Cellular expression of Noc2, a Rab effector protein, in endocrine and exocrine tissues in the mouse.
Noc2 is a Rab effector which participates in regulated exocytosis. It is expressed abundantly in endocrine cells but at low levels in exocrine tissues. Noc2-deficient mice, however, exhibit marked accumulation of secretory granules in exocrine cells rather than endocrine cells. In the present study, we investigated localization of Noc2 immunohistochemically in various endocrine and exocrine tissues in normal mice. Western blotting detected a Noc2-immunoreactive band of 38 kDa in isolated pancreatic islets, the adrenal gland, pituitary gland, and thyroid gland. Immunostaining for Noc2 labeled endocrine cells in the adrenal medulla and adenohypophysis, pancreatic islet cells, thyroid parafollicular cells, and gut endocrine cells, supporting the notion that Noc2 is a Rab effector protein shared by amine/peptide-secreting endocrine cells. Besides endocrine tissues, granular ducts in salivary glands contained Noc2. Although immunostaining failed to detect Noc2 in acinar cells of all exocrine glands examined, reverse transcriptase-polymerase chain reaction analysis detected the mRNA expression in exocrine pancreas. Ultrastructurally, Noc2 immunoreactivity was associated with the limiting membrane of granules in both pancreatic endocrine and salivary duct exocrine cells. The cellular and subcellular localizations of Noc2 should yield key information on its functional significance as well as account for the phenotype in Noc2-deficient mice.
Teramae
Hiroki
H
Laboratory of Histology and Cytology, Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Sapporo 060-8638, Japan.
Fujimoto
Wakako
W
Seino
Susumu
S
Iwanaga
Toshihiko
T
D048868:Adaptor Proteins, Signal Transducing; D000311:Adrenal Glands / Q000737:chemistry; D000818:Animals; D004702:Endocrine Glands / Q000737:chemistry*; D005088:Exocrine Glands / Q000737:chemistry*; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D007515:Islets of Langerhans / Q000737:chemistry; D051379:Mice; D018345:Mice, Knockout; D010902:Pituitary Gland / Q000737:chemistry; D011506:Proteins / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis; D012469:Salivary Glands / Q000737:chemistry; D013961:Thyroid Gland / Q000737:chemistry
D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D012333:RNA, Messenger; C484660:Rph3al protein, mouse