The disulfide-bonded loop of chromogranin B mediates membrane binding and directs sorting from the trans-Golgi network to secretory granules

Glombik, Michael M.; Krömer, Andreas; Salm, Thorsten; Huttner, Wieland B.; Gerdes, Hans‐Hermann

doi:10.1093/emboj/18.4.1059

Cited by 113 publications

(100 citation statements)

References 44 publications

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“…30), and this aggregation has repeatedly been suggested to play a role in sorting of regulated secretory proteins. Interestingly, aggregation is neither necessary nor sufficient for sorting in PC12 cells (12,16). To test if the missorting of CgA341 in GH4C1 cells could be explained by a lack of aggregation, the sorting and aggregation of wild-type CgA, CgA341, and the constitutive secretory pathway marker SEAP (28) were separately determined by immunoblotting (CgA) or alkaline phosphatase activity (SEAP).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, pro-opiomelanocortin (POMC) 1 is sorted by binding to carboxypeptidase E and this sorting depends on an N-terminal disulfide bridge in POMC (9). Chromogranins contain a similar N-terminal disulfide bond that is both necessary and sufficient for sorting in PC12 cells (11)(12)(13)(14), although carboxypeptidase E does not appear to mediate this sorting (11,15). While chromogranins aggregate at low pH and in the presence of calcium, this aggregation is neither necessary nor sufficient for sorting in PC12 cells (12,16).…”

mentioning

confidence: 99%

“…Chromogranins contain a similar N-terminal disulfide bond that is both necessary and sufficient for sorting in PC12 cells (11)(12)(13)(14), although carboxypeptidase E does not appear to mediate this sorting (11,15). While chromogranins aggregate at low pH and in the presence of calcium, this aggregation is neither necessary nor sufficient for sorting in PC12 cells (12,16). In contrast, a narrowly defined aggregation domain is necessary for sorting of pro-atrial natriuretic factor to the regulated secretory pathway in AtT-20 cells (17).…”

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confidence: 99%

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N- and C-terminal Domains Direct Cell Type-specific Sorting of Chromogranin A to Secretory Granules

Cowley

Moore

Darling

et al. 2000

Journal of Biological Chemistry

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Chromogranins are a family of regulated secretory proteins that are stored in secretory granules in endocrine and neuroendocrine cells and released in response to extracellular stimulation (regulated secretion). A conserved N-terminal disulfide bond is necessary for sorting of chromogranins in neuroendocrine PC12 cells. Surprisingly, this disulfide bond is not necessary for sorting of chromogranins in endocrine GH4C1 cells. To investigate the sorting mechanism in GH4C1 cells, we made several mutant forms removing highly conserved N-and C-terminal regions of bovine chromogranin A. Removing the conserved N-terminal disulfide bond and the conserved C-terminal dimerization and tetramerization domain did not affect the sorting of chromogranin A to the regulated secretory pathway. In contrast, removing the C-terminal 90 amino acids of chromogranin A caused rerouting to the constitutive secretory pathway and impaired aggregation properties as compared with wildtype chromogranin A. Since this mutant was sorted to the regulated secretory pathway in PC12 cells, these results demonstrate that chromogranins contain independent N-and C-terminal sorting domains that function in a cell type-specific manner. Moreover, this is the first evidence that low pH/calcium-induced aggregation is necessary for sorting of a chromogranin to the regulated secretory pathway of endocrine cells.Peptide hormones and neuropeptides are stored at high concentrations in secretory granules of endocrine and neuroendocrine cells. This storage is required for the proteolytic processing of prohormones and the subsequent rapid release of active peptides in response to extracellular stimulation (for review, see Refs.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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N- and C-terminal Domains Direct Cell Type-specific Sorting of Chromogranin A to Secretory Granules

Cowley

Moore

Darling

et al. 2000

Journal of Biological Chemistry

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“…The transport of PrP in the presence of DTT and when both cysteine residues are mutated suggests that the disulfide bridge is not required for the prion protein to pass through the quality control check points. Other proteins, such as chromogranin B, which also contains a single disulfide bridge, are transported through the secretory pathway in the presence of DTT, although mis-sorting may occur (29,30). The importance of the disulfide bridge in prion disease is underlined by the finding that the disulfide bridge is required for the conversion of PrP C to PrP SC (31).…”

