015; 27:669-85. [PMID: 26700321 PMCID: PMC4750926 DOI: 10.1091/mbc.e15-09-0638] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/18/2015] [Indexed: 11/11/2022] Open
Abstract
Syntaxin-1 is the central SNARE protein for neuronal exocytosis. It interacts with Munc18-1 through its cytoplasmic domains, including the N-terminal peptide (N-peptide). Here we examine the role of the N-peptide binding in two conformational states ("closed" vs. "open") of syntaxin-1 using PC12 cells and Caenorhabditis elegans. We show that expression of "closed" syntaxin-1A carrying N-terminal single point mutations (D3R, L8A) that perturb interaction with the hydrophobic pocket of Munc18-1 rescues impaired secretion in syntaxin-1-depleted PC12 cells and the lethality and lethargy of unc-64 (C. elegans orthologue of syntaxin-1)-null mutants. Conversely, expression of the "open" syntaxin-1A harboring the same mutations fails to rescue the impairments. Biochemically, the L8A mutation alone slightly weakens the binding between "closed" syntaxin-1A and Munc18-1, whereas the same mutation in the "open" syntaxin-1A disrupts it. Our results reveal a striking interplay between the syntaxin-1 N-peptide and the conformational state of the protein. We propose that the N-peptide plays a critical role in intracellular trafficking of syntaxin-1, which is dependent on the conformational state of this protein. Surprisingly, however, the N-peptide binding mode seems dispensable for SNARE-mediated exocytosis per se, as long as the protein is trafficked to the plasma membrane.
Collapse
Affiliation(s)
- Seungmee Park
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Na-Ryum Bin
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Maaran Rajah
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Byungjin Kim
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Ting-Chieh Chou
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Soo-Young Ann Kang
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Kyoko Sugita
- Division of Genetics and Development, Krembil Discovery Tower, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Leon Parsaud
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Matthew Smith
- Division of Signaling Biology, MaRS Toronto Medical Discovery Tower, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 1L7, Canada Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Philippe P Monnier
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada Division of Genetics and Development, Krembil Discovery Tower, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Mitsuhiko Ikura
- Division of Genetics and Development, Krembil Discovery Tower, University Health Network, Toronto, ON M5T 2S8, Canada Division of Signaling Biology, MaRS Toronto Medical Discovery Tower, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Shuzo Sugita
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| |
Collapse
|
25
|
Knowles BC, Weis VG, Yu S, Roland JT, Williams JA, Alvarado GS, Lapierre LA, Shub MD, Gao N, Goldenring JR. Rab11a regulates syntaxin 3 localization and microvillus assembly in enterocytes. J Cell Sci 2015; 128:1617-26. [PMID: 25673875 DOI: 10.1242/jcs.163303] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/02/2015] [Indexed: 02/02/2023] Open
Abstract
Rab11a is a key component of the apical recycling endosome that aids in the trafficking of proteins to the luminal surface in polarized epithelial cells. Utilizing conditional Rab11a-knockout specific to intestinal epithelial cells, and human colonic epithelial CaCo2-BBE cells with stable Rab11a knockdown, we examined the molecular and pathological impact of Rab11a deficiency on the establishment of apical cell polarity and microvillus morphogenesis. We demonstrate that loss of Rab11a induced alterations in enterocyte polarity, shortened microvillar length and affected the formation of microvilli along the lateral membranes. Rab11a deficiency in enterocytes altered the apical localization of syntaxin 3. These data affirm the role of Rab11a in apical membrane trafficking and the maintenance of apical microvilli in enterocytes.
Collapse
Affiliation(s)
- Byron C Knowles
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Victoria G Weis
- Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Shiyan Yu
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Joseph T Roland
- Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Janice A Williams
- Vanderbilt Ingraham Cancer Center: Cell Imaging Shared Resource, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Gabriela S Alvarado
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Lynne A Lapierre
- Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| | - Mitchell D Shub
- Phoenix Children's Hospital and the Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA Rutgers Cancer Institute of New Jersey, Piscataway, NJ 08903, USA
| | - James R Goldenring
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37235, USA Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37235, USA
| |
Collapse
|
26
|
Chen D, Li L, Yan J, Yang X, You Y, Zhou Y, Ling X. The loss of αSNAP downregulates the expression of occludin in the intestinal epithelial cell of acute pancreatitis model. Pancreatology 2014; 14:347-55. [PMID: 25278303 DOI: 10.1016/j.pan.2014.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 06/11/2014] [Accepted: 06/23/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND OBJECTIVE Intestinal barrier damage is an important event during the occurrence and progression of severe acute pancreatitis. The expression of occludin, one of the main components of the intestinal barrier proteins, is regulated by various factors related to intestinal barrier formation and the remodeling process. The αSNAP, as a novel membrane protein, is ubiquitously expressed in intestinal epithelial cells. This study aimed to investigate the role of αSNAP in acute pancreatitis and the relationship between occludin and αSNAP. METHODS Mild and severe acute pancreatitis models were established by retrograde injections of 0.5% and 3.8% sodium taurocholate solutions, respectively, into rat pancreaticobiliary ducts. The animals were killed at 1, 2, and 3 days after the injection, and the pathological changes of the pancreas and intestinal mucosa, the changes in intestinal permeability, and the protein expression of occludin and αSNAP were assessed. Cultured epithelial IEC-6 cells were further infected with lentiviral αSNAP shRNA, cell apoptosis was determined with flow cytometry (FCM), and any changes in occludin expression were detected by Western blotting and immunofluorescent staining. RESULTS This pathologic study of a rat acute pancreatitis model indicated pancreatic tissue necrosis and inflammatory cell infiltration; the intestinal villi in the severe acute pancreatitis (SAP) group demonstrated edema, lodging, atrophy, and intestinal epithelial cell necrosis, and shedding. The intestinal permeability in rats with pancreatitis increased significantly. The SAP group showed significantly increased levels of serum TNF-α and endotoxins. The results of immunofluorescent staining and Western blotting revealed that compared with the SO (sham operation) and MAP (mild acute pancreatitis) groups, the SAP group displayed significantly downregulated protein expressions of αSNAP and occludin in the intestinal epithelial cells. After the lentiviral transduction of αSNAP shRNA, apoptosis in IEC-6 cells was drastically increased, whereas the expression of occludin was decreased significantly. CONCLUSION The downregulated expression of αSNAP in intestinal epithelial cells leads to reduced occludin expression and enhanced apoptosis of intestinal epithelial cells. Hence, the permeability of the intestinal barrier may be increased in a severe acute pancreatitis model.
