Electron microscopic immunocytochemical evidence for the involvement of the convertases PC1 and PC2 in the processing of proinsulin in pancreatic beta-cellsD Malide, NG Seidah, M Chretien and M Bendayan Department of Anatomy, Universite de Montreal, Quebec, Canada. Endoproteolytic cleavage of pairs of basic amino acids is the key mechanism in the specific processing of precursor hormone molecules. Two endoproteases, PC1 (or PC3) and PC2, have recently been implicated in the conversion of proinsulin. Using antibodies against these proteases and proinsulin, followed by protein A-gold complex, we performed an immunocytochemical study for precise identification of the subcellular compartments involved in the processing of insulin. Both PC1 and PC2 immunoreactivities followed a pattern of gradually increasing density along the secretory pathway, being higher in the immature granules. Proinsulin labeling was detected in the Golgi apparatus and in the coated immature secretory granules located mainly in the Golgi area. Using double labeling, we demonstrated the presence of PC1 and/or PC2 in the majority of proinsulin-rich granules. In addition, we provided evidence that PC1 and PC2 are co-localized within the same granules. Co-expression of PC1 and PC2 with proinsulin in islet beta-cells indicates that these proteases are actively involved, probably in a sequential manner, in the conversion of proinsulin into insulin.
Volume 43,
Issue 1,
pp. 11-19,
01/01/1995
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A. Dey, C. Norrbom, X. Zhu, J. Stein, C. Zhang, K. Ueda, and D. F. Steiner Furin and Prohormone Convertase 1/3 Are Major Convertases in the Processing of Mouse Pro-Growth Hormone-Releasing Hormone Endocrinology, April 1, 2004; 145(4): 1961 - 1971. [Abstract] [Full Text] [PDF] |
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A. Catania, S. Gatti, G. Colombo, and J. M. Lipton Targeting Melanocortin Receptors as a Novel Strategy to Control Inflammation Pharmacol. Rev., March 1, 2004; 56(1): 1 - 29. [Abstract] [Full Text] [PDF] |
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Y. Yaoi, M. Suzuki, H. Tomura, S. Kurabuchi, Y. Sasayama, and S. Tanaka Expression and Localization of Prohormone Convertase PC1 in the Calcitonin-producing Cells of the Bullfrog Ultimobranchial Gland J. Histochem. Cytochem., November 1, 2003; 51(11): 1459 - 1466. [Abstract] [Full Text] [PDF] |
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S. Kurabuchi and S. Tanaka Immunocytochemical Localization of Prohormone Convertases PC1 and PC2 in the Mouse Thyroid Gland and Respiratory Tract J. Histochem. Cytochem., July 1, 2002; 50(7): 903 - 910. [Abstract] [Full Text] [PDF] |
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K. L. Regnauld, E. Leteurtre, S. J. Gutkind, C. P. Gespach, and S. Emami Activation of adenylyl cyclases, regulation of insulin status, and cell survival by Galpha olf in pancreatic beta -cells Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2002; 282(3): R870 - R880. [Abstract] [Full Text] [PDF] |
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B. B. Toure, J. S. Munzer, A. Basak, S. Benjannet, J. Rochemont, C. Lazure, M. Chretien, and N. G. Seidah Biosynthesis and Enzymatic Characterization of Human SKI-1/S1P and the Processing of Its Inhibitory Prosegment J. Biol. Chem., January 28, 2000; 275(4): 2349 - 2358. [Abstract] [Full Text] [PDF] |
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A. Arias, C. Velez-Granell, G Mayer, and M Bendayan Colocalization of chaperone Cpn60, proinsulin and convertase PC1 within immature secretory granules of insulin-secreting cells suggests a role for Cpn60 in insulin processing J. Cell Sci., January 6, 2000; 113(11): 2075 - 2083. [Abstract] [PDF] |
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S. Dhanvantari and P. L. Brubaker Proglucagon Processing in an Islet Cell Line: Effects of PC1 Overexpression and PC2 Depletion Endocrinology, April 1, 1998; 139(4): 1630 - 1637. [Abstract] [Full Text] [PDF] |
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L. Muller, R. Picart, A. Barret, N. G. Seidah, and C. Tougard Immunocytochemical Localization of the Prohormone Convertases PC1 and PC2 in Rat Prolactin Cells J. Histochem. Cytochem., January 1, 1998; 46(1): 101 - 108. [Abstract] [Full Text] |
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J. S. Munzer, A. Basak, M. Zhong, A. Mamarbachi, J. Hamelin, D. Savaria, C. Lazure, S. Benjannet, M. Chretien, and N. G. Seidah In Vitro Characterization of the Novel Proprotein Convertase PC7 J. Biol. Chem., August 8, 1997; 272(32): 19672 - 19681. [Abstract] [Full Text] [PDF] |
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S. Tanaka, T. Yora, K. Nakayama, K. Inoue, and K. Kurosumi Proteolytic Processing of Pro-opiomelanocortin Occurs in Acidifying Secretory Granules of AtT-20 Cells J. Histochem. Cytochem., January 1, 1997; 45(3): 425 - 436. [Abstract] [Full Text] [PDF] |
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E. Decroly, S. Wouters, C. Di Bello, C. Lazure, J.-M. Ruysschaert, and N. G. Seidah Identification of the Paired Basic Convertases Implicated in HIV gp160 Processing Based on in Vitro Assays and Expression in CD4+ Cell Lines J. Biol. Chem., November 29, 1996; 271(48): 30442 - 30450. [Abstract] [Full Text] [PDF] |
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J. W.M. Creemers, E. F. Usac, N. A. Bright, J.-W. Van de Loo, E. Jansen, W. J.M. Van de Ven, and J. C. Hutton Identification of a Transferable Sorting Domain for the Regulated Pathway in the Prohormone Convertase PC2 J. Biol. Chem., October 11, 1996; 271(41): 25284 - 25291. [Abstract] [Full Text] [PDF] |
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G. N. Hendy, H. P. J. Bennett, B. F. Gibbs, C. Lazure, R. Day, and N. G. Seidah Proparathyroid Hormone Is Preferentially Cleaved to Parathyroid Hormone by the Prohormone Convertase Furin J. Biol. Chem., April 21, 1995; 270(16): 9517 - 9525. [Abstract] [Full Text] [PDF] |
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