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Lieu ZZ, Derby MC, Teasdale RD, Hart C, Gunn P, Gleeson PA. The golgin GCC88 is required for efficient retrograde transport of cargo from the early endosomes to the trans-Golgi network. Mol Biol Cell 2007; 18:4979-91. [PMID: 17914056 PMCID: PMC2096601 DOI: 10.1091/mbc.e07-06-0622] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Retrograde transport pathways from early/recycling endosomes to the trans-Golgi network (TGN) are poorly defined. We have investigated the role of TGN golgins in retrograde trafficking. Of the four TGN golgins, p230/golgin-245, golgin-97, GCC185, and GCC88, we show that GCC88 defines a retrograde transport pathway from early endosomes to the TGN. Depletion of GCC88 in HeLa cells by interference RNA resulted in a block in plasma membrane-TGN recycling of two cargo proteins, TGN38 and a CD8 mannose-6-phosphate receptor cytoplasmic tail fusion protein. In GCC88-depleted cells, cargo recycling was blocked in the early endosome. Depletion of GCC88 dramatically altered the TGN localization of the t-SNARE syntaxin 6, a syntaxin required for endosome to TGN transport. Furthermore, the transport block in GCC88-depleted cells was rescued by syntaxin 6 overexpression. Internalized Shiga toxin was efficiently transported from endosomes to the Golgi of GCC88-depleted cells, indicating that Shiga toxin and TGN38 are internalized by distinct retrograde transport pathways. These findings have identified an essential role for GCC88 in the localization of TGN fusion machinery for transport from early endosomes to the TGN, and they have allowed the identification of a retrograde pathway which differentially selects TGN38 and mannose-6-phosphate receptor from Shiga toxin.
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Affiliation(s)
- Zi Zhao Lieu
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Merran C. Derby
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Rohan D. Teasdale
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Charles Hart
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Priscilla Gunn
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Paul A. Gleeson
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
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52
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Holloway ZG, Grabski R, Szul T, Styers ML, Coventry JA, Monaco AP, Sztul E. Activation of ADP-ribosylation factor regulates biogenesis of the ATP7A-containing trans-Golgi network compartment and its Cu-induced trafficking. Am J Physiol Cell Physiol 2007; 293:C1753-67. [PMID: 17913844 DOI: 10.1152/ajpcell.00253.2007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ATP7A (MNK) regulates copper homeostasis by translocating from a compartment localized within the trans-Golgi network to the plasma membrane (PM) in response to increased copper load. The mechanisms that regulate the biogenesis of the MNK compartment and the trafficking of MNK are unclear. Here we show that the architecture of the MNK compartment is linked to the structure of the Golgi ribbon. Depletion of p115 tethering factor, which causes fragmentation of the Golgi ribbon, also disrupts the MNK compartment. In p115-depleted cells, MNK localizes to punctate structures that pattern on Golgi ministacks dispersed throughout the cell. Despite altered localization MNK trafficking still occurs, and MNK relocates from and returns to the fragmented compartment in response to copper. We further show that the biogenesis of the MNK compartment requires activation of ADP-ribosylation factor (Arf)1 GTPase, shown previously to facilitate the biogenesis of the Golgi ribbon. Activation of cellular Arf1 is prevented by 1) expressing an inactive "empty" form of Arf (Arf1/N126I), 2) expressing an inactive form of GBF1 (GBF1/E794K), guanine nucleotide exchange factor for Arf1, or 3) treating cells with brefeldin A, an inhibitor of GBF1 that disrupts MNK into a diffuse pattern. Importantly, preventing Arf activation inhibits copper-responsive trafficking of MNK to the PM. Our findings support a model in which active Arf is essential for the generation of the MNK compartment and for copper-responsive trafficking of MNK from there to the PM. Our findings provide an exciting foundation for identifying Arf1 effectors that facilitate the biogenesis of the MNK compartment and MNK traffic.
