Prosomatostatin II processing is initiated in the trans-Golgi network of anglerfish pancreatic cells
Bourdais, J.; Devilliers, G.; Girard, R.; Morel, A.; Benedetti, L.; Cohen, P.
Biochemical and Biophysical Research Communications 170(3): 1263-1272
1990
ISSN/ISBN: 0006-291X PMID: 1975170 Document Number: 359511
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).