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Fischer AAM, Schatz L, Baaske J, Römer W, Weber W, Thuenauer R. Real-time monitoring of cell surface protein arrival with split luciferases. Traffic 2023; 24:453-462. [PMID: 37403269 DOI: 10.1111/tra.12908] [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: 02/27/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/06/2023]
Abstract
Each cell in a multicellular organism permanently adjusts the concentration of its cell surface proteins. In particular, epithelial cells tightly control the number of carriers, transporters and cell adhesion proteins at their plasma membrane. However, sensitively measuring the cell surface concentration of a particular protein of interest in live cells and in real time represents a considerable challenge. Here, we introduce a novel approach based on split luciferases, which uses one luciferase fragment as a tag on the protein of interest and the second fragment as a supplement to the extracellular medium. Once the protein of interest arrives at the cell surface, the luciferase fragments complement and generate luminescence. We compared the performance of split Gaussia luciferase and split Nanoluciferase by using a system to synchronize biosynthetic trafficking with conditional aggregation domains. The best results were achieved with split Nanoluciferase, for which luminescence increased more than 6000-fold upon recombination. Furthermore, we showed that our approach can separately detect and quantify the arrival of membrane proteins at the apical and basolateral plasma membrane in single polarized epithelial cells by detecting the luminescence signals with a microscope, thus opening novel avenues for characterizing the variations in trafficking in individual epithelial cells.
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Affiliation(s)
- Alexandra A M Fischer
- Signaling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Larissa Schatz
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Technology Platform Light Microscopy, University of Hamburg, Hamburg, Germany
| | - Julia Baaske
- Signaling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Winfried Römer
- Signaling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wilfried Weber
- Signaling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany
| | - Roland Thuenauer
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Technology Platform Light Microscopy, University of Hamburg, Hamburg, Germany
- Technology Platform Microscopy and Image Analysis (TP MIA), Leibniz Institute of Virology (LIV), Hamburg, Germany
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2
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de Caestecker C, Macara IG. A Size Filter Regulates Apical Protein Sorting. RESEARCH SQUARE 2023:rs.3.rs-3210598. [PMID: 37577471 PMCID: PMC10418535 DOI: 10.21203/rs.3.rs-3210598/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Despite decades of research, apical sorting of epithelial membrane proteins remains incompletely understood. We noted that apical cytoplasmic domains are smaller than those of basolateral proteins; however, the reason for this discrepancy is unknown. We investigated whether a size barrier at the trans-Golgi network (TGN) might hinder apical sorting of proteins with large cytoplasmic tails. We focused on Crb3 and Ace2 as representative apical proteins with short cytoplasmic tails. By incorporating a streptavidin-binding peptide, these proteins can be trapped in the endoplasmic reticulum (ER) until addition of biotin, which triggers synchronous release to the Golgi and subsequent transport to the apical cortex. Strikingly, departure from the Golgi could be significantly delayed simply by increasing cytoplasmic bulk. Moreover, large and small Crb3 segregated into spatially distinct Golgi regions as detected by super resolution imaging. Biologically, Crb3 forms a complex through its cytoplasmic tail with the Pals1 protein, which could also delay departure, but although associated at the ER and Golgi, we found that Pals1 disassociates prior to Crb3 departure. Notably, a non-dissociable mutant Pals1 hampers the exit of Crb3. We conclude that an unexpected mechanism involving a size filter at the TGN facilitates apical sorting of proteins with small cytoplasmic domains and that timely release of Pals1, to reduce cytoplasmic domain size, is essential for the normal kinetics of Crb3 sorting.
