Psychiatry related information on Sycn

• Syncollin is differentially expressed in rat proximal small intestine and regulated by feeding behavior [1].

High impact information on Sycn

• The secretory granule protein syncollin binds to syntaxin in a Ca2(+)-sensitive manner [2].
• We suggest that syncollin acts as a Ca2(+)-sensitive regulator of exocytosis in exocrine tissues [2].
• Here we show that the membranes of exocrine secretory granules contain an 18-kDa protein, syncollin, that binds to syntaxin at low Ca2+ concentrations and dissociates at concentrations known to stimulate exocytosis [2].
• Syncollin was first demonstrated to be a protein capable of affecting granule fusion in a cell-free system, but later studies revealed its luminal localization in zymogen granules [3].
• Syncollin was found to be associated with detergent-insoluble cholesterol/glycolipid-enriched complexes [4].

Biological context of Sycn

• Transfection of syncollin appeared not to impede insulin biosynthesis and processing, since cellular contents of proinsulin and insulin and the number of secretory granules were not altered [3].

Anatomical context of Sycn

• In fully differentiated acinar cells syncollin-positive vesicles were detected in the apical region of the cells, whereas in neonatal acinar cells they were found clustered near the cell nucleus [5].
• Syncollin was expressed in the rat pancreas, spleen, duodenum, and colon [1].
• Treatment with a phorbol ester triggered the release of syncollin indicating that in HL-60 cells it is a secretory protein that can be mobilized upon stimulation [6].
• By immunohistological studies, syncollin was detected in neutrophilic granulocytes of the spleen [6].
• Intragranular targeting of syncollin, but not a syncollinGFP chimera, inhibits regulated insulin exocytosis in pancreatic beta-cells [7].

Associations of Sycn with chemical compounds

• Cholesterol-dependent interaction of syncollin with the membrane of the pancreatic zymogen granule [8].
• Despite this in vitro interaction, it is now clear that syncollin is present on the luminal side of the zymogen granule membrane [8].
• Extraction of cholesterol from the granule membrane by treatment with methyl-beta-cyclodextrin causes the detachment of syncollin, and this effect is enhanced at a high salt concentration [8].
• Cross-linking experiments with purified syncollin, and granule content and membrane proteins revealed a direct interaction between syncollin and GP-2, a major glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein [4].
• Detergent-solubilized, purified syncollin migrates on sucrose density gradients as a large (120-kDa) protein, suggesting that it exists naturally as a homo-oligomer [9].

Other interactions of Sycn

• Immunocytochemical analysis of the distribution of syncollin in fully differentiated and neonatal acinar cells revealed a granular pattern that corresponded with that of the zymogen-granule markers synaptobrevin 2 and amylase [5].

Analytical, diagnostic and therapeutic context of Sycn

• When unheated or cross-linked samples of membrane-derived syncollin are analysed by SDS/PAGE, higher-order forms are seen in addition to the monomer, which has an apparent molecular mass of 16 kDa [8].
• RT-PCR and S1 nuclease protection assay were used to clarify the 5'-end of syncollin [1].
• In situ hybridization localized syncollin expression in the pancreas to acinar cells and in the duodenum to villus epithelial cells [1].
• Electron microscopy of negatively stained syncollin revealed doughnut-shaped structures of outer diameter 10 nm and inner diameter 3 nm [9].
• Atomic force microscopy (AFM) of syncollin on mica supports at pH 7.6 showed particles of molecular volume 155 nm(3) [9].

References