Phosphatidylinositol (4,5)-bisphosphate-dependent activation of dynamins I and II lacking the proline/arginine-rich domains
Phosphatidylinositol (4,5)-bisphosphate-dependent activation of dynamins I and II lacking the proline/arginine-rich domains
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DOI：
10.1074/jbc.272.41.25999
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发表时间：
1997-10-10
影响因子：
4.8
通讯作者：
Albanesi, JP
中科院分区：
文献类型：
--
作者：
Lin, HC;Barylko, B;Albanesi, JP
动力蛋白包括参与内吞作用早期阶段的gtp酶家族。神经元特异性动力蛋白I的GTPase活性可由微管、带负电荷的磷脂囊泡和Src同源3蛋白（包括Grb2）刺激。这些激活剂先前被证明与酶的羧基末端区域的富含脯氨酸/精氨酸的结构域（PRD）结合。Dynamin II是一种普遍表达的蛋白，以前没有被纯化或鉴定过。在这项研究中，大鼠动力蛋白II和D746（缺乏PRD的动力蛋白II截断突变体）的酶学特性已经被表征。动力蛋白II比动力蛋白I具有更高的基础活性，但两种类型的动力蛋白受到微管、Grb2和磷脂的刺激相似。D746不被微管或Grb2激活，这突出了PRD在这些相互作用中的重要性，但它被含有磷脂酰丝氨酸或磷脂酰肌醇-4,5-二磷酸的磷脂囊泡激活。此外，与以前的报告相反，磷脂刺激的动力蛋白自组装似乎不需要PRD，而动力蛋白是调节其活性的关键因素。对牛脑动力蛋白I进行有限的蛋白水解消化以去除PRD，也获得了类似的结果。我们的数据强调了动力蛋白pleckstrin同源结构域在磷脂调节GTPase活性中的潜在参与。
Dynamins comprise a family of GTPases that participate in the early stages of endocytosis. The GTPase activity of neuronal specific dynamin I is stimulated by microtubules, negatively charged phospholipid vesicles, and Src homology 3-containing proteins, including Grb2. These activators were previously shown to bind to a proline/arginine-rich domain (PRD) in the carboxyl-terminal region of the enzyme. Dynamin II, which is ubiquitously expressed, had not been purified or characterized previously. In this study, the enzymatic properties of rat dynamin II and of D746, a dynamin II truncation mutant lacking the PRD, have been characterized. Dynamin II has a higher basal activity than dynamin I, but the two types of dynamin are stimulated similarly by microtubules, Grb2, and phospholipids. D746 is not activated by microtubules or Grb2, highlighting the significance of the PRD for these interactions, but it is activated by phospholipid vesicles containing phosphatidylserine or phosphatidylinositol-4,5-bisphosphate. Moreover, in contrast to previous reports, the PRD appears not to be required for phospholipid-stimulated self-assembly of dynamin, which is a key element in the regulation of its activity. Similar results were obtained with bovine brain dynamin I that had been subjected to limited proteolytic digestion to remove the PRD. Our data highlight the potential involvement of dynamin pleckstrin homology domains in the regulation of GTPase activity by phospholipids.