Evidence for functional homology in the F-actin binding domains of gelsolin and alpha-actinin: implications for the requirements of severing and capping.
Evidence for functional homology in the F-actin binding domains of gelsolin and alpha-actinin: implications for the requirements of severing and capping.
复制标题
凝溶胶蛋白和 α-肌动蛋白的 F-肌动蛋白结合域功能同源性的证据：对切断和加帽要求的影响。
DOI：
10.1083/jcb.119.4.835
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发表时间：
1992-11
影响因子：
7.8
通讯作者：
Weeds, A G
中科院分区：
文献类型：
--
作者：
Way, M;Pope, B;Weeds, A G
凝胶蛋白和α -肌动蛋白的f -肌动蛋白结合域在肌动蛋白丝上竞争相同的位点，具有相似的结合亲和力。两者都含有大约125个氨基酸的串联重复序列，其中第一个被证明含有肌动蛋白结合位点。我们用-肌动蛋白取代了凝胶中nh2末端一半的f -肌动蛋白结合域。这种杂交体切断细丝的效率几乎与凝胶或其nh2末端一半一样，但与后者不同的是，它需要钙离子。这种杂合体结合了两个肌动蛋白单体，并在钙存在或不存在的情况下将纤维的倒钩端盖住。杂交产生的帽与凝胶的结合亲和力较低，而且不稳定：它从丝端解离，半衰期约为15分钟。虽然这两种不同的F-actin结合结构域之间没有扩展序列同源性，但我们的实验表明它们在功能上是等同的，并为微丝断裂的机制提供了新的见解。
The F-actin binding domains of gelsolin and alpha-actinin compete for the same site on actin filaments with similar binding affinities. Both contain tandem repeats of approximately 125 amino acids, the first of which is shown to contain the actin-binding site. We have replaced the F-actin binding domain in the NH2-terminal half of gelsolin by that of alpha-actinin. The hybrid severs filaments almost as efficiently as does gelsolin or its NH2-terminal half, but unlike the latter, requires calcium ions. The hybrid binds two actin monomers and caps the barbed ends of filaments in the presence or absence of calcium. The cap produced by the hybrid binds with lower affinity than that of gelsolin and is not stable: It dissociates from filament ends with a half life of approximately 15 min. Although there is no extended sequence homology between these two different F-actin binding domains, our experiments show that they are functionally equivalent and provide new insights into the mechanism of microfilament severing.