Bertelli E, Regoli M, Gambelli F, Lucattelli M, Lungarella G, Bastianini A
Department of Biomedical Sciences, University of Siena, Siena, Italy.
J Histochem Cytochem. 2000 Sep;48(9):1233-42. doi: 10.1177/002215540004800907.
To elucidate the role of intermediate filament proteins in endocrine cells, we investigated the expression and subcellular distribution of GFAP in mouse islets of Langerhans. For this purpose, combined immunocytochemical and biochemical analysis with a panel of antibodies was carried out to identify GFAP-immunoreactive cells in mouse endocrine pancreas. Cell fractionation into NP-40-soluble and detergent/high salt-insoluble components was performed to assess whether GFAP was located in the cytosolic and/or cytoskeletal compartments of immunoreactive cells. Immunoelectron microscopic analysis was carried out to determine the subcellular distribution of the protein. Peripheral islet cells were stained with anti-GFAP antiserum. These cells were identified as glucagon-secreting cells by immunocytochemical staining of consecutive sections with anti-somatostatin, anti-GFAP, and anti-glucagon antisera. Western blotting analysis of both NP-40-soluble and detergent/high-salt insoluble fractions of isolated islets of Langerhans allowed detection of GFAP in both cytosolic and cytoskeletal compartments. Interestingly, however, the former location was highly predominant. In addition, immunoelectron microscopy localized GFAP associated with the periphery of secretory granules. On the basis of these results, an intriguing role for GFAP in secretory events should be strongly suspected.(J Histochem Cytochem 48:1233-1242, 2000)
为了阐明中间丝蛋白在内分泌细胞中的作用，我们研究了胶质纤维酸性蛋白（GFAP）在小鼠胰岛中的表达及亚细胞分布。为此，我们采用一组抗体进行了免疫细胞化学和生化联合分析，以鉴定小鼠内分泌胰腺中GFAP免疫反应性细胞。通过将细胞分离为NP - 40可溶性和去污剂/高盐不溶性成分，来评估GFAP是否位于免疫反应性细胞的胞质和/或细胞骨架区室。进行免疫电子显微镜分析以确定该蛋白的亚细胞分布。用抗GFAP抗血清对胰岛外周细胞进行染色。通过用抗生长抑素、抗GFAP和抗胰高血糖素抗血清对连续切片进行免疫细胞化学染色，将这些细胞鉴定为分泌胰高血糖素的细胞。对分离的小鼠胰岛的NP - 40可溶性和去污剂/高盐不溶性部分进行蛋白质免疫印迹分析，结果显示在胞质和细胞骨架区室中均能检测到GFAP。然而，有趣的是，前者的定位占主导地位。此外，免疫电子显微镜显示GFAP定位于分泌颗粒的外周。基于这些结果，强烈怀疑GFAP在分泌活动中具有有趣的作用。（《组织化学与细胞化学杂志》48:1233 - 1242, 2000）
