Evidence for γ-actin as a Z disc component in skeletal myofibers

Papponen, Hinni; Kaisto, Tuula; Leinonen, Sanna; Kaakinen, Mika; Metsikkö, Kalervo

doi:10.1016/j.yexcr.2008.10.021

Cited by 19 publications

(14 citation statements)

References 31 publications

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“…Three actin isoforms exist in skeletal muscle: alpha-actin that mediates sarcomeric organization and muscle contraction 20 and cytoskeletal beta- and gamma-actins 20 that regulate trafficking and stability of plasma membrane proteins such as nicotinic receptors 21 , Ca 2+ channels 22 and the glucose transporter GLUT4 23, 24 . Similar to that reported for dynamin-2 11, 12 , cytoskeletal gamma-actin localizes in areas of active membrane remodeling and trafficking 25 . Furthermore, the skeletal muscle-specific ablation of gamma-actin in mice progressively leads to a CNM-like disease 26 , suggesting that defects in actin dynamics may associate with myopathic phenotypes.…”

Section: Introductionsupporting

confidence: 82%

Dynamin-2 mutations linked to Centronuclear Myopathy impair actin-dependent trafficking in muscle cells

González‐Jamett

Báez‐Matus

Olivares

et al. 2017

Sci Rep

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Dynamin-2 is a ubiquitously expressed GTP-ase that mediates membrane remodeling. Recent findings indicate that dynamin-2 also regulates actin dynamics. Mutations in dynamin-2 cause dominant centronuclear myopathy (CNM), a congenital myopathy characterized by progressive weakness and atrophy of skeletal muscles. However, the muscle-specific roles of dynamin-2 affected by these mutations remain elusive. Here we show that, in muscle cells, the GTP-ase activity of dynamin-2 is involved in de novo actin polymerization as well as in actin-mediated trafficking of the glucose transporter GLUT4. Expression of dynamin-2 constructs carrying CNM-linked mutations disrupted the formation of new actin filaments as well as the stimulus-induced translocation of GLUT4 to the plasma membrane. Similarly, mature muscle fibers isolated from heterozygous knock-in mice that harbor the dynamin-2 mutation p.R465W, an animal model of CNM, exhibited altered actin organization, reduced actin polymerization and impaired insulin-induced translocation of GLUT4 to the sarcolemma. Moreover, GLUT4 displayed aberrant perinuclear accumulation in biopsies from CNM patients carrying dynamin-2 mutations, further suggesting trafficking defects. These results suggest that dynamin-2 is a key regulator of actin dynamics and GLUT4 trafficking in muscle cells. Our findings also support a model in which impairment of actin-dependent trafficking contributes to the pathological mechanism in dynamin-2-associated CNM.

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Section: Introductionsupporting

confidence: 82%

Dynamin-2 mutations linked to Centronuclear Myopathy impair actin-dependent trafficking in muscle cells

González‐Jamett

Báez‐Matus

Olivares

et al. 2017

Sci Rep

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“…In addition to the thin filament network, skeletal myofibrils also contain a network of nonmuscle γ-actin and nonmuscle γ-tropomyosin that connects sarcomeres to costameres (Craig and Pardo, 1983; Rybakova et al ., 2000; Nakata et al ., 2001; Kee et al ., 2004; Papponen et al ., 2009). The localization of the γ-actin and γ-tropomyosin with respect to α-actinin (Kee et al ., 2004) is strikingly similar to our observation of FMNL1 in cardiomyocytes (Figures 3 and 6A).…”

Section: Discussionmentioning

confidence: 99%

Critical roles for multiple formins during cardiac myofibril development and repair

Rosado

Barber

Berciu

et al. 2014

MBoC

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“…Other recent studies detected γ cyto -actin in costameres as well as in a novel zone adjacent to the z-disk [Kee et al, 2004]. Finally, different groups have detected γ cyto -actin only in z-disks and not in costameres [Nakata et al, 2001; Papponen et al, 2009]. …”

Section: Mechanisms Of Isoform-specific Functionsmentioning

confidence: 94%

The actin gene family: Function follows isoform

Perrin¹,

Ervasti²

2010

Cytoskeleton

288

270

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Although actin is often thought of as a single protein, in mammals it actually consists of six different isoforms encoded by separate genes. Each isoform is remarkably similar to every other isoform, with only slight variations in amino acid sequence. Nevertheless, recent work indicates that actin isoforms carry out unique cellular functions. Here, we review evidence drawn from localization studies, mouse models, and biochemical characterization to suggest a model for how in vivo mixing of actin isoforms may influence cytoskeletal function in cells. © 2010 Wiley-Liss, Inc.

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Evidence for γ-actin as a Z disc component in skeletal myofibers

Cited by 19 publications

References 31 publications

Dynamin-2 mutations linked to Centronuclear Myopathy impair actin-dependent trafficking in muscle cells

Dynamin-2 mutations linked to Centronuclear Myopathy impair actin-dependent trafficking in muscle cells

Critical roles for multiple formins during cardiac myofibril development and repair

The actin gene family: Function follows isoform

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