Section: Discussionmentioning

confidence: 99%

Prion Protein Glycosylation Is Sensitive to Redox Change

Capellari

Zaidi

Urig

et al. 1999

Journal of Biological Chemistry

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The conversion of soluble prion protein into an insoluble, pathogenic, protease-resistant isoform is a key event in the development of prion diseases. Although the mechanism by which the conversion engenders a pathogenic event is unclear, there is increasing evidence to suggest that this may depend on the function of the prion protein in preventing oxidative damage. Therefore, in this study, we assessed the interrelationship between redox-sensitive cysteine, glycosylation, and prion metabolism. Cells were treated with a thioreductant, dithiothreitol, to assess the effect of the cellular oxidation state on the synthesis of the prion protein. This change in redox balance affected the glycosylation of the prion protein, resulting in the sole production of glycosylated forms. The role of the single disulfide bridge in mediating this effect within the prion protein was confirmed by mutating the cysteine residues involved in its formation. These data suggest that conditions that increase the rate of formation of the disulfide bridge favor formation of the unglycosylated prion protein. Thus, since the presence of glycans on the prion protein is protective against its pathogenic conversion, a change in the redox status of the cell would increase the risk of developing a prion disease by favoring the production of the unglycosylated form.

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“…Pancreatic beta cells and beta cell lines are also known to synthesise, in addition to insulin, a number of other secretory proteins, including members of the granin family, chromogranin A and chromogranin B (CgB) [7][8][9][10]. Based on intracellular distribution studies [7,8] and on data obtained in other cell lines (AtT20 and PC12), these granins are believed to play important roles both in the sorting, packaging and processing of secretion products [11][12][13][14], and in the storage of Ca 2+ within SG lumina [15]. Moreover chromogranin A and/or peptides derived from its processing have been reported to play autocrine, paracrine and endocrine functions upon discharge [16][17][18][19], while CgB has been shown to induce an autocrine inhibition of insulin release from beta cells [20].…”

Section: Introductionmentioning

confidence: 99%

Beta cell chromogranin B is partially segregated in distinct granules and can be released separately from insulin in response to stimulation

et al. 2008

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Aims/hypothesis We investigated, in three beta cell lines (INS-1E, RIN-5AH, betaTC3) and in human and rodent primary beta cells, the storage and release of chromogranin B, a secretory protein expressed in beta cells and postulated to play an autocrine role. We asked whether chromogranin B is stored together with and discharged in constant ratio to insulin upon various stimuli. Methods The intracellular distribution of insulin and chromogranin B was revealed by immunofluorescence followed by three-dimensional image reconstruction and by immunoelectron microscopy; their stimulated discharge was measured by ELISA and immunoblot analysis of homogenates and incubation media. Results Insulin and chromogranin B, co-localised in the Golgi complex/trans-Golgi network, appeared largely segregated from each other in the secretory granule compartment. In INS-1E cells, the percentage of granules positive only for insulin or chromogranin B and of those positive for both was 66, 7 and 27%, respectively. In resting cells, both insulin and chromogranin B were concentrated in the granule cores; upon stimulation, chromogranin B (but not insulin) was largely redistributed to the core periphery and the surrounding halo. Strong stimulation with a secretagogue mixture induced parallel release of insulin and chromogranin B, whereas with 3-isobutyl-1-methylxantine and forskolin ± high glucose release of chromogranin B predominated. Weak, Ca 2+ -dependent stimulation with ionomycin or carbachol induced exclusive release of chromogranin B, suggesting a higher Ca 2+ sensitivity of the specific granules. Conclusions/interpretation The unexpected complexity of the beta cell granule population in terms

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The disulfide-bonded loop of chromogranin B mediates membrane binding and directs sorting from the trans-Golgi network to secretory granules

Cited by 113 publications

References 44 publications

N- and C-terminal Domains Direct Cell Type-specific Sorting of Chromogranin A to Secretory Granules

N- and C-terminal Domains Direct Cell Type-specific Sorting of Chromogranin A to Secretory Granules

Prion Protein Glycosylation Is Sensitive to Redox Change

Beta cell chromogranin B is partially segregated in distinct granules and can be released separately from insulin in response to stimulation

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