Distinct specificity in the recognition of phosphoinositides by the pleckstrin homology domains of dynamin and Bruton's tyrosine kinase
Distinct specificity in the recognition of phosphoinositides by the pleckstrin homology domains of dynamin and Bruton's tyrosine kinase
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DOI：
10.1002/j.1460-2075.1996.tb01014.x
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发表时间：
1996-11-15
期刊：
影响因子：
11.4
通讯作者：
Panayotou, G
中科院分区：
文献类型：
--
作者：
Salim, K;Bottomley, MJ;Panayotou, G
Pleckstrin Homology(PH)结构域可通过与磷脂酰肌醇的特异性相互作用作为膜定位模块。这些相互作用可能代表对第二信使的反应，有可能受到可溶性肌醇多磷酸的调节。基于生物传感器的分析被用来探测PH结构域与含有不同磷脂的单层脂质体之间的相互作用，并证明了不同的磷脂酰肌醇的特异性。Dynamin PH结构域与含有磷脂酰肌醇-4，5-二磷酸[PI(4，5)P-2]的脂质体以及更弱的含有磷脂酰肌醇-4-磷酸[PI(4)P]的脂质体发生特异性相互作用。这与肌醇磷脂对动力蛋白GTP酶的激活有关。然而，缺乏PH结构域的动力蛋白突变体的功能性GTP酶不能被PI(4，5)P-2激活。通过分子模拟和核磁共振光谱预测的假定结合口袋中的点突变，可以选择性地取消磷脂酰肌醇-PH结构域的相互作用。相比之下，Bruton的酪氨酸激酶(BTK)PH结构域特异性地结合了含有磷脂酰肌醇-3，4，5-三磷酸[PI(3，4，5)P-3]的脂质体：这种相互作用需要Arg28，这是一种在一些X连锁无丙种球蛋白血症患者中被发现突变的残基。通过对候选结合口袋的模拟，对这些不同的特异性提出了合理的解释，并得到了核磁共振光谱的支持。
Pleckstrin homology (PH) domains may act as membrane localization modules through specific interactions with phosphoinositide phospholipids. These interactions could represent responses to second messengers, with scope for regulation by soluble inositol polyphosphates. A biosensor-based assay was used here to probe interactions between PH domains and unilamellar liposomes containing different phospholipids and to demonstrate specificity for distinct phosphoinositides. The dynamin PH domain specifically interacted with liposomes containing phosphatidylinositol-4,5-bisphosphate [PI(4,5)P-2] and, more weakly, with liposomes containing phosphatidylinositol-4-phosphate [PI(4)P]. This correlates with phosphoinositide activation of the dynamin GTPase. The functional GTPase of a dynamin mutant lacking the PH domain, however, cannot be activated by PI(4,5)P-2. The phosphoinositide-PH domain interaction can be abolished selectively by point mutations in the putative binding pocket predicted by molecular modelling and NMR spectroscopy. In contrast, the Bruton's tyrosine kinase (Btk) PH domain specifically bound liposomes containing phosphatidylinositol-3,4,5-trisphosphate [PI(3,4,5)P-3]: an interaction requiring Arg28, a residue found to be mutated in some X-linked agammaglobulinaemia patients. A rational explanation for these different specificities is proposed through modelling of candidate binding pockets and is supported by NMR spectroscopy.