The LIM domain protein UNC-95 is required for the assembly of muscle attachment structures and is regulated by the RING finger protein RNF-5 in C. elegans

Here, we describe a new muscle LIM domain protein, UNC-95, and identify it as a novel target for the RING finger protein RNF-5 in the Caenorhabditis elegans body wall muscle. unc-95(su33) animals have disorganized muscle actin and myosin-containing filaments as a result of a failure to assemble normal muscle adhesion structures. UNC-95 is active downstream of PAT-3/β-integrin in the assembly pathways of the muscle dense body and M-line attachments, and upstream of DEB-1/vinculin in the dense body assembly pathway. The translational UNC-95::GFP fusion construct is expressed in dense bodies, M-lines, and muscle–muscle cell boundaries as well as in muscle cell bodies. UNC-95 is partially colocalized with RNF-5 in muscle dense bodies and its expression and localization are regulated by RNF-5. rnf-5(RNAi) or a RING domain deleted mutant, rnf-5(tm794), exhibit structural defects of the muscle attachment sites. Together, our data demonstrate that UNC-95 constitutes an essential component of muscle adhesion sites that is regulated by RNF-5.

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DYC-1, a Protein Functionally Linked to Dystrophin in Caenorhabditis elegans Is Associated with the Dense Body, Where It Interacts with the Muscle LIM Domain Protein ZYX-1

Molecular Biology of the Cell ◽

10.1091/mbc.e07-05-0497 ◽

2008 ◽

Vol 19 (3) ◽

pp. 785-796 ◽

Cited By ~ 16

Author(s):

Claire Lecroisey ◽

Edwige Martin ◽

Marie-Christine Mariol ◽

Laure Granger ◽

Yannick Schwab ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Dense Body ◽

Striated Muscles ◽

Lim Domain ◽

Functional Link ◽

C Elegans ◽

Lim Domain Protein ◽

Muscle Necrosis ◽

Domain Protein

In Caenorhabditis elegans, mutations of the dystrophin homologue, dys-1, produce a peculiar behavioral phenotype (hyperactivity and a tendency to hypercontract). In a sensitized genetic background, dys-1 mutations also lead to muscle necrosis. The dyc-1 gene was previously identified in a genetic screen because its mutation leads to the same phenotype as dys-1, suggesting that the two genes are functionally linked. Here, we report the detailed characterization of the dyc-1 gene. dyc-1 encodes two isoforms, which are expressed in neurons and muscles. Isoform-specific RNAi experiments show that the absence of the muscle isoform, and not that of the neuronal isoform, is responsible for the dyc-1 mutant phenotype. In the sarcomere, the DYC-1 protein is localized at the edges of the dense body, the nematode muscle adhesion structure where actin filaments are anchored and linked to the sarcolemma. In yeast two-hybrid assays, DYC-1 interacts with ZYX-1, the homologue of the vertebrate focal adhesion LIM domain protein zyxin. ZYX-1 localizes at dense bodies and M-lines as well as in the nucleus of C. elegans striated muscles. The DYC-1 protein possesses a highly conserved 19 amino acid sequence, which is involved in the interaction with ZYX-1 and which is sufficient for addressing DYC-1 to the dense body. Altogether our findings indicate that DYC-1 may be involved in dense body function and stability. This, taken together with the functional link between the C. elegans DYC-1 and DYS-1 proteins, furthermore suggests a requirement of dystrophin function at this structure. As the dense body shares functional similarity with both the vertebrate Z-disk and the costamere, we therefore postulate that disruption of muscle cell adhesion structures might be the primary event of muscle degeneration occurring in the absence of dystrophin, in C. elegans as well as vertebrates.

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RING finger protein 10 attenuates vascular restenosis by inhibiting vascular smooth muscle cell hyperproliferation in vivo and vitro

IUBMB Life ◽

10.1002/iub.1995 ◽

2018 ◽

Vol 71 (5) ◽

pp. 632-642 ◽

Cited By ~ 2

Author(s):

Siyu Li ◽

Guiquan Yu ◽

Fuyu Jing ◽

Hui Chen ◽

Aoyi Liu ◽

...

