Jans S W, van Bilsen M, Reutelingsperger C P, Borgers M, de Jong Y F, van der Vusse G J
Department of Physiology, Cardiovascular Research Institute Maastricht, University of Limburg, The Netherlands.
J Mol Cell Cardiol. 1995 Jan;27(1):335-48. doi: 10.1016/s0022-2828(08)80031-4.
Annexins are a family of proteins with calcium- and phospholipid-binding properties. The present study was performed to identify which members of the annexin family are present in rat heart and to determine the cellular and subcellular distribution of annexin V, the most prominent annexin in rat cardiac tissue, in isolated ventricular myocytes and cultured endothelial and fibroblast-like cells. The presence of annexin I plus II, III, IV, V and VI in rat cardiac tissue was positively established with western blot analysis. Immunohistochemistry and western blot analysis revealed that annexin V is present in both cardiomyocytes and non-myocytal cells of the heart. In endothelial cells and fibroblast-like cells annexin V is predominantly localized in the cytoplasm and in cardiac myocytes in close vicinity of the sarcolemma. This last finding is confirmed by electron microscopy. Northern blot analysis demonstrated that all cell types investigated showed expression of annexin V. Annexin V mRNA levels were highest in the fibroblast-like cells, followed by the endothelial cells, and a weak signal was observed in the cardiomyocytes. By means of a sandwich-type enzyme-linked immunosorbent assay (ELISA) annexin V content in intact adult rat heart, isolated myocytes, cultured cardiac endothelial cells and fibroblast-like cells was found to be 0.70, 0.17, 1.63 and 3.84 micrograms/mg total protein, respectively. The differences in subcellular localization of annexin V in myocytes and non-myocytes suggest differences in biological function of annexin V in the various cell types.
膜联蛋白是一类具有钙和磷脂结合特性的蛋白质。本研究旨在确定大鼠心脏中存在哪些膜联蛋白家族成员，并确定膜联蛋白V（大鼠心脏组织中最主要的膜联蛋白）在分离的心室肌细胞以及培养的内皮细胞和成纤维样细胞中的细胞和亚细胞分布。通过蛋白质印迹分析确定了大鼠心脏组织中存在膜联蛋白I、II、III、IV、V和VI。免疫组织化学和蛋白质印迹分析显示，膜联蛋白V存在于心脏的心肌细胞和非心肌细胞中。在内皮细胞和成纤维样细胞中，膜联蛋白V主要定位于细胞质中，而在心肌细胞中则位于肌膜附近。这一发现通过电子显微镜得到了证实。Northern印迹分析表明，所有研究的细胞类型均显示有膜联蛋白V的表达。膜联蛋白V的mRNA水平在成纤维样细胞中最高，其次是内皮细胞，在心肌细胞中观察到较弱的信号。通过夹心型酶联免疫吸附测定（ELISA）发现，完整成年大鼠心脏、分离的心肌细胞、培养的心脏内皮细胞和成纤维样细胞中的膜联蛋白V含量分别为0.70、0.17、1.63和3.84微克/毫克总蛋白。膜联蛋白V在心肌细胞和非心肌细胞中的亚细胞定位差异表明，膜联蛋白V在不同细胞类型中的生物学功能存在差异。
