文章基本信息

标题：Two Regions Responsible for the Actin Binding of p57, a Mammalian Coronin Family Actin-Binding Protein
本地全文：下载
作者：Teruaki Oku ; Saotomo Itoh ; Masamitsu Okano 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2003
卷号：26
期号：4
页码：409-416
DOI：10.1248/bpb.26.409
出版社：The Pharmaceutical Society of Japan
摘要：The actin-binding protein p57, a member of the coronin protein family, is expressed in a variety of immune cells. It has five WD repeats and a coiled-coil motif containing a leucine zipper, both of which are known to mediate protein–protein interactions. In order to identify the precise actin-binding regions in p57, and to assess the contribution of these structural motifs, we prepared various truncated p57 as fusion proteins with glutathione S -transferase (GST) and examined their actin-binding activity. A co-sedimentation assay demonstrated that p57^1—371 (C-terminal truncated p57) had the ability to bind F-actin, but p57^372—461 (a fragment containing the coiled-coil motif) did not. A segment consisting of the N-terminal 34 amino acids of p57 (p57^1—34) was found to bind to F-actin in the co-sedimentation assay. Furthermore, fluorescence microscopic observation showed that p57^1—34 was co-localized with F-actin in COS-1 cells after the transfection with the p57^1—34 construct. Deletion of ¹⁰KFRHVF¹⁵, a sequence conserved among coronin-related proteins, from p57^1—34 abolished its actin-binding activity, suggesting that this sequence with basic and hydrophobic amino acids is crucial for p57 to bind to F-actin. However, the N-terminal deletion mutant p57^63—461 retained the binding ability to F-actin. This result suggests the presence of a second actin-binding region. Further deletion analysis revealed that p57^111—204, which includes the second and third WD repeats, also exhibited weak actin-binding activity in the co-sedimentation assay. Taken together, these data strongly suggest that at least two regions within Met-1 to Asp-34 and Ile-111 to Glu-204 of p57 are responsible for its binding to the actin cytoskeleton.
关键词：actin-binding protein;coronin;cytoskeleton;WD repeats;leucine zipper