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Affiliation(s)
- Christian de Caestecker
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine; Nashville TN 37205, U.S
| | - Ian G. Macara
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine; Nashville TN 37205, U.S
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3
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Koetemann A, Wollscheid B. Apicobasal Surfaceome Architecture Encodes for Polarized Epithelial Functionality and Depends on Tumor Suppressor PTEN. Int J Mol Sci 2022; 23:ijms232416193. [PMID: 36555834 PMCID: PMC9788433 DOI: 10.3390/ijms232416193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
The loss of apicobasal polarity during the epithelial-to-mesenchymal transition (EMT) is a hallmark of cancer and metastasis. The key feature of this polarity in epithelial cells is the subdivision of the plasma membrane into apical and basolateral domains, with each orchestrating specific intra- and extracellular functions. Epithelial transport and signaling capacities are thought to be determined largely by the quality, quantity, and nanoscale organization of proteins residing in these membrane domains, the apicobasal surfaceomes. Despite its implications for cancer, drug uptake, and infection, our current knowledge of how the polarized surfaceome is organized and maintained is limited. Here, we used chemoproteomic surfaceome scanning to establish proteotype maps of apicobasal surfaceomes and reveal quantitative distributions of, i.e., surface proteases, phosphatases, and tetraspanins as potential key regulators of polarized cell functionality. We show further that the tumor suppressor PTEN regulates polarized surfaceome architecture and uncover a potential role in collective cell migration. Our differential surfaceome analysis provides a molecular framework to elucidate polarized protein networks regulating epithelial functions and PTEN-associated cancer progression.
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Affiliation(s)
- Anika Koetemann
- Department of Health Sciences and Technology, Institute of Translational Medicine, ETH Zurich, 8049 Zurich, Switzerland
- Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
| | - Bernd Wollscheid
- Department of Health Sciences and Technology, Institute of Translational Medicine, ETH Zurich, 8049 Zurich, Switzerland
- Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
- Correspondence:
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4
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Francis CR, Kushner EJ. Trafficking in blood vessel development. Angiogenesis 2022; 25:291-305. [PMID: 35449244 PMCID: PMC9249721 DOI: 10.1007/s10456-022-09838-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/03/2022] [Indexed: 02/17/2023]
Abstract
Blood vessels demonstrate a multitude of complex signaling programs that work in concert to produce functional vasculature networks during development. A known, but less widely studied, area of endothelial cell regulation is vesicular trafficking, also termed sorting. After moving through the Golgi apparatus, proteins are shuttled to organelles, plugged into membranes, recycled, or degraded depending on the internal and extrinsic cues. A snapshot of these protein-sorting systems can be viewed as a trafficking signature that is not only unique to endothelial tissue, but critically important for blood vessel form and function. In this review, we will cover how vesicular trafficking impacts various aspects of angiogenesis, such as sprouting, lumen formation, vessel stabilization, and secretion, emphasizing the role of Rab GTPase family members and their various effectors.
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Affiliation(s)
- Caitlin R Francis
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA
| | - Erich J Kushner
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA.
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5
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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.
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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:
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6
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Role of Glycans on Key Cell Surface Receptors That Regulate Cell Proliferation and Cell Death. Cells 2021; 10:cells10051252. [PMID: 34069424 PMCID: PMC8159107 DOI: 10.3390/cells10051252] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
Cells undergo proliferation and apoptosis, migration and differentiation via a number of cell surface receptors, most of which are heavily glycosylated. This review discusses receptor glycosylation and the known roles of glycans on the functions of receptors expressed in diverse cell types. We included growth factor receptors that have an intracellular tyrosine kinase domain, growth factor receptors that have a serine/threonine kinase domain, and cell-death-inducing receptors. N- and O-glycans have a wide range of functions including roles in receptor conformation, ligand binding, oligomerization, and activation of signaling cascades. A better understanding of these functions will enable control of cell survival and cell death in diseases such as cancer and in immune responses.
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7
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Levic DS, Ryan S, Marjoram L, Honeycutt J, Bagwell J, Bagnat M. Distinct roles for luminal acidification in apical protein sorting and trafficking in zebrafish. J Cell Biol 2020; 219:133852. [PMID: 32328632 PMCID: PMC7147097 DOI: 10.1083/jcb.201908225] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/20/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
Epithelial cell physiology critically depends on the asymmetric distribution of channels and transporters. However, the mechanisms targeting membrane proteins to the apical surface are still poorly understood. Here, we performed a visual forward genetic screen in the zebrafish intestine and identified mutants with defective apical targeting of membrane proteins. One of these mutants, affecting the vacuolar H+-ATPase gene atp6ap1b, revealed specific requirements for luminal acidification in apical, but not basolateral, membrane protein sorting and transport. Using a low temperature block assay combined with genetic and pharmacologic perturbation of luminal pH, we monitored transport of newly synthesized membrane proteins from the TGN to apical membrane in live zebrafish. We show that vacuolar H+-ATPase activity regulates sorting of O-glycosylated proteins at the TGN, as well as Rab8-dependent post-Golgi trafficking of different classes of apical membrane proteins. Thus, luminal acidification plays distinct and specific roles in apical membrane biogenesis.
