Procollagen Traverses the Golgi Stack without Leaving the Lumen of Cisternae

Bonfanti, Lidia; Mironov, Aleksandr; Martı́nez-Menárguez, José A.; Martella, Oliviano; Fusella, Aurora; Baldassarre, Massimiliano; Buccione, Roberto; Geuze, Hans J.; Luini, Alberto

doi:10.1016/s0092-8674(00)81723-7

Cited by 380 publications

(360 citation statements)

References 31 publications

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“…Thus, procollagen I-III C-propeptide processing may occur intracellularly or extracellularly, in a cell type-specific/tissue-specific manner. The major fibrillar procollagens appear to form intracellular aggregates prior to secretion (Birk and Trelstad, 1984;Bonfanti et al, 1998;Canty et al, 2004), and these aggregates may constitute the normal in vivo substrates for pCP activity. The latter possibility is supported by the finding that aggregated type I procollagen is processed more rapidly by pCP activity than is monomeric procollagen .…”

Section: Fibrillar Collagensmentioning

confidence: 99%

The bone morphogenetic protein 1/Tolloid-like metalloproteinases

2007

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A decade ago, bone morphogenetic protein 1 (BMP1) was shown to provide the activity necessary for proteolytic removal of the C-propeptides of procollagens I-III: precursors of the major fibrillar collagens. Subsequent studies have shown BMP1 to be the prototype of a small group of extracellular metalloproteinases that play manifold roles in regulating formation of the extracellular matrix (ECM). Soon after initial cloning of BMP1, genetic studies showed the related Drosophila proteinase Tolloid (TLD) to be necessary for formation of the dorsal-ventral axis in early embryogenesis. It is now clear that the BMP1/TLD-like proteinases, conserved in species ranging from Drosophila to humans, act in dorsal-ventral patterning via activation of transforming growth factor β (TGFβ)-like proteins BMP2, BMP4 (vertebrates) and decapentaplegic (arthropods). More recently, it has become apparent that the BMP1/TLD-like proteinases are key activators of a broader subset of the TGFβ superfamily of proteins, with implications that these proteinases may be key in orchestrating formation of ECM with growth factor activation and BMP signaling in morphogenetic processes.

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Section: Fibrillar Collagensmentioning

confidence: 99%

The bone morphogenetic protein 1/Tolloid-like metalloproteinases

2007

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“…The current model for transport through the Golgi apparatus postulates that anterograde transport is an indirect consequence of retrograde transport of Golgi resident enzymes from earlier to later compartments (Bonfanti et al, 1998;Glick and Malhotra, 1998;de Graffenried and Bertozzi, 2004). Retrograde transport of many proteins is mediated by the COPI coat, a heptameric complex that cycles between membranes and cytoplasm (Bonifacino and LippincottSchwartz, 2003;Duden, 2003;Lee et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In the cisternal maturation model of Golgi traffic, glycosylation enzymes and fusion machinery are transported from later Golgi compartments back to earlier ones and from the cis-Golgi and/or intermediate compartment to the endoplasmic reticulum (ER) (Bonfanti et al, 1998;Glick and Malhotra, 1998). In this way, an early Golgi compartment is transformed into a later one when it receives incoming glycosylation enzymes from this later compartment (de Graffenried and Bertozzi, 2004).…”

Section: Introductionmentioning

confidence: 99%

Mutations in a Highly Conserved Region of the Arf1p ActivatorGEA2Block Anterograde Golgi Transport but Not COPI Recruitment to Membranes

Park

Hartnell

Jackson

2005

MBoC

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We have identified an important functional region of the yeast Arf1 activator Gea2p upstream of the catalytic Sec7 domain and characterized a set of temperature-sensitive (ts) mutants with amino acid substitutions in this region. These gea2-ts mutants block or slow transport of proteins traversing the secretory pathway at exit from the endoplasmic reticulum (ER) and the early Golgi, and accumulate both ER and early Golgi membranes. No defects in two types of retrograde trafficking/sorting assays were observed. We find that a substantial amount of COPI is associated with Golgi membranes in the gea2-ts mutants, even after prolonged incubation at the nonpermissive temperature. COPI in these mutants is released from Golgi membranes by brefeldin A, a drug that binds directly to Gea2p and blocks Arf1 activation. Our results demonstrate that COPI function in sorting of at least three retrograde cargo proteins within the Golgi is not perturbed in these mutants, but that forward transport is severely inhibited. Hence this region of Gea2p upstream of the Sec7 domain plays a role in anterograde transport that is independent of its role in recruiting COPI for retrograde transport, at least of a subset of Golgi-ER cargo.

