The pleckstrin homology domains of dynamin isoforms require oligomerization for high affinity phosphoinositide binding
The pleckstrin homology domains of dynamin isoforms require oligomerization for high affinity phosphoinositide binding
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DOI：
10.1074/jbc.273.42.27725
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发表时间：
1998-10-16
影响因子：
4.8
通讯作者：
Lemmon, MA
中科院分区：
文献类型：
--
作者：
Klein, DE;Lee, A;Lemmon, MA
发动蛋白是100-kDa的GTP酶，参与形成内吞囊泡所需的断裂事件。两种主要描述的哺乳动物发动蛋白（发动蛋白-1和发动蛋白-2）都含有普列克底物蛋白同源（PH）结构域，其涉及发动蛋白与酸性磷脂（最值得注意的是磷酸肌醇）的结合（和活化）。我们表明，PH结构域的两个发动蛋白亚型需要低聚化的高亲和力磷酸肌醇结合。只有当PH结构域通过与谷胱甘肽S-转移酶融合或通过单个工程化分子间二硫键二聚化时，才检测到强磷酸肌醇结合。磷脂酰肌醇结合特异性合理地同意不同的磷脂对发动蛋白GT3活性的影响。虽然他们在抑制肾上腺嗜铬细胞快速内吞作用的能力不同，动力蛋白-1和动力蛋白-2 PH结构域表现出相同的磷酸肌醇结合特异性。由于发动蛋白PH结构域与磷酸肌醇的结合需要寡聚化，因此PH结构域介导的磷酸肌醇结合将有利于完整发动蛋白的寡聚化（其具有自缔合的固有倾向）。我们建议，发动蛋白PH结构域，从而介导所观察到的合作结合的发动蛋白的膜含有酸性磷脂，并促进自组装，这是至关重要的刺激其GTdR活性和其能力，实现膜断裂。
The dynamins are 100-kDa GTPases involved in the scission event required for formation of endocytotic vesicles. The two main described mammalian dynamins (dynamin-1 and dynamin-2) both contain a pleckstrin homology (PH) domain, which has been implicated in dynamin binding to (and activation by) acidic phospholipids, most notably phosphoinositides. We demonstrate that the PH domains of both dynamin isoforms require oligomerization for high affinity phosphoinositide binding. Strong phosphoinositide binding was detected only when the PH domains were dimerized by fusion to glutathione S-transferase, or via a single engineered intermolecular disulfide bond. Phosphoinositide binding specificities agreed reasonably with reported effects of different phospholipids on dynamin GTPase activity. Although they differ in their ability to inhibit rapid endocytosis in adrenal chromaffin cells, the dynamin-1 and dynamin-2 PH domains showed identical phosphoinositide binding specificities. Since oligomerization is required for binding of the dynamin PH domain to phosphoinositides, it follows that PH domain mediated phosphoinositide binding will favor oligomerization of intact dynamin (which has an inherent tendency to self-associate). We propose that the dynamin PH domain thus mediates the observed cooperative binding of dynamin to membranes containing acidic phospholipids and promotes the self-assembly that is critical for both stimulation of its GTPase activity and its ability to achieve membrane scission.