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Affiliation(s)
| | - Sean Ryan
- Department of Cell Biology, Duke University, Durham, NC
| | | | | | | | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC
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8
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Fast-diffusing p75 NTR monomers support apoptosis and growth cone collapse by neurotrophin ligands. Proc Natl Acad Sci U S A 2019; 116:21563-21572. [PMID: 31515449 PMCID: PMC6815156 DOI: 10.1073/pnas.1902790116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neurotrophins (NTs) are homodimeric growth factors displaying fundamental roles in the nervous system. Their activity stems from binding and activation of 3 different receptor types in nervous cell membranes. The p75 NT receptor (p75NTR) was the first to be discovered in 1986; nevertheless, for the numerous structural and functional facets so far reported, its activation mechanisms have remained elusive. Here, we demonstrate that its pleiotropic functions are regulated by different redistributions of the receptors, which crucially depend on the available NT and on the involved subcellular compartment but are unrelated to its oligomerization state. Single-particle studies proved receptors to be monomers with a fast-diffusive behavior in the membrane with, at most, transient self-interactions on the millisecond time scale. The p75 neurotrophin (NT) receptor (p75NTR) plays a crucial role in balancing survival-versus-death decisions in the nervous system. Yet, despite 2 decades of structural and biochemical studies, a comprehensive, accepted model for p75NTR activation by NT ligands is still missing. Here, we present a single-molecule study of membrane p75NTR in living cells, demonstrating that the vast majority of receptors are monomers before and after NT activation. Interestingly, the stoichiometry and diffusion properties of the wild-type (wt) p75NTR are almost identical to those of a receptor mutant lacking residues previously believed to induce oligomerization. The wt p75NTR and mutated (mut) p75NTR differ in their partitioning in cholesterol-rich membrane regions upon nerve growth factor (NGF) stimulation: We argue that this is the origin of the ability of wt p75NTR , but not of mut p75NTR, to mediate immature NT (proNT)-induced apoptosis. Both p75NTR forms support proNT-induced growth cone retraction: We show that receptor surface accumulation is the driving force for cone collapse. Overall, our data unveil the multifaceted activity of the p75NTR monomer and let us provide a coherent interpretative frame of existing conflicting data in the literature.
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9
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Cutrale F, Rodriguez D, Hortigüela V, Chiu CL, Otterstrom J, Mieruszynski S, Seriola A, Larrañaga E, Raya A, Lakadamyali M, Fraser SE, Martinez E, Ojosnegros S. Using enhanced number and brightness to measure protein oligomerization dynamics in live cells. Nat Protoc 2019; 14:616-638. [DOI: 10.1038/s41596-018-0111-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Yin X, Kang JH, Andrianifahanana M, Wang Y, Jung MY, Hernandez DM, Leof EB. Basolateral delivery of the type I transforming growth factor beta receptor is mediated by a dominant-acting cytoplasmic motif. Mol Biol Cell 2017; 28:2701-2711. [PMID: 28768825 PMCID: PMC5620377 DOI: 10.1091/mbc.e17-05-0334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 12/25/2022] Open
Abstract
A novel motif within the cytoplasmic tail of the type I TGF-β receptor (TβRI) controls basolateral delivery. While this element functions independent of TβRI recycling and heteromeric TGF-β receptor trafficking, it can dominantly direct an apically expressed receptor to the basolateral membrane in polarized epithelial cells. Delivery of biomolecules to the correct subcellular locales is critical for proper physiological function. To that end, we have previously determined that type I and II transforming growth factor beta (TGF-β) receptors (TβRI and TβRII, respectively) localize to the basolateral domain in polarized epithelia. While TβRII targeting was shown to be regulated by sequences between amino acids 529 and 538, the analogous region(s) within TβRI is unknown. To address that question, sequential cytoplasmic TβRI truncations and point mutations identified a targeting motif between residues 158 and 163 (VxxEED) required for basolateral TβRI expression. Further studies documented that receptor internalization, down-regulation, direct recycling, or Smad signaling were unaffected by motif mutations that caused TβRI mislocalization. However, inclusion of amino acids 148–217 containing the targeting motif was able to direct basolateral expression of the apically sorted nerve growth factor receptor (NGFR, p75; extracellular and transmembrane regions) in a dominant manner. Finally, coexpression of apically targeted type I and type II TGF-β receptors mediated Smad3 signaling from the apical membrane of polarized epithelial cells. These findings demonstrate that the absence of apical TGF-β signaling in normal epithelia is primarily a reflection of domain-specific receptor expression and not an inability to couple with the signaling machinery.
