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

Moulder, Gary; Cremona, Gina H.; Duerr, Janet S.; Stirman, Jeffrey N.; Fields, Stephen D.; Martin, Wendy; Qadota, Hiroshi; Benian, Guy M.; Lu, Hang; Barstead, Robert

doi:10.1016/j.jmb.2010.08.055

Cited by 30 publications

(46 citation statements)

References 61 publications

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“…We used Bristol N2 as the wild-type strain and the following mutant strains: atn-1(ok84) (obtained from Dr. Bob Barstead; (Moulder et al, 2010)), unc-98(sf19) [Mercer et al, 2003], unc-54(s74) [Moerman et al, 1982] and unc-94(sf20) [Stevenson et al, 2007]. N2 (Bristol) and unc-54(s74) were obtained from the Caenorhabditis Genetics Center.…”

Section: Methodsmentioning

confidence: 99%

High‐resolution imaging of muscle attachment structures in Caenorhabditis elegans

et al. 2017

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We used structured illumination microscopy (SIM) to obtain super-resolution images of muscle attachment structures in C. elegans striated muscle. SIM imaging of M-line components revealed two patterns: PAT-3 (β-integrin) and proteins that interact in a complex with the cytoplasmic tail of β-integrin and localize to the basal muscle cell membrane (UNC-112 (kindlin), PAT-4 (ILK), UNC-97 (PINCH), PAT-6 (α-parvin) and UNC-95), are found in discrete, angled segments with gaps. In contrast, proteins localized throughout the depth of the M-line (UNC-89 (obscurin) and UNC-98) are imaged as continuous lines. Systematic immunostaining of muscle cell boundaries revealed that dense body components close to the basal muscle cell membrane also localize at cell boundaries. SIM imaging of muscle cell boundaries reveal “zipper-like” structures. Electron micrographs reveal electron dense material similar in appearance to dense bodies located adjacent to the basolateral cell membranes of adjacent muscle cells separated by ECM. Moreover, by EM, there are a variety of features of the muscle cell boundaries that help explain the zipper-like pattern of muscle protein localization observed by SIM. Short dense bodies in atn-1 mutants that are null for α-actinin and lack the deeper extensions of dense bodies, showed “zipper-like” structures by SIM similar to cell boundary structures, further indicating that the surface-proximal components of dense bodies form the “zipper-like” structures at cell boundaries. Moreover, mutants in thin and thick filament components do not have “dot-like” dense bodies, suggesting that myofilament tension is required for assembly or maintenance of proper dense body shape.

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Section: Methodsmentioning

confidence: 99%

High‐resolution imaging of muscle attachment structures in Caenorhabditis elegans

et al. 2017

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“…All of these proteins are known or suspected to be located at dense bodies or I-bands, and most are known or suspected to function with α-actinin. α-actinin, a well studied F-actin crosslinking protein, is a major component of nematode dense bodies and vertebrate muscle Z disks [33,17]. …”

Section: Resultsmentioning

confidence: 99%

“…atn-1(ok84) null mutants have abnormally short and broad dense bodies and yet display normal movement on an agar surface by casual observation, and normal swimming in liquid. In contrast, our assay showed that this mutant has a reduced ability to bend as compared to wild type [17]. The bending aspect of locomotion was restored to wild type levels in mutant animals carrying integrated copies of the wild type atn-1 gene.…”

Section: Introductionmentioning

confidence: 96%

“…This assay measures the maximum amount of bending the adult worm makes as it moves backwards upon anterior mechanical stimulation. Our test case for the assay was the null mutant of the single α-actinin gene in the nematode, atn-1 [17]. atn-1(ok84) null mutants have abnormally short and broad dense bodies and yet display normal movement on an agar surface by casual observation, and normal swimming in liquid.…”

Section: Introductionmentioning

confidence: 99%

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Bending amplitude – A new quantitative assay of C. elegans locomotion: Identification of phenotypes for mutants in genes encoding muscle focal adhesion components

