Giambanco I, Sorci G, Antonioli S, Rambotti M G, Spreca A, Bocchini V, Donato R
Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
FEBS Lett. 1993 May 24;323(1-2):45-50. doi: 10.1016/0014-5793(93)81445-6.
The subcellular distribution of annexin V, a calcium-dependent phospholipid- and membrane-binding protein, in a human-derived cell line, GL15, was investigated by immunocytochemistry at light and electron microscope levels. Annexin V was found diffusely in the cytoplasm and associated with plasma membranes, membranes delimiting cytoplasmic vacuoles, membranes of the endoplasmic reticulum, and filamentous structures the identity of which remains to be established. By immunocytochemistry at the light microscope level and immunochemistry, the expression of annexin V in these cells was found to depend on cellular growth stage, being maximal soon after plating and progressively declining thereafter. However, re-expression of annexin V was observed whenever cell proliferation slowed down or arrested. These findings suggest that annexin V in glioma cells is mostly expressed in connection with cell differentiation. Also, the present ultrastructural data suggest that plasma membranes, membranes of the endoplasmic reticulum and the cytoskeleton are prominent sites of action of annexin V in vivo, thus lending support to the possibility that this protein might have a role in the regulation of cytoskeleton elements and/or of the structural organization of membranes.
膜联蛋白V是一种钙依赖性磷脂结合膜蛋白，利用免疫细胞化学技术在光学显微镜和电子显微镜水平上研究了其在人源细胞系GL15中的亚细胞分布。发现膜联蛋白V弥散于细胞质中，并与质膜、界定细胞质空泡的膜、内质网膜以及身份尚待确定的丝状结构相关联。通过光学显微镜水平的免疫细胞化学和免疫化学方法发现，这些细胞中膜联蛋白V的表达取决于细胞生长阶段，在接种后不久达到最大值，此后逐渐下降。然而，每当细胞增殖减缓或停滞时，就会观察到膜联蛋白V的重新表达。这些发现表明，胶质瘤细胞中的膜联蛋白V大多与细胞分化相关表达。此外，目前的超微结构数据表明，质膜、内质网膜和细胞骨架是膜联蛋白V在体内的主要作用部位，因此支持了这种蛋白可能在细胞骨架成分调节和/或膜结构组织中发挥作用的可能性。
