GTP-dependent binding of ADP-ribosylation factor to coatomer in close proximity to the binding site for dilysine retrieval motifs and p23
GTP-dependent binding of ADP-ribosylation factor to coatomer in close proximity to the binding site for dilysine retrieval motifs and p23
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DOI：
10.1074/jbc.274.20.14198
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发表时间：
1999-05-14
影响因子：
4.8
通讯作者：
Wieland, FT
中科院分区：
文献类型：
--
作者：
Zhao, LY;Helms, JB;Wieland, FT
采用定点光交联法确定作用于ADP-核糖化因子(ARF)下游的组分。为此，在ARF分子的假定效应区域的不同位置加入了不耐光的苯丙氨酸类似物。根据掺入位置的不同，我们发现ARF与辅瘤复合体的两个亚基-β-COP和伽马-COP以及与胞浆蛋白(类似于185 kDa)的相互作用都是特异的和依赖于GTP的。此外，我们还观察到ARF分子在高尔基体膜上形成同源二聚体。这些数据表明，ARF与辅酶A的结合部位在其β亚基和伽玛亚基的界面上，这与辅酶与高尔基膜相互作用的第二个部位非常接近，后者是胞质二碱/二苯丙氨酸基序在伽玛-COP中的结合部位。
A site-directed photocross-linking approach was employed to determine components that act downstream of ADP-ribosylation factor (ARF). To this end, a photolabile phenylalanine analog was incorporated at various positions of the putative effector region of the ARF molecule. Depending on the position of incorporation, we find specific and GTP-dependent interactions of ARF with two subunits of the coatomer complex, beta-COP and gamma-COP, as well as an interaction with a cytosolic protein (similar to 185 kDa). In addition, we observe homodimer formation of ARF molecules at the Golgi membrane. These data suggest that the binding site of ARF to coatomer is at the interface of its beta- and gamma-subunits, and this is in close proximity to the second site of interaction of coatomer with the Golgi membrane, the binding site within gamma-COP for cytosolic dibasic/diphenylalanine motifs.