PHOSPHORYLATION REDUCES THE AFFINITY OF PROTEIN-4.1 FOR SPECTRIN
PHOSPHORYLATION REDUCES THE AFFINITY OF PROTEIN-4.1 FOR SPECTRIN
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DOI：
10.1021/bi00355a047
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发表时间：
1986-04-08
期刊：
影响因子：
2.9
通讯作者：
TAO, M
中科院分区：
文献类型：
--
作者：
EDER, PS;SOONG, CJ;TAO, M
研究了膜激酶和酪蛋白激酶A对蛋白4.1的磷酸化作用。每一种激酶催化每一摩尔蛋白质中2摩尔磷酸的掺入。反应混合物中两种激酶的存在并没有导致磷酸盐掺入蛋白质的增加。对32p标记蛋白4.1的酸水解产物的分析表明，放射性分布在磷苏氨酸和磷丝氨酸之间，比例约为2比1。采用蔗糖密度梯度离心法研究了磷酸化对蛋白4.1与spectrin结合的影响。蛋白4.1对spectrin的亲和力从KD的2倍降低了约5倍。10-6 M， KD为9.4倍。10-6 M，通过磷酸化。另一方面，spectrin的磷酸化似乎略微增加了它对蛋白4.1的亲和力。结果表明，磷酸化可能导致细胞骨架网络松弛，形成更灵活的膜结构，这对红细胞功能很重要。
The phosphorylation of protein 4.1 by the membrane kinase and casein kinase A has been investigated. Each of these kinases catalyzed the incorporation of 2 mol of phosphate per mol of protein 4.1. The presence of both kinases in the reaction mixture did not lead to an increase in the incorporation of phosphates into the protein. An analysis of the acid hydrolysis products of the 32P-labeled protein 4.1 indicated that the radioactivities are distributed between phosphothreonine and phosphoserine in a ratio of about 2 to 1. The effects of phosphorylation on the binding of protein 4.1 to spectrin were investigated by usng sucrose density gradient centrifugation. The affinity of protein 4.1 for spectrin was reduced about 5-fold, from a KD of 2 .times. 10-6 M to a KD of 9.4 .times. 10-6 M, by phosphorylation. The phosphorylation of spectrin, on the other hand, appeared to increase slightly its affinity for protein 4.1. The results suggest that phosphorylation may lead to a relaxation of the cytosketetal network and the formation of a more flexible membrane structure that is important to red cell function.