α-actinin is required for the proper assembly of Z-disk/focal-adhesion-like structures and for efficient locomotion in Caenorhabditis elegans.
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.
Moulder
Gary L
GL
Department of Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
Cremona
Gina H
GH
Duerr
Janet
J
Stirman
Jeffrey N
JN
Fields
Stephen D
SD
Martin
Wendy
W
Qadota
Hiroshi
H
Benian
Guy M
GM
Lu
Hang
H
Barstead
Robert J
RJ
D000185:Actinin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D022001:Focal Adhesions / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D017238:Genes, Helminth; D008124:Locomotion / Q000502:physiology; D008856:Microscopy, Fluorescence; D009132:Muscles / Q000502:physiology; D009154:Mutation; D010641:Phenotype; D034622:RNA Interference
D029742:Caenorhabditis elegans Proteins; D000185:Actinin