Roles for α2p24 and COPI in Endoplasmic Reticulum Cargo Exit Site Formation

Lavoie, Christine; Paiement, Jacques; Dominguez, Michel; Roy, Line; Dahan, Sophie; Gushue, Jennifer N.; Bergeron, John J.M.

doi:10.1083/jcb.146.2.285

Cited by 93 publications

(106 citation statements)

References 55 publications

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“…5), this could also explain the observed changes in Golgi structure. This is consistent with recent data showing COPI to be necessary for the in vitro formation of vesiculo-tubular clusters (TC precursors) from transitional ER microsomes (63).…”

Section: Figsupporting

confidence: 82%

Membrane Recruitment of Coatomer and Binding to Dilysine Signals Are Separate Events

Gomez

Scales

Kreis

et al. 2000

Journal of Biological Chemistry

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Section: Figsupporting

confidence: 82%

Membrane Recruitment of Coatomer and Binding to Dilysine Signals Are Separate Events

Gomez

Scales

Kreis

et al. 2000

Journal of Biological Chemistry

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“…Furthermore, a study on the reconstitution of the secretory pathway in a cell-free assay suggests that p25 plays a role in the de novo formation of the ERGIC (Lavoie et al, 1999). Based on these findings, we considered the possibility that the knockdowns might also induce changes at the level of the ERGIC.…”

Section: Cargo Receptor Silencing Destabilizes the Ergic Without Affementioning

confidence: 99%

The Cargo Receptors Surf4, Endoplasmic Reticulum-Golgi Intermediate Compartment (ERGIC)-53, and p25 Are Required to Maintain the Architecture of ERGIC and Golgi

Mitrović

Ben-Tekaya

Koegler

et al. 2008

MBoC

116

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Rapidly cycling proteins of the early secretory pathway can operate as cargo receptors. Known cargo receptors are abundant proteins, but it remains mysterious why their inactivation leads to rather limited secretion phenotypes. Studies of Surf4, the human orthologue of the yeast cargo receptor Erv29p, now reveal a novel function of cargo receptors. Surf4 was found to interact with endoplasmic reticulum-Golgi intermediate compartment (ERGIC)-53 and p24 proteins. Silencing Surf4 together with ERGIC-53 or silencing the p24 family member p25 induced an identical phenotype characterized by a reduced number of ERGIC clusters and fragmentation of the Golgi apparatus without effect on anterograde transport. Live imaging showed decreased stability of ERGIC clusters after knockdown of p25. Silencing of Surf4/ERGIC-53 or p25 resulted in partial redistribution of coat protein (COP) I but not Golgi matrix proteins to the cytosol and partial resistance of the cis-Golgi to brefeldin A. These findings imply that cargo receptors are essential for maintaining the architecture of ERGIC and Golgi by controlling COP I recruitment. INTRODUCTIONThe secretory pathway of higher eukaryotic cells is composed of the three membrane organelles endoplasmic reticulum (ER), ER-Golgi intermediate compartment (ERGIC), and Golgi (Bonifacino and Glick, 2004;Appenzeller-Herzog and Hauri, 2006). Maintenance of these organelles requires a balance of anterograde (secretory) and retrograde vesicular traffic. Anterograde traffic from ER to ERGIC is mediated by coat protein (COP) II vesicles that form at ER exit sites (Aridor et al., 1995;Zeuschner et al., 2006) and fuse with the ERGIC that consists of a few hundred tubulovesicular membrane clusters in vicinity of ER exit sites (AppenzellerHerzog and Hauri, 2006). Transport from ERGIC to Golgi is mediated by pleomorphic vesicles (Ben-Tekaya et al., 2005) that carry COP I (Presley et al., 1997;Scales et al., 1997), although the mechanism of their formation remains unknown. Retrograde traffic mediated by COP I vesicles can occur from ERGIC or Golgi and recycles membrane proteins that possess either dilysine signals, including ERGIC-53 and KDEL-receptor, or diphenylalanine signals, such as members of the 24 protein family. This rapid COP I-dependent recycling is distinct from the slow Golgi-to-ER recycling of Golgi resident proteins that is COP I independent and can be either constitutive or induced (Storrie, 2005).Major constituents of anterograde and retrograde transport vesicles are transmembrane cargo receptors that mediate protein sorting by linking soluble cargo on the luminal side and coat assembly on the cytoplasmic side. To date, only few cargo receptors have been studied in detail. The polytopic transmembrane protein Erv29p is known to cycle between ER and Golgi in yeast and to operate as a cargo receptor (Belden and Barlowe, 2001). Erv29p is required for efficient packaging of the glycosylated ␣-factor pheromone precursor into COP II vesicles departing from the ER. Maturation of carboxypeptidase Y...