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Affiliation(s)
- Zoe G Holloway
- Wellcome Trust Centre for Human Genetics; University of Oxford, Headington, Oxford, UK
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53
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Werner D. Molecular Biology and Ecology of the Rhizobia–Legume Symbiosis. THE RHIZOSPHERE 2007. [DOI: 10.1201/9781420005585.ch9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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54
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Derby MC, Lieu ZZ, Brown D, Stow JL, Goud B, Gleeson PA. The trans-Golgi Network Golgin, GCC185, is Required for Endosome-to-Golgi Transport and Maintenance of Golgi Structure. Traffic 2007; 8:758-73. [PMID: 17488291 DOI: 10.1111/j.1600-0854.2007.00563.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Four mammalian golgins are specifically targeted to the trans-Golgi network (TGN) membranes via their C-terminal GRIP domains. The TGN golgins, p230/golgin-245 and golgin-97, are recruited via the GTPase Arl1, whereas the TGN golgin GCC185 is recruited independently of Arl1. Here we show that GCC185 is localized to a region of the TGN distinct from Arl1 and plays an essential role in maintaining the organization of the Golgi apparatus. Using both small interfering RNA (siRNA) and microRNA (miRNA), we show that depletion of GCC185 in HeLa cells frequently resulted in fragmentation of the Golgi apparatus. Golgi apparatus fragments were dispersed throughout the cytoplasm and contained both cis and trans markers. Trafficking of anterograde and retrograde cargo was analysed over an extended period following GCC185 depletion. Early effects of GCC185 depletion included a perturbation in the distribution of the mannose-6-phosphate receptor and a block in shiga toxin trafficking to the Golgi apparatus, which occurred in parallel with the fragmentation of the Golgi ribbon. Internalized shiga toxin accumulated in Rab11-positive endosomes, indicating GCC185 is essential for transport between the recycling endosome and the TGN. In contrast, the plasma membrane-TGN recycling protein TGN38 was efficiently transported into GCC185-depleted Golgi apparatus fragments throughout a 96-h period, and anterograde transport of E-cadherin was functional until a late stage of GCC185 depletion. This study demonstrated (i) a more effective long-term depletion of GCC185 using miRNA than siRNA and (ii) a dual role for the GCC185 golgin in the regulation of endosome-to-TGN membrane transport and in the organization of the Golgi apparatus.
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Affiliation(s)
- Merran C Derby
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia, and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
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55
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Derby MC, Gleeson PA. New Insights into Membrane Trafficking and Protein Sorting. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 261:47-116. [PMID: 17560280 DOI: 10.1016/s0074-7696(07)61002-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein transport in the secretory and endocytic pathways is a multistep process involving the generation of transport carriers loaded with defined sets of cargo, the shipment of the cargo-loaded transport carriers between compartments, and the specific fusion of these transport carriers with a target membrane. The regulation of these membrane-mediated processes involves a complex array of protein and lipid interactions. As the machinery and regulatory processes of membrane trafficking have been defined, it is increasingly apparent that membrane transport is intimately connected with a number of other cellular processes, such as quality control in the endoplasmic reticulum (ER), cytoskeletal dynamics, receptor signaling, and mitosis. The fidelity of membrane trafficking relies on the correct assembly of components on organelles. Recruitment of peripheral proteins plays a critical role in defining organelle identity and the establishment of membrane subdomains, essential for the regulation of vesicle transport. The molecular mechanisms for the biogenesis of membrane subdomains are also central to understanding how cargo is sorted and segregated and how different populations of transport carriers are generated. In this review we will focus on the emerging themes of organelle identity, membrane subdomains, regulation of Golgi trafficking, and advances in dissecting pathways in physiological systems.
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Affiliation(s)
- Merran C Derby
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
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56
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Matheson LA, Hanton SL, Brandizzi F. Traffic between the plant endoplasmic reticulum and Golgi apparatus: to the Golgi and beyond. CURRENT OPINION IN PLANT BIOLOGY 2006; 9:601-9. [PMID: 17010656 DOI: 10.1016/j.pbi.2006.09.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 09/20/2006] [Indexed: 05/12/2023]
Abstract
Significant advances have been made in recent years that have increased our understanding of the trafficking to and from membranes that are functionally linked to the Golgi apparatus in plants. New routes from the Golgi to organelles outside the secretory pathway are now being identified, revealing the importance of the Golgi apparatus as a major sorting station in the plant cell. This review discusses our current perception of Golgi structure and organization as well as the molecular mechanisms that direct traffic in and out of the Golgi.