Collapse
Affiliation(s)
- Daixing Chen
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Lili Li
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Jing Yan
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Yang You
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Yuan Zhou
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Xianlong Ling
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| |
Collapse
|
27
|
Wiegerinck CL, Janecke AR, Schneeberger K, Vogel GF, van Haaften-Visser DY, Escher JC, Adam R, Thöni CE, Pfaller K, Jordan AJ, Weis CA, Nijman IJ, Monroe GR, van Hasselt PM, Cutz E, Klumperman J, Clevers H, Nieuwenhuis EES, Houwen RHJ, van Haaften G, Hess MW, Huber LA, Stapelbroek JM, Müller T, Middendorp S. Loss of syntaxin 3 causes variant microvillus inclusion disease. Gastroenterology 2014; 147:65-68.e10. [PMID: 24726755 DOI: 10.1053/j.gastro.2014.04.002] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 04/04/2014] [Accepted: 04/06/2014] [Indexed: 01/07/2023]
Abstract
Microvillus inclusion disease (MVID) is a disorder of intestinal epithelial differentiation characterized by life-threatening intractable diarrhea. MVID can be diagnosed based on loss of microvilli, microvillus inclusions, and accumulation of subapical vesicles. Most patients with MVID have mutations in myosin Vb that cause defects in recycling of apical vesicles. Whole-exome sequencing of DNA from patients with variant MVID showed homozygous truncating mutations in syntaxin 3 (STX3). STX3 is an apical receptor involved in membrane fusion of apical vesicles in enterocytes. Patient-derived organoid cultures and overexpression of truncated STX3 in Caco-2 cells recapitulated most characteristics of variant MVID. We conclude that loss of STX3 function causes variant MVID.
Collapse
Affiliation(s)
- Caroline L Wiegerinck
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Andreas R Janecke
- Division of Human Genetics, Biocenter Innsbruck, Innsbruck, Austria; Department of Pediatrics I, Biocenter Innsbruck, Innsbruck, Austria
| | - Kerstin Schneeberger
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Georg F Vogel
- Division of Cell Biology, Biocenter Innsbruck, Innsbruck, Austria; Division of Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria
| | - Désirée Y van Haaften-Visser
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Cell Biology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Johanna C Escher
- Pediatric Gastroenterology, Sophia Children's Hospital, Erasmus MC, Rotterdam, The Netherlands
| | - Rüdiger Adam
- Pediatric Gastroenterology, Department of Pediatric and Adolescent Medicine, University Medical Centre, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Cornelia E Thöni
- Division of Cell Biology, Biocenter Innsbruck, Innsbruck, Austria; Division of Pathology, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Canada
| | - Kristian Pfaller
- Division of Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria
| | - Alexander J Jordan
- Pediatric Gastroenterology, Department of Pediatric and Adolescent Medicine, University Medical Centre, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Cleo-Aron Weis
- Institute of Pathology, University Medical Centre, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Isaac J Nijman
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Glen R Monroe
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter M van Hasselt
- Division of Pediatrics, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ernest Cutz
- Division of Pathology, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Canada
| | - Judith Klumperman
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, The Netherlands; University Medical Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hans Clevers
- Hubrecht Institute for Developmental Biology and Stem Cell Research, Royal Dutch Academy of Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Edward E S Nieuwenhuis
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Roderick H J Houwen
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gijs van Haaften
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Michael W Hess
- Division of Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria
| | - Lukas A Huber
- Division of Cell Biology, Biocenter Innsbruck, Innsbruck, Austria
| | - Janneke M Stapelbroek
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Thomas Müller
- Department of Pediatrics I, Biocenter Innsbruck, Innsbruck, Austria.
| | - Sabine Middendorp
- Division of Pediatrics, Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
| |
Collapse
|
28
|
Rodriguez-Boulan E, Macara IG. Organization and execution of the epithelial polarity programme. Nat Rev Mol Cell Biol 2014; 15:225-42. [PMID: 24651541 DOI: 10.1038/nrm3775] [Citation(s) in RCA: 504] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epithelial cells require apical-basal plasma membrane polarity to carry out crucial vectorial transport functions and cytoplasmic polarity to generate different cell progenies for tissue morphogenesis. The establishment and maintenance of a polarized epithelial cell with apical, basolateral and ciliary surface domains is guided by an epithelial polarity programme (EPP) that is controlled by a network of protein and lipid regulators. The EPP is organized in response to extracellular cues and is executed through the establishment of an apical-basal axis, intercellular junctions, epithelial-specific cytoskeletal rearrangements and a polarized trafficking machinery. Recent studies have provided insight into the interactions of the EPP with the polarized trafficking machinery and how these regulate epithelial polarization and depolarization.