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Affiliation(s)
- Xueqian Yin
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Jeong-Han Kang
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Mahefatiana Andrianifahanana
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Youli Wang
- Division of Nephrology, Augusta University, Augusta, GA 30904
| | - Mi-Yeon Jung
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Danielle M Hernandez
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Edward B Leof
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
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11
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Disparate Regulatory Mechanisms Control Fat3 and P75NTR Protein Transport through a Conserved Kif5-Interaction Domain. PLoS One 2016; 11:e0165519. [PMID: 27788242 PMCID: PMC5082931 DOI: 10.1371/journal.pone.0165519] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/13/2016] [Indexed: 11/19/2022] Open
Abstract
Directed transport delivers proteins to specific cellular locations and is one mechanism by which cells establish and maintain polarized cellular architectures. The atypical cadherin Fat3 directs the polarized extension of dendrites in retinal amacrine cells by influencing the distribution of cytoskeletal regulators during retinal development, however the mechanisms regulating the distribution of Fat3 remain unclear. We report a novel Kinesin/Kif5 Interaction domain (Kif5-ID) in Fat3 that facilitates Kif5B binding, and determines the distribution of Fat3 cytosolic domain constructs in neurons and MDCK cells. The Kif5-ID sequence is conserved in the neurotrophin receptor P75NTR, which also binds Kif5B, and Kif5-ID mutations similarly result in P75NTR mislocalization. Despite these similarities, Kif5B-mediated protein transport is differentially regulated by these two cargos. For Fat3, the Kif5-ID is regulated by alternative splicing, and the timecourse of splicing suggests that the distribution of Fat3 may switch between early and later stages of retinal development. In contrast, P75NTR binding to Kif5B is enhanced by tyrosine phosphorylation and thus has the potential to be dynamically regulated on a more rapid time scale.
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12
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Staudt C, Gilis F, Tevel V, Jadot M, Boonen M. A conserved glycine residue in the C-terminal region of human ATG9A is required for its transport from the endoplasmic reticulum to the Golgi apparatus. Biochem Biophys Res Commun 2016; 479:404-409. [PMID: 27663665 DOI: 10.1016/j.bbrc.2016.09.097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 09/19/2016] [Indexed: 10/21/2022]
Abstract
ATG9A is the only polytopic protein of the mammalian autophagy-related protein family whose members regulate autophagosome formation during macroautophagy. At steady state, ATG9A localizes to several intracellular sites, including the Golgi apparatus, endosomes and the plasma membrane, and it redistributes towards autophagosomes upon autophagy induction. Interestingly, the transport of yeast Atg9 to the pre-autophagosomal structure depends on its self-association, which is mediated by a short amino acid motif located in the C-terminal region of the protein. Here, we investigated whether the residues that align with this motif in human ATG9A (V515-C519) are also required for its trafficking in mammalian cells. Interestingly, our findings support that human ATG9A self-interacts as well, and that this process promotes transport of ATG9A molecules through the Golgi apparatus. Furthermore, our data reveal that the transport of ATG9A out of the ER is severely impacted after mutation of the conserved V515-C519 motif. Nevertheless, the mutated ATG9A molecules could still interact with each other, indicating that the molecular mechanism of self-interaction differs in mammalian cells compared to yeast. Using sequential amino acid substitutions of glycine 516 and cysteine 519, we found that the stability of ATG9A relies on both of these residues, but that only the former is required for efficient transport of human ATG9A from the endoplasmic reticulum to the Golgi apparatus.
