ARF-GAP–mediated interaction between the ER-Golgi v-SNAREs and the COPI coat

In eukaryotic cells, secretion is achieved by vesicular transport. Fusion of such vesicles with the correct target compartment relies on SNARE proteins on both vesicle (v-SNARE) and the target membranes (t-SNARE). At present it is not clear how v-SNAREs are incorporated into transport vesicles. Here, we show that binding of ADP-ribosylation factor (ARF)–GTPase-activating protein (GAP) to ER-Golgi v-SNAREs is an essential step for recruitment of Arf1p and coatomer, proteins that together form the COPI coat. ARF-GAP acts catalytically to recruit COPI components. Inclusion of v-SNAREs into COPI vesicles could be mediated by direct interaction with the coat. The mechanisms by which v-SNAREs interact with COPI and COPII coat proteins seem to be different and may play a key role in determining specificity in vesicle budding.

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ADP-ribosylation factor and coatomer couple fusion to vesicle budding

The Journal of Cell Biology ◽

10.1083/jcb.124.4.415 ◽

1994 ◽

Vol 124 (4) ◽

pp. 415-424 ◽

Cited By ~ 77

Author(s):

Z Elazar ◽

L Orci ◽

J Ostermann ◽

M Amherdt ◽

G Tanigawa ◽

...

Keyword(s):

Brefeldin A ◽

Retrograde Transport ◽

Coated Vesicles ◽

Coat Proteins ◽

Vesicle Budding ◽

Adp Ribosylation ◽

Golgi Membranes ◽

Transport Vesicles ◽

Donor And Acceptor ◽

Adp Ribosylation Factor

The coat proteins required for budding COP-coated vesicles from Golgi membranes, coatomer and ADP-ribosylation factor (ARF) protein, are shown to be required to reconstitute the orderly process of transport between Golgi cisternae in which fusion of transport vesicles begins only after budding ends. When either coat protein is omitted, fusion is uncoupled from budding-donor and acceptor compartments pair directly without an intervening vesicle. Coupling may therefore results from the sequestration of fusogenic membrane proteins into assembling coated vesicles that are only exposed when the coat is removed after budding is complete. This mechanism of coupling explains the phenomenon of "retrograde transport" triggered by uncouplers such as the drug brefeldin A.

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An ACAP1-containing clathrin coat complex for endocytic recycling

The Journal of Cell Biology ◽

10.1083/jcb.200608033 ◽

2007 ◽

Vol 178 (3) ◽

pp. 453-464 ◽

Cited By ~ 71

Author(s):

Jian Li ◽

Peter J. Peters ◽

Ming Bai ◽

Jun Dai ◽

Erik Bos ◽

...

Keyword(s):

Cell Migration ◽

Glucose Homeostasis ◽

Glucose Transporter ◽

Critical Role ◽

Coat Proteins ◽

Gtpase Activating Protein ◽

Endocytic Recycling ◽

Basic Understanding ◽

Glucose Transporter Type 4 ◽

Adp Ribosylation Factor

Whether coat proteins play a widespread role in endocytic recycling remains unclear. We find that ACAP1, a GTPase-activating protein (GAP) for ADP-ribosylation factor (ARF) 6, is part of a novel clathrin coat complex that is regulated by ARF6 for endocytic recycling in two key physiological settings, stimulation-dependent recycling of integrin that is critical for cell migration and insulin-stimulated recycling of glucose transporter type 4 (Glut4), which is required for glucose homeostasis. These findings not only advance a basic understanding of an early mechanistic step in endocytic recycling but also shed key mechanistic insights into major physiological events for which this transport plays a critical role.

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Structure of clathrin cages and coats in ice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014213x ◽

1986 ◽

Vol 44 ◽

pp. 94-97

Author(s):

G.P.A. Vigers ◽

R.A. Crowther ◽

B.M.F. Pearse

Keyword(s):

Electron Microscopy ◽

Heavy Chain ◽

Outer Part ◽

Coated Vesicles ◽

Eukaryotic Cells ◽

Coat Proteins ◽

Terminal Domain ◽

Clathrin Heavy Chain ◽

Membrane Components

Clathrin forms the polyhedral cage of coated vesicles, which mediate the transfer of selected membrane components within eukaryotic cells. Clathrin cages and coated vesicles have been extensively studied by electron microscopy of negatively stained preparations and shadowed specimens. From these studies the gross morphology of the outer part of the polyhedral coat has been established and some features of the packing of clathrin trimers into the coat have also been described. However these previous studies have not revealed any internal details about the position of the terminal domain of the clathrin heavy chain, the location of the 100kd-50kd accessory coat proteins or the interactions of the coat with the enclosed membrane.

