ADP ribosylation factor-like protein 2 (Arl2) regulates the interaction of tubulin-folding cofactor D with native tubulin.
ADP ribosylation factor-like protein 2 (Arl2) regulates the interaction of tubulin-folding cofactor D with native tubulin.
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DOI：
10.1083/jcb.149.5.1087
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发表时间：
2000-05-29
期刊：
影响因子：
--
通讯作者：
Cowan NJ
中科院分区：
文献类型：
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作者：
Bhamidipati A;Lewis SA;Cowan NJ
ADP核糖基化因子样蛋白（Arls）是一个功能未知的小单体G蛋白家族。在这里，我们表明，Arl 2相互作用的微管蛋白特异性伴侣蛋白，称为辅因子D。辅因子C、D和E组装α/β-微管蛋白异二聚体，并与天然微管蛋白相互作用，刺激其水解GTP，从而共同作为β-微管蛋白GTP酶活化蛋白（GAP）。我们发现，Arl 2下调微管蛋白GAP活性的C，D，和E，并抑制D的天然微管蛋白在体外的结合。我们还发现，在培养的细胞中的辅因子D或E的过度表达的结果在微管蛋白异二聚体和微管的破坏。Arl 2特异性地阻止辅因子D对微管蛋白和微管的破坏，但不阻止辅因子E对微管蛋白和微管的破坏。我们基于经典Ras家族突变的已知性质产生了Arl 2的突变形式。在体外和体内使用这些改变形式的Arl 2的实验证明，GDP结合的Arl 2与辅因子D相互作用，从而避免微管蛋白和微管破坏。这些数据确立了Arl 2在体内调节微管蛋白折叠辅因子与天然微管蛋白的相互作用中的作用。
The ADP ribosylation factor-like proteins (Arls) are a family of small monomeric G proteins of unknown function. Here, we show that Arl2 interacts with the tubulin-specific chaperone protein known as cofactor D. Cofactors C, D, and E assemble the α/β- tubulin heterodimer and also interact with native tubulin, stimulating it to hydrolyze GTP and thus acting together as a β-tubulin GTPase activating protein (GAP). We find that Arl2 downregulates the tubulin GAP activity of C, D, and E, and inhibits the binding of D to native tubulin in vitro. We also find that overexpression of cofactors D or E in cultured cells results in the destruction of the tubulin heterodimer and of microtubules. Arl2 specifically prevents destruction of tubulin and microtubules by cofactor D, but not by cofactor E. We generated mutant forms of Arl2 based on the known properties of classical Ras-family mutations. Experiments using these altered forms of Arl2 in vitro and in vivo demonstrate that it is GDP-bound Arl2 that interacts with cofactor D, thereby averting tubulin and microtubule destruction. These data establish a role for Arl2 in modulating the interaction of tubulin-folding cofactors with native tubulin in vivo.