Phosphorylation of calmodulin by permeabilized fibroblasts overexpressing the human epidermal growth factor receptor
Phosphorylation of calmodulin by permeabilized fibroblasts overexpressing the human epidermal growth factor receptor
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DOI：
10.1515/bchm.1997.378.1.31
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发表时间：
1997-01-01
影响因子：
3.7
通讯作者：
Villalobo, A
中科院分区：
文献类型：
--
作者：
DeFrutos, T;MartinNieto, J;Villalobo, A
洗涤剂透化的EGFR-T17成纤维细胞，其过表达人表皮生长因子（EGF）受体，以EGF刺激的方式磷酸化聚-L-（谷氨酸，酪氨酸）和外源性钙调蛋白。钙调蛋白的磷酸化需要阳离子多肽的存在，例如聚-L-（赖氨酸）或组蛋白，其对钙调蛋白磷酸化产生双相作用。最佳阳离子多肽/钙调蛋白的摩尔比为0.3和7，分别为聚-L-（赖氨酸）和组蛋白。钙调素磷酸化的最大水平，在没有游离钙的情况下，达到了，并观察到在非常低的浓度（Ki= 0.2 μ M）的阳离子，这一过程的强烈抑制。磷酸盐掺入钙调素主要发生在酪氨酸残基上，并被EGF刺激34倍。
Detergent-permeabilized EGFR-T17 fibroblasts, which overexpress the human epidermal growth factor (EGF) receptor, phosphorylate both poly-L-(glutamic acid, tyrosine) and exogenous calmodulin in an EGF-stimulated manner. Phosphorylation of calmodulin requires the presence of cationic polypeptides, such as poly-L-(lysine) or histones, which exert a biphasic effect toward calmodulin phosphorylation. Optimum cationic polypeptide/calmodulin molar ratios of 0.3 and 7 were determined for poly-L-(lysine) and histones, respectively. Maximum levels of calmodulin phosphorylation were attained in the absence of free calcium, and a strong inhibition of this process was observed at very low concentrations (Ki= 0.2 mu M) of this cation. The incorporation of phosphate into calmodulin occurred predominantly on tyrosine residue(s) and was stimulated 34-fold by EGF.