Prosomatostatin II processing is initiated in the trans-Golgi network of anglerfish pancreatic cells |
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Authors: | J Bourdais G Devilliers R Girard A Morel L Benedetti P Cohen |
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Institution: | Groupe de Neurobiochimie Cellulaire et Moléculaire, URA 554 du CNRS, Université Pierre et Marie Curie, Paris. |
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Abstract: | Anglerfish prosomatostatin II, the precursor of somatostatin-28 II, is produced in different cells from prosomatostatin I, by a cleavage at Arg73. Antibodies were raised against the carboxy-terminal 64-72] portion of the precursor II upstream from somatostatin-28 II sequence. These antibodies recognized only this epitope when unmasked from the entire precursor, allowing the detection of the 1-72] domain which was isolated from pancreatic islets extracts. The antibodies were used to monitor the peptide bond cleavage occurring at the carboxy terminus of Arg73 to generate somatostatin-28 II. Immunocytochemistry revealed labeling both in the vesicles budding from the trans-Golgi network and in the dense core granules. Together, these data support the conclusions that i) prohormone processing is initiated in the Golgi apparatus of the pancreatic islet cells; ii) the "non-hormonal" 1-72] amino-terminal domain of the precursor may be involved in some intra and/or extra-cellular function(s). |
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