RECEPTOR-MEDIATED ENDOCYTOSIS OF TRANSFERRIN BY DEVELOPING ERYTHROID-CELLS FROM THE FETAL RAT-LIVER
RECEPTOR-MEDIATED ENDOCYTOSIS OF TRANSFERRIN BY DEVELOPING ERYTHROID-CELLS FROM THE FETAL RAT-LIVER
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DOI：
10.1177/31.2.6300220
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发表时间：
1983-01-01
影响因子：
3.2
通讯作者：
YEOH, GCT
中科院分区：
文献类型：
--
作者：
IACOPETTA, BJ;MORGAN, EH;YEOH, GCT
用荧光显微镜和透射电镜研究了胎鼠肝脏发育中的红系细胞对转铁蛋白的结合和摄取。将细胞与荧光缀合的转铁蛋白在37 ℃温育20分钟后，C，通过荧光显微镜观察转铁蛋白以集中在离散的斑块中。早期的正常成红细胞也表现出大量的标签在一个单一的区域的细胞的方式类似帽形成。在去核过程中，大多数结合的转铁蛋白分布在细胞质中，直接围绕着突出的细胞核。通过定量荧光显微镜测量在不同发育阶段与红系细胞结合的转铁蛋白量的差异。最大的标记被发现在嗜碱性成正幼细胞阶段，并结合转铁蛋白的能力下降了10倍，在成熟的网织红细胞。转铁蛋白结合在发展过程中的相对变化几乎相同的刀豆球蛋白A结合采用相同的技术测量。转铁蛋白结合红系细胞的荧光显微镜下获得的结果延长EM使用转铁蛋白共轭铁蛋白。在该分辨率下，转铁蛋白-铁蛋白被观察到在37 ℃孵育5分钟后浓缩在类似于包被的小凹的表面结构中和细胞内囊泡中。C.通过20分钟的孵育，几乎所有的转铁蛋白共轭物内化的早期normoblasts在囊泡和多泡体靠近高尔基复合体。该区域可能是通过荧光显微镜观察到的帽，其特征在于超微结构的存在下，许多线粒体，多泡体，中心粒对和核糖体的情况下。转铁蛋白通过受体介导的内吞作用进入红系细胞。部分细胞内途径涉及溶酶体样细胞器。
Fluorescence microscopy and EM were used to study the binding and uptake of transferrin by developing erythroid cells from the fetal rat liver. Following incubation of the cells with fluorescently conjugated transferrin for 20 min at 37.degree. C, transferrin was visualized by fluorescence microscopy to be concentrated in discrete patches. Early normoblasts also showed a large amount of labeling in a single area of the cell in a manner resembling cap formation. During enucleation most of the bound transferrin was distributed in the cytoplasm immediately surrounding the extruding nucleus. Differences in the amount of transferrin binding to erythroid cells at various stages of development were measured by quantitative fluorescence microscopy. Maximal labeling was found at the basophilic normoblast stage, and the capacity to bind transferrin decreased 10-fold during maturation to the reticulocyte. Relative changes in transferrin binding during development were almost identical to those measured for concanavalin A binding employing the same technique. Results obtained by fluorescence microscopy on the binding of transferrin to erythroid cells were extended by EM using transferrin conjugated to ferritin. At this resolution transferrin-ferritin was seen to be concentrated in surface structures similar to coated pits and in intracellular vesicles after 5 min incubation at 37.degree. C. By 20 min incubation, nearly all the transferrin conjugate internalized by early normoblasts was in vesicles and multivesicular bodies in close proximity to the Golgi complex. This region is probably the cap observed by fluorescence microscopy and was characterized ultrastructurally by the presence of numerous mitochondria, multivesicular bodies, a centriole pair and the absence of ribosomes. Transferrin enters erythroid cells by receptor-mediated endocytosis. Part of the intracellular pathway involves lysosome-like organelles.