Adducin preferentially recruits spectrin to the fast growing ends of actin filaments in a complex requiring the MARCKS-related domain and a newly defined oligomerization domain
Adducin preferentially recruits spectrin to the fast growing ends of actin filaments in a complex requiring the MARCKS-related domain and a newly defined oligomerization domain
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DOI：
10.1074/jbc.273.30.19329
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发表时间：
1998-07-24
影响因子：
4.8
通讯作者：
Bennett, V
中科院分区：
文献类型：
--
作者：
Li, XL;Matsuoka, Y;Bennett, V
内收蛋白是一种与红细胞和可能的其他细胞的膜骨架中的血影蛋白和肌动蛋白相关的蛋白质，内收蛋白在体外测定中具有与肌动蛋白丝的侧面结合、覆盖肌动蛋白丝的快速生长末端以及：将血影蛋白聚集到肌动蛋白丝上，这项研究提供的证据表明，内收蛋白表现出对肌动蛋白丝的快速生长末端的偏好，用于将血影蛋白招募到肌动蛋白，与肌动蛋白直接结合，β-内收蛋白-（335-726）促进血影蛋白募集到肌动蛋白丝快速生长末端的凝溶胶蛋白敏感位点，在15 nM时具有半最大活性，并募集到凝溶胶蛋白不敏感位点，在75 nM时具有半最大活性。β-内收蛋白（335-726）在直接结合试验中也表现出对肌动蛋白丝末端的偏好;内收蛋白与丝末端的凝溶胶蛋白敏感位点结合的半最大浓度为60 nM，与侧向位点结合的Kd为1.5 μ M。与细丝末端的半最大结合所需的60 nM β-内收蛋白（335-726）浓度与半最大肌动蛋白加帽活性所需的150 nM浓度在相同范围内。内收蛋白与肌动蛋白的所有相互作用都需要豆蔻酰化的富含丙氨酸的蛋白激酶底物相关结构域以及位于内收蛋白颈部结构域的新定义的寡聚化位点。令人惊讶的是，内收蛋白的头部结构域不是血影蛋白-肌动蛋白相互作用所必需的，尽管它可以在形成四聚体中发挥作用。内收蛋白的相对活性意味着内收蛋白在细胞中的重要作用是与肌动蛋白丝的快速生长末端形成复合物，该复合物募集血影蛋白并防止肌动蛋白亚基的添加或丢失。
Adducin is a protein associated with spectrin and actin in membrane skeletons of erythrocytes sind possibly other cells, Adducin has activities in in vitro assays of association with the sides of actin filaments, capping the fast growing ends of actin filaments, and: recruiting spectrin to actin filaments, This study presents evidence that adducin exhibits a preference for the fast growing ends of actin filaments for recruiting spectrin to actin and for direct association with actin, beta-Adducin-(335-726) promoted recruitment of spectrin to gelsolin-sensitive sites at fast growing ends of actin filaments with half-maximal activity at 15 nM and to gelsolin-insensitive sites with half-maximal activity at 75 nM,. beta-Adducin(335-726) also exhibited a preference for actin filament ends in direct binding assays; the half-maximal concentration for binding of adducin to gelsolin-sensitive sites at filament ends was 60 nM, and the K-d for binding to lateral sites was 1.5 mu M. The concentration of beta-adducin(335-726) of 60 nM required for half-maximal binding to filament ends is in the same range as the concentration of 150 nM required for half-maximal actin capping activity. All interactions of adducin with actin require the myristoylated alanine-rich protein kinase substrate-related domain as well as a newly defined oligomerization site localized in the neck domain of adducin. Surprisingly, the head domain of adducin is not required for spectrin-actin interactions, although it could play a role in forming tetramers, The relative activities of adducin imply that an important role of adducin in cells is to form a complex with the fast growing ends of actin filaments that recruits spectrin and prevents addition or loss of actin subunits.