Collapse
Affiliation(s)
- Enrique Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Weill Cornell Medical College, 1300 York Avenue, LC-301 New York City, New York 10065, USA
| | - Ian G Macara
- Department of Cell & Developmental Biology, Vanderbilt University Medical Center, 465 21st Avenue South, U 3209 MRB III, Nashville Tennessee 37232, USA
| |
Collapse
|
29
|
Liu X, Heidelberger R, Janz R. Phosphorylation of syntaxin 3B by CaMKII regulates the formation of t-SNARE complexes. Mol Cell Neurosci 2014; 60:53-62. [PMID: 24680688 DOI: 10.1016/j.mcn.2014.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 02/04/2014] [Accepted: 03/09/2014] [Indexed: 10/25/2022] Open
Abstract
Ribbon synapses in the retina lack the t-SNARE (target-soluble N-ethylmaleimide-sensitive factor attachment protein receptor) syntaxin 1A that is found in conventional synapses of the nervous system, but instead contain the related isoform syntaxin 3B. Previous studies have demonstrated that syntaxin 3B is essential for synaptic vesicle exocytosis in ribbon synapses, but syntaxin 3B is less efficient than syntaxin 1A in binding the t-SNARE protein SNAP-25 and catalyzing vesicle fusion. We demonstrate here that syntaxin 3B is localized mainly on the presynaptic membrane of retinal ribbon synapses and that a subset of syntaxin 3B is localized in close proximity to the synaptic ribbon. We show further, that syntaxin 3B can be phosphorylated by the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). We determine that the phosphorylation site is located close to the N-terminus at T14. Syntaxin 3B with a phosphomimetic mutation (T14E) had a stronger binding affinity for SNAP-25 compared with wild type syntaxin 3B. We propose that phosphorylation of syntaxin 3B by CaMKII can modulate the assembly of the SNARE complex in ribbon synapses of the retina, and might regulate the exocytosis of synaptic vesicles in ribbon synapses.
Collapse
Affiliation(s)
- Xiaoqin Liu
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, United States
| | - Ruth Heidelberger
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, United States
| | - Roger Janz
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, United States.
| |
Collapse
|
30
|
Tanimizu N, Nishikawa Y, Ichinohe N, Akiyama H, Mitaka T. Sry HMG box protein 9-positive (Sox9+) epithelial cell adhesion molecule-negative (EpCAM-) biphenotypic cells derived from hepatocytes are involved in mouse liver regeneration. J Biol Chem 2014; 289:7589-98. [PMID: 24482234 DOI: 10.1074/jbc.m113.517243] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
It has been shown that mature hepatocytes compensate tissue damages not only by proliferation and/or hypertrophy but also by conversion into cholangiocyte-like cells. We found that Sry HMG box protein 9-positive (Sox9(+)) epithelial cell adhesion molecule-negative (EpCAM(-)) hepatocyte nuclear factor 4α-positive (HNF4α(+)) biphenotypic cells showing hepatocytic morphology appeared near EpCAM(+) ductular structures in the livers of mice fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing diet. When Mx1-Cre:ROSA mice, which were injected with poly(I:C) to label mature hepatocytes, were fed with the DDC diet, we found LacZ(+)Sox9(+) cells near ductular structures. Although Sox9(+)EpCAM(-) cells adjacent to expanding ducts likely further converted into ductular cells, the incidence was rare. To know the cellular characteristics of Sox9(+)EpCAM(-) cells, we isolated them as GFP(+)EpCAM(-) cells from DDC-injured livers of Sox9-EGFP mice. Sox9(+)EpCAM(-) cells proliferated and could differentiate to functional hepatocytes in vitro. In addition, Sox9(+)EpCAM(-) cells formed cysts with a small central lumen in collagen gels containing Matrigel® without expressing EpCAM. These results suggest that Sox9(+)EpCAM(-) cells maintaining biphenotypic status can establish cholangiocyte-type polarity. Interestingly, we found that some of the Sox9(+) cells surrounded luminal spaces in DDC-injured liver while they expressed HNF4α. Taken together, we consider that in addition to converting to cholangiocyte-like cells, Sox9(+)EpCAM(-) cells provide luminal space near expanded ductular structures to prevent deterioration of the injuries and potentially supply new hepatocytes to repair damaged tissues.
Collapse
Affiliation(s)
- Naoki Tanimizu
- From the Department of Tissue Development and Regeneration, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556
| | | | | | | | | |
Collapse
|
31
|
Szalinski CM, Labilloy A, Bruns JR, Weisz OA. VAMP7 modulates ciliary biogenesis in kidney cells. PLoS One 2014; 9:e86425. [PMID: 24466086 PMCID: PMC3899255 DOI: 10.1371/journal.pone.0086425] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 12/12/2013] [Indexed: 12/02/2022] Open
Abstract
Epithelial cells elaborate specialized domains that have distinct protein and lipid compositions, including the apical and basolateral surfaces and primary cilia. Maintaining the identity of these domains is required for proper cell function, and requires the efficient and selective SNARE-mediated fusion of vesicles containing newly synthesized and recycling proteins with the proper target membrane. Multiple pathways exist to deliver newly synthesized proteins to the apical surface of kidney cells, and the post-Golgi SNAREs, or VAMPs, involved in these distinct pathways have not been identified. VAMP7 has been implicated in apical protein delivery in other cell types, and we hypothesized that this SNARE would have differential effects on the trafficking of apical proteins known to take distinct routes to the apical surface in kidney cells. VAMP7 expressed in polarized Madin Darby canine kidney cells colocalized primarily with LAMP2-positive compartments, and siRNA-mediated knockdown modulated lysosome size, consistent with the known function of VAMP7 in lysosomal delivery. Surprisingly, VAMP7 knockdown had no effect on apical delivery of numerous cargoes tested, but did decrease the length and frequency of primary cilia. Additionally, VAMP7 knockdown disrupted cystogenesis in cells grown in a three-dimensional basement membrane matrix. The effects of VAMP7 depletion on ciliogenesis and cystogenesis are not directly linked to the disruption of lysosomal function, as cilia lengths and cyst morphology were unaffected in an MDCK lysosomal storage disorder model. Together, our data suggest that VAMP7 plays an essential role in ciliogenesis and lumen formation. To our knowledge, this is the first study implicating an R-SNARE in ciliogenesis and cystogenesis.
