The COPII cage: unifying principles of vesicle coat assembly

Gürkan, Cemal; Stagg, Scott M.; LaPointe, Paul; Balch, William E.

doi:10.1038/nrm2025

Cited by 194 publications

(168 citation statements)

References 90 publications

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“…If the folding of ERAD substrates takes place with the help of ER chaperones, the folded proteins may dissociate from Bap31 and be incorporated into COPII vesicles at peripheral ER exit sites (Ellgaard and Helenius, 2003). Perhaps because it takes some time for inefficiently folding proteins to be matured, they may move with Bap31 in a dynein-dynactin-dependent manner from the peripheral ER to the juxtanuclear region where ER exit sites are concentrated (Gurkan et al, 2006). When folding occurs, ERAD substrates exit the ER from the juxtanuclear exit sites.…”

Section: Possible Implication For Bap31 Cyclingmentioning

confidence: 99%

“…To explore this possibility, we investigated whether chemicals that perturb microtubule-dependent membrane transport from the ER affect Bap31 localization. H89 blocks protein export out of the ER (Jamora et al, 1999) perhaps by mildly inhibiting the binding of COPII proteins to ER exit sites (Aridor and Balch, 2000; Lee and Linstedt, 2000), where COPII-coated vesicles involved in ER-to-Golgi transport are formed (Gurkan et al, 2006). It also blocks Golgi disassembly occurring during mitosis, likely by keeping Arf1, a small GTPase that regulates the recruitment of COPI to membranes (LippincottSchwartz and Liu, 2006), in an active state (Altan-Bonnet et al, 2003).…”

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confidence: 99%

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Bap31 Is an Itinerant Protein That Moves between the Peripheral Endoplasmic Reticulum (ER) and a Juxtanuclear Compartment Related to ER-associated Degradation

Wakana

Takai

Nakajima

et al. 2008

MBoC

102

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Certain endoplasmic reticulum (ER)-associated degradation (ERAD) substrates with transmembrane domains are segregated from other ER proteins and sorted into a juxtanuclear subcompartment, known as the ER quality control compartment. Bap31 is an ER protein with three transmembrane domains, and it is assumed to be a cargo receptor for ER export of some transmembrane proteins, especially those prone to ERAD. Here, we show that Bap31 is a component of the ER quality control compartment and that it moves between the peripheral ER and a juxtanuclear ER or ER-related compartment distinct from the conventional ER-Golgi intermediate compartment. The third and second transmembrane domains of Bap31 are principally responsible for the movement to and recycling from the juxtanuclear region, respectively. This cycling was blocked by depolymerization of microtubules and disruption of dynein-dynactin function. Overexpression of Sar1p and Arf1 mutants affected Bap31 cycling, suggesting that this cycling pathway is related to the conventional vesicular transport pathways. INTRODUCTIONThe endoplasmic reticulum (ER) exhibits a reticular tubular network that extends from the nucleus to the cell periphery along microtubule tracks. It performs a variety of functions, including the synthesis, posttranslational modifications, quality control, and export of secretory and membrane proteins; the synthesis of lipids; stress response; Ca 2ϩ storage; and apoptosis. Most, if not all, of these functions are managed by subdomains, such as the rough and smooth ER and transitional ER sites. Each subdomain contains a unique set of proteins that are responsible for its function and organization. ER subdomains are relatively stable, but they can be transformed into alternative structures in response to cellular conditions (for review, see Voeltz et al., 2002;Levine and Rabouille, 2005;Borgese et al., 2006;Vedrenne and Hauri, 2006).Several studies showed the presence of a specialized ER subdomain that is related to ER-associated degradation (ERAD). ERAD is part of a quality control system that ensures the delivery of only correctly folded or assembled secretory and membrane proteins to their final destinations. Newly synthesized proteins that fail to fold or assemble correctly are retained in the ER, retrotranslocated to the cytosol, and degraded by the ubiquitin-proteasome system (for review, see Ellgaard and Helenius, 2003;Meusser et al., 2005;Rö misch, 2005). Studies using mammalian cells demonstrated that transmembrane ERAD substrates are segregated into "ER quality control compartments," which become discernible at the juxtanuclear region upon inhibition of ERAD by proteasome inhibitors (Kamhi-Nesher et al., 2001;Spiliotis et al., 2002). In Saccharomyces cerevisiae, ectopically expressed cystic fibrosis transmembrane conductance regulator (CFTR) is segregated from other ER proteins and accumulates in ER-associated compartments (Kiser et al., 2001;Zhang et al., 2001;Huyer et al., 2004). Degradation of CFTR in yeast is independent of ER-to-Golgi tr...

