A subset of p23 localized on secretory granules in pancreatic beta-cells.
A subset of p23 localized on secretory granules in pancreatic beta-cells.
复制标题
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
M. Hosaka;Tsuyoshi Watanabe;Y. Yamauchi;Y. Sakai;M. Suda;Shin Mizutani;T. Takeuchi;T. Isobe
中科院分区：
文献类型：
--
作者：
M. Hosaka;Tsuyoshi Watanabe;Y. Yamauchi;Y. Sakai;M. Suda;Shin Mizutani;T. Takeuchi;T. Isobe
与神经元突触囊泡相比，分泌颗粒膜上参与其生物合成和胞吐作用的蛋白质的特性较差。因此，分泌颗粒膜制备从小鼠胰腺β细胞系MIN 6通过亚细胞分级分离，和蛋白质成分进行了分析，通过微型二维液相色谱与电喷雾串联质谱。使用这种蛋白质组学方法，p24家族蛋白，p23，出乎意料地发现在颗粒部分，虽然p24蛋白通常被认为是在内质网和高尔基体之间的早期分泌途径的功能。我们进一步表明p23在内分泌细胞中高水平表达。此外，免疫细胞化学分析胰腺β-细胞在光镜和电子显微镜水平表明，一个显着的量的p23是本地化的胰岛素颗粒膜上，虽然它是最强烈的集中在顺式高尔基室，如先前所示的非内分泌细胞。这些研究结果表明，一小部分p23进入后高尔基室，并可能在生物发生和/或质量控制的SG。
Proteins on the membrane of secretory granules (SGs) involved in their biogenesis and exocytosis are poorly characterized compared with those of synaptic vesicle in neurons. Thus the secretory granule membrane was prepared from a mouse pancreatic beta-cell line MIN6 by subcellular fractionation, and protein constituents were analyzed by microscale two-dimensional liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Using this proteomics approach, one of the p24 family proteins, p23, was unexpectedly found in the granule fraction, although p24 proteins are generally regarded as functioning in the early secretory pathways between the endoplasmic reticulum and the Golgi apparatus. We further showed that p23 is expressed at high levels in endocrine cells. Furthermore, immunocytochemical analyses of pancreatic beta-cells at the light and electron microscopic levels demonstrated that a significant amount of p23 is localized on the insulin granule membrane, although it is most intensely concentrated at the cis-Golgi compartment as previously shown in non-endocrine cells. These findings suggest that a fraction of p23 enters post-Golgi compartments and may function in the biogenesis and/or quality control of SGs.