Collapse
Affiliation(s)
- Christina M. Szalinski
- Renal Electrolyte Division, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
| | - Anatália Labilloy
- Renal Electrolyte Division, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
- Ciência sem Fronteiras, CNPq, Brasilia, Brazil
| | - Jennifer R. Bruns
- Renal Electrolyte Division, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
| | - Ora A. Weisz
- Renal Electrolyte Division, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
32
|
Brochetta C, Suzuki R, Vita F, Soranzo MR, Claver J, Madjene LC, Attout T, Vitte J, Varin-Blank N, Zabucchi G, Rivera J, Blank U. Munc18-2 and syntaxin 3 control distinct essential steps in mast cell degranulation. THE JOURNAL OF IMMUNOLOGY 2013; 192:41-51. [PMID: 24323579 DOI: 10.4049/jimmunol.1301277] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mast cell degranulation requires N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) and mammalian uncoordinated18 (Munc18) fusion accessory proteins for membrane fusion. However, it is still unknown how their interaction supports fusion. In this study, we found that small interfering RNA-mediated silencing of the isoform Munc18-2 in mast cells inhibits cytoplasmic secretory granule (SG) release but not CCL2 chemokine secretion. Silencing of its SNARE-binding partner syntaxin 3 (STX3) also markedly inhibited degranulation, whereas combined knockdown produced an additive inhibitory effect. Strikingly, while Munc18-2 silencing impaired SG translocation, silencing of STX3 inhibited fusion, demonstrating unique roles of each protein. Immunogold studies showed that both Munc18-2 and STX3 are located on the granule surface, but also within the granule matrix and in small nocodazole-sensitive clusters of the cytoskeletal meshwork surrounding SG. After stimulation, clusters containing both effectors were detected at fusion sites. In resting cells, Munc18-2, but not STX3, interacted with tubulin. This interaction was sensitive to nocodazole treatment and decreased after stimulation. Our results indicate that Munc18-2 dynamically couples the membrane fusion machinery to the microtubule cytoskeleton and demonstrate that Munc18-2 and STX3 perform distinct, but complementary, functions to support, respectively, SG translocation and membrane fusion in mast cells.
Collapse
Affiliation(s)
- Cristiana Brochetta
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Ryo Suzuki
- Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892
| | - Francesca Vita
- Department of Life Sciences Department of Physiology and Pathology, University of Trieste, Italy
| | - Maria Rosa Soranzo
- Department of Life Sciences Department of Physiology and Pathology, University of Trieste, Italy
| | - Julien Claver
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Lydia Celia Madjene
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Tarik Attout
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Joana Vitte
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Nadine Varin-Blank
- Inserm U978, 93000 Bobigny, France.,Laboratoire d'excellence "Inflamex," Unité de Formation et de Recherche Santé-Médecine-Biologie Humaine, 93000 Bobigny, France
| | - Giuliano Zabucchi
- Department of Life Sciences Department of Physiology and Pathology, University of Trieste, Italy
| | - Juan Rivera
- Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892
| | - Ulrich Blank
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| |
Collapse
|
33
|
Abstract
Hepatocytes, like other epithelia, are situated at the interface between the organism's exterior and the underlying internal milieu and organize the vectorial exchange of macromolecules between these two spaces. To mediate this function, epithelial cells, including hepatocytes, are polarized with distinct luminal domains that are separated by tight junctions from lateral domains engaged in cell-cell adhesion and from basal domains that interact with the underlying extracellular matrix. Despite these universal principles, hepatocytes distinguish themselves from other nonstriated epithelia by their multipolar organization. Each hepatocyte participates in multiple, narrow lumina, the bile canaliculi, and has multiple basal surfaces that face the endothelial lining. Hepatocytes also differ in the mechanism of luminal protein trafficking from other epithelia studied. They lack polarized protein secretion to the luminal domain and target single-spanning and glycosylphosphatidylinositol-anchored bile canalicular membrane proteins via transcytosis from the basolateral domain. We compare this unique hepatic polarity phenotype with that of the more common columnar epithelial organization and review our current knowledge of the signaling mechanisms and the organization of polarized protein trafficking that govern the establishment and maintenance of hepatic polarity. The serine/threonine kinase LKB1, which is activated by the bile acid taurocholate and, in turn, activates adenosine monophosphate kinase-related kinases including AMPK1/2 and Par1 paralogues has emerged as a key determinant of hepatic polarity. We propose that the absence of a hepatocyte basal lamina and differences in cell-cell adhesion signaling that determine the positioning of tight junctions are two crucial determinants for the distinct hepatic and columnar polarity phenotypes.