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The amino terminus of ADP-ribosylation factor (ARF) 1 is essential for interaction with Gs and ARF GTPase-activating protein.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)43906-3 ◽

1994 ◽

Vol 269 (47) ◽

pp. 29490-29494 ◽

Cited By ~ 5

Author(s):

P A Randazzo ◽

T Terui ◽

S Sturch ◽

R A Kahn

Keyword(s):

Amino Terminus ◽

Gtpase Activating Protein ◽

Adp Ribosylation ◽

Adp Ribosylation Factor

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Concentration of Sec12 at ER exit sites via interaction with cTAGE5 is required for collagen export

The Journal of Cell Biology ◽

10.1083/jcb.201312062 ◽

2014 ◽

Vol 206 (6) ◽

pp. 751-762 ◽

Cited By ~ 66

Author(s):

Kota Saito ◽

Koh Yamashiro ◽

Noriko Shimazu ◽

Tomoya Tanabe ◽

Kenji Kontani ◽

...

Keyword(s):

Direct Interaction ◽

Secretory Proteins ◽

Nucleotide Exchange ◽

Guanine Nucleotide Exchange ◽

Transport Vesicles ◽

Nucleotide Exchange Factor ◽

Receptor Component ◽

Er Exit Sites ◽

Guanosine Triphosphatase ◽

Trimeric Structure

Mechanisms for exporting variably sized cargo from the endoplasmic reticulum (ER) using the same machinery remain poorly understood. COPII-coated vesicles, which transport secretory proteins from the ER to the Golgi apparatus, are typically 60–90 nm in diameter. However, collagen, which forms a trimeric structure that is too large to be accommodated by conventional transport vesicles, is also known to be secreted via a COPII-dependent process. In this paper, we show that Sec12, a guanine-nucleotide exchange factor for Sar1 guanosine triphosphatase, is concentrated at ER exit sites and that this concentration of Sec12 is specifically required for the secretion of collagen VII but not other proteins. Furthermore, Sec12 recruitment to ER exit sites is organized by its direct interaction with cTAGE5, a previously characterized collagen cargo receptor component, which functions together with TANGO1 at ER exit sites. These findings suggest that the export of large cargo requires high levels of guanosine triphosphate–bound Sar1 generated by Sec12 localized at ER exit sites.

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SpoVID Guides SafA to the Spore Coat inBacillus subtilis

Journal of Bacteriology ◽

10.1128/jb.183.10.3041-3049.2001 ◽

2001 ◽

Vol 183 (10) ◽

pp. 3041-3049 ◽

Cited By ~ 56

Author(s):

Amanda J. Ozin ◽

Craig S. Samford ◽

Adriano O. Henriques ◽

Charles P. Moran

Keyword(s):

Direct Interaction ◽

Spore Coat ◽

Coat Proteins ◽

Yeast Two Hybrid System ◽

Spore Coat Proteins ◽

Basement Layer ◽

Two Hybrid ◽

Spore Coat Protein

ABSTRACT Bacteria assemble complex structures by targeting proteins to specific subcellular locations. The protein coat that encasesBacillus subtilis spores is an example of a structure that requires coordinated targeting and assembly of more than 24 polypeptides. The earliest stages of coat assembly require the action of three morphogenetic proteins: SpoIVA, CotE, and SpoVID. In the first steps, a basement layer of SpoIVA forms around the surface of the forespore, guiding the subsequent positioning of a ring of CotE protein about 75 nm from the forespore surface. SpoVID localizes near the forespore membrane where it functions to maintain the integrity of the CotE ring and to anchor the nascent coat to the underlying spore structures. However, it is not known which spore coat proteins interact directly with SpoVID. In this study we examined the interaction between SpoVID and another spore coat protein, SafA, in vivo using the yeast two-hybrid system and in vitro. We found evidence that SpoVID and SafA directly interact and that SafA interacts with itself. Immunofluorescence microscopy showed that SafA localized around the forespore early during coat assembly and that this localization of SafA was dependent on SpoVID. Moreover, targeting of SafA to the forespore was also dependent on SpoIVA, as was targeting of SpoVID to the forespore. We suggest that the localization of SafA to the spore coat requires direct interaction with SpoVID.

