alpha-Actinin Is Required for the Proper Assembly of Z-Disk/Focal-Adhesion-Like Structures and for Efficient Locomotion in Caenorhabditis elegans

• Type of Material: Article
• Authors: Gary L. Moulder, Oklahoma Medical Research Foundation; Gina H. Cremona, Georgia Institute of Technology; Janet Duerr, Oklahoma Medical Research Foundation; Jeffrey N. Stirman, Georgia Institute of Technology; Stephen D. Fields, Oklahoma Medical Research Foundation; Wendy Martin, Oklahoma Medical Research Foundation; Hiroshi Qadota, Emory University; Guy Benian, Emory University; Hang Lu, Georgia Institute of Technology; Robert J. Barstead, Oklahoma Medical Research Foundation
• Language: English
• Date: 2010-11-05
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2010 Elsevier Ltd.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jmb.2010.08.055
• Title of Journal or Parent Work: Journal of Molecular Biology
• ISSN: 0022-2836
• Volume: 403
• Issue: 4
• Start Page: 516
• End Page: 528
• Grant/Funding Information: This work was supported by a grant from the Muscular Dystrophy Association of America to RJB, and grant AR052133 from the National Institutes of Health to GMB.
• Keywords: focal adhesion; TALIN CONTAINS; Science & Technology; Life Sciences & Biomedicine; alpha-actinin; INTRAMOLECULAR ASSOCIATION; muscle; MUSCLE; VINCULIN-BINDING-SITE; Caenorhabditis elegans; DENSE-BODY; TAIL DOMAINS; MUSCULAR-DYSTROPHY; Biochemistry & Molecular Biology; SPECTRIN REPEAT; FOCAL SEGMENTAL GLOMERULOSCLEROSIS; C-ELEGANS
• Research Categories: Biology, Cell; Biology, Molecular

Abstract

The actin binding protein α-actinin is a major component of focal adhesions found in vertebrate cells and of focal-adhesion-like structures found in the body wall muscle of the nematode Caenorhabditis elegans. To study its in vivo function in this genetic model system, we isolated a strain carrying a deletion of the single C. elegans α-actinin gene. We assessed the cytological organization of other C. elegans focal adhesion proteins and the ultrastructure of the mutant. The mutant does not have normal dense bodies, as observed by electron microscopy; however, these dense-body-like structures still contain the focal adhesion proteins integrin, talin, and vinculin, as observed by immunofluorescence microscopy. Actin is found in normal-appearing I-bands, but with abnormal accumulations near muscle cell membranes. Although swimming in water appeared grossly normal, use of automated methods for tracking the locomotion of individual worms revealed a defect in bending. We propose that the reduced motility of α-actinin null is due to abnormal dense bodies that are less able to transmit the forces generated by actin/myosin interactions.