Collapse
Affiliation(s)
- Aleksandr Treyer
- Albert Einstein College of Medicine, Department of Developmental and Molecular Biology, Bronx, New York, USA
| | | |
Collapse
|
34
|
Hendricks MR, Bomberger JM. Who's really in control: microbial regulation of protein trafficking in the epithelium. Am J Physiol Cell Physiol 2013; 306:C187-97. [PMID: 24133062 DOI: 10.1152/ajpcell.00277.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Due to evolutionary pressure, there are many complex interactions at the interface between pathogens and eukaryotic host cells wherein host cells attempt to clear invading microorganisms and pathogens counter these mechanisms to colonize and invade host tissues. One striking observation from studies focused on this interface is that pathogens have multiple mechanisms to modulate and disrupt normal cellular physiology to establish replication niches and avoid clearance. The precision by which pathogens exert their effects on host cells makes them excellent tools to answer questions about cell physiology of eukaryotic cells. Furthermore, an understanding of these mechanisms at the host-pathogen interface will benefit our understanding of how pathogens cause disease. In this review, we describe a few examples of how pathogens disrupt normal cellular physiology and protein trafficking at epithelial cell barriers to underscore how pathogens modulate cellular processes to cause disease and how this knowledge has been utilized to learn about cellular physiology.
Collapse
Affiliation(s)
- Matthew R Hendricks
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | | |
Collapse
|
35
|
Extracellular syntaxin4 triggers the differentiation program in teratocarcinoma F9 cells that impacts cell adhesion properties. Cell Tissue Res 2013; 354:581-91. [DOI: 10.1007/s00441-013-1680-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 06/13/2013] [Indexed: 12/24/2022]
|
36
|
|
37
|
Abstract
Epithelial cells have an apical-basolateral axis of polarity, which is required for epithelial functions including barrier formation, vectorial ion transport and sensory perception. Here we review what is known about the sorting signals, machineries and pathways that maintain this asymmetry, and how polarity proteins interface with membrane-trafficking pathways to generate membrane domains de novo. It is becoming apparent that membrane traffic does not simply reinforce polarity, but is critical for the generation of cortical epithelial cell asymmetry.
Collapse
|
38
|
Shono M, Yoshioka R, Chatani Y, Hirai Y. Ectopic Expression of Syntaxin3 Affects Behaviors of B16 Melanoma by Controlling Actin Dynamics. Cell Struct Funct 2013; 38:97-107. [DOI: 10.1247/csf.12032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Michiko Shono
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University
| | - Ryosuke Yoshioka
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University
| | - Yoshimitsu Chatani
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University
| | - Yohei Hirai
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University
| |
Collapse
|
39
|
Masaki T. Polarization and myelination in myelinating glia. ISRN NEUROLOGY 2012; 2012:769412. [PMID: 23326681 PMCID: PMC3544266 DOI: 10.5402/2012/769412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/13/2012] [Indexed: 01/13/2023]
Abstract
Myelinating glia, oligodendrocytes in central nervous system and Schwann cells in peripheral nervous system, form myelin sheath, a multilayered membrane system around axons enabling salutatory nerve impulse conduction and maintaining axonal integrity. Myelin sheath is a polarized structure localized in the axonal side and therefore is supposed to be formed based on the preceding polarization of myelinating glia. Thus, myelination process is closely associated with polarization of myelinating glia. However, cell polarization has been less extensively studied in myelinating glia than other cell types such as epithelial cells. The ultimate goal of this paper is to provide insights for the field of myelination research by applying the information obtained in polarity study in other cell types, especially epithelial cells, to cell polarization of myelinating glia. Thus, in this paper, the main aspects of cell polarization study in general are summarized. Then, they will be compared with polarization in oligodendrocytes. Finally, the achievements obtained in polarization study for epithelial cells, oligodendrocytes, and other types of cells will be translated into polarization/myelination process by Schwann cells. Then, based on this model, the perspectives in the study of Schwann cell polarization/myelination will be discussed.
Collapse
Affiliation(s)
- Toshihiro Masaki
- Department of Medical Science, Teikyo University of Science, 2-2-1 Senju-Sakuragi, Adachi-ku, Tokyo 120-0045, Japan
| |
Collapse
|
40
|
Naydenov NG, Brown B, Harris G, Dohn MR, Morales VM, Baranwal S, Reynolds AB, Ivanov AI. A membrane fusion protein αSNAP is a novel regulator of epithelial apical junctions. PLoS One 2012; 7:e34320. [PMID: 22485163 PMCID: PMC3317505 DOI: 10.1371/journal.pone.0034320] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/28/2012] [Indexed: 12/31/2022] Open
Abstract
Tight junctions (TJs) and adherens junctions (AJs) are key determinants of the structure and permeability of epithelial barriers. Although exocytic delivery to the cell surface is crucial for junctional assembly, little is known about the mechanisms controlling TJ and AJ exocytosis. This study was aimed at investigating whether a key mediator of exocytosis, soluble N-ethylmaleimide sensitive factor (NSF) attachment protein alpha (αSNAP), regulates epithelial junctions. αSNAP was enriched at apical junctions in SK-CO15 and T84 colonic epithelial cells and in normal human intestinal mucosa. siRNA-mediated knockdown of αSNAP inhibited AJ/TJ assembly and establishment of the paracellular barrier in SK-CO15 cells, which was accompanied by a significant down-regulation of p120-catenin and E-cadherin expression. A selective depletion of p120 catenin effectively disrupted AJ and TJ structure and compromised the epithelial barrier. However, overexpression of p120 catenin did not rescue the defects of junctional structure and permeability caused by αSNAP knockdown thereby suggesting the involvement of additional mechanisms. Such mechanisms did not depend on NSF functions or induction of cell death, but were associated with disruption of the Golgi complex and down-regulation of a Golgi-associated guanidine nucleotide exchange factor, GBF1. These findings suggest novel roles for αSNAP in promoting the formation of epithelial AJs and TJs by controlling Golgi-dependent expression and trafficking of junctional proteins.