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Section: Introductionmentioning

confidence: 99%

“…For Sar1p, this is Sec12p, a transmembrane protein of the ER ; for Arf1p, the most likely candidates are Gea1/2p and ARNO (ARF nucleotide binding site opener; Chardin et al, 1996;Peyroche et al, 1996). Regarding COPIcoated vesicles, coatomer also interacts with the cytoplasmic domain of two types of transmembrane proteins: either a member of the p23/24 protein family (Bremser et al, 1999;Lavoie et al, 1999) or a dilysine motif present on type I membrane-spanning ER resident proteins (Cosson and Letourneur, 1994).Coatomer has been isolated from mammalian (Waters et al., 1991) and yeast (Duden et al, 1994) cells and consists of seven polypeptides: ␣ -COP (Ret1p), 135 kD; ␤ -COP (Sec26p), 107 kD; ␤ '-COP (Sec27p), 102 kD; ␥ -COP (Sec21p), 97 kD; ␦ -COP (Ret2p), 57 kD; -COP (Sec28p), 36 kD; and -COP (Ret3p), 21 kD. ␥ -COP contains a binding site for both dilysine retrieval motifs and the diphenylalanine motif of p23 (Harter and Wieland, 1998).…”

mentioning

confidence: 99%

In Situ Localization and in Vitro Induction of Plant COPI-Coated Vesicles

et al. 2000

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Coat protein (COP)-coated vesicles have been shown to mediate protein transport through early steps of the secretory pathway in yeast and mammalian cells. Here, we attempt to elucidate their role in vesicular trafficking of plant cells, using a combined biochemical and ultrastructural approach. Immunogold labeling of cryosections revealed that COPI proteins are localized to microvesicles surrounding or budding from the Golgi apparatus. COPI-coated buds primarily reside on the cis -face of the Golgi stack. In addition, COPI and Arf1p show predominant labeling of the cis -Golgi stack, gradually diminishing toward the trans -Golgi stack. In vitro COPI-coated vesicle induction experiments demonstrated that Arf1p as well as coatomer could be recruited from cauliflower cytosol onto mixed endoplasmic reticulum (ER)/ Golgi membranes. Binding of Arf1p and coatomer is inhibited by brefeldin A, underlining the specificity of the recruitment mechanism. In vitro vesicle budding was confirmed by identification of COPI-coated vesicles through immunogold negative staining in a fraction purified from isopycnic sucrose gradient centrifugation. Similar in vitro induction experiments with tobacco ER/Golgi membranes prepared from transgenic plants overproducing barley ␣ -amylase-HDEL yielded a COPI-coated vesicle fraction that contained ␣ -amylase as well as calreticulin. INTRODUCTIONProtein trafficking in the secretory and endocytotic pathways is facilitated by coated vesicles (Rothman and Wieland, 1996;Robinson et al., 1998). Research on mammalian and yeast cells has established that two different types of non-clathrin-coated vesicles are responsible for transport events occurring between the endoplasmic reticulum (ER) and the Golgi apparatus and for intra-Golgi transport. Whereas investigators generally agree that COPIIcoated vesicles bud from the ER and transport proteins in the anterograde direction (Barlowe et al., 1994;Bannykh and Balch, 1998), the function of COPI-coated vesicles remains controversial. Strong evidence suggests that COPIcoated vesicles are responsible for the recycling of escaped ER-resident proteins from post-ER compartments (Letourneur et al., 1994), but data have also been presented supporting a role in anterograde transport of proteins, especially within the Golgi stack (Orci et al., 1997;Lippincott-Schwartz et al., 1998).The formation of both types of COP-coated vesicles involves the recruitment of a coat protein complex (coatomer for COPI-coated vesicles, Sec23/24 and Sec13/31 dimers for COPII-coated vesicles) by a membrane-associated GTP binding protein (Arf1p and Sar1p for COPI and COPII, respectively; Schekman and Orci, 1996). Both Arf1p and Sar1p exist in the cytosol as GDP-bound forms and become converted to the GTP form through the action of a membrane-associated exchange factor, guanine nucleotide exchange factor (Helms and Rothman, 1992). For Sar1p, this is Sec12p, a transmembrane protein of the ER ; for Arf1p, the most likely candidates are Gea1/2p and ARNO (ARF nucleotide binding site opener; ...

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Roles for α2p24 and COPI in Endoplasmic Reticulum Cargo Exit Site Formation

Cited by 93 publications

References 55 publications

Membrane Recruitment of Coatomer and Binding to Dilysine Signals Are Separate Events

Membrane Recruitment of Coatomer and Binding to Dilysine Signals Are Separate Events

The Cargo Receptors Surf4, Endoplasmic Reticulum-Golgi Intermediate Compartment (ERGIC)-53, and p25 Are Required to Maintain the Architecture of ERGIC and Golgi

In Situ Localization and in Vitro Induction of Plant COPI-Coated Vesicles

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