title: Calsyntenins are secretory granule proteins in anterior pituitary gland and pancreatic islet alpha cells.
abstract: Calsyntenins are members of the cadherin superfamily of cell adhesion molecules. They are present in postsynaptic membranes of excitatory neurons and in vesicles in transit to neuronal growth cones. In the current study, calsyntenin-1 (CST-1) and calsyntenin-3 (CST-3) were identified by mass spectrometric analysis (LC-MS/MS) of integral membrane proteins from highly enriched secretory granule preparations from bovine anterior pituitary gland. Immunofluorescence microscopy on thin frozen sections of rat pituitary revealed that CST-1 was present only in gonadotropes where it colocalized with follicle-stimulating hormone in secretory granules. In contrast, CST-3 was present not only in gonadotrope secretory granules but also in those of somatotropes and thyrotropes. Neither protein was detected in mammatropes. In addition, CST-1 was also localized to the glucagon-containing secretory granules of alpha cells in the pancreatic islets of Langerhans. Results indicate that calsyntenins function outside the nervous system and potentially are modulators of endocrine function.
authors.affiliation: Department of Cell Biology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA. rindlm01@med.nyu.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rindler
authors.forename: Chong-Feng
authors.initials: CF
authors.lastname: Xu
authors.forename: Iwona
authors.initials: I
authors.lastname: Gumper
authors.forename: Chuan
authors.initials: C
authors.lastname: Cen
authors.forename: Peter
authors.initials: P
authors.lastname: Sonderegger
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Neubert
mesh_terms: D000818:Animals; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D002853:Chromatography, Liquid; D050416:Glucagon-Secreting Cells / Q000378:metabolism*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D022142:Secretory Vesicles / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D015820:Cadherins; D002135:Calcium-Binding Proteins; C503227:Clstn1 protein, mouse; C472554:Clstn3 protein, mouse; D008565:Membrane Proteins