Collapse
Affiliation(s)
- Nayden G. Naydenov
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Bryan Brown
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Gianni Harris
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Michael R. Dohn
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Victor M. Morales
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Somesh Baranwal
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Albert B. Reynolds
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Andrei I. Ivanov
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
- * E-mail:
| |
Collapse
|
41
|
CPEB-mediated ZO-1 mRNA localization is required for epithelial tight-junction assembly and cell polarity. Nat Commun 2012; 3:675. [PMID: 22334078 PMCID: PMC4334452 DOI: 10.1038/ncomms1678] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 01/11/2012] [Indexed: 01/06/2023] Open
Abstract
CPEB is a translational regulatory sequence-specific RNA-binding protein that controls germ cell development. Here we show that CPEB heterozygous female mice are fertile but contain disorganized mammary epithelial cells, in which zonal occludens-1 and claudin-3, apical tight-junction proteins, are mislocalized. CPEB depletion from mammary epithelial cells disrupts zonal occludens-1 apical localization and tight-junction distribution; conversely, ectopic expression of CPEB enhances zonal occludens-1 localization. CPEB and zonal occludens-1 mRNA are co-localized apically and zonal occludens-1 3' untranslated region-binding sites for CPEB are necessary for RNA localization. In a three-dimensional culture system that models lumen-containing mammary ducts, depletion of CPEB or zonal occludens-1 impairs central cavity formation, indicating a loss of cell polarity. Cavity formation in zonal occludens-1-depleted cells is rescued when they are transduced with zonal occludens-1 mRNA containing, but not lacking, CPEB-binding sites. Our data demonstrate that CPEB-mediated zonal occludens-1 mRNA localization is essential for tight-junction assembly and mammary epithelial cell polarity.
Collapse
|
42
|
Touihri S, Knöll C, Stierhof YD, Müller I, Mayer U, Jürgens G. Functional anatomy of the Arabidopsis cytokinesis-specific syntaxin KNOLLE. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:755-64. [PMID: 21838778 DOI: 10.1111/j.1365-313x.2011.04736.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In plant cytokinesis, Golgi/trans-Golgi network-derived vesicles are targeted to the plane of cell division where they fuse with one another to form the partitioning membrane (cell plate). This membrane fusion requires a specialised syntaxin (Qa-SNARE), named KNOLLE in Arabidopsis. KNOLLE is only made during the M-phase of the cell cycle, targeted to the plane of cell division and degraded in the vacuole at the end of cytokinesis. To identify the parts of KNOLLE required for proper targeting and function in membrane fusion, we generated chimeric syntaxins comprising complementary fragments from KNOLLE and MVB-localized PEP12 (SYP21). Surprisingly, targeting of the chimeric protein was not specified by the C-terminal membrane anchor. Rather the N-terminal region including helix Ha and the adjacent linker to helix Hb appeared to played a critical role. However, deletion of this N-terminal fragment from KNOLLE (KN(Δ1-82) ) had the same effect as its presence in the chimeric protein (KN(1-82) -PEP12(64-279) ), suggesting that targeting to the plane of cell division occurs by default, i.e. when no sorting signal would target the syntaxin to a specific endomembrane compartment. Once the full-length syntaxin accumulated at the plane of division, phenotypic rescue of the knolle mutant only required the SNARE domain plus the adjacent linker connecting helix Hc to the SNARE domain from KNOLLE. Our results suggest that targeting of syntaxin to the plane of cell division occurs without active sorting, whereas syntaxin-mediated membrane fusion requires sequence-specific features.
Collapse
Affiliation(s)
- Sonja Touihri
- Zentrum für Molekularbiologie der Pflanzen, Entwicklungsgenetik, University of Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany
| | | | | | | | | | | |
Collapse
|
43
|
Karan S, Tam BM, Moritz OL, Baehr W. Targeting of mouse guanylate cyclase 1 (Gucy2e) to Xenopus laevis rod outer segments. Vision Res 2011; 51:2304-11. [PMID: 21945483 DOI: 10.1016/j.visres.2011.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 09/02/2011] [Accepted: 09/03/2011] [Indexed: 11/18/2022]
Abstract
Photoreceptor guanylate cyclase (GC1) is a transmembrane protein and responsible for synthesis of cGMP, the secondary messenger of phototransduction. It consists of an extracellular domain, a single transmembrane domain, and an intracellular domain. It is unknown how GC1 targets to the outer segments where it resides. To identify a putative GC1 targeting signal, we generated a series of peripheral membrane and transmembrane constructs encoding extracellular and intracellular mouse GC1 fragments fused to EGFP. The constructs were expressed in Xenopus laevis rod photoreceptors under the control of the rhodopsin promoter. We examined the localization of GFP-GC1 fusion proteins containing the complete GC1 sequence, or partial GC1 sequences, which were membrane-associated via either the GC1 transmembrane domain or the rhodopsin C-terminal palmitoyl chains. Full-length GFP-GC1 targeted to the rod outer segment disk rims. As a group, fusion proteins containing the entire cytoplasmic domain of GC1 targeted to the OS, whereas other fusion proteins containing portions of the cytoplasmic or the extracellular domains did not. We conclude that GC1 likely has no single linear peptide-based OS targeting signal. Our results suggest targeting is due to either multiple weak signals in the cytoplasmic domain of GC1, or co-transport to the OS with an accessory protein.
