A phosphatidylinositol 3-kinase and phosphatidylinositol transfer protein act synergistically in formation of constitutive transport vesicles from the trans-Golgi network
A phosphatidylinositol 3-kinase and phosphatidylinositol transfer protein act synergistically in formation of constitutive transport vesicles from the trans-Golgi network
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DOI：
10.1074/jbc.273.17.10349
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发表时间：
1998-04-24
影响因子：
4.8
通讯作者：
Howell, KE
中科院分区：
文献类型：
--
作者：
Jones, SM;Alb, JG;Howell, KE
目前的证据表明，磷脂酰肌醇 (PI) 激酶和磷脂酰肌醇转移蛋白 (PITP) 参与驱动酵母和哺乳动物跨高尔基体网络 (TGN) 的囊泡运输。我们在一项测定肝细胞无细胞系统中 TGN 组成型转运囊泡形成的测定中测试了这些胞质蛋白之间的相互作用。该反应依赖于一种新型 PI 3-激酶，我们现在报道，在限制胞质的条件下，纯化的 PI 3-激酶和 PITP 功能性地协同驱动胞吐囊泡的形成。在酵母和哺乳动物 PITP 中都观察到了这种协同作用，并且它还延伸到了 PI 3-磷酸的形成。这些共同发现表明，PI 3-激酶和 PITP 协同形成 PI 3-磷酸池，这对于肝细胞 TGN 形成胞吐囊泡至关重要。
Current evidence suggests that phosphatidylinositol (PI) kinases and phosphatidylinositol transfer protein (PITP) are involved in driving vesicular traffic from yeast and mammalian trans-Golgi network (TGN). We have tested the interaction between these cytosolic proteins in an assay that measures the formation of constitutive transport vesicles from the TGN in a hepatocyte cell-free system. This reaction is dependent on a novel PI 3-kinase, and we now report that, under conditions of limiting cytosol, purified PI 3-kinase and PITP functionally cooperate to drive exocytic vesicle formation. This synergy was observed with both yeast and mammalian PITPs, and it also extended to the formation of PI 3-phosphate. These collective findings indicate that the PI 3-kinase and PITP synergize to form a pool of PI 3-phosphate that is essential for formation of exocytic vesicles from the hepatocyte TGN.