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Affiliation(s)
- Loren A Matheson
- Department of Biology, 112 Science Place, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
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57
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Reddy JV, Burguete AS, Sridevi K, Ganley IG, Nottingham RM, Pfeffer SR. A functional role for the GCC185 golgin in mannose 6-phosphate receptor recycling. Mol Biol Cell 2006; 17:4353-63. [PMID: 16885419 PMCID: PMC1635343 DOI: 10.1091/mbc.e06-02-0153] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mannose 6-phosphate receptors (MPRs) deliver newly synthesized lysosomal enzymes to endosomes and then recycle to the Golgi. MPR recycling requires Rab9 GTPase; Rab9 recruits the cytosolic adaptor TIP47 and enhances its ability to bind to MPR cytoplasmic domains during transport vesicle formation. Rab9-bearing vesicles then fuse with the trans-Golgi network (TGN) in living cells, but nothing is known about how these vesicles identify and dock with their target. We show here that GCC185, a member of the Golgin family of putative tethering proteins, is a Rab9 effector that is required for MPR recycling from endosomes to the TGN in living cells, and in vitro. GCC185 does not rely on Rab9 for its TGN localization; depletion of GCC185 slightly alters the Golgi ribbon but does not interfere with Golgi function. Loss of GCC185 triggers enhanced degradation of mannose 6-phosphate receptors and enhanced secretion of hexosaminidase. These data assign a specific pathway to an interesting, TGN-localized protein and suggest that GCC185 may participate in the docking of late endosome-derived, Rab9-bearing transport vesicles at the TGN.
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Affiliation(s)
- Jonathan V. Reddy
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307
| | | | - Khambhampaty Sridevi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307
| | - Ian G. Ganley
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307
| | - Ryan M. Nottingham
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307
| | - Suzanne R. Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307
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58
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Spooner RA, Smith DC, Easton AJ, Roberts LM, Lord JM. Retrograde transport pathways utilised by viruses and protein toxins. Virol J 2006; 3:26. [PMID: 16603059 PMCID: PMC1524934 DOI: 10.1186/1743-422x-3-26] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 04/07/2006] [Indexed: 11/15/2022] Open
Abstract
A model has been presented for retrograde transport of certain toxins and viruses from the cell surface to the ER that suggests an obligatory interaction with a glycolipid receptor at the cell surface. Here we review studies on the ER trafficking cholera toxin, Shiga and Shiga-like toxins, Pseudomonas exotoxin A and ricin, and compare the retrograde routes followed by these protein toxins to those of the ER trafficking SV40 and polyoma viruses. We conclude that there is in fact no obligatory requirement for a glycolipid receptor, nor even with a protein receptor in a lipid-rich environment. Emerging data suggests instead that there is no common pathway utilised for retrograde transport by all of these pathogens, the choice of route being determined by the particular receptor utilised.
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Affiliation(s)
- Robert A Spooner
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Daniel C Smith
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Andrew J Easton
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Lynne M Roberts
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - J Michael Lord
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
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59
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Lock JG, Hammond LA, Houghton F, Gleeson PA, Stow JL. E-cadherin transport from the trans-Golgi network in tubulovesicular carriers is selectively regulated by golgin-97. Traffic 2006; 6:1142-56. [PMID: 16262725 DOI: 10.1111/j.1600-0854.2005.00349.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
E-cadherin is a cell-cell adhesion protein that is trafficked and delivered to the basolateral cell surface. Membrane-bound carriers for the post-Golgi exocytosis of E-cadherin have not been characterized. Green fluorescent protein (GFP)-tagged E-cadherin (Ecad-GFP) is transported from the trans-Golgi network (TGN) to the recycling endosome on its way to the cell surface in tubulovesicular carriers that resemble TGN tubules labeled by members of the golgin family of tethering proteins. Here, we examine the association of golgins with tubular carriers containing E-cadherin as cargo. Fluorescent GRIP domains from golgin proteins replicate the membrane binding of the full-length proteins and were coexpressed with Ecad-GFP. The GRIP domains of p230/golgin-245 and golgin-97 had overlapping but nonidentical distributions on the TGN; both domains were on TGN-derived tubules but only the golgin-97 GRIP domain coincided with Ecad-GFP tubules in live cells. When the Arl1-binding endogenous golgins, p230/golgin-245 and golgin-97 were displaced from Golgi membranes by overexpression of the p230 GRIP domain, trafficking of Ecad-GFP was inhibited. siRNA knockdown of golgin-97 also inhibited trafficking of Ecad-GFP. Thus, the GRIP domains of p230/golgin-245 and golgin-97 bind discriminately to distinct membrane subdomains of the TGN. Golgin-97 is identified as a selective and essential component of the tubulovesicular carriers transporting E-cadherin out of the TGN.