Collapse
Affiliation(s)
- Sukanya Karan
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | | | | | | |
Collapse
|
44
|
Abstract
The asymmetric polarization of cells allows specialized functions to be performed at discrete subcellular locales. Spatiotemporal coordination of polarization between groups of cells allowed the evolution of metazoa. For instance, coordinated apical-basal polarization of epithelial and endothelial cells allows transport of nutrients and metabolites across cell barriers and tissue microenvironments. The defining feature of such tissues is the presence of a central, interconnected luminal network. Although tubular networks are present in seemingly different organ systems, such as the kidney, lung, and blood vessels, common underlying principles govern their formation. Recent studies using in vivo and in vitro models of lumen formation have shed new light on the molecular networks regulating this fundamental process. We here discuss progress in understanding common design principles underpinning de novo lumen formation and expansion.
Collapse
|
45
|
Reales E, Sharma N, Low SH, Fölsch H, Weimbs T. Basolateral sorting of syntaxin 4 is dependent on its N-terminal domain and the AP1B clathrin adaptor, and required for the epithelial cell polarity. PLoS One 2011; 6:e21181. [PMID: 21698262 PMCID: PMC3115984 DOI: 10.1371/journal.pone.0021181] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 05/22/2011] [Indexed: 12/14/2022] Open
Abstract
Generation of epithelial cell polarity requires mechanisms to sort plasma membrane proteins to the apical and basolateral domains. Sorting involves incorporation into specific vesicular carriers and subsequent fusion to the correct target membranes mediated by specific SNARE proteins. In polarized epithelial cells, the SNARE protein syntaxin 4 localizes exclusively to the basolateral plasma membrane and plays an important role in basolateral trafficking pathways. However, the mechanism of basolateral targeting of syntaxin 4 itself has remained poorly understood. Here we show that newly synthesized syntaxin 4 is directly targeted to the basolateral plasma membrane in polarized Madin-Darby canine kidney (MDCK) cells. Basolateral targeting depends on a signal that is centered around residues 24–29 in the N-terminal domain of syntaxin 4. Furthermore, basolateral targeting of syntaxin 4 is dependent on the epithelial cell-specific clathrin adaptor AP1B. Disruption of the basolateral targeting signal of syntaxin 4 leads to non-polarized delivery to both the apical and basolateral surface, as well as partial intercellular retention in the trans-Golgi network. Importantly, disruption of the basolateral targeting signal of syntaxin 4 leads to the inability of MDCK cells to establish a polarized morphology which suggests that restriction of syntaxin 4 to the basolateral domain is required for epithelial cell polarity.
Collapse
Affiliation(s)
- Elena Reales
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Nikunj Sharma
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Seng Hui Low
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Heike Fölsch
- Department of Cell and Molecular Biology, Northwestern University, Chicago, Illinois, United States of America
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
- * E-mail:
| |
Collapse
|
46
|
Abstract
CNS myelination by oligodendrocytes requires directed transport of myelin membrane components and a timely and spatially controlled membrane expansion. In this study, we show the functional involvement of the R-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (R-SNARE) proteins VAMP3/cellubrevin and VAMP7/TI-VAMP in myelin membrane trafficking. VAMP3 and VAMP7 colocalize with the major myelin proteolipid protein (PLP) in recycling endosomes and late endosomes/lysosomes, respectively. Interference with VAMP3 or VAMP7 function using small interfering RNA-mediated silencing and exogenous expression of dominant-negative proteins diminished transport of PLP to the oligodendroglial cell surface. In addition, the association of PLP with myelin-like membranes produced by oligodendrocytes cocultured with cortical neurons was reduced. We furthermore identified Syntaxin-4 and Syntaxin-3 as prime acceptor Q-SNAREs of VAMP3 and VAMP7, respectively. Analysis of VAMP3-deficient mice revealed no myelination defects. Interestingly, AP-3δ-deficient mocha mice, which suffer from impaired secretion of lysosome-related organelles and missorting of VAMP7, exhibit a mild dysmyelination characterized by reduced levels of select myelin proteins, including PLP. We conclude that PLP reaches the cell surface via at least two trafficking pathways with distinct regulations: (1) VAMP3 mediates fusion of recycling endosome-derived vesicles with the oligodendroglial plasma membrane in the course of the secretory pathway; (2) VAMP7 controls exocytosis of PLP from late endosomal/lysosomal organelles as part of a transcytosis pathway. Our in vivo data suggest that exocytosis of lysosome-related organelles controlled by VAMP7 contributes to myelin biogenesis by delivering cargo to the myelin membrane.
