2 OF THE 3 ACTIN-BINDING DOMAINS OF GELSOLIN BIND TO THE SAME SUBDOMAIN OF ACTIN - IMPLICATIONS FOR CAPPING AND SEVERING MECHANISMS
2 OF THE 3 ACTIN-BINDING DOMAINS OF GELSOLIN BIND TO THE SAME SUBDOMAIN OF ACTIN - IMPLICATIONS FOR CAPPING AND SEVERING MECHANISMS
复制标题
DOI：
10.1016/0014-5793(91)80206-i
复制
发表时间：
1991-03-11
期刊：
影响因子：
3.5
通讯作者：
WEEDS, AG
中科院分区：
文献类型：
--
作者：
POPE, B;WAY, M;WEEDS, AG
凝溶胶蛋白结合成核复合物中的两个单体，与钙中的G-肌动蛋白结合并覆盖肌动蛋白丝。 然而，在其6个重复序列片段中已鉴定出3个肌动蛋白结合结构域，对应于S1、S2-3和S4-6，仅结合G-肌动蛋白，而S2-3特异性结合F-肌动蛋白。 三个域中的两个域（S2-3和S4-6）需要用于成核，而不同的一对域（S1和S2-3）需要用于切断。 在这里，我们第一次表明，独特的域成核（S4-6）或切断（S1）竞争相同的区域上的亚结构域1的G-肌动蛋白。 我们进一步表明，在G缓冲液条件下，S2-3与肌动蛋白单体的结合较弱，并且当S1或S4-6也结合时，这种相互作用持续存在。 因此，凝溶胶蛋白与肌动蛋白上的两个不同区域相关联。 由于S2-3不结合单体肌动蛋白在F-缓冲液中，我们建议，其高亲和力1：1化学计量的丝亚基反映了与两个相邻的亚基的相互作用。
Gelsolin binds two monomers in the nucleating complex with G-actin in calcium and caps actin filaments. However, 3 actin-binding domains have been identified within its 6 repeating sequence segments corresponding to S1, S2-3 and S4-6 bind only G-actin whereas S2-3 binds specifically to F-actin. Two of the three domains (S2-3 and S4-6) are required for nucleation and a different pair (S1 and S2-3) for severing. Here we show for the first time that the domains unique to nucleation (S4-6) or severing (S1) compete for the same region on subdomain 1 of G-actin. We further show that S2-3 binds actin monomers weakly in G-buffer conditions and that this interaction persists when S1 or S4-6 are also bound. Thus gelsolin associates with two distinct regions on actin. Since S2-3 does not bind monomeric actin in F-buffer, we suggest that its high affinity 1:1 stoichiometry for filament subunits reflects interaction with two adjacent subunits.