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Affiliation(s)
- John G Lock
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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60
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Abstract
Coiled-coil and multisubunit tethers have emerged as key regulators of membrane traffic and organellar architecture. The restricted subcellular localization of tethers and their ability to interact with Rabs and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) suggests that tethers participate in determining the specificity of membrane fusion. An accepted model of tether function considers them molecular “bridges” that link opposing membranes before SNARE pairing. This model has been extended by findings in various experimental systems, suggesting that tethers may have other functions. Recent reports implicate tethers in the assembly of SNARE complexes, cargo selection and transit, cytoskeletal events, and localized attachment of regulatory proteins. A concept of tethers as scaffolding machines that recruit protein components involved in varied cellular responses is emerging. In this model, tethers function as integration switches that simultaneously transmit information to coordinate distinct processes required for membrane traffic.
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Affiliation(s)
- Elizabeth Sztul
- Dept. of Cell Biology, Univ. of Alabama at Birmingham, 1918 Univ. Blvd., Birmingham, AL 35294, USA.
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61
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Abstract
Small GTP-binding proteins of the Rab and Arf (ADP-ribosylation factor) families play a central role in the membrane trafficking pathways of eukaryotic cells. The prototypical members of the Arf family are Arf1-Arf6 and Sar1, which have well-characterized roles in membrane traffic or cytoskeletal reorganization. However, eukaryotic genomes encode additional proteins, which share the characteristic structural features of the Arf family, but the role of these 'Arf-like' (Arl) proteins is less well understood. This review discusses Arl1, a GTPase that is widely conserved in evolution, and which is localized to the Golgi in all species so far examined. The best-characterized effectors of Arl1 are coiled-coil proteins which share a C-terminal GRIP domain, but other apparent effectors include the GARP (Golgi-associated retrograde protein)/VFT (Vps fifty-three) vesicle-tethering complex and Arfaptin 2. As least some of these proteins are believed to have a role in membrane traffic. Genetic analysis in a number of species has shown that Arl1 is not essential for exocytosis, but rather suggest that it is required for traffic from endosomes to the Golgi.
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Affiliation(s)
- S Munro
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
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62
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Schermer B, Höpker K, Omran H, Ghenoiu C, Fliegauf M, Fekete A, Horvath J, Köttgen M, Hackl M, Zschiedrich S, Huber TB, Kramer-Zucker A, Zentgraf H, Blaukat A, Walz G, Benzing T. Phosphorylation by casein kinase 2 induces PACS-1 binding of nephrocystin and targeting to cilia. EMBO J 2005; 24:4415-24. [PMID: 16308564 PMCID: PMC1356326 DOI: 10.1038/sj.emboj.7600885] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 11/03/2005] [Indexed: 11/09/2022] Open
Abstract
Mutations in proteins localized to cilia and basal bodies have been implicated in a growing number of human diseases. Access of these proteins to the ciliary compartment requires targeting to the base of the cilia. However, the mechanisms involved in transport of cilia proteins to this transitional zone are elusive. Here we show that nephrocystin, a ciliary protein mutated in the most prevalent form of cystic kidney disease in childhood, is expressed in respiratory epithelial cells and accumulates at the base of cilia, overlapping with markers of the basal body area and the transition zone. Nephrocystin interacts with the phosphofurin acidic cluster sorting protein (PACS)-1. Casein kinase 2 (CK2)-mediated phosphorylation of three critical serine residues within a cluster of acidic amino acids in nephrocystin mediates PACS-1 binding, and is essential for colocalization of nephrocystin with PACS-1 at the base of cilia. Inhibition of CK2 activity abrogates this interaction and results in the loss of correct nephrocystin targeting. These data suggest that CK2-dependent transport processes represent a novel pathway of targeting proteins to the cilia.