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Section: Possible Implication For Bap31 Cyclingmentioning

confidence: 99%

mentioning

confidence: 99%

Bap31 Is an Itinerant Protein That Moves between the Peripheral Endoplasmic Reticulum (ER) and a Juxtanuclear Compartment Related to ER-associated Degradation

Wakana

Takai

Nakajima

et al. 2008

MBoC

102

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“…The COPII coat, which consists of the small GTPase Sar1p, Sec23/24 complex, and Sec13/31 complex, selects vesicle cargo through recognition of export signals and forms ER-derived vesicles through assembly of an outer layer cage structure (1,2). Cytoplasmically exposed ER export signals have been identified in secretory cargo including the C-terminal dihydrophic and diacidic motifs (3,4).…”

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confidence: 99%

Molecular Dissection of Erv26p Identifies Separable Cargo Binding and Coat Protein Sorting Activities

Bue

Barlowe

2009

Journal of Biological Chemistry

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“…This process has been extensively studied, particularly in budding yeast (1). Proteins destined to traffic from the ER to the Golgi are packaged into COPII (coat protein complex II)-coated vesicles (2)(3)(4). COPII is composed of at least five proteins, a small GTPase SAR1 and two cytosolic protein complexes, SEC23-SEC24 and SEC13-SEC31 (5).…”

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confidence: 99%

SEC23B is required for the maintenance of murine professional secretory tissues

Tao

Zhu

Wang

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

105

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In eukaryotic cells, newly synthesized secretory proteins require COPII (coat protein complex II) to exit the endoplasmic reticulum (ER). COPII contains five core components: SAR1, SEC23, SEC24, SEC13, and SEC31. SEC23 is a GTPase-activating protein that activates the SAR1 GTPase and also plays a role in cargo recognition. Missense mutations in the human COPII paralogues SEC23A and SEC23B result in craniolenticulosutural dysplasia and congenital dyserythropoietic anemia type II, respectively. We now report that mice completely deficient for SEC23B are born with no apparent anemia phenotype, but die shortly after birth, with degeneration of professional secretory tissues. In SEC23B-deficient embryonic pancreas, defects occur in exocrine and endocrine tissues shortly after differentiation. Pancreatic acini are completely devoid of zymogen granules, and the ER is severely distended. Similar ultrastructural alterations are also observed in salivary glands, but not in liver. Accumulation of proteins in the ER lumen activates the proapoptotic pathway of the unfolded protein response, suggesting a central role for apoptosis in the degeneration of these tissues in SEC23B-deficient embryos. Although maintenance of the secretory pathway should be required by all cells, our findings reveal a surprising tissue-specific dependence on SEC23B for the ER exit of highly abundant cargo, with high levels of SEC23B expression observed in professional secretory tissues. The disparate phenotypes in mouse and human could result from residual SEC23B function associated with the hypomorphic mutations observed in humans, or alternatively, might be explained by a species-specific shift in function between the closely related SEC23 paralogues. mammalian embryo abnormalities | vesicular transport protein | genetics | secretory granules | pancreatitis I n eukaryotic cells, secreted proteins and proteins that are targeted to the plasma membrane and internal organelles are synthesized in the endoplasmic reticulum (ER) and sorted through the secretory pathway. This process has been extensively studied, particularly in budding yeast (1). Proteins destined to traffic from the ER to the Golgi are packaged into COPII (coat protein complex II)-coated vesicles (2-4). COPII is composed of at least five proteins, a small GTPase SAR1 and two cytosolic protein complexes, SEC23-SEC24 and SEC13-SEC31 (5). The GTP-bound form of SAR1 binds to the ER membrane and recruits the SEC23-SEC24 heterodimer to form the "prebudding complex," which in turn recruits the outer coat composed of SEC13-SEC31 heterotetramers to complete the COPII coat structure (6).The COPII complex captures cargo into vesicles and mediates vesicle budding from the ER. Cargo recognition appears to be mediated primarily by the SEC24 subunit, which recognizes divergent export signals located in the cytosolic domain of cargo proteins (7,8). SEC23 and SAR1 also play a role in the recognition of at least a subset of cargos (9, 10). SEC23 is a GTPaseactivating protein (GAP) that activates the SAR1...

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The COPII cage: unifying principles of vesicle coat assembly

Cited by 194 publications

References 90 publications

Bap31 Is an Itinerant Protein That Moves between the Peripheral Endoplasmic Reticulum (ER) and a Juxtanuclear Compartment Related to ER-associated Degradation

Bap31 Is an Itinerant Protein That Moves between the Peripheral Endoplasmic Reticulum (ER) and a Juxtanuclear Compartment Related to ER-associated Degradation

Molecular Dissection of Erv26p Identifies Separable Cargo Binding and Coat Protein Sorting Activities

SEC23B is required for the maintenance of murine professional secretory tissues

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