Kimura N, Shiraishi S, Mizunashi K, Ohtsu H, Kimura I
Department of Pathology, Second Department of Internal Medicine, First Department of Pharmacology, Tohoku University, Sendai, Japan.
J Histochem Cytochem. 2001 Mar;49(3):341-6. doi: 10.1177/002215540104900308.
Synaptotagmin I (STG I) is a Ca(2+) sensor and one of the synaptic vesicle proteins that mediate exocytosis. To determine the mechanism of release of large granules from mast cells, we studied by immunohistochemistry the presence of STG I in mast cells in normal human tissues simultaneously with the mast cell markers mast cell tryptase (tryptase) and c-kit. The tumor cells of systemic mast cell disease (SMCD) and a human mast cell leukemia cell line (HMC-1) were also examined. Human mast cells in normal tissues and the tumor cells of SMCD expressed STG I as well as mast cell tryptase (tryptase) and c-kit. STG I mRNA and its products in HMC-1 were examined by RT-PCR analysis and immunocytochemistry, respectively. STG I expression in HMC-1 cells was compared with that in cells stimulated and non-stimulated by phorbol 12-myristate 13-acetate and also with that in NB-1 and PC12 cells, known to express STG I. STG I mRNA was detected in both non-stimulated and stimulated HMC-1 cells and in NB-1 and PC12 cells. STG I immunoreactivity was weaker than NB-1 or PC12 immunoreactivity. However, it increased in the stimulated HMC-1 cells. Mast cells expressed STG I in various states. STG I may mediate exocytosis of large granules in mast cells.
突触结合蛋白I（STG I）是一种Ca(2+)传感器，也是介导胞吐作用的突触囊泡蛋白之一。为了确定肥大细胞中大颗粒的释放机制，我们通过免疫组织化学研究了正常人组织中肥大细胞中STG I的存在情况，并同时检测了肥大细胞标记物肥大细胞类胰蛋白酶（类胰蛋白酶）和c-kit。还对系统性肥大细胞病（SMCD）的肿瘤细胞和人肥大细胞白血病细胞系（HMC-1）进行了检测。正常组织中的人肥大细胞以及SMCD的肿瘤细胞均表达STG I、肥大细胞类胰蛋白酶（类胰蛋白酶）和c-kit。分别通过RT-PCR分析和免疫细胞化学检测了HMC-1中的STG I mRNA及其产物。将HMC-1细胞中STG I的表达与经佛波酯12-肉豆蔻酸酯13-乙酸酯刺激和未刺激的细胞中的表达进行了比较，还与已知表达STG I的NB-1和PC12细胞中的表达进行了比较。在未刺激和刺激的HMC-1细胞以及NB-1和PC12细胞中均检测到了STG I mRNA。STG I免疫反应性弱于NB-1或PC12的免疫反应性。然而，在刺激的HMC-1细胞中其免疫反应性增强。肥大细胞在各种状态下均表达STG I。STG I可能介导肥大细胞中大颗粒的胞吐作用。
