DOWN REGULATION OF EPIDERMAL GROWTH-FACTOR RECEPTORS - DIRECT DEMONSTRATION OF RECEPTOR DEGRADATION IN HUMAN-FIBROBLASTS
DOWN REGULATION OF EPIDERMAL GROWTH-FACTOR RECEPTORS - DIRECT DEMONSTRATION OF RECEPTOR DEGRADATION IN HUMAN-FIBROBLASTS
复制标题
DOI：
10.1083/jcb.98.3.1048
复制
发表时间：
1984-01-01
影响因子：
7.8
通讯作者：
CARPENTER, G
中科院分区：
文献类型：
--
作者：
STOSCHECK, CM;CARPENTER, G
用放射性氨基酸前体标记表皮生长因子（EGF）受体，然后用特异性抗EGF受体抗血清免疫沉淀法测定细胞置于非放射性培养基中时表皮生长因子（EGF）受体的降解率，以此来测定受体的代谢。在人成纤维细胞中，EGF受体的降解速率（t1/2= 10.1 h）快于细胞总蛋白的降解速率。将EGF加入非放射性培养基后，预标记受体在人成纤维细胞中的半衰期缩短至1.2 h。这些数据通过对受体蛋白的直接分析表明，在下调过程中，EGF受体被迅速降解。在加入EGF后5-10分钟，观察到受体降解增强。甲胺、氯喹、碘乙酸或25度孵育可阻断egf诱导的受体降解。C.人成纤维细胞中EGF诱导的下调导致EGF受体蛋白总量的减少。采用放射标记细胞蛋白和受体免疫沉淀法测定EGF受体蛋白的含量。EGF受体由。apprx组成。0.0035%的人成纤维细胞蛋白。
The metabolism of the receptor for epidermal growth factor (EGF) was measured by labeling the receptor in vivo with radioactive amino acid precursors and then determining, by immunoprecipitation with specific anti-EGF receptor antisera, the rate of degradation of the receptor when the cells are placed in a nonradioactive medium. In human fibroblasts the rate of EGF receptor degradation (t1/2= 10.1 h) was faster than the rate of degradation of total cell protein. When EGF was added to the nonradioactive medium, the half-life of prelabeled receptor was decreased to 1.2 h in human fibroblasts. These data demonstrate by direct analysis of receptor protein that during down regulation the EGF receptor is rapidly degraded. Enhanced receptor degradation was observed 5-10 min after the addition of EGF. The EGF-induced degradation of the receptor was blocked by methylamine, chloroquine, iodoacetate, or incubation at 25.degree. C. EGF-induced down regulation in human fibroblasts results in a decrease in the total amount of EGF receptor protein present. The amount of EGF receptor protein was quantitated by radiolabeling cellular protein and immunoprecipitation of the receptor. The EGF receptor constitutes .apprx. 0.0035% of the cellular protein in human fibroblasts.