Collapse
|
47
|
Torres J, Funk HM, Zegers MMP, ter Beest MBA. The syntaxin 4 N terminus regulates its basolateral targeting by munc18c-dependent and -independent mechanisms. J Biol Chem 2011; 286:10834-46. [PMID: 21278252 DOI: 10.1074/jbc.m110.186668] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
To generate and maintain epithelial cell polarity, specific sorting of proteins into vesicles destined for the apical and basolateral domain is required. Syntaxin 3 and 4 are apical and basolateral SNARE proteins important for the specificity of vesicle fusion at the apical and basolateral plasma membrane domains, respectively, but how these proteins are specifically targeted to these domains themselves is unclear. Munc18/SM proteins are potential regulators of this process. Like syntaxins, they are crucial for exocytosis and vesicle fusion. However, how munc18c and syntaxin 4 regulate the function of each other is unclear. Here, we investigated the requirement of syntaxin 4 in the delivery of basolateral membrane and secretory proteins, the basolateral targeting of syntaxin 4, and the role of munc18c in this targeting. Depletion of syntaxin 4 resulted in significant reduction of basolateral targeting, suggesting no compensation by other syntaxin forms. Mutational analysis identified amino acids Leu-25 and to a lesser extent Val-26 as essential for correct localization of syntaxin 4. Recently, it was shown that the N-terminal peptide of syntaxin 4 is involved in binding to munc18c. A mutation in this region that affects munc18c binding shows that munc18c binding is required for stabilization of syntaxin 4 at the plasma membrane but not for its correct targeting. We conclude that the N terminus serves two functions in membrane targeting. First, it harbors the sorting motif, which targets syntaxin 4 basolaterally in a munc18c-independent manner and second, it allows for munc18c binding, which stabilizes the protein in a munc18c-dependent manner.
Collapse
Affiliation(s)
- Jacqueline Torres
- Department of Surgery, The University of Chicago, Chicago, Illinois 60637, USA
| | | | | | | |
Collapse
|
48
|
Nelson WJ. Remodeling epithelial cell organization: transitions between front-rear and apical-basal polarity. Cold Spring Harb Perspect Biol 2010; 1:a000513. [PMID: 20066074 DOI: 10.1101/cshperspect.a000513] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Polarized epithelial cells have a distinctive apical-basal axis of polarity for vectorial transport of ions and solutes across the epithelium. In contrast, migratory mesenchymal cells have a front-rear axis of polarity. During development, mesenchymal cells convert to epithelia by coalescing into aggregates that undergo epithelial differentiation. Signaling networks and protein complexes comprising Rho family GTPases, polarity complexes (Crumbs, PAR, and Scribble), and their downstream effectors, including the cytoskeleton and the endocytic and exocytic vesicle trafficking pathways, together regulate the distributions of plasma membrane and cytoskeletal proteins between front-rear and apical-basal polarity. The challenge is to understand how these regulators and effectors are adapted to regulate symmetry breaking processes that generate cell polarities that are specialized for different cellular activities and functions.
Collapse
Affiliation(s)
- W James Nelson
- Department of Biology, Stanford University, Stanford, California 94305, USA.
| |
Collapse
|
49
|
Collaco A, Marathe J, Kohnke H, Kravstov D, Ameen N. Syntaxin 3 is necessary for cAMP- and cGMP-regulated exocytosis of CFTR: implications for enterotoxigenic diarrhea. Am J Physiol Cell Physiol 2010; 299:C1450-60. [PMID: 20844248 DOI: 10.1152/ajpcell.00029.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Enterotoxins elaborated by Vibrio cholerae and Escherichia coli cannot elicit fluid secretion in the absence of functional cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels. After enterotoxin exposure, CFTR channels are rapidly recruited from endosomes and undergo exocytic insertion into the apical plasma membrane of enterocytes to increase the number of channels on the cell surface by at least fourfold. However, the molecular machinery that orchestrates exocytic insertion of CFTR into the plasma membrane is largely unknown. The present study used immunofluorescence, immunoblotting, surface biotinylation, glutathione S-transferase (GST) pulldown assays, and immunoprecipitation to identify components of the exocytic soluble N-ethylmaleimide (NEM)-sensitive factor attachment receptor (SNARE) vesicle fusion machinery in cyclic nucleotide-activated exocytosis of CFTR in rat jejunum and polarized intestinal Caco-2(BB)e cells. Syntaxin 3, an intestine-specific SNARE, colocalized with CFTR on the apical domain of enterocytes in rat jejunum and polarized Caco-2(BB)e cells. Coimmunoprecipitation and GST binding studies confirmed that syntaxin 3 interacts with CFTR in vivo. Moreover, heat-stable enterotoxin (STa) activated exocytosis of both CFTR and syntaxin 3 to the surface of rat jejunum. Silencing of syntaxin 3 by short hairpin RNA (shRNA) interference abrogated cyclic nucleotide-stimulated exocytosis of CFTR in cells. These observations reveal a new and important role for syntaxin 3 in the pathophysiology of enterotoxin-elicited diarrhea.
Collapse
Affiliation(s)
- Anne Collaco
- Department of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | | | | | | | | |
Collapse
|
50
|
An ESRP-regulated splicing programme is abrogated during the epithelial-mesenchymal transition. EMBO J 2010; 29:3286-300. [PMID: 20711167 DOI: 10.1038/emboj.2010.195] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2010] [Accepted: 07/20/2010] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing achieves coordinated changes in post-transcriptional gene expression programmes through the activities of diverse RNA-binding proteins. Epithelial splicing regulatory proteins 1 and 2 (ESRP1 and ESRP2) are cell-type-specific regulators of transcripts that switch splicing during the epithelial-mesenchymal transition (EMT). To define a comprehensive programme of alternative splicing that is regulated during the EMT, we identified an extensive ESRP-regulated splicing network of hundreds of alternative splicing events within numerous genes with functions in cell-cell adhesion, polarity, and migration. Loss of this global ESRP-regulated epithelial splicing programme induces the phenotypic changes in cell morphology that are observed during the EMT. Components of this splicing signature provide novel molecular markers that can be used to characterize the EMT. Bioinformatics and experimental approaches revealed a high-affinity ESRP-binding motif and a predictive RNA map that governs their activity. This work establishes the ESRPs as coordinators of a complex alternative splicing network that adds an important post-transcriptional layer to the changes in gene expression that underlie epithelial-mesenchymal transitions during development and disease.
Collapse
|