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Membrane curvature and the control of GTP hydrolysis in Arf1 during COPI vesicle formation

Biochemical Society Transactions ◽

10.1042/bst0330619 ◽

2005 ◽

Vol 33 (4) ◽

pp. 619-622 ◽

Cited By ~ 24

Author(s):

B. Antonny ◽

J. Bigay ◽

J.-F. Casella ◽

G. Drin ◽

B. Mesmin ◽

...

Keyword(s):

Lipid Membranes ◽

Membrane Curvature ◽

Gtp Hydrolysis ◽

Membrane Fission ◽

Transport Vesicles ◽

Highly Sensitive ◽

Copi Vesicle ◽

Membrane Budding ◽

Gtpase Cycle ◽

Adp Ribosylation Factor

The GTP switch of the small G-protein Arf1 (ADP-ribosylation factor 1) on lipid membranes promotes the polymerization of the COPI (coat protein complex I) coat, which acts as a membrane deforming shell to form transport vesicles. Real-time measurements for coat assembly on liposomes gives insights into how the GTPase cycle of Arf1 is coupled in time with the polymerization of the COPI coat and the resulting membrane deformation. One key parameter seems to be the membrane curvature. Arf-GAP1 (where GAP stands for GTPase-activating protein), which promotes GTP hydrolysis in the Arf1–COPI complex is highly sensitive to lipid packing. Its activity on Arf1-GTP increases by two orders of magnitude as the diameter of the liposomes approaches that of authentic transport vesicles (60 nm). This suggests that during membrane budding, Arf1-GTP molecules are progressively eliminated from the coated area where the membrane curvature is positive, but are protected from Arf-GAP1 at the bud neck due to the negative curvature of this region. As a result, the coat should be stable as long as the bud remains attached and should disassemble as soon as membrane fission occurs.

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ARFGAP1 promotes the formation of COPI vesicles, suggesting function as a component of the coat

The Journal of Cell Biology ◽

10.1083/jcb.200206015 ◽

2002 ◽

Vol 159 (1) ◽

pp. 69-78 ◽

Cited By ~ 135

Author(s):

Jia-Shu Yang ◽

Stella Y. Lee ◽

Minggeng Gao ◽

Sylvain Bourgoin ◽

Paul A. Randazzo ◽

...

Keyword(s):

Coat Protein ◽

Gap Functions ◽

Vesicle Formation ◽

Golgi Membrane ◽

Gtpase Activating Protein ◽

Cargo Proteins ◽

Adp Ribosylation Factor ◽

Soluble Components ◽

Cargo Sorting

The role of GTPase-activating protein (GAP) that deactivates ADP-ribosylation factor 1 (ARF1) during the formation of coat protein I (COPI) vesicles has been unclear. GAP is originally thought to antagonize vesicle formation by triggering uncoating, but later studies suggest that GAP promotes cargo sorting, a process that occurs during vesicle formation. Recent models have attempted to reconcile these seemingly contradictory roles by suggesting that cargo proteins suppress GAP activity during vesicle formation, but whether GAP truly antagonizes coat recruitment in this process has not been assessed directly. We have reconstituted the formation of COPI vesicles by incubating Golgi membrane with purified soluble components, and find that ARFGAP1 in the presence of GTP promotes vesicle formation and cargo sorting. Moreover, the presence of GTPγS not only blocks vesicle uncoating but also vesicle formation by preventing the proper recruitment of GAP to nascent vesicles. Elucidating how GAP functions in vesicle formation, we find that the level of GAP on the reconstituted vesicles is at least as abundant as COPI and that GAP binds directly to the dilysine motif of cargo proteins. Collectively, these findings suggest that ARFGAP1 promotes vesicle formation by functioning as a component of the COPI coat.

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