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Affiliation(s)
- Catherine Staudt
- URPhyM-Laboratoire de Chimie Physiologique, University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Florentine Gilis
- URPhyM-Laboratoire de Chimie Physiologique, University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Virginie Tevel
- URPhyM-Laboratoire de Chimie Physiologique, University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Michel Jadot
- URPhyM-Laboratoire de Chimie Physiologique, University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Marielle Boonen
- URPhyM-Laboratoire de Chimie Physiologique, University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium.
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13
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Gershoni-Emek N, Chein M, Gluska S, Perlson E. Amyotrophic lateral sclerosis as a spatiotemporal mislocalization disease: location, location, location. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 315:23-71. [PMID: 25708461 DOI: 10.1016/bs.ircmb.2014.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Spatiotemporal localization of signals is a fundamental feature impacting cell survival and proper function. The cell needs to respond in an accurate manner in both space and time to both intra- and intercellular environment cues. The regulation of this comprehensive process involves the cytoskeleton and the trafficking machinery, as well as local protein synthesis and ligand-receptor mechanisms. Alterations in such mechanisms can lead to cell dysfunction and disease. Motor neurons that can extend over tens of centimeters are a classic example for the importance of such events. Changes in spatiotemporal localization mechanisms are thought to play a role in motor neuron degeneration that occurs in amyotrophic lateral sclerosis (ALS). In this review we will discuss these mechanisms and argue that possible misregulated factors can lead to motor neuron degeneration in ALS.
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Affiliation(s)
- Noga Gershoni-Emek
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Michael Chein
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Shani Gluska
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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14
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Herrick-Davis K, Grinde E, Lindsley T, Teitler M, Mancia F, Cowan A, Mazurkiewicz JE. Native serotonin 5-HT2C receptors are expressed as homodimers on the apical surface of choroid plexus epithelial cells. Mol Pharmacol 2015; 87:660-73. [PMID: 25609374 DOI: 10.1124/mol.114.096636] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a prominent class of plasma membrane proteins that regulate physiologic responses to a wide variety of stimuli and therapeutic agents. Although GPCR oligomerization has been studied extensively in recombinant cells, it remains uncertain whether native receptors expressed in their natural cellular environment are monomers, dimers, or oligomers. The goal of this study was to determine the monomer/oligomer status of a native GPCR endogenously expressed in its natural cellular environment. Native 5-HT2C receptors in choroid plexus epithelial cells were evaluated using fluorescence correlation spectroscopy (FCS) with photon counting histogram (PCH). An anti-5-HT2C fragment antigen binding protein was used to label native 5-HT2C receptors. A known monomeric receptor (CD-86) served as a control for decoding the oligomer status of native 5-HT2C receptors by molecular brightness analysis. FCS with PCH revealed molecular brightness values for native 5-HT2C receptors equivalent to the molecular brightness of a homodimer. 5-HT2C receptors displayed a diffusion coefficient of 5 × 10(-9) cm(2)/s and were expressed at 32 receptors/μm(2) on the apical surface of choroid plexus epithelial cells. The functional significance and signaling capabilities of the homodimer were investigated in human embryonic kidney 293 cells using agonists that bind in a wash-resistant manner to one or both protomers of the homodimer. Whereas agonist binding to one protomer resulted in G protein activation, maximal stimulation required occupancy of both protomers. This study is the first to demonstrate the homodimeric structure of 5-HT2C receptors endogenously expressed in their native cellular environment, and identifies the homodimer as a functional signaling unit.
