Distribution of tropomyosin isoforms in different types of single fibers isolated from bovine skeletal muscles

Oe, Mika; Ojima, Koichi; Nakajima, Ikuyo; Chikuni, Koichi; Shibata, Masahiro; Muroya, Susumu

doi:10.1016/j.meatsci.2016.04.013

Cited by 18 publications

(11 citation statements)

References 23 publications

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“…In contrast to skeletal muscle, in cardiac tissue of large mammals, the a-chain of Tpm is predominant, which leads to a preferential presence of the aa-homodimer (16).…”

Section: Discussionmentioning

confidence: 98%

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Myopathic mutations in the β‐chain of tropomyosin differently affect the structural and functional properties of ββ‐ and αβ‐dimers

et al. 2018

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Tropomyosin (Tpm) is an actin-binding protein that plays a vital role in the regulation of muscle contraction. Fast skeletal muscles express 2 Tpm isoforms, α (Tpm 1.1) and β (Tpm 2.2), resulting in the existence of 2 forms of dimeric Tpm molecule: αα-homodimer and αβ-heterodimer. ββ-Homodimer is unstable and absent in the native state, despite which most of the studies of myopathy-relating Tpm mutations have been performed on the ββ-homodimer. Here, we applied different methods to investigate the effects of myopathic mutations R133W and N202K in the β-chain of Tpm on properties of αβ-heterodimers and to compare them with the features of ββ-homodimers with the same mutations. The results show that properties of αβ-Tpm and ββ-Tpm with substitutions in the β-chain differ significantly, and this indicates that the effects of myopathic mutations in the Tpm β-chain should be studied on the Tpm αβ-heterodimer.-Bershitsky, S. Y., Logvinova, D. S., Shchepkin, D. V., Kopylova, G. V., Matyushenko, A. M. Myopathic mutations in the β-chain of tropomyosin differently affect the structural and functional properties of ββ- and αβ-dimers.

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“…In contrast to skeletal muscle, in cardiac tissue of large mammals, the a-chain of Tpm is predominant, which leads to a preferential presence of the aa-homodimer (16).…”

Section: Discussionmentioning

confidence: 98%

“…The isoform Tpm 1.1 (a-Tpm, TPM1 gene product) is expressed in cardiac and skeletal muscles, Tpm 2.2 (b-Tpm, TPM2 gene product), is expressed in fast and slow skeletal muscles, and Tpm 3.1 (g-Tpm, TPM3 gene) is expressed only in slow skeletal muscles (15,16).…”

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confidence: 99%

Myopathic mutations in the β‐chain of tropomyosin differently affect the structural and functional properties of ββ‐ and αβ‐dimers

et al. 2018

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“…Three isoforms are specific for striated muscle-isoforms Tpm1.1 and Tpm2.2 are expressed in all types of striated muscle at various levels, and Tpm3.12 is restricted to slow muscle fibers (Pieples and Wieczorek 2000;Corbett et al 2005). Detailed analyses of tropomyosin expression in single fibers of different bovine muscle types demonstrated that in large animals Tpm1.1 and Tpm3.12 are found exclusively in fast and slow fibers, respectively (Oe et al 2016). All three isoforms exist either as homoor heterodimers (Janco et al 2013;Jin et al 2016;Peng et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Thin filament dysfunctions caused by mutations in tropomyosin Tpm3.12 and Tpm1.1

Moraczewska

2019

J Muscle Res Cell Motil

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Tropomyosin is the major regulator of the thin filament. In striated muscle its function is to bind troponin complex and control the access of myosin heads to actin in a Ca 2+-dependent manner. It also participates in the maintenance of thin filament length by regulation of tropomodulin and leiomodin, the pointed end-binding proteins. Because the size of the overlap between actin and myosin filaments affects the number of myosin heads which interact with actin, the filament length is one of the determinants of force development. Numerous point mutations in genes encoding tropomyosin lead to single amino acid substitutions along the entire length of the coiled coil that are associated with various types of cardiomyopathy and skeletal muscle disease. Specific regions of tropomyosin interact with different binding partners; therefore, the mutations affect diverse tropomyosin functions. In this review, results of studies on mutations in the genes TPM1 and TPM3, encoding Tpm1.1 and Tpm3.12, are described. The paper is particularly focused on mutation-dependent alterations in the mechanisms of actin-myosin interactions and dynamics of the thin filament at the pointed end.

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“…Total RNAs were isolated from differentiating 3T3‐L1 adipocytes and mouse myoblasts with an RNeasy kit (Qiagen). First‐strand cDNA was synthesized with a ReverTra Ace qPCR RT kit (Toyobo Co., Ltd., Osaka, Japan), and qPCR assay was performed as previously described [22]. The primer combinations used in the present study are shown in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Immature adipocyte‐derived exosomes inhibit expression of muscle differentiation markers

et al. 2021

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Exosomes are released from a variety of cells to communicate with recipient cells. Exosomes contain microRNAs (miRNAs), which are noncoding RNAs that suppress target genes. Our previous proteomic study (FEBS Open Bio 2016, 6, 816–826) demonstrated that 3T3‐L1 adipocytes secrete exosome components as well as growth factors, inspiring us to investigate what type of miRNA is involved in adipocyte‐secreted exosomes and what functions they carry out in recipient cells. Here, we profiled miRNAs in 3T3‐L1 adipocyte‐secreted exosomes and revealed suppression of muscle differentiation by adipocyte‐derived exosomes. Through our microarray analysis, we detected over 300 exosomal miRNAs during adipocyte differentiation. Exosomal miRNAs present during adipocyte differentiation included not only pro‐adipogenic miRNAs but also miRNAs associated with muscular dystrophy. Gene ontology analysis predicted that the target genes of miRNAs are associated primarily with transcriptional regulation. To further investigate whether adipocyte‐secreted exosomes regulate the expression levels of genes involved in muscle differentiation, we treated cultured myoblasts with adipocyte‐derived exosome fractions. Intriguingly, the expression levels of myogenic regulatory factors, Myog and Myf6, and other muscle differentiation markers, myosin heavy‐chain 3 and insulin‐like growth factor 2, were significantly downregulated in myoblasts treated with adipocyte‐derived exosomes. Immature adipocyte‐derived exosomes exhibited a stronger suppressive effect than mature adipocyte‐derived exosomes. Our results suggest that adipocytes suppress the expression levels of muscle differentiation‐associated genes in myoblasts via adipocyte‐secreted exosomes containing miRNAs.

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Distribution of tropomyosin isoforms in different types of single fibers isolated from bovine skeletal muscles

Cited by 18 publications

References 23 publications

Myopathic mutations in the β‐chain of tropomyosin differently affect the structural and functional properties of ββ‐ and αβ‐dimers

Myopathic mutations in the β‐chain of tropomyosin differently affect the structural and functional properties of ββ‐ and αβ‐dimers

Thin filament dysfunctions caused by mutations in tropomyosin Tpm3.12 and Tpm1.1

Immature adipocyte‐derived exosomes inhibit expression of muscle differentiation markers

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