Nahabedian

Qadota

Stirman

et al. 2012

Methods

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The nematode Caenorhabditis elegans uses striated muscle in its body wall for locomotion. The myofilament lattice is organized such that all the thin filament attachment structures (dense bodies, analogous to Z-disks) and thick filament organizing centers (M-lines) are attached to the muscle cell membrane. Thus, the force of muscle contraction is transmitted through these structures and allows locomotion of the worm. Dense bodies and M-lines are compositionally similar to focal adhesions and costameres, and are based on integrin and associated proteins. Null mutants for many of the newly discovered dense body and M-line proteins do not have obvious locomotion defects when observed casually, or when assayed by counting the number of times a worm moves back and forth in liquid. We hypothesized that many of these proteins, located as they are in muscle focal adhesions, function in force transmission, but we had not used an appropriate or sufficiently sensitive assay to reveal this function. Recently, we have developed a new quantitative assay of C. elegans locomotion that measures the maximum bending amplitude of an adult worm as it moves backwards. The assay had been used to reveal locomotion defects for null mutants of genes encoding ATN-1 (α-actinin) and PKN-1 (protein kinase N). Here, we describe the details of this method, and apply it to 21 loss of function mutants in 17 additional genes, most of which encode components of muscle attachment structures. As compared to wild type, mutations in 11 genes were found to have less ability to bend, and mutations in one gene were found to have greater ability to bend. Loss of function mutants for eight proteins had been reported to have normal locomotion (ZYX-1(zyxin), ALP-1 (Enigma), DIM-1, SCPL-1), or locomotion that was not previously investigated (FRG-1 (FRG1), KIN-32 (focal adhesion kinase, LIM-8), or had only slightly decreased locomotion (PFN-3 (profilin)).

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“…54,55 These types of screens resulting in adult Unc genes have probably been saturated and as noted above total 40 genes. However, semiautomated and high-throughput methods for screening adults for mutants having abnormal localization of GFP-tagged proteins 56 that may in the future use "computer vision" for pattern recognition, and newer methods for assessing nematode motility 57,58 open the door to identifying additional mutant genes in the future.…”

Section: Strength Of C Elegans As a Model Genetic Systemmentioning

confidence: 99%

Caenorhabditis elegans Muscle

Benian

Epstein²

2011

Circulation Research

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Abstract:The nematode Caenorhabditis elegans has become established as a major experimental organism with applications to many biomedical research areas. The body wall muscle cells are a useful model for the study of human cardiomyocytes and their homologous structures and proteins. The ability to readily identify mutations affecting these proteins and structures in C elegans and to be able to rigorously characterize their genotypes and phenotypes at the cellular and molecular levels permits mechanistic studies of the responsible interactions relevant to the inherited human cardiomyopathies. Future work in C elegans muscle holds great promise in uncovering new mechanisms in the pathogenesis of these cardiac disorders. (Circ Res. 2011;109:1082-1095.) Key Words: cardiomyopathies Ⅲ Caenorhabditis elegans sarcomere structure Ⅲ sarcomere assembly Ⅲ model genetics C ardiomyopathies are a diverse set of heart muscle diseases associated with mechanical and electric dysfunction and high risk of sudden cardiac death and cardiac failure. The 2 major clinical types of inherited cardiomyopathy are hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) 1-3 (Figure 1). Clinical histories indicate a positive family history in about 60% of HCM, and in 20% to 35% of DCM cases. The remaining primary HCM or DCM cases are strongly suspected to be unrecognized familial disease or new mutations. The most common inheritance pattern is autosomal dominant, but at a much lower frequency, autosomal recessive and X-linked recessive inheritance patterns are also observed. Over the past 20 years, more than 450 mutations in 20 genes have been discovered as causing HCM. Nearly all of the affected proteins are components of the sarcomere. The genes most commonly affected encode ␤-myosin heavy chain 4,5 and myosin-binding protein C 6,7 (accounting for at least 25% each), and troponin T, troponin I, tropomyosin, and regulatory myosin light chain (accounting for approximately 2-5% each). 2,8 To date, mutations in more than 30 genes result in DCM. Most of these genes also encode sarcomeric proteins. Interestingly, different mutations in the same gene can result in either HCM or DCM. Currently, we only know the causative mutation for 50% of the cases of HCM, and 20% of the cases of DCM. Despite knowing that mutations in so many different sarcomere and sarcomere-associated proteins result in HCM and DCM, the exact molecular mechanisms by which these mutations result in clinical heart hypertrophy or dilatation, are unknown.

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

Cited by 30 publications

References 61 publications

High‐resolution imaging of muscle attachment structures in Caenorhabditis elegans

High‐resolution imaging of muscle attachment structures in Caenorhabditis elegans

Bending amplitude – A new quantitative assay of C. elegans locomotion: Identification of phenotypes for mutants in genes encoding muscle focal adhesion components

Caenorhabditis elegans Muscle

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