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Affiliation(s)
- Katharine Herrick-Davis
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Ellinor Grinde
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Tara Lindsley
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Milt Teitler
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Filippo Mancia
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Ann Cowan
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Joseph E Mazurkiewicz
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
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15
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Marchetti L, Luin S, Bonsignore F, de Nadai T, Beltram F, Cattaneo A. Ligand-induced dynamics of neurotrophin receptors investigated by single-molecule imaging approaches. Int J Mol Sci 2015; 16:1949-79. [PMID: 25603178 PMCID: PMC4307343 DOI: 10.3390/ijms16011949] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 01/05/2015] [Indexed: 01/14/2023] Open
Abstract
Neurotrophins are secreted proteins that regulate neuronal development and survival, as well as maintenance and plasticity of the adult nervous system. The biological activity of neurotrophins stems from their binding to two membrane receptor types, the tropomyosin receptor kinase and the p75 neurotrophin receptors (NRs). The intracellular signalling cascades thereby activated have been extensively investigated. Nevertheless, a comprehensive description of the ligand-induced nanoscale details of NRs dynamics and interactions spanning from the initial lateral movements triggered at the plasma membrane to the internalization and transport processes is still missing. Recent advances in high spatio-temporal resolution imaging techniques have yielded new insight on the dynamics of NRs upon ligand binding. Here we discuss requirements, potential and practical implementation of these novel approaches for the study of neurotrophin trafficking and signalling, in the framework of current knowledge available also for other ligand-receptor systems. We shall especially highlight the correlation between the receptor dynamics activated by different neurotrophins and the respective signalling outcome, as recently revealed by single-molecule tracking of NRs in living neuronal cells.
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Affiliation(s)
- Laura Marchetti
- National Enterprise for nanoScience and nanoTechnology (NEST) Laboratory, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, Pisa I-56127, Italy.
| | - Stefano Luin
- National Enterprise for nanoScience and nanoTechnology (NEST) Laboratory, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, Pisa I-56127, Italy.
| | - Fulvio Bonsignore
- National Enterprise for nanoScience and nanoTechnology (NEST) Laboratory, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, Pisa I-56127, Italy.
| | - Teresa de Nadai
- Biology Laboratory (BioSNS), Scuola Normale Superiore and Istituto di Neuroscienze-CNR, via Moruzzi 1, Pisa I-56100, Italy.
| | - Fabio Beltram
- National Enterprise for nanoScience and nanoTechnology (NEST) Laboratory, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, Pisa I-56127, Italy.
| | - Antonino Cattaneo
- Biology Laboratory (BioSNS), Scuola Normale Superiore and Istituto di Neuroscienze-CNR, via Moruzzi 1, Pisa I-56100, Italy.
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16
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Weidemann T, Mücksch J, Schwille P. Fluorescence fluctuation microscopy: a diversified arsenal of methods to investigate molecular dynamics inside cells. Curr Opin Struct Biol 2014; 28:69-76. [DOI: 10.1016/j.sbi.2014.07.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/11/2014] [Indexed: 11/26/2022]
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17
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Youker RT, Teng H. Measuring protein dynamics in live cells: protocols and practical considerations for fluorescence fluctuation microscopy. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:90801. [PMID: 25260867 PMCID: PMC4183152 DOI: 10.1117/1.jbo.19.9.090801] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 08/12/2014] [Accepted: 07/31/2014] [Indexed: 06/03/2023]
Abstract
Quantitative analysis of protein complex stoichiometries and mobilities are critical for elucidating the mechanisms that regulate cellular pathways. Fluorescence fluctuation spectroscopy (FFS) techniques can measure protein dynamics, such as diffusion coefficients and formation of complexes, with extraordinary precision and sensitivity. Complete calibration and characterization of the microscope instrument is necessary in order to avoid artifacts during data acquisition and to capitalize on the full capabilities of FFS techniques. We provide an overview of the theory behind FFS techniques, discuss calibration procedures, provide protocols, and give practical considerations for performing FFS experiments. One important parameter recovered from FFS measurements is the relative molecular brightness that can correlate with oligomerization. Three methods for measuring molecular brightness (fluorescence correlation spectroscopy, photon-counting histogram, and number and brightness analysis) recover similar values when measuring samples under ideal conditions in vitro. However, examples are given illustrating that these different methods used for calculating molecular brightness of fluorescent molecules in cells are not always equivalent. Methods relying on spot measurements are more prone to bleaching and movement artifacts that can lead to underestimation of brightness values. We advocate for the use of multiple FFS techniques to study molecular brightnesses to overcome and compliment limitations of individual techniques.
