High-Level Expression of Golsyn/Syntabulin in Glandular Epithelium and its Role in the Secretory Process

ABSTRACT

We recently identified a novel gene, named GOLSYN/Syntabulin, on human chromosome 8q23.2. In neurons, GOLSYN/Syntabulin functions as a molecule linking syntaxin 1-containing vesicles to kinesin, and thus plays an essential role in the transport of vesicles and mitochondria along neuronal processes. GOLSYN/Syntabulin is ubiquitously expressed in most peripheral tissues besides various brain regions. However, the physiological function in the periphery remains unknown. In this study, we determined the expression of Golsyn/Syntabulin in various mouse organs by immunohistochemical analysis using anti-GOLSYN antibody. Golsyn/Syntabulin was abundantly expressed in the glandular epithelium in the various peripheral organs examined: In exocrine glands, it was expressed in secretory cells, such as chief cells in the stomach and pancreatic acinar cells; and in endocrine glands, it was detected in pancreatic islet cells, which are endocrine cells that produce and release hormones including insulin and glucagon. The expression of Golsyn/Syntabulin was drastically decreased in pancreas and liver by fasting, but it was not affected in the testis, which has no secretory glands for food digestion. Subsequent refeeding recovered Golsyn/Syntabulin expression in pancreas and liver tissues to almost control levels, indicating the association of its expression with food intake. Further, administration of gastrin or pilocarpine led to a remarkable increase in the expression level of Golsyn/Syntabulin in the pancreas. Since food intake, gastrin, and pilocarpine are known to stimulate the secretion of pancreatic enzymes, Golsyn/Syntabulin may play an important role in the secretion process, including transport of secretory vesicles and/or exocytosis, in glandular epithelium.