The Caenorhabditis elegans paxillin orthologue, PXL-1, is required for pharyngeal muscle contraction and for viability

• Type of Material: Article
• Authors: Adam Warner, University of British Columbia; Hiroshi Qadota, Emory University; Guy Benian, Emory University; A. Wayne Vogl, University of British Columbia; Donald G. Moerman, University of British Columbia
• Language: English
• Date: 2011-07-15
• Publisher: American Society for Cell Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2011 Warner et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License.
• License: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1091/mbc.E10-12-0941
• Title of Journal or Parent Work: Molecular Biology of the Cell
• ISSN: 1059-1524
• Volume: 22
• Issue: 14
• Start Page: 2551
• End Page: 2563
• Grant/Funding Information: This research was supported by grants from the Canadian Institute for Health Research and the National Science and Engineering Research Council of Canada to D.G.M. and Grant AR052133 from the National Institutes of Health to G.M.B. D.G.M. also received support from the Canadian Institute for Advanced Research.
• Keywords: BODY-WALL MUSCLE; THICK FILAMENTS; INTEGRIN ADHESION COMPLEXES; Science & Technology; EXTRACELLULAR-MATRIX DEGRADATION; Life Sciences & Biomedicine; Cell Biology; ADAPTER PROTEIN; FOCAL ADHESIONS; PROTEIN PAXILLIN; C-ELEGANS; ATTACHMENT STRUCTURES; LIM DOMAIN
• Research Categories: Health Sciences, Pathology; Biology, Cell

Abstract

We have identified the gene C28H8.6 (pxl-1) as the Caenorhabditis elegans orthologue of vertebrate paxillin. PXL-1 contains the four C-terminal LIM domains conserved in paxillin across all species and three of the five LD motifs found in the N-terminal half of most paxillins. In body wall muscle, PXL-1 antibodies and a full-length green fluorescent protein translational fusion localize to adhesion sites in the sarcomere, the functional repeat unit in muscle responsible for contraction. PXL-1 also localizes to ring-shaped structures near the sarcolemma in pharyngeal muscle corresponding to podosome-like sites of actin attachment. Our analysis of a loss-of-function allele of pxl-1, ok1483, shows that loss of paxillin leads to early larval arrested animals with paralyzed pharyngeal muscles and eventual lethality, presumably due to an inability to feed. We rescued the mutant phenotype by expressing paxillin solely in the pharynx and found that these animals survived and are essentially wild type in movement and body wall muscle structure. This indicates a differential requirement for paxillin in these two types of muscle. In pharyngeal muscle it is essential for contraction, whereas in body wall muscle it is dispensable for filament assembly, sarcomere stability, and ultimately movement.