Myomesin and M protein: Differential expression in embryonic fibers during pectoral muscle development

Grove, Barbara Kay; Holmbom, Birgitta; Thornell, Lars‐Eric

doi:10.1111/j.1432-0436.1987.tb00056.x

Cited by 26 publications

(15 citation statements)

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“…Expression of myomesin 3 in skeletal muscle is fiber type specific, with the highest levels in type IIA fibers (intermediate speed) and lower levels in type I fibers. The restricted expression pattern makes myomesin 3 more comparable with M-protein, which is expressed in a fiber type-specific manner in chicken, 8,21,22 mouse 7 and rat, 23 whereas myomesin is universally present in all kinds of vertebrate striated muscles tested so far. 6,7 The data of expression of myomesin family members in mouse muscles, from this study and a previous one, 7 are summarised in Table 3.…”

Section: Discussionmentioning

confidence: 96%

Myomesin 3, a Novel Structural Component of the M-band in Striated Muscle

Schoenauer

Lange

Hirschy

et al. 2008

Journal of Molecular Biology

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Section: Discussionmentioning

confidence: 96%

Myomesin 3, a Novel Structural Component of the M-band in Striated Muscle

Schoenauer

Lange

Hirschy

et al. 2008

Journal of Molecular Biology

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“…Only in skeletal slow-twitch muscle is any similar repression of an adult myomesin isoform observed. Myomesin 2 is initially present in slow-twitch (type I) myofibers but then is lost during postnatal maturation (Carlsson et al, 1990;Grove et al, 1985Grove et al, , 1987Grove et al, , 1989Grove and Thornell, 1988). This observation cannot, however, reconcile the postnatal loss of Myom1, Myom2 and a structural M-line from EOM, since 80-85% of its myofibers are fast-twitch (Porter and Baker, 1996;Porter et al, 1995;Spencer and Porter, 1988), a functional mode generally regarded as dependent upon an M-line and the associated muscle CK.…”

Section: Discussionmentioning

confidence: 99%

Postnatal suppression of myomesin, muscle creatine kinase and the M-line in rat extraocular muscle

Porter

Merriam

Gong

et al. 2003

Journal of Experimental Biology

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SUMMARYThe M-line and its associated creatine kinase (CK) M-isoform (CK-M) are ubiquitous features of skeletal and cardiac muscle. The M-line maintains myosin myofilaments in register, links the contractile apparatus to the cytoskeleton for external force transfer and localizes CK-based energy storage and transfer to the site of highest ATP demand. We establish here that the muscle group responsible for movements of the eye, extraocular muscle (EOM),is divergent from other striated muscles in lacking both an M-line and its associated CK-M. Although an M-line forms during myogenesis, both in vivo and in vitro, it is actively repressed after birth. Transcripts of the major M-line structural proteins, myomesin 1 and myomesin 2, follow the same pattern of postnatal downregulation, while the embryonic heart-specific EH-myomesin 1 transcript is expressed early and retained in adult eye muscle. By immunocytochemistry, myomesin protein is absent from adult EOM sarcomeres. M-line suppression does not occur in organotypic co-culture with oculomotor motoneurons, suggesting that the mechanism for suppression may lie in muscle group-specific activation or workload patterns experienced only in vivo. The M-line is, however, still lost in dark-reared rats, despite the developmental delay this paradigm produces in the visuomotor system and EOMs. EOM was low in all CK isoform transcripts except for the sarcomeric mitochondrial (Ckmt2) isoform. Total CK enzyme activity of EOM was one-third that of hindlimb muscle. These findings are singularly unique among fast-twitch skeletal muscles. Since EOM exhibits isoform diversity for other sarcomeric proteins, the M-line/CK-M divergence probably represents a key physiological adaptation for the unique energetics and functional demands placed on this muscle group in voluntary and reflexive eye movements.

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“…The structure intimately involved in the second control mechanism is the sarcomeric M band (Squire et al, 1987;Fü rst et al, 1998). The major structural proteins that most likely participate in establishing M band structure are titin (Nave et al, 1989;Vinkemeier et al, 1993;Obermann et al, 1996), myomesin (Grove et al, 1984;Vinkemeier et al, 1993;Obermann et al, 1996), and M-protein (Grove et al, 1987;Vinkemeier et al, 1993;Obermann et al, 1996). While titin and myomesin were found in all cross-striated muscle fibers starting in early development, M-protein was found to be restricted to fast skeletal and cardiac muscle fibers in the adult animal, subsequent to a transient expression in all muscle fibers late in embryonic development (Carlsson et al, 1990;Grove et al, 1985;Fü rst et al, 1989).…”

Section: Introductionmentioning

confidence: 97%