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“…There are three prevailing theories for how membrane and luminal cargo are transported: (i) by carrier vesicles that move cargo between physically distinct Golgi cisternae in both the anterograde and retrograde directions (1,2), (ii) by the forward movement or ''progression'' of the cisternae themselves, accompanied by vesicle movement in the retrograde direction (3)(4)(5), or (iii) by both mechanisms acting in concert (6)(7)(8). Direct membrane connections between cisternae at different levels of the Golgi also have been proposed (8)(9)(10)(11).…”

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confidence: 99%

Direct continuities between cisternae at different levels of the Golgi complex in glucose-stimulated mouse islet beta cells

Marsh

Volkmann

McIntosh

et al. 2004

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

169

137

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Direct continuity between the membranes of cisternae in the Golgi complex in mammalian cells rarely has been observed; when seen, its documentation has been equivocal. Here we have used dualaxis electron microscope tomography to examine the architecture of the Golgi in three dimensions at Ϸ6-nm resolution in rapidly frozen, freeze-substituted murine cells that make and secrete insulin in response to glucose challenge. Our data show three types of direct connections between Golgi cisternae that are normally distinct from one another. These connections all ''bypass'' interceding cisternae. We propose that when pancreatic beta cells are stimulated to synthesize and secrete insulin rapidly in vivo, such connections provide a continuous lumen that facilitates the rapid transit of large amounts of newly made protein for secretion. The heterotypic fusion of cisternae, even transiently, raises important questions about the molecular mechanisms that (i) facilitate the fusion͞fission of cisternal membranes and control the directionality and specificity of such events, and (ii) retain Golgi processing enzymes at specific places within individual cisternae when two cisternae at different levels in the Golgi have fused, maintaining the sequential processing hierarchy that is a hallmark of Golgi organization.T he mechanisms by which proteins and lipids move through the Golgi complex remain controversial. There are three prevailing theories for how membrane and luminal cargo are transported: (i) by carrier vesicles that move cargo between physically distinct Golgi cisternae in both the anterograde and retrograde directions (1, 2), (ii) by the forward movement or ''progression'' of the cisternae themselves, accompanied by vesicle movement in the retrograde direction (3-5), or (iii) by both mechanisms acting in concert (6-8). Direct membrane connections between cisternae at different levels of the Golgi also have been proposed (8-11). Lippincott-Schwartz and colleagues (11) have suggested that such connections might constitute a major mechanism for transport through the Golgi stack, based on data that show first order kinetics for the rate of transport of exogenous viral glycoprotein of vesicular stomatitis virus through the Golgi following its overexpression in cultured cells. Convincing evidence for direct continuity between nonequivalent cisternae has been limited or lacking, although connectivity between cisternae at equivalent levels of the Golgi ribbon is well documented (12)(13)(14).In this study, rapid freezing followed by freeze-substitution fixation of endocrine tissue isolated from mouse pancreas, together with techniques for analyzing electron microscope (EM) data in 3D at Ϸ6-nm resolution (15), have allowed us to capture and visualize such events in ''professional'' secretory cells stimulated to make and secrete large amounts of protein.Our observations of membrane trafficking in primary cells maintained in organ culture and stimulated to secrete at high levels suggest that the overexpression of proteins from transg...

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Procollagen Traverses the Golgi Stack without Leaving the Lumen of Cisternae

Cited by 380 publications

References 31 publications

The bone morphogenetic protein 1/Tolloid-like metalloproteinases

The bone morphogenetic protein 1/Tolloid-like metalloproteinases

Mutations in a Highly Conserved Region of the Arf1p ActivatorGEA2Block Anterograde Golgi Transport but Not COPI Recruitment to Membranes

Direct continuities between cisternae at different levels of the Golgi complex in glucose-stimulated mouse islet beta cells

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