Caenorhabditis elegans Gelsolin-like Protein 1 Is a Novel Actin Filament-severing Protein with Four Gelsolin-like Repeats

• Type of Material: Article
• Authors: Tuula Klaavuniemi, Emory University; Sawako Yamashiro, Emory University; Shoichiro Ono, Emory University
• Language: English
• Date: 2008-09-19
• Publisher: American Society for Biochemistry and Molecular Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2008, The American Society for Biochemistry and Molecular Biology, Inc.
• Final Published Version (URL): http://www.jbc.org/content/283/38/26071
• Title of Journal or Parent Work: Journal of Biological Chemistry
• ISSN: 0021-9258
• Volume: 283
• Issue: 38
• Start Page: 26071
• End Page: 26080
• Grant/Funding Information: This work was supported, in whole or in part, by National Institutes of Health Grant R01 AR48615.; The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
• Research Categories: Chemistry, Biochemistry; Biology, Molecular; Health Sciences, Pathology

Abstract

The gelsolin family of proteins is a major class of actin regulatory proteins that sever, cap, and nucleate actin filaments in a calcium-dependent manner and are involved in various cellular processes. Typically, gelsolin-related proteins have three or six repeats of gelsolin-like (G) domain, and each domain plays a distinct role in severing, capping, and nucleation. The Caenorhabditis elegans gelsolin-like protein-1 (gsnl-1) gene encodes an unconventional gelsolin-related protein with four G domains. Sequence alignment suggests that GSNL-1 lacks two G domains that are equivalent to fourth and fifth G domains of gelsolin. In vitro, GSNL-1 severed actin filaments and capped the barbed end in a calcium-dependent manner. However, unlike gelsolin, GSNL-1 remained bound to the side of F-actin with a submicromolar affinity and did not nucleate actin polymerization, although it bound to G-actin with high affinity. These results indicate that GSNL-1 is a novel member of the gelsolin family of actin regulatory proteins and provide new insight into functional diversity and evolution of gelsolin-related proteins.