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Affiliation(s)
| | - Katja Höpker
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Heymut Omran
- Childrens Hospital, University Hospital Freiburg, Freiburg, Germany
| | | | - Manfred Fliegauf
- Childrens Hospital, University Hospital Freiburg, Freiburg, Germany
| | - Andrea Fekete
- Childrens Hospital, University Hospital Freiburg, Freiburg, Germany
| | - Judit Horvath
- Childrens Hospital, University Hospital Freiburg, Freiburg, Germany
| | - Michael Köttgen
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Matthias Hackl
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | | | - Tobias B Huber
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | | | | | - Andree Blaukat
- Department of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | - Gerd Walz
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Thomas Benzing
- Renal Division, University Hospital Freiburg, Freiburg, Germany
- Renal Division, University Hospital, Hugstetterstrasse 55, 79106 Freiburg, Germany. Tel.: +49 761 270 3559; Fax: +49 761 270 3270; E-mail:
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63
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Snyder CM, Mardones GA, Ladinsky MS, Howell KE. GMx33 associates with the trans-Golgi matrix in a dynamic manner and sorts within tubules exiting the Golgi. Mol Biol Cell 2005; 17:511-24. [PMID: 16236792 PMCID: PMC1345686 DOI: 10.1091/mbc.e05-07-0682] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The trans-Golgi matrix consists of a group of proteins dynamically associated with the trans-Golgi and thought to be involved in anterograde and retrograde Golgi traffic, as well as interactions with the cytoskeleton and maintenance of the Golgi structure. GMx33 is localized to the cytoplasmic face of the trans-Golgi and is also present in a large cytoplasmic pool. Here we demonstrate that GMx33 is dynamically associated with the trans-Golgi matrix, associating and dissociating with the Golgi in seconds. GMx33 can be locked onto the trans-Golgi matrix by GTPgammaS, indicating that its association is regulated in a GTP-dependent manner like several other Golgi matrix proteins. Using live-cell imaging we show that GMx33 exits the Golgi associated with tubules and within these tubules GMx33 segregates from transmembrane proteins followed by fragmentation of the tubules into smaller tubules and vesicles. Within vesicles produced by an in vitro budding reaction, GMx33 remains segregated in a matrixlike tail region that sometimes contains Golgin-245. This trans-matrix often links a few vesicles together. Together these data suggest that GMx33 is a member of the trans-Golgi matrix and offer clues regarding the role of the trans-Golgi matrix in sorting and exit from the Golgi.
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Affiliation(s)
- Christopher M Snyder
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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64
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Yoshino A, Setty SRG, Poynton C, Whiteman EL, Saint-Pol A, Burd CG, Johannes L, Holzbaur EL, Koval M, McCaffery JM, Marks MS. tGolgin-1 (p230, golgin-245) modulates Shiga-toxin transport to the Golgi and Golgi motility towards the microtubule-organizing centre. J Cell Sci 2005; 118:2279-93. [PMID: 15870108 DOI: 10.1242/jcs.02358] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
tGolgin-1 (trans-Golgi p230, golgin-245) is a member of a family of large peripheral membrane proteins that associate with the trans-Golgi network (TGN) via a C-terminal GRIP domain. Some GRIP-domain proteins have been implicated in endosome-to-TGN transport but no function for tGolgin-1 has been described. Here, we show that tGolgin-1 production is required for efficient retrograde distribution of Shiga toxin from endosomes to the Golgi. Surprisingly, we also found an indirect requirement for tGolgin-1 in Golgi positioning. In HeLa cells depleted of tGolgin-1, the normally centralized Golgi and TGN membranes were displaced to the periphery, forming `mini stacks'. These stacks resembled those in cells with disrupted microtubules or dynein-dynactin motor, in that they localized to endoplasmic-reticulum exit sites, maintained their secretory capacity and cis-trans polarity, and were relatively immobile by video microscopy. The mini stacks formed concomitant with a failure of pre-Golgi elements to migrate along microtubules towards the microtubule-organizing centre. The requirement for tGolgin-1 in Golgi positioning did not appear to reflect direct binding of tGolgin-1 to motile pre-Golgi membranes, because distinct Golgi and tGolgin-1-containing TGN elements that formed after recovery of HeLa cells from brefeldin-A treatment moved independently toward the microtubule-organizing centre. These data demonstrate that tGolgin-1 functions in Golgi positioning indirectly, probably by regulating retrograde movement of cargo required for recruitment or activation of dynein-dynactin complexes on newly formed Golgi elements.
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Affiliation(s)
- Atsuko Yoshino
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6082, USA
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