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Affiliation(s)
- Robert T. Youker
- University of Pittsburgh School of
Medicine, Renal-Electrolyte Division, Pittsburgh, Pennsylvania
15261, United States
- Western Carolina University,
Department of Biology, Cullowhee, North Carolina 28723, United
States
| | - Haibing Teng
- Carnegie Mellon University,
Molecular Biosensor and Imaging Center (MBIC), Pittsburgh, Pennsylvania 15213,
United States
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18
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Tewari R, Jarvela T, Linstedt AD. Manganese induces oligomerization to promote down-regulation of the intracellular trafficking receptor used by Shiga toxin. Mol Biol Cell 2014; 25:3049-58. [PMID: 25079690 PMCID: PMC4230593 DOI: 10.1091/mbc.e14-05-1003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Manganese down-regulates the Shiga toxin receptor GPP130, which protects against lethal toxin doses. This study reveals a major aspect of the mechanism. Manganese binds GPP130, inducing GPP130 oligomerization, which is required and sufficient to redirect GPP130 out of the Golgi toward lysosomes. Manganese (Mn) protects cells against lethal doses of purified Shiga toxin by causing the degradation of the cycling transmembrane protein GPP130, which the toxin uses as a trafficking receptor. Mn-induced GPP130 down-regulation, in addition to being a potential therapeutic approach against Shiga toxicosis, is a model for the study of metal-regulated protein sorting. Significantly, however, the mechanism by which Mn regulates GPP130 trafficking is unknown. Here we show that a transferable trafficking determinant within GPP130 bound Mn and that Mn binding induced GPP130 oligomerization in the Golgi. Alanine substitutions blocking Mn binding abrogated both oligomerization of GPP130 and GPP130 sorting from the Golgi to lysosomes. Further, oligomerization was sufficient because forced aggregation, using a drug-controlled polymerization domain, redirected GPP130 to lysosomes in the absence of Mn. These experiments reveal metal-induced oligomerization as a Golgi sorting mechanism for a medically relevant receptor for Shiga toxin.
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Affiliation(s)
- Ritika Tewari
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Timothy Jarvela
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adam D Linstedt
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
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19
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Labilloy A, Youker RT, Bruns JR, Kukic I, Kiselyov K, Halfter W, Finegold D, do Monte SJH, Weisz OA. Altered dynamics of a lipid raft associated protein in a kidney model of Fabry disease. Mol Genet Metab 2014; 111:184-92. [PMID: 24215843 PMCID: PMC3946758 DOI: 10.1016/j.ymgme.2013.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 10/12/2013] [Indexed: 02/07/2023]
Abstract
Accumulation of globotriaosylceramide (Gb3) and other neutral glycosphingolipids with galactosyl residues is the hallmark of Fabry disease, a lysosomal storage disorder caused by deficiency of the enzyme alpha-galactosidase A (α-gal A). These lipids are incorporated into the plasma membrane and intracellular membranes, with a preference for lipid rafts. Disruption of raft mediated cell processes is implicated in the pathogenesis of several human diseases, but little is known about the effects of the accumulation of glycosphingolipids on raft dynamics in the context of Fabry disease. Using siRNA technology, we have generated a polarized renal epithelial cell model of Fabry disease in Madin-Darby canine kidney cells. These cells present increased levels of Gb3 and enlarged lysosomes, and progressively accumulate zebra bodies. The polarized delivery of both raft-associated and raft-independent proteins was unaffected by α-gal A knockdown, suggesting that accumulation of Gb3 does not disrupt biosynthetic trafficking pathways. To assess the effect of α-gal A silencing on lipid raft dynamics, we employed number and brightness (N&B) analysis to measure the oligomeric status and mobility of the model glycosylphosphatidylinositol (GPI)-anchored protein GFP-GPI. We observed a significant increase in the oligomeric size of antibody-induced clusters of GFP-GPI at the plasma membrane of α-gal A silenced cells compared with control cells. Our results suggest that the interaction of GFP-GPI with lipid rafts may be altered in the presence of accumulated Gb3. The implications of our results with respect to the pathogenesis of Fabry disease are discussed.
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Affiliation(s)
- Anatália Labilloy
- Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261, USA; Ciência sem Fronteiras, CNPq, Brazil
| | - Robert T Youker
- Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jennifer R Bruns
- Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ira Kukic
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Kirill Kiselyov
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Willi Halfter
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - David Finegold
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | | | - Ora A Weisz
- Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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