Prosomatostatin II processing is initiated in the trans-Golgi network of anglerfish pancreatic cells.
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).
Bourdais
J
J
Groupe de Neurobiochimie Cellulaire et Moléculaire, URA 554 du CNRS, Université Pierre et Marie Curie, Paris.
Devilliers
G
G
Girard
R
R
Morel
A
A
Benedetti
L
L
Cohen
P
P
D000818:Animals; D005399:Fishes; D006056:Golgi Apparatus / Q000378:metabolism*; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D010179:Pancreas / Q000378:metabolism* / Q000648:ultrastructure; D011498:Protein Precursors / Q000276:immunology / Q000378:metabolism*; D013004:Somatostatin / Q000276:immunology / Q000378:metabolism*
D011498:Protein Precursors; D013004:Somatostatin; C028456:prosomatostatin