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cell ◽

Muscle Cell ◽

Vascular Smooth Muscle Cell ◽

Ring Finger ◽

Ring Finger Protein ◽

Finger Protein ◽

Vascular Restenosis

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A Bioassay-Guided Fractionation of Rosemary Leaf Extract Identifies Carnosol as a Major Hypertrophy Inducer in Human Skeletal Muscle Cells

Nutrients ◽

10.3390/nu13124190 ◽

2021 ◽

Vol 13 (12) ◽

pp. 4190

Author(s):

Sylvie Morel ◽

Gérald Hugon ◽

Manon Vitou ◽

Marie Védère ◽

Françoise Fons ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Cell ◽

Ubiquitin Ligase ◽

Human Skeletal Muscle ◽

Ring Finger ◽

Ring Finger Protein ◽

Promoting Effect ◽

Finger Protein ◽

Human Skeletal Muscle Cells ◽

Bioassay Guided Fractionation

A good quality of life requires maintaining adequate skeletal muscle mass and strength, but therapeutic agents are lacking for this. We developed a bioassay-guided fractionation approach to identify molecules with hypertrophy-promoting effect in human skeletal muscle cells. We found that extracts from rosemary leaves induce muscle cell hypertrophy. By bioassay-guided purification we identified the phenolic diterpene carnosol as the compound responsible for the hypertrophy-promoting activity of rosemary leaf extracts. We then evaluated the impact of carnosol on the different signaling pathways involved in the control of muscle cell size. We found that activation of the NRF2 signaling pathway by carnosol is not sufficient to mediate its hypertrophy-promoting effect. Moreover, carnosol inhibits the expression of the ubiquitin ligase E3 Muscle RING Finger protein-1 that plays an important role in muscle remodeling, but has no effect on the protein synthesis pathway controlled by the protein kinase B/mechanistic target of rapamycin pathway. By measuring the chymotrypsin-like activity of the proteasome, we found that proteasome activity was significantly decreased by carnosol and Muscle RING Finger 1 inactivation. These results strongly suggest that carnosol can induce skeletal muscle hypertrophy by repressing the ubiquitin-proteasome system-dependent protein degradation pathway through inhibition of the E3 ubiquitin ligase Muscle RING Finger protein-1.

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ZYX-1, the unique zyxin protein of Caenorhabditis elegans, is involved in dystrophin-dependent muscle degeneration

Molecular Biology of the Cell ◽

10.1091/mbc.e12-09-0679 ◽

2013 ◽

Vol 24 (8) ◽

pp. 1232-1249 ◽

Cited By ~ 10

Author(s):

Claire Lecroisey ◽

Nicolas Brouilly ◽

Hiroshi Qadota ◽

Marie-Christine Mariol ◽

Nicolas C. Rochette ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Dense Body ◽

High Mobility ◽

Muscle Degeneration ◽

Lim Domain ◽

C Elegans ◽

Dense Bodies ◽

Lim Domain Protein ◽

Body Wall Muscles ◽

Two Hybrid

In vertebrates, zyxin is a LIM-domain protein belonging to a family composed of seven members. We show that the nematode Caenorhabditis elegans has a unique zyxin-like protein, ZYX-1, which is the orthologue of the vertebrate zyxin subfamily composed of zyxin, migfilin, TRIP6, and LPP. The ZYX-1 protein is expressed in the striated body-wall muscles and localizes at dense bodies/Z-discs and M-lines, as well as in the nucleus. In yeast two-hybrid assays ZYX-1 interacts with several known dense body and M-line proteins, including DEB-1 (vinculin) and ATN-1 (α-actinin). ZYX-1 is mainly localized in the middle region of the dense body/Z-disk, overlapping the apical and basal regions containing, respectively, ATN-1 and DEB-1. The localization and dynamics of ZYX-1 at dense bodies depend on the presence of ATN-1. Fluorescence recovery after photobleaching experiments revealed a high mobility of the ZYX-1 protein within muscle cells, in particular at dense bodies and M-lines, indicating a peripheral and dynamic association of ZYX-1 at these muscle adhesion structures. A portion of the ZYX-1 protein shuttles from the cytoplasm into the nucleus, suggesting a role for ZYX-1 in signal transduction. We provide evidence that the zyx-1 gene encodes two different isoforms, ZYX-1a and ZYX-1b, which exhibit different roles in dystrophin-dependent muscle degeneration occurring in a C. elegans model of Duchenne muscular dystrophy.

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