Oligomerized transferrin receptors are selectively retained by a lumenal sorting signal in a long-lived endocytic recycling compartment.
Oligomerized transferrin receptors are selectively retained by a lumenal sorting signal in a long-lived endocytic recycling compartment.
复制标题
DOI：
10.1083/jcb.129.6.1509
复制
发表时间：
1995-06
期刊：
影响因子：
--
通讯作者：
Maxfield FR
中科院分区：
文献类型：
--
作者：
Marsh EW;Leopold PL;Jones NL;Maxfield FR
表面受体的交联导致内吞系统中受体运输的改变。为了更好地理解受体交联影响配体和受体胞内转运的细胞和分子机制，我们研究了转铁蛋白受体（TfR）与通过转铁蛋白（Tf）的化学交联制备的多价转铁蛋白（Tf 10）结合的胞内转运。Tf10的内化速度比Tf慢约2倍，保留时间比Tf长4倍，在CHO细胞中不被降解。用荧光显微镜和电子显微镜研究了Tf10的细胞内定位。Tf10没有交付给溶酶体途径，然后低密度脂蛋白，但仍然可以访问Tf在pericentriolar内吞再循环室至少60分钟。保留的Tf10是TfR相关的证明减少表面TfR的数量时，细胞与Tf10孵育。TF 10的存在下，在回收隔室没有影响贩运随后内吞的TF。Tf10在回收隔室中的保留不需要TfR的胞质结构域，因为Tf10在与野生型TfR或胞质尾中仅具有4个氨基酸的突变受体结合时以相同的速率退出细胞。因此，表面受体通过多价配体的交联充当再循环隔室内的内腔保留信号。这里提供的数据表明，由Tf 10标记的再循环隔室是一个长寿的细胞器沿着早期内体再循环途径，保持融合可访问随后内吞的Tf。
Cross-linking of surface receptors results in altered receptor trafficking in the endocytic system. To better understand the cellular and molecular mechanisms by which receptor cross-linking affects the intracellular trafficking of both ligand and receptor, we studied the intracellular trafficking of the transferrin receptor (TfR) bound to multivalent-transferrin (Tf10) which was prepared by chemical cross- linking of transferrin (Tf). Tf10 was internalized about two times slower than Tf and was retained four times longer than Tf, without being degraded in CHO cells. The intracellular localization of Tf10 was investigated using fluorescence and electron microscopy. Tf10 was not delivered to the lysosomal pathway followed by low density lipoprotein but remained accessible to Tf in the pericentriolar endocytic recycling compartment for at least 60 min. The retained Tf10 was TfR-associated as demonstrated by a reduction in surface TfR number when cells were incubated with Tf10. The presence of Tf10 within the recycling compartment did not affect trafficking of subsequently endocytosed Tf. Retention of Tf10 within the recycling compartment did not require the cytoplasmic domain of the TfR since Tf10 exited cells with the same rate when bound to the wild-type TfR or a mutated receptor with only four amino acids in the cytoplasmic tail. Thus, cross-linking of surface receptors by a multivalent ligand acts as a lumenal retention signal within the recycling compartment. The data presented here show that the recycling compartment labeled by Tf10 is a long-lived organelle along the early endosome recycling pathway that remains fusion accessible to subsequently endocytosed Tf.