ArfGAP1 dynamics and its role in COPI coat assembly on Golgi membranes of living cells.
ArfGAP1 dynamics and its role in COPI coat assembly on Golgi membranes of living cells.
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DOI：
10.1083/jcb.200410142
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发表时间：
2005-03-28
影响因子：
7.8
通讯作者：
Lippincott-Schwartz, Jennifer
中科院分区：
文献类型：
--
作者：
Liu, Wei;Duden, Rainer;Phair, Robert D;Lippincott-Schwartz, Jennifer
分泌性蛋白质的运输依赖于COPI外壳，COPI外壳通过在高尔基膜上组装成晶格，将货物集中在特定位置，并使这些位置的膜变形为被包裹的芽和载体。负责催化Arf1 GTP水解的gtase激活蛋白（GAP）是该系统的重要组成部分，但ArfGAP被招募到外壳的机制，其在外壳内的稳定性及其在维持外壳中的作用尚不清楚。在这里，我们使用FRAP来监测活细胞中gfp标记的ArfGAP1， Arf1和coatomer的膜周转。ArfGAP1进行了快速的细胞质/高尔基体交换，约40%的交换取决于ArfGAP1与涂层和Arf1的接触，并受到分泌负荷的影响。Arf1的永久激活导致ArfGAP1以涂层依赖的方式被捕获在高尔基体上。这些数据表明，ArfGAP1、coatomer和Arf1在体内COPI外壳的组装-拆卸周期中发挥着相互依赖的作用。
Secretory protein trafficking relies on the COPI coat, which by assembling into a lattice on Golgi membranes concentrates cargo at specific sites and deforms the membranes at these sites into coated buds and carriers. The GTPase-activating protein (GAP) responsible for catalyzing Arf1 GTP hydrolysis is an important part of this system, but the mechanism whereby ArfGAP is recruited to the coat, its stability within the coat, and its role in maintenance of the coat are unclear. Here, we use FRAP to monitor the membrane turnover of GFP-tagged versions of ArfGAP1, Arf1, and coatomer in living cells. ArfGAP1 underwent fast cytosol/Golgi exchange with ∼40% of the exchange dependent on engagement of ArfGAP1 with coatomer and Arf1, and affected by secretory cargo load. Permanent activation of Arf1 resulted in ArfGAP1 being trapped on the Golgi in a coatomer-dependent manner. These data suggest that ArfGAP1, coatomer and Arf1 play interdependent roles in the assembly–disassembly cycle of the COPI coat in vivo.