Mitogenic agents induce redistribution of transferrin receptors from internal pools to the cell surface.
Mitogenic agents induce redistribution of transferrin receptors from internal pools to the cell surface.
复制标题
有丝分裂剂诱导转铁蛋白受体从内部池重新分布到细胞表面。
DOI：
10.1042/bj2380721
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Kaplan,J
中科院分区：
文献类型：
--
作者：
Ward,DM;Kaplan,J
在无血清培养基中孵育血清生长的HeLa细胞会导致125 I-二铁转铁蛋白与细胞表面的结合快速（t1/2 3 min）减少30-60%。在无血清培养基中向细胞中加入胎牛血清导致结合活性快速（t1/2 3 min）和浓度依赖性增加。配体结合的丧失或获得是表面受体数量变化的结果，而不是配体-受体亲和力的改变。发现多种激素（胰岛素、胰岛素样生长因子、白细胞介素1和血小板衍生因子）可模拟血清对受体数量的影响。表面受体数量的改变被认为是钙依赖性的。表面受体数量的变化是独立的受体的生物合成速率或绝对细胞含量的受体。胰岛素或血清对Hela细胞转铁蛋白受体分布的影响不受转铁蛋白存在的影响，表明这种细胞类型中的受体分布是不依赖于配体的。在小鼠L-细胞、人皮肤成纤维细胞和J774巨噬细胞肿瘤细胞中也观察到血清或胰岛素改变表面转铁蛋白受体数量的能力。然而，转铁蛋白受体K562和EB病毒转化的人成淋巴细胞不改变这些代理商。主要分布在表面上的受体（即表皮生长因子或低密度脂蛋白受体）的数量未因添加促有丝分裂剂而改变。这些结果扩展了我们以前的研究[H.S. Wiley & J. Kaplan（1984）Proc. Natl. Acad. Sci. U.S.A. 81，7456-7460]，证明促有丝分裂剂可诱导受体库在所选细胞类型中的再分布。
Incubation of serum-growth HeLa cells in serum-free medium causes a rapid (t1/2 3 min) 30-60% decrease in the binding of 125I-diferric transferrin to the cell surface. Addition of fetal bovine serum to cells in serum-free medium results in a rapid (t1/2 3 min) and concentration-dependent increase in binding activity. The loss or gain in ligand binding is a result of changes in surface receptor number rather than an alteration in ligand-receptor affinity. A variety of hormones (insulin, insulin-like growth factor, interleukin 1 and platelet-derived factor) were found to mimic the effect of serum on receptor number. The alteration in surface receptor number was found to be calcium-dependent. Changes in surface receptor number were independent of either receptor biosynthetic rate or the absolute cellular content of receptors. The effect of insulin or serum on Hela cell transferrin receptor distribution was unaffected by the presence of transferrin, demonstrating that receptor distribution in this cell type is ligand-independent. The ability of serum or insulin to modify surface transferrin receptor number was also observed in mouse L-cells, human skin fibroblasts, and J774 macrophage tumour cells. However, transferrin receptors on K562 and Epstein-Barr virus-transformed human lymphoblasts were unaltered by these agents. The quantities of receptors whose distribution is predominantly on the surface (i.e. epidermal growth factor or low density lipoprotein receptor) were unaltered by addition of the mitogenic agents. These results extend our previous studies [H.S. Wiley & J. Kaplan (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 7456-7460] demonstrating that mitogenic agents can induce redistribution of receptor pools in selected cell types.