Abnormal insulin binding and membrane physical properties of a Friend erythroleukemia clone resistant to dimethylsulfoxide-induced differentiation.
Abnormal insulin binding and membrane physical properties of a Friend erythroleukemia clone resistant to dimethylsulfoxide-induced differentiation.
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对二甲亚砜诱导的分化具有抗性的 Friend 红白血病克隆的异常胰岛素结合和膜物理特性。
DOI：
10.1016/0167-4889(84)90052-1
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Ginsberg,BH
中科院分区：
文献类型：
--
作者：
Simon,I;Brown,TJ;Ginsberg,BH
我们比较了三个不同的Friend红白血病克隆的胰岛素结合力、质膜流动性和磷脂组成，其中一个是野生型(FLC)，一个是突变体(R3)，一个是野生型F+。R3克隆是一种无分化的DMSO抗性克隆(R3)，它改变了细胞膜的流动性，显著改变了胰岛素的结合特性。R3受体与胰岛素结合，就像它只有一类低亲和力的受体，缺乏负协同作用。Scatchard图是线性的，没有配体诱导的解离加速。R3的Hill系数为1，表示没有协作性，而DMSO诱导的两个克隆(FLC和F+)的Hill系数为0.3，表示“负协作性”。此外，R3的胰岛素受体对胰岛素的亲和力降低，表现为竞争一半示踪剂结合所需的胰岛素量增加了40倍(R3为41 nM，FLC和F+为1 nM)。计算机拟合的负协作性模型分析表明，R3有95000个受体位点/细胞，高亲和力常数K̄e为0.016 nM−1，低亲和力常数K̄f为0.012 nM−1。两个二甲基亚砜诱导的克隆约有40 000个受体位点，K̄e为0.11 nM−1，K̄f为0.02 nM−1。R3的脂类组成与DMSO诱导的克隆不同。R3的不饱和脂肪酸与饱和脂肪酸的重量比为2.5，而FLC克隆的不饱和脂肪酸与饱和脂肪酸的重量比较低，为1.9。这些结果与我们早期在FLC上的发现一致，即非常高的膜流动性与胰岛素受体结合特性的变化有关。
We have compared insulin binding, plasma membrane fluidity, and phospholipid composition of three different Friend erythroleukemia clones, a wild type (FLC) a mutant (R3) and the revertant to wild type F+. The R3 clone is a non-differentiating DMSO-resistant clone (R3) and has altered membrane fluidity and dramatically altered insulin-binding properties. The receptor of R3 bound insulin as if it possessed a single class of low affinity receptors that lacks the property of negative cooperativity. The Scatchard plot is linear and there is no ligand-induced acceleration of dissociation. The Hill coefficient for R3 is 1, implying ‘no cooperativity’, whereas the Hill coefficient for the two DMSO-inducible clones,(FLC and F+) is 0.3, implying ‘negative cooperativity’. In addition, the insulin receptor of R3 has a decreased affinity for insulin, manifested as a 40-fold increase in the amount of insulin required to compete for half of the tracer binding (41 nM for R3 vs. 1 nM for FLC and F+). Computer-fitted Scatchard plots analyzed by the negative cooperativity model reveal that R3 has 95 000 receptor sites/cell, with a high affinity constant K ̄ e of 0.016 nM− 1, and a low affinity constant, K ̄ f of 0.012 nM− 1. Both DMSO-inducible clones have about 40 000 receptor sites/cell with K ̄ e of 0.11 nM− 1 and K ̄ f of 0.02 nM− 1. Electron spin resonance measurements with the 5-nitroxy stearate spin probe demonstrate that R3 had a more fluid plasma membrane than the FLC and F+ clones. The lipid composition of R3 is different from that of the DMSO-inducible clones. The weight ratio for unsaturated fatty acids to saturated fatty acids for R3 is 2.5, and the FLC clone has a lower ratio of 1.9. These results are consistent with our earlier findings in FLC that very high membrane fluidity is associated with alterations in the binding properties of the insulin receptor.