BINDING OF NEOMYCIN TO PHOSPHATIDYLINOSITOL 4,5-BISPHOSPHATE (PIP2)
BINDING OF NEOMYCIN TO PHOSPHATIDYLINOSITOL 4,5-BISPHOSPHATE (PIP2)
复制标题
DOI：
10.1016/0005-2736(89)90529-4
复制
发表时间：
1989-02-13
期刊：
影响因子：
--
通讯作者：
MCLAUGHLIN, S
中科院分区：
文献类型：
--
作者：
GABEV, E;KASIANOWICZ, J;MCLAUGHLIN, S
Schacht（Schacht，J.（1976）J. Neurochem。27，1119-1124）证明新霉素（一种氨基糖苷类抗生素）与4，5-二磷酸磷脂酰肌醇（PIP 2）以高亲和力结合。我们研究了新霉素与PIP 2的结合，通过用多层双层囊泡进行电泳迁移率测量和用单层膜进行表面电位测量。双层和单层由PIP 2和卵磷脂（PC）在pH 7的0.1M KCl中的混合物形成。新霉素不结合PC; 10-3 M新霉素既不影响PC囊泡的zeta电位，也不影响PC单层的表面电位。相比之下，10-6 M新霉素降低PC/PIP 2囊泡（5、9和17 mol%PIP 2）的ζ电位的大小，并且单层（17 mol%PIP 2）的表面电位至10-4 M新霉素将PC/PIP 2囊泡的ζ电位降低至零。我们可以用Gouy-Chapman-Stern理论描述我们的数据，假设1：1新霉素-PIP 2复合物的内在缔合常数为105 M-1。新霉素被广泛用于细胞生物学中干扰第二信使的产生，我们讨论了我们的研究结果与这些研究的相关性。具体地，10 - 6 M新霉素结合双层或单层中> 50%的PIP 2，但需要10- 5 ± 10 -3 M新霉素来影响透化血小板、肥大细胞和海胆卵中PIP 2的周转。这一结果与以下假设一致，即这些质膜的内小叶中的大多数PIP 2不能被新霉素接近，因为它与蛋白质相关。
Schacht (Schacht, J. (1976) J. Neurochem. 27, 1119-1124) demonstrated that neomycin, an aminoglycoside antibiotic, binds with high affinity to phosphatidylinositol 4,5-bisphosphate (PIP2). We investigated the binding of neomycin to PIP2 by making electrophoretic mobility measurements with multilamellar bilayer vesicles and surface potential measurements with monolayers. The bilayers and monolayers were formed from mixtures of PIP2 and egg phosphatidylcholine (PC) in 0.1 M KCl at pH 7. Neomycin does not bind to PC; 10-3 M neomycin affects neither the zeta potential of PC vesicles not the surface potential of PC monolayers. In contrast, 10-6 M neomycin reduces the magnitude of the zeta potential of PC/PIP2 vesicles (5, 9, and 17 mol% PIP2) and the surface potential of monolayers (17 mol% PIP2) to 10-4 M) of neomycin reduce the zeta potential of the PC/PIP2 vesicles to zero. We could describe our data with the Gouy-Chapman-Stern theory assuming the intrinsic association constant of the 1:1 neomycin-PIP2 complex is 105 M-1. Neomycin is widely used in cell biology to interfere with the generation of second messengers; we discuss the relevance of our results to these studies. Specifically, 10 -6 M neomycin binds > 50% of the PIP2 in a bilayer or monolayer but 10-5.sbd.10-3 M neomycin is required to affect the turnover of PIP2 in permeabilized platelets, mast cells, and sea urchin eggs. This result is consistent with a hypothesis that most of the PIP2 in the inner leaflet of these plasma membranes is not accessible to neomycin because it is associated with proteins.