GAIP participates in budding of membrane carriers at the trans-Golgi network
GAIP participates in budding of membrane carriers at the trans-Golgi network
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DOI：
10.1034/j.1600-0854.2003.00106.x
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发表时间：
2003-03-01
期刊：
影响因子：
4.5
通讯作者：
Stow, JL
中科院分区：
文献类型：
--
作者：
Wylie, FG;Lock, JG;Stow, JL
G α相互作用蛋白（GAIP）是G蛋白信号蛋白的调节剂，其动态地与囊泡相关联，并且已经涉及膜运输，尽管其具体作用尚不清楚。使用体外出芽试验，我们表明，GAIP被招募到一个特定的人口的trans-Golgi网络衍生的囊泡，这些是不同的coatomer或网格蛋白包被囊泡。一个截断突变体（NT-GAIP）编码的N-末端的一半GAIP被招募到反高尔基体网络膜在囊泡载体的形成。NT-GAIP的过表达诱导长的、被包覆的小管的形成，所述小管被微管稳定。出芽试验和活细胞成像的结果表明，这些小管仍然附着在高尔基体上，而不是作为载体囊泡释放出来。NT-GAIP表达阻断膜出芽并导致管状载体中间体的积累。NT-GAIP修饰的小管能够装载水泡性口炎病毒蛋白G-绿色荧光蛋白作为后高尔基体、胞吐货物，并且在表达NT-GAIP的细胞中，水泡性口炎病毒蛋白G-绿色荧光蛋白的表面递送减少。我们得出结论，GAIP功能作为一个重要组成部分的膜出芽机器的一个子集后高尔基体胞吐载体来自trans-Golgi网络。
Galpha interacting protein (GAIP) is a regulator of G protein signaling protein that associates dynamically with vesicles and has been implicated in membrane trafficking, although its specific role is not yet known. Using an in vitro budding assay, we show that GAIP is recruited to a specific population of trans-Golgi network-derived vesicles and that these are distinct from coatomer or clathrin-coated vesicles. A truncation mutant (NT-GAIP) encoding only the N-terminal half of GAIP is recruited to trans -Golgi network membranes during the formation of vesicle carriers. Overexpression of NT-GAIP induces the formation of long, coated tubules, which are stabilized by microtubules. Results from the budding assay and from imaging in live cells show that these tubules remain attached to the Golgi stack rather than being released as carrier vesicles. NT-GAIP expression blocks membrane budding and results in the accumulation of tubular carrier intermediates. NT-GAIP-decorated tubules are competent to load vesicular stomatitis virus protein G-green fluorescent protein as post-Golgi, exocytic cargo and in cells expressing NT-GAIP there is reduced surface delivery of vesicular stomatitis virus protein G-green fluorescent protein. We conclude that GAIP functions as an essential part of the membrane budding machinery for a subset of post-Golgi exocytic carriers derived from the trans-Golgi network.