¹Department of Biological Sciences and Biotechnology, State Key Laboratory of Biomembranes, Tsinghua University, Beijing 100084, China

Correspondence: Sen Fang Sui, Tel: +86-10-62784768; E-mail: suisf@mail.tsinghua.edu.cn

Received 17 June 2005; Revised 19 October 2005; Accepted 22 October 2005.

Abstract

The actin-binding protein p57 is a member of mammalian coronin-like proteins. The roles of this protein in phagocytic processes conceivably depend on its interactions with F-actin. Two regions, p57^1-34 and p57^111-204, were previously reported to be actin-binding sites. In this study, we found that the C-terminal region of p57, p57^297-461, also possessed F-actin binding activity. Furthermore, the leucine zipper domain at the C-terminus of p57^297-461 was essential for this actin-binding activity. The F-actin cross-linking assay revealed that the region contained in p57^297-461 was sufficient to cross-link actin filaments. Our results strongly suggested that there was a